Bio

Clinical Focus


  • Pathology
  • Pathology and Laboratory Medicine
  • Hematology
  • Cancer > Hematology

Academic Appointments


Administrative Appointments


  • Attending Physician, Hematology Service, Stanford Hospital (1995 - Present)
  • Director, Coagulation and Molecular Pathology Laboratories, Stanford Hospital (1995 - Present)

Professional Education


  • Fellowship:Stanford University (1993) CA
  • Residency:Stanford University (1988) CA
  • Board Certification: Internal Medicine, American Board of Internal Medicine (1987)
  • Internship:Stanford University School of Medicine (1985) CA
  • Medical Education:Tufts University (1984) MA
  • MD, Tufts Univ. School of Medicine, Medicine (1984)
  • BA, UC Santa Cruz, Chemistry (1979)

Research & Scholarship

Current Research and Scholarly Interests


Active projects:
1. Translating advances in genomics for patient care. Currently we are using next generation sequencing approaches to characterize the clonal population in T or B cell cancers,
how theses cells reconstitute following transplantation, and their role in disease progression and complications such as graft-versus-host disease.
2.Using traditional and next generation genomic approaches to characterize the molecular basis of myeloproliferative neoplasms
3. Molecular basis of pediatric immune thrombocytopenia - underlying etiology, what differentiates the 80% who spontaneously remit form those who develop chronic disease, identification of molecular biomarkers predicting response to thrombopoietin agonists
4. Whole genome studies of families with interesting pedigrees - inherited thrombocytopenia, thrombosis following exposure to oral contraceptives

Clinical Trials


  • A Longitudinal Study of Plasma EBV DNA in Nasopharyngeal Carcinoma From Both Endemic and Non-Endemic Patient Populations Not Recruiting

    1. To determine the prognostic implication of plasma Epstein-Bar Virus (EBV) DNA concentrations, as measured by quantitative polymerase chain reaction (PCR) in patients with nasopharyngeal carcinoma (NPC). 2. To relate pretreatment plasma EBV DNA concentration to WHO classification of these tumors both in endemic and non-endemic areas. 3. To determine whether pretreatment plasma EBV DNA can serve as a prognostic factor for both endemic and non-endemic patient populations.

    Stanford is currently not accepting patients for this trial. For more information, please contact Quynh-Thu Le, 650-498-6184.

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  • Integrated Whole-Genome Analysis of Hematologic Disorders Recruiting

    To identify mutations, changes in DNA copy number, structural rearrangements, or altered microRNA/mRNA expression that are important for the initiation, progression, or treatment response of hematologic disorders.

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  • Bone Marrow Grafting for Leukemia and Lymphoma Recruiting

    Bone Marrow Grafting for Leukemia and Lymphoma

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  • Phase II Fludarabine, Cytoxan and FCCAM in Untreated B-Cell Chronic Lymphocytic Leukemia Not Recruiting

    The purpose of the study is to evaluate the safety and efficacy of fludarabine and cyclophosphamide followed by subcutaneous Campath® in previously untreated CLL patients. Another goal is to prospectively evaluate the influence of pre-treatment CD38 expression, immunoglobulin VH gene mutation status, Zap70 expression, and cytogenetic abnormalities on outcome. In addition, the study hopes to further evaluate treatment efficacy with quantitative assessments of minimal residual disease by flow cytometry for the CLL-specific CD19+/CD5+/CD20+/CD79b+ population.

    Stanford is currently not accepting patients for this trial. For more information, please contact Nini Estevez, (650) 725 - 4041.

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  • Phase 2 Study of Temozolomide to Treat Poor Risk / Refractory Acute Myeloid Leukemia Not Recruiting

    Open-label, non-randomized, parallel assignment, phase 2 trial assessing the safety and efficacy of distinct temozolomide treatment regimens for patients with AML and poor prognosis

    Stanford is currently not accepting patients for this trial. For more information, please contact Richa Rajwanshi, (650) 736 - 4031.

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  • Evaluation of Pathwork Tissue of Origin (TOO) Test for Human Malignancies Not Recruiting

    The pathworks tissue of origin test is a microarray-based test with the goal of identifying the tissue of origin in patients with metastatic tumors of unknown primary site.

    Stanford is currently not accepting patients for this trial. For more information, please contact James Zehnder, (650) 723 - 9232.

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Teaching

2013-14 Courses


Postdoctoral Advisees


Publications

Journal Articles


  • STAT3 mutations are frequent in CD30+ T-cell lymphomas and T-cell large granular lymphocytic leukemia. Leukemia Ohgami, R. S., Ma, L., Merker, J. D., Martinez, B., Zehnder, J. L., Arber, D. A. 2013; 27 (11): 2244-2247

    View details for DOI 10.1038/leu.2013.104

    View details for PubMedID 23563237

  • Minimal residual disease quantification using consensus primers and high- throughput IGH sequencing predicts post-transplant relapse in chronic lymphocytic leukemia LEUKEMIA Logan, A. C., Zhang, B., Narasimhan, B., Carlton, V., Zheng, J., Moorhead, M., Krampf, M. R., Jones, C. D., Waqar, A. N., Faham, M., Zehnder, J. L., Miklos, D. B. 2013; 27 (8): 1659-1665

    Abstract

    Quantification of minimal residual disease (MRD) following allogeneic hematopoietic cell transplantation (allo-HCT) predicts post-transplant relapse in patients with chronic lymphocytic leukemia (CLL). We utilized an MRD-quantification method that amplifies immunoglobulin heavy chain (IGH) loci using consensus V and J segment primers followed by high-throughput sequencing (HTS), enabling quantification with a detection limit of one CLL cell per million mononuclear cells. Using this IGH-HTS approach, we analyzed MRD patterns in over 400 samples from 40 CLL patients who underwent reduced-intensity allo-HCT. Nine patients relapsed within 12 months post-HCT. Of the 31 patients in remission at 12 months post-HCT, disease-free survival was 86% in patients with MRD <10(-4) and 20% in those with MRD ?10(-4) (relapse hazard ratio (HR) 9.0; 95% confidence interval (CI) 2.5-32; P<0.0001), with median follow-up of 36 months. Additionally, MRD predicted relapse at other time points, including 9, 18 and 24 months post-HCT. MRD doubling time <12 months with disease burden ?10(-5) was associated with relapse within 12 months of MRD assessment in 50% of patients, and within 24 months in 90% of patients. This IGH-HTS method may facilitate routine MRD quantification in clinical trials.Leukemia advance online publication, 12 March 2013; doi:10.1038/leu.2013.52.

    View details for DOI 10.1038/leu.2013.52

    View details for Web of Science ID 000322823200006

    View details for PubMedID 23419792

  • A distinct evolution of the T-cell repertoire categorizes treatment refractory gastrointestinal acute graft-versus-host disease BLOOD Meyer, E. H., Hsu, A. R., Liliental, J., Loehr, A., Florek, M., Zehnder, J. L., Strober, S., Lavori, P., Miklos, D. B., Johnson, D. S., Negrin, R. S. 2013; 121 (24): 4955-4962

    Abstract

    Steroid refractory gastrointestinal (GI) acute graft versus host disease (aGVHD) is a major cause of mortality in hematopoietic stem cell transplantation (HCT) without immune markers to establish a diagnosis or guide therapy. We found that T cell receptor ? (TCR?) CDR3 repertoire sequencing reveals patterns that could eventually serve as a disease biomarker of T cell alloreactivity in aGVHD. We identified T cell clones in GI biopsies in a heterogeneous group of 15 allogeneic HCT patients with GI aGVHD symptoms. Seven steroid-refractory aGVHD patients showed a more conserved TCR? clonal structure between different biopsy sites in the GI tract than eight primary-therapy responsive patients. Tracking GI clones identified at endoscopy longitudinally in the blood also revealed an increased clonal expansion in patients with steroid-refractory disease. Immune repertoire sequencing-based methods could enable a novel personalized way to guide diagnosis and therapy in diseases where T cell activity is a major determinant.

    View details for DOI 10.1182/blood-2013-03-489757

    View details for Web of Science ID 000321896300024

  • Desktop transcriptome sequencing from archival tissue to identify clinically relevant translocations. American journal of surgical pathology Sweeney, R. T., Zhang, B., Zhu, S. X., Varma, S., Smith, K. S., Montgomery, S. B., van de Rijn, M., Zehnder, J., West, R. B. 2013; 37 (6): 796-803

    Abstract

    Somatic mutations, often translocations or single nucleotide variations, are pathognomonic for certain types of cancers and are increasingly of clinical importance for diagnosis and prediction of response to therapy. Conventional clinical assays only evaluate 1 mutation at a time, and targeted tests are often constrained to identify only the most common mutations. Genome-wide or transcriptome-wide high-throughput sequencing (HTS) of clinical samples offers an opportunity to evaluate for all clinically significant mutations with a single test. Recently a "desktop version" of HTS has become available, but most of the experience to date is based on data obtained from high-quality DNA from frozen specimens. In this study, we demonstrate, as a proof of principle, that translocations in sarcomas can be diagnosed from formalin-fixed paraffin-embedded (FFPE) tissue with desktop HTS. Using the first generation MiSeq platform, full transcriptome sequencing was performed on FFPE material from archival blocks of 3 synovial sarcomas, 3 myxoid liposarcomas, 2 Ewing sarcomas, and 1 clear cell sarcoma. Mapping the reads to the "sarcomatome" (all known 83 genes involved in translocations and mutations in sarcoma) and using a novel algorithm for ranking fusion candidates, the pathognomonic fusions and the exact breakpoints were identified in all cases of synovial sarcoma, myxoid liposarcoma, and clear cell sarcoma. The Ewing sarcoma fusion gene was detectable in FFPE material only with a sequencing platform that generates greater sequencing depth. The results show that a single transcriptome HTS assay, from FFPE, has the potential to replace conventional molecular diagnostic techniques for the evaluation of clinically relevant mutations in cancer.

    View details for DOI 10.1097/PAS.0b013e31827ad9b2

    View details for PubMedID 23598961

  • Indolent T-Lymphoblastic Proliferation (iT-LBP): A Review of Clinical and Pathologic Features and Distinction from Malignant T-Lymphoblastic Lymphoma ADVANCES IN ANATOMIC PATHOLOGY Ohgami, R. S., Arber, D. A., Zehnder, J. L., Natkunam, Y., Warnke, R. A. 2013; 20 (3): 137-140

    Abstract

    In recent years, a new pathologic entity has emerged: indolent T-lymphoblastic proliferation (iT-LBP). iT-LBPs share immunophenotypic similarities with T-lymphoblastic lymphoma; however, T-lymphoblastic proliferations are clinically indolent, and unlike the malignant counterpart, these expansions of nonclonal terminal deoxynucleotidyl transferase (TdT)+ T cells do not require treatment. Here we review the clinical and pathologic features, which are required for an accurate diagnosis of an iT-LBP. We demonstrate specific criteria can be used to accurately diagnose iT-LBP, notably: (1) confluent groups of TdT+ T cells in a biopsy specimen, (2) relative preservation of surrounding normal lymphoid architecture, (3) TdT+ T cells without morphologic atypia, (4) absence of thymic epithelium, (5) nonclonal TdT+ T cells, (6) immunophenotype of developmentally normal immature thymic T cells, and (7) clinical evidence of indolence (follow-up >6 mo without progression).

    View details for DOI 10.1097/PAP.0b013e31828d17ec

    View details for Web of Science ID 000317588700001

    View details for PubMedID 23574769

  • Sequential azacitidine plus lenalidomide combination for elderly patients with untreated acute myeloid leukemia. Haematologica Pollyea, D. A., Zehnder, J., Coutre, S., Gotlib, J. R., Gallegos, L., Abdel-Wahab, O., Greenberg, P., Zhang, B., Liedtke, M., Berube, C., Levine, R., Mitchell, B. S., Medeiros, B. C. 2013; 98 (4): 591-596

    Abstract

    There are limited treatment options for older patients with acute myeloid leukemia and prognosis of these patients remains poor, thereby warranting development of novel therapies. We evaluated the efficacy and safety of azacitidine in combination with lenalidomide as front-line therapy for older patients with acute myeloid leukemia. Patients ? 60 years of age with untreated acute myeloid leukemia received azacitidine 75 mg/m2 for 7 days followed by escalating doses of lenalidomide daily for 21 days starting on day 8 of each cycle every 6 weeks. Patients received continued therapy until disease progression, unacceptable toxicity, or completion of 12 cycles. Forty-two patients (median age, 74 years) were enrolled with equal distribution according to European LeukemiaNet risk. The overall response rate was 40% (rate of complete remission with or without complete recovery of blood counts = 28%). The median time to complete remission with or without complete recovery of blood counts was 12 weeks, and duration of this status was 28 weeks (range, 4 - >104 weeks). Therapy-related acute myeloid leukemia and a high score on the Hematopoietic Cell Transplantation Comorbidity Index were negative predictors of response. Early death was noted in 17% of patients. Grades ? 3 toxicities were uncommon and most adverse events were gastrointestinal, fatigue and myelosuppression. In conclusion, a sequential combination of azacitidine plus lenalidomide has clinical activity in older patients with acute myeloid leukemia, and further studies of this combination are underway.

    View details for DOI 10.3324/haematol.2012.076414

    View details for PubMedID 23242596

  • Discordant aPTT and anti-Xa values and outcomes in hospitalized patients treated with intravenous unfractionated heparin. Annals of pharmacotherapy Price, E. A., Jin, J., Nguyen, H. M., Krishnan, G., Bowen, R., Zehnder, J. L. 2013; 47 (2): 151-158

    Abstract

    Both the activated partial thromboplastin time (aPTT) and anti-Xa assay can be used to monitor unfractionated heparin (UFH). Following implementation of an anti-Xa method for heparin dosing protocols in our hospital, we became aware of many patients with discordant aPTT and anti-Xa values.To determine the frequency of discordant aPTT and anti-Xa values in a large cohort of hospitalized patients treated with UFH, as well as the demographics, coagulation status, indication for UFH, and clinical outcomes in this population.All aPTT and anti-Xa values from adults hospitalized between February and August 2009 at Stanford Hospital who were treated with UFH were analyzed. All samples were drawn simultaneously. A polynomial fit correlating aPTT and anti-Xa with a 99% confidence limit was designed. Paired aPTT/anti-Xa values were grouped according to whether the paired values fell within or outside of the concordant area. Patients were placed into groups based on concordance status, and clinical outcomes were assessed.A total of 2321 paired values from 539 patients were studied; 42% of data pairs had a high aPTT value relative to the anti-Xa value. Patients with elevated baseline prothrombin time/international normalized ratio or aPTT frequently demonstrated disproportionate relative prolongation of the aPTT. Patients with at least 2 consecutive high aPTT to anti-Xa values had increased 21-day major bleeding (9% vs 3%; p = 0.0316) and 30-day mortality (14% dead vs 5% dead at 30 days; p = 0.0202) compared with patients with consistently concordant values.aPTT and anti-Xa values are frequently discordant when used to measure UFH in hospitalized patients. A disproportionate prolongation of the aPTT relative to the anti-Xa was the most common discordant pattern in our study. Patients with relatively high aPTT to anti-Xa values appear to be at increased risk of adverse outcomes. Monitoring both aPTT and Xa values may have utility in managing such patients.

    View details for DOI 10.1345/aph.1R635

    View details for PubMedID 23386070

  • 2-Hydroxyglutarate in IDH mutant acute myeloid leukemia: predicting patient responses, minimal residual disease and correlations with methylcytosine and hydroxymethylcytosine levels LEUKEMIA & LYMPHOMA Pollyea, D. A., Kohrt, H. E., Zhang, B., Zehnder, J., Schenkein, D., Fantin, V., Straley, K., Vasanthakumar, A., Abdel-Wahab, O., Levine, R., Godley, L. A., Medeiros, B. C. 2013; 54 (2): 408-410

    View details for DOI 10.3109/10428194.2012.701009

    View details for Web of Science ID 000313285400034

    View details for PubMedID 22680765

  • Comprehensive whole-genome sequencing of an early-stage primary myelofibrosis patient defines low mutational burden and nonrecurrent candidate genes. Haematologica Merker, J. D., Roskin, K. M., Ng, D., Pan, C., Fisk, D. G., King, J. J., Hoh, R., Stadler, M., Okumoto, L. M., Abidi, P., Hewitt, R., Jones, C. D., Gojenola, L., Clark, M. J., Zhang, B., Cherry, A. M., George, T. I., Snyder, M., Boyd, S. D., Zehnder, J. L., Fire, A. Z., Gotlib, J. 2013

    Abstract

    In order to identify novel somatic mutations associated with classic BCR/ABL1-negative myeloproliferative neoplasms, we performed high-coverage genome sequencing of DNA from peripheral blood granulocytes and cultured skin fibroblasts from a patient with MPL W515K-positive primary myelofibrosis. The primary myelofibrosis genome had a low somatic mutation rate, consistent with that observed in similar hematopoietic tumor genomes. Interfacing of whole-genome DNA sequence data with RNA expression data identified three somatic mutations of potential functional significance: a nonsense mutation in CARD6, implicated in modulation of NF-kappaB activation; a 19-base pair deletion involving a potential regulatory region in the 5'-untranslated region of BRD2, implicated in transcriptional regulation and cell cycle control; and a non-synonymous point mutation in KIAA0355, an uncharacterized protein. Additional mutations in three genes (CAP2, SOX30, and MFRP) were also evident, albeit with no support for expression at the RNA level. Re-sequencing of these six genes in 178 patients with polycythemia vera, essential thrombocythemia, and myelofibrosis did not identify recurrent somatic mutations in these genes. Finally, we describe methods for reducing false-positive variant calls in the analysis of hematologic malignancies with a low somatic mutation rate. This trial is registered with ClinicalTrials.gov (NCT01108159).

    View details for PubMedID 23872309

  • TdT(+) T-lymphoblastic Populations Are Increased in Castleman Disease, in Castleman Disease in Association With Follicular Dendritic Cell Tumors, and in Angioimmunoblastic T-cell Lymphoma AMERICAN JOURNAL OF SURGICAL PATHOLOGY Ohgami, R. S., Zhao, S., Ohgami, J. K., Leavitt, M. O., Zehnder, J. L., West, R. B., Arber, D. A., Natkunam, Y., Warnke, R. A. 2012; 36 (11): 1619-1628

    Abstract

    T-lymphoblastic lymphoma is an aggressive neoplasm requiring prompt clinical treatment. Conversely, indolent T-lymphoblastic proliferation mimics T-lymphoblastic lymphoma but consists of a proliferation of non-neoplastic TdT+ T cells, requiring no treatment. Recently, we identified several cases of indolent T-lymphoblastic proliferations in extrathymic lymphoid tissues: 1 in a patient suffering from Castleman disease (CD) associated with a follicular dendritic cell sarcoma/tumor, 1 in a patient with a history of angioimmunoblastic T-cell lymphoma (AITL), and 1 in association with acinic cell carcinoma. Interestingly, in the case of the patient with a history of AITL, these TdT+ T cells were seen in multiple anatomic sites over the span of 5 years. Here we review these 3 cases and extend our findings by demonstrating that TdT+ T-lymphoblastic populations are increased in lymph nodes of patients with CD (P=0.011), CD in association with follicular dendritic cell tumors, and AITL (P<0.01) compared with other T-cell or B-cell lymphomas or reactive lymph nodes. Finally, analysis of 352 nonhematolymphoid tumors including carcinomas, melanomas, and sarcomas demonstrates that TdT+ T cells are not increased in these tumors. Our studies not only present several detailed cases of indolent T-lymphoblastic proliferations, but also correlate these populations with specific hematologic diseases.

    View details for DOI 10.1097/PAS.0b013e318264e223

    View details for Web of Science ID 000310059600004

    View details for PubMedID 23060347

  • Prophylactic rituximab after allogeneic transplantation decreases B-cell alloimmunity with low chronic GVHD incidence BLOOD Arai, S., Sahaf, B., Narasimhan, B., Chen, G. L., Jones, C. D., Lowsky, R., Shizuru, J. A., Johnston, L. J., Laport, G. G., Weng, W., Benjamin, J. E., Schaenman, J., Brown, J., Ramirez, J., Zehnder, J. L., Negrin, R. S., Miklos, D. B. 2012; 119 (25): 6145-6154

    Abstract

    B cells are involved in the pathogenesis of chronic GVHD (cGVHD). We hypothesized that prophylactic anti-B-cell therapy delivered 2 months after transplantation would decrease allogeneic donor B-cell immunity and possibly the incidence of cGVHD. Therefore, in the present study, patients with high-risk chronic lymphocytic leukemia (n = 22) and mantle-cell lymphoma (n = 13) received a total lymphoid irradiation of 80 cGy for 10 days and antithymocyte globulin 1.5 mg/kg/d for 5 days. Rituximab (375 mg/m(2)) was infused weekly on days 56, 63, 70, and 77 after transplantation. The incidence of acute GVHD was 6%. The cumulative incidence of cGVHD was 20%. Nonrelapse mortality was 3%. Rituximab treatment after allogeneic transplantation significantly reduced B-cell allogeneic immunity, with complete prevention of alloreactive H-Y Ab development in male patients with female donors (P = .01). Overall survival and freedom from progression at 4 years for chronic lymphocytic leukemia patients were 73% and 47%, respectively; for mantle-cell lymphoma patients, they were 69% and 53%, respectively.

    View details for DOI 10.1182/blood-2011-12-395970

    View details for Web of Science ID 000307398700030

    View details for PubMedID 22563089

  • Aggressive EBV-associated Lymphoproliferative Disorder: A Prodrome to Diffuse Large B-cell Lymphoma? APPLIED IMMUNOHISTOCHEMISTRY & MOLECULAR MORPHOLOGY Batra, R., Medeiros, B. C., Zehnder, J. L., Warnke, R. A., Natkunam, Y. 2012; 20 (3): 325-330

    Abstract

    A 19-year-old male patient presented with intermittent high fever and left cervical lymphadenopathy. The lymph node biopsy findings were interpreted as "Epstein-Barr virus (EBV)-associated lymphoproliferative disorder consistent with infectious mononucleosis." No molecular studies were performed at that time. The patient was followed without treatment. Five months later, the patient again presented with fever, lymphadenopathy, and splenomegaly. The lymph node biopsy showed features of a diffuse large B-cell lymphoma. Molecular studies on this lymph node biopsy showed a clonal EBV population, although polymerase chain reaction studies failed to reveal a clonal B-cell or T-cell population. A concurrent bone marrow biopsy showed features consistent with hemophagocytic syndrome. He had elevated ferritin, soluble interleukin-2 receptors and persistent EBV viremia. The patient responded to Rituxan for a short period with undetectable EBV levels. Subsequent right cervical lymph node, liver, and jejunal biopsies showed involvement by diffuse large B-cell lymphoma and the patient expired soon thereafter.

    View details for Web of Science ID 000303140100012

    View details for PubMedID 22505014

  • Controversies in Heparin Monitoring AMERICAN JOURNAL OF HEMATOLOGY Zehnder, J., Price, E., Jin, J. 2012; 87: S137-S140

    View details for DOI 10.1002/ajh.23210

    View details for Web of Science ID 000302999500024

    View details for PubMedID 22495972

  • Safety, efficacy and biological predictors of response to sequential azacitidine and lenalidomide for elderly patients with acute myeloid leukemia LEUKEMIA Pollyea, D. A., Kohrt, H. E., Gallegos, L., Figueroa, M. E., Abdel-Wahab, O., Zhang, B., Bhattacharya, S., Zehnder, J., Liedtke, M., Gotlib, J. R., Coutre, S., Berube, C., Melnick, A., Levine, R., Mitchell, B. S., Medeiros, B. C. 2012; 26 (5): 893-901

    Abstract

    Acute myeloid leukemia (AML) is a disease of the elderly. Poor outcomes with standard therapies necessitate novel approaches. Outpatient regimens sufficiently potent and well tolerated to induce remissions and enable continuation therapy may be beneficial. In this phase-1 study, we determined the maximum tolerated dose (MTD) and the efficacy for sequential azacitidine and lenalidomide as remission induction and continuation therapy in elderly, previously untreated patients. We investigated the impact on global DNA methylation and bone marrow cytokines, and sought biological predictors of response. Eighteen patients were enrolled. The MTD was not reached. Median follow-up was 8.2 months (10.3 months for survivors). Common adverse events included fatigue, injection site reactions, constipation, nausea, pruritus and febrile neutropenia. Ten patients responded (56%), and the rate of complete remissions (CRs) or CRs with incomplete recovery of blood counts for evaluable patients was 44% (7/16). The median response duration was 6.2 months. DNA demethylation and changes in bone marrow cytokines were observed; responders had a unique cytokine profile and a trend towards lower methylation levels. Sequential azacitidine and lenalidomide was well tolerated with encouraging clinical and biological activity in previously untreated elderly AML patients. This trial is registered at ClinicalTrials.gov (NCT00890929).

    View details for DOI 10.1038/leu.2011.294

    View details for Web of Science ID 000303883500005

    View details for PubMedID 22033493

  • Tailored temozolomide therapy according to MGMT methylation status for elderly patients with acute myeloid leukemia AMERICAN JOURNAL OF HEMATOLOGY Medeiros, B. C., Kohrt, H. E., Gotlib, J., Coutre, S. E., Zhang, B., Arber, D. A., Zehnder, J. L. 2012; 87 (1): 45-50

    Abstract

    Temozolomide sensitivity is determined by methylation of the O(6)-methylguanine-DNA methyltransferase (MGMT) promoter. This study assessed whether the temozolomide dose can be tailored by MGMT promoter status and whether protracted, low-dose temozolomide can "prime" blasts in patients with unmethylated MGMT (unMGMT). Elderly patients with high-risk AML were stratified by MGMT methylation. Patients with methylated MGMT (mMGMT) received temozolomide 200 mg/m(2) orally for 7 days every 4 weeks, while patients with unMGMT received temozolomide 100 mg/m(2) orally for 14 days followed by 200 mg/m(2) orally for 7 days every 6weeks. Of 36 patients (median age, 75 years), 31 (86%) had an unMGMT promoter. Overall response rate for the entire cohort was 36%. Patients with mMGMT and unMGMT had similar response rates (40% vs. 29%). Median duration of response and overall survival (OS) among responders were 29 and 35 weeks, respectively. Induction deaths (ID) occurred in 25% of patients, mostly caused by disease progression. Hematological toxicities were the most common adverse event. Toxicities were similar between patients on conventional versus protracted schedules. High HCT-CI scores were predictive of lower CR rate, higher ID, and shorter OS, while bone marrow blast count <50% at screening predicted for improved responses. Temozolomide, dosed according to MGMT methylation status, demonstrated modest clinical activity in elderly patients with AML, especially in those presenting with fewer comorbidities and low disease burden. The trial was registered on www.ClinicalTrials.gov as #NCT00611247.

    View details for DOI 10.1002/ajh.22191

    View details for Web of Science ID 000298257700010

    View details for PubMedID 22052619

  • High-throughput VDJ sequencing for quantification of minimal residual disease in chronic lymphocytic leukemia and immune reconstitution assessment PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Logan, A. C., Gao, H., Wang, C., Sahaf, B., Jones, C. D., Marshall, E. L., Buno, I., Armstrong, R., Fire, A. Z., Weinberg, K. I., Mindrinos, M., Zehnder, J. L., Boyd, S. D., Xiao, W., Davis, R. W., Miklos, D. B. 2011; 108 (52): 21194-21199

    Abstract

    The primary cause of poor outcome following allogeneic hematopoietic cell transplantation (HCT) for chronic lymphocytic leukemia (CLL) is disease recurrence. Detection of increasing minimal residual disease (MRD) following HCT may permit early intervention to prevent clinical relapse; however, MRD quantification remains an uncommon diagnostic test because of logistical and financial barriers to widespread use. Here we describe a method for quantifying CLL MRD using widely available consensus primers for amplification of all Ig heavy chain (IGH) genes in a mixture of peripheral blood mononuclear cells, followed by high-throughput sequencing (HTS) for disease-specific IGH sequence quantification. To achieve accurate MRD quantification, we developed a systematic bioinformatic methodology to aggregate cancer clone sequence variants arising from systematic and random artifacts occurring during IGH-HTS. We then compared the sensitivity of IGH-HTS, flow cytometry, and allele-specific oligonucleotide PCR for MRD quantification in 28 samples collected from 6 CLL patients following allogeneic HCT. Using amplimer libraries generated with consensus primers from patient blood samples, we demonstrate the sensitivity of IGH-HTS with 454 pyrosequencing to be 10(-5), with a high correlation between quantification by allele-specific oligonucleotide PCR and IGH-HTS (r = 0.85). From the same dataset used to quantify MRD, IGH-HTS also allowed us to profile IGH repertoire reconstitution after HCT-information not provided by the other MRD methods. IGH-HTS using consensus primers will broaden the availability of MRD quantification in CLL and other B cell malignancies, and this approach has potential for quantitative evaluation of immune diversification following transplant and nontransplant therapies.

    View details for DOI 10.1073/pnas.1118357109

    View details for Web of Science ID 000298479900065

    View details for PubMedID 22160699

  • A novel splice donor mutation in the thrombopoietin gene leads to exon 2 skipping in a Filipino family with hereditary thrombocythemia. Blood Zhang, B., Ng, D., Jones, C., Oh, S. T., Nolan, G. P., Salehi, S., Wong, W., Zehnder, J. L., Gotlib, J. 2011; 118 (26): 6988-6990

    View details for DOI 10.1182/blood-2011-10-386177

    View details for PubMedID 22194398

  • Clonally identical Hodgkin's disease develops after allogeneic hematopoietic cell transplant for CLL BONE MARROW TRANSPLANTATION Tseng, D., Jones, C. D., Anderson, M., Warnke, R., Zehnder, J. L., Miklos, D. B. 2011; 46 (12): 1576-1578

    View details for DOI 10.1038/bmt.2010.340

    View details for Web of Science ID 000298326500015

    View details for PubMedID 21258419

  • Refining the diagnosis of T-cell large granular lymphocytic leukemia by combining distinct patterns of antigen expression with T-cell clonality studies LEUKEMIA Ohgami, R. S., Ohgami, J. K., Pereira, I. T., Gitana, G., Zehnder, J. L., Arber, D. A. 2011; 25 (9): 1439-1443

    Abstract

    T-cell large granular lymphocytic (LGL) leukemia is a complex diagnosis, requiring persistent clonal expansions of LGLs, and cytopenias. Often the diagnosis is unclear as non-clonal expansions of LGLs commonly occur in reactive conditions. To better understand T-LGL leukemia, we performed a comprehensive clinicopathologic analysis of 85 patients with LGL expansions. Interestingly, distinct CD8+(dim)/CD57+ populations, seen by flow cytometry, were significantly associated with clonal T-LGL leukemia (P < 0.001) as well as neutropenia (median absolute neutrophil count (ANC) 1.45 vs 3.19 × 10(9)/l; P = 0.0017). Furthermore, cases with distinct CD8+(dim)/CD57+ populations and monoclonal T cells had even lower ANCs (median ANC 1.41 × 10(9)/l; P = 0.001) compared with cases without these dual criteria. Additionally, complete or partial loss of CD5 expression was independently associated with clonal T-LGL leukemia (P<0.001) and neutropenia (median ANC 1.41 vs 2.70 × 10(9)/l; P = 0.002). This study describes specific immunophenotypic parameters to better define clonal cases of T-LGL leukemia associated with significant neutropenia.

    View details for DOI 10.1038/leu.2011.107

    View details for Web of Science ID 000294665400008

    View details for PubMedID 21617700

  • Evaluation of a Gene Expression Microarray-based Assay to Determine Tissue Type of Origin on a Diverse Set of 49 Malignancies AMERICAN JOURNAL OF SURGICAL PATHOLOGY Beck, A. H., Rodriguez-Paris, J., Zehnder, J., Schrijver, I. 2011; 35 (7): 1030-1037

    Abstract

    The Tissue of Origin Frozen (TOO-FRZ) assay from Pathwork Diagnostics has been cleared by the Food and Drug Administration as a diagnostic study for malignancies of unknown primary. The goal of this study was to evaluate the performance of TOO-FRZ on a diverse collection of malignancies. We collected a diverse set of 49 malignancies. We classified each case into 1 of 4 groups: common morphology from a tissue type included in the TOO-FRZ assay (n=29), uncommon morphology from a tissue type included in the TOO-FRZ assay (n=10), tumor from a tissue type not included in the TOO-FRZ assay (n=3), and malignancies of unknown primary (n=7). We found strong diagnostic performance for common morphologies from tissue types on the TOO-FRZ [overall accuracy=26 of 29 (90%, 95% CI, 73% to 97%)], with perfect performance in all tissue types except gastric (0 of 2) and pancreatic (1 of 2) tissues. There was a significant decline in performance for uncommon morphologies from tissue types included in the TOO-FRZ assay [6 of 10 (60%) cases with an indeterminate result, 1 of 10 (10%) cases with an incorrect prediction, and 3 of 10 (30%) with a correct prediction] and for tumors from tissue types not included in the assay (incorrect prediction in 2 of 3 cases). For the 7 malignancies of unknown primary in our study set, the TOO-FRZ provided a likely clinically useful result in only 2 of 7 cases. These results provide an insight into the strengths and limitations of this molecular assay for the surgical pathologist, and our findings suggest future directions for research in this area.

    View details for DOI 10.1097/PAS.0b013e3182178b59

    View details for Web of Science ID 000291676200011

    View details for PubMedID 21602661

  • Mutagenesis of Varicella-Zoster Virus Glycoprotein I (gI) Identifies a Cysteine Residue Critical for gE/gI Heterodimer Formation, gI Structure, and Virulence in Skin Cells JOURNAL OF VIROLOGY Oliver, S. L., Sommer, M. H., Reichelt, M., Rajamani, J., Vlaycheva-Beisheim, L., Stamatis, S., Cheng, J., Jones, C., Zehnder, J., Arvin, A. M. 2011; 85 (9): 4095-4110

    Abstract

    Varicella-zoster virus (VZV) is the alphaherpesvirus that causes chicken pox (varicella) and shingles (zoster). The two VZV glycoproteins gE and gI form a heterodimer that mediates efficient cell-to-cell spread. Deletion of gI yields a small-plaque-phenotype virus, ?gI virus, which is avirulent in human skin using the xenograft model of VZV pathogenesis. In the present study, 10 mutant viruses were generated to determine which residues were required for the typical function of gI. Three phosphorylation sites in the cytoplasmic domain of gI were not required for VZV virulence in vivo. Two deletion mutants mapped a gE binding region in gI to residues 105 to 125. A glycosylation site, N116, in this region did not affect virulence. Substitution of four cysteine residues highly conserved in the Alphaherpesvirinae established that C95 is required for gE/gI heterodimer formation. The C95A and ?105-125 (with residues 105 to 125 deleted) viruses had small-plaque phenotypes with reduced replication kinetics in vitro similar to those of the ?gI virus. The ?105-125 virus was avirulent for human skin in vivo. In contrast, the C95A mutant replicated in vivo but with significantly reduced kinetics compared to those of the wild-type virus. In addition to abolished gE/gI heterodimer formation, gI from the C95A or the ?105-125 mutant was not recognized by monoclonal antibodies that detect the canonical conformation of gI, demonstrating structural disruption of gI in these viruses. This alteration prevented gI incorporation into virus particles. Thus, residues C95 and 105 to 125 are critical for gI structure required for gE/gI heterodimer formation, virion incorporation, and ultimately, effective viral spread in human skin.

    View details for DOI 10.1128/JVI.02596-10

    View details for Web of Science ID 000289618600005

    View details for PubMedID 21345964

  • The role of vanin-1 and oxidative stress-related pathways in distinguishing acute and chronic pediatric ITP BLOOD Zhang, B., Lo, C., Shen, L., Sood, R., Jones, C., Cusmano-Ozog, K., Park-Snyder, S., Wong, W., Jeng, M., Cowan, T., Engleman, E. G., Zehnder, J. L. 2011; 117 (17): 4569-4579

    Abstract

    Pediatric immune thrombocytopenia (ITP) is usually self-limited. However, approximately 20% of children develop chronic ITP, which can be associated with significant morbidity because of long-term immunosuppression and splenectomy in refractory cases. To explore the molecular mechanism of chronic ITP compared with acute ITP, we studied 63 pediatric patients with ITP. Gene expression analysis of whole blood revealed distinct signatures for acute and chronic ITP. Oxidative stress-related pathways were among the most significant chronic ITP-associated pathways. Overexpression of VNN1, an oxidative stress sensor in epithelial cells, was most strongly associated with progression to chronic ITP. Studies of normal persons demonstrated VNN1 expression in a variety of blood cells. Exposure of blood mononuclear cells to oxidative stress inducers elicited dramatic up-regulation of VNN1 and down-regulation of PPAR?, indicating a role for VNN1 as a peripheral blood oxidative stress sensor. Assessment of redox state by tandem mass spectrometry demonstrated statistically significant lower glutathione ratios in patients with ITP versus healthy controls; lower glutathione ratios were also seen in untreated patients with ITP compared with recently treated patients. Our work demonstrates distinct patterns of gene expression in acute and chronic ITP and implicates oxidative stress pathways in the pathogenesis of chronic pediatric ITP.

    View details for DOI 10.1182/blood-2010-09-304931

    View details for Web of Science ID 000289984800022

    View details for PubMedID 21325602

  • Varicella-Zoster Virus Glycoprotein E Is a Critical Determinant of Virulence in the SCID Mouse-Human Model of Neuropathogenesis JOURNAL OF VIROLOGY Zerboni, L., Berarducci, B., Rajamani, J., Jones, C. D., Zehnder, J. L., Arvin, A. 2011; 85 (1): 98-111

    Abstract

    Varicella-zoster virus (VZV) is a neurotropic alphaherpesvirus. VZV infection of human dorsal root ganglion (DRG) xenografts in immunodeficient mice models the infection of sensory ganglia. We examined DRG infection with recombinant VZV (recombinant Oka [rOka]) and the following gE mutants: gE?27-90, gE?Cys, gE-AYRV, and gE-SSTT. gE?27-90, which lacks the gE domain that interacts with a putative receptor insulin-degrading enzyme (IDE), replicated as extensively as rOka, producing infectious virions and significant cytopathic effects within 14 days of inoculation. Since neural cells express IDE, the gE/IDE interaction was dispensable for VZV neurotropism. In contrast, gE?Cys, which lacks gE/gI heterodimer formation, was significantly impaired at early times postinfection; viral genome copy numbers increased slowly, and infectious virus production was not detected until day 28. Delayed replication was associated with impaired cell-cell spread in ganglia, similar to the phenotype of a gI deletion mutant (rOka?gI). However, at later time points, infection of satellite cells and other supportive nonneuronal cells resulted in extensive DRG tissue damage and cell loss such that cytopathic changes observed at day 70 were more severe than those for rOka-infected DRG. The replication of gE-AYRV, which is impaired for trans-Golgi network (TGN) localization, and the replication of gE-SSTT, which contains mutations in an acidic cluster, were equivalent to that of rOka, causing significant cytopathic effects and infectious virus production by day 14; genome copy numbers were equivalent to those of rOka. These experiments suggest that the gE interaction with cellular IDE, gE targeting to TGN sites of virion envelopment, and phosphorylation at SSTT are dispensable for VZV DRG infection, whereas the gE/gI interaction is critical for VZV neurovirulence.

    View details for DOI 10.1128/JVI.01902-10

    View details for Web of Science ID 000285095800008

    View details for PubMedID 20962081

  • Development of Antibodies to Human Thrombin and Factor V in a Patient Exposed to Topical Bovine Thrombin PEDIATRIC BLOOD & CANCER Lo, C. Y., Jones, C., Glader, B., Zehnder, J. L. 2010; 55 (6): 1195-1197

    Abstract

    Bovine topical thrombin is commonly used for local hemostasis in pediatric surgery. Acquired inhibitors to coagulation factors, particularly to factor V and bovine thrombin, have been infrequently reported in the pediatric population. We report a 3-year-old male who developed a coagulopathy and clinical bleeding after cardiothoracic surgery, during which bovine topical thrombin was used for local hemostasis. Laboratory tests revealed elevated prothrombin, partial thromboplastin, and thrombin times, and a low factor V activity level. He was found to have both human-thrombin and factor V inhibitors, among the first reported cases of these combined inhibitors secondary to bovine topical thrombin. He was treated with intravenous immunoglobulin and steroids with a rapid and durable response.

    View details for DOI 10.1002/pbc.22699

    View details for Web of Science ID 000283757600028

    View details for PubMedID 20979176

  • Development of North American Consensus Guidelines for Medical Laboratories That Perform and Interpret Platelet Function Testing Using Light Transmission Aggregometry AMERICAN JOURNAL OF CLINICAL PATHOLOGY Hayward, C. P., Moffat, K. A., Raby, A., Israels, S., Plumhoff, E., Flynn, G., Zehnder, J. L. 2010; 134 (6): 955-963

    Abstract

    Platelet function testing is important for the diagnostic evaluation of common and rare bleeding disorders. Our study goals were to promote best practices and reduce unnecessary testing variances by developing North American guidelines on platelet function testing. Guidelines were developed by consensus for expert recommendations (minimum level for approval, 70%) that included recommendations on the evaluation and interpretation of light transmission platelet aggregometry (LTA). To assess consensus, medical opinions on recommendations were gathered from diagnostic laboratories that perform LTA, in collaboration with the Quality Management Program-Laboratory Services (QMP-LS) in Ontario, Canada (10 laboratories), and the North American Specialized Coagulation Laboratory Association (NASCOLA; 47 laboratories, 5 overlapping the QMP-LS group). Adequate consensus was achieved for all and 89% of recommendations for the QMP-LS and NASCOLA groups, respectively. The recommendations adopted provide North American laboratories with additional guidance on platelet function testing, including how to interpret LTA abnormalities.

    View details for DOI 10.1309/AJCP9V3RRVNZMKDS

    View details for Web of Science ID 000284440100013

    View details for PubMedID 21088160

  • Heparin-induced thrombocytopenia: Current status and diagnostic challenges AMERICAN JOURNAL OF HEMATOLOGY Otis, S. A., Zehnder, J. L. 2010; 85 (9): 700-706

    Abstract

    Heparin-induced thrombocytopenia (HIT) is a fairly common and potentially catastrophic complication of heparin therapy. Diagnosing HIT remains a challenge, as the patients at risk often have other reasons for thrombocytopenia and/or thrombosis. HIT is considered a clinicopathologic disorder whose diagnosis is generally made on the basis of both clinical criteria and the presence of "HIT antibodies" in the patient's serum or plasma. There are two basic laboratory approaches to detect HIT antibodies. The immunoassays detect antibodies based on their binding properties, whereas the functional assays detect antibodies based on their platelet-activating properties. Prompt and accurate diagnosis of HIT is imperative, as overdiagnosis exposes patients to alternative anticoagulants and their associated bleeding risks, whereas under- or delayed diagnosis leaves patients vulnerable to the thromboembolic sequelae of HIT, which can be life threatening. A critical interpretation of laboratory results by the clinician is an essential component of diagnosing HIT. This requires a keen understanding of the current concepts in the pathophysiologic mechanisms of the disease, and the application of these concepts when interpreting the results of both the functional and immunoassays. Equally important is an awareness of the strengths and weaknesses, as well as the current lack of standardization and proficiency testing, of these assays.

    View details for DOI 10.1002/ajh.21770

    View details for Web of Science ID 000281601900012

    View details for PubMedID 20665476

  • Complete donor T-cell engraftment 30 days after allogeneic transplantation predicts molecular remission in high-risk chronic lymphocytic leukaemia BRITISH JOURNAL OF HAEMATOLOGY Jones, C. D., Arai, S., Lowsky, R., Tyan, D. B., Zehnder, J. L., Miklos, D. B. 2010; 150 (5): 637-639
  • Novel mutations in the inhibitory adaptor protein LNK drive JAK-STAT signaling in patients with myeloproliferative neoplasms BLOOD Oh, S. T., Simonds, E. F., Jones, C., Hale, M. B., Goltsev, Y., Gibbs, K. D., Merker, J. D., Zehnder, J. L., Nolan, G. P., Gotlib, J. 2010; 116 (6): 988-992

    Abstract

    Dysregulated Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling due to activation of tyrosine kinases is a common feature of myeloid malignancies. Here we report the first human disease-related mutations in the adaptor protein LNK, a negative regulator of JAK-STAT signaling, in 2 patients with JAK2 V617F-negative myeloproliferative neoplasms (MPNs). One patient exhibited a 5 base-pair deletion and missense mutation leading to a premature stop codon and loss of the pleckstrin homology (PH) and Src homology 2 (SH2) domains. A second patient had a missense mutation (E208Q) in the PH domain. BaF3-MPL cells transduced with these LNK mutants displayed augmented and sustained thrombopoietin-dependent growth and signaling. Primary samples from MPN patients bearing LNK mutations exhibited aberrant JAK-STAT activation, and cytokine-responsive CD34(+) early progenitors were abnormally abundant in both patients. These findings indicate that JAK-STAT activation due to loss of LNK negative feedback regulation is a novel mechanism of MPN pathogenesis.

    View details for DOI 10.1182/blood-2010-02-270108

    View details for Web of Science ID 000280881700021

    View details for PubMedID 20404132

  • Hereditary diffuse gastric cancer due to a previously undescribed CDH1 splice site mutation HUMAN PATHOLOGY Matsukuma, K. E., Mullins, F. M., Dietz, L., Zehnder, J. L., Ford, J. M., Chun, N. M., Schrijver, I. 2010; 41 (8): 1200-1203

    Abstract

    Our patient was a 52-year-old man who was diagnosed with signet ring cell gastric adenocarcinoma. An extensive family history of gastric cancer raised suspicion for hereditary diffuse gastric cancer. Sequencing of the patient's CDH1 gene revealed a novel point mutation in a strictly conserved splice site within intron 6, c.833-2 A > G. This mutation was predicted to result in loss of function due to defective RNA splicing. To characterize the pathogenic mechanism of this mutation, we amplified the patient's CDH1 gene products by reverse transcriptase polymerase chain reaction. Primers flanking the region of the mutation detected 3 distinct transcripts. In addition to the wild-type product, a larger product consistent with activation of a cryptic splice site within intron 6 and a smaller product shown to result from exon 7 skipping were detected. In summary, we have identified a novel CDH1 mutation in a large hereditary diffuse gastric cancer kindred and identified its pathogenic mechanism.

    View details for DOI 10.1016/j.humpath.2010.01.022

    View details for Web of Science ID 000280128300019

    View details for PubMedID 20624523

  • Individual Variation in the Germline Ig Gene Repertoire Inferred from Variable Region Gene Rearrangements JOURNAL OF IMMUNOLOGY Boyd, S. D., Gaeta, B. A., Jackson, K. J., Fire, A. Z., Marshall, E. L., Merker, J. D., Maniar, J. M., Zhang, L. N., Sahaf, B., Jones, C. D., Simen, B. B., Hanczaruk, B., Nguyen, K. D., Nadeau, K. C., Egholm, M., Miklos, D. B., Zehnder, J. L., Collins, A. M. 2010; 184 (12): 6986-6992

    Abstract

    Individual variation in the Ig germline gene repertoire leads to individual differences in the combinatorial diversity of the Ab repertoire, but the study of such variation has been problematic. The application of high-throughput DNA sequencing to the study of rearranged Ig genes now makes this possible. The sequencing of thousands of VDJ rearrangements from an individual, either from genomic DNA or expressed mRNA, should allow their germline IGHV, IGHD, and IGHJ repertoires to be inferred. In addition, where previously mere glimpses of diversity could be gained from sequencing studies, new large data sets should allow the rearrangement frequency of different genes and alleles to be seen with clarity. We analyzed the DNA of 108,210 human IgH chain rearrangements from 12 individuals and determined their individual IGH genotypes. The number of reportedly functional IGHV genes and allelic variants ranged from 45 to 60, principally because of variable levels of gene heterozygosity, and included 14 previously unreported IGHV polymorphisms. New polymorphisms of the IGHD3-16 and IGHJ6 genes were also seen. At heterozygous loci, remarkably different rearrangement frequencies were seen for the various IGHV alleles, and these frequencies were consistent between individuals. The specific alleles that make up an individual's Ig genotype may therefore be critical in shaping the combinatorial repertoire. The extent of genotypic variation between individuals is highlighted by an individual with aplastic anemia who appears to lack six contiguous IGHD genes on both chromosomes. These deletions significantly alter the potential expressed IGH repertoire, and possibly immune function, in this individual.

    View details for DOI 10.4049/jimmunol.1000445

    View details for Web of Science ID 000278516700047

    View details for PubMedID 20495067

  • Comprehensive and Efficient HBB Mutation Analysis for Detection of beta-Hemoglobinopathies in a Pan-Ethnic Population AMERICAN JOURNAL OF CLINICAL PATHOLOGY Chan, O. T., Westover, K. D., Dietz, L., Zehnder, J. L., Schrijver, I. 2010; 133 (5): 700-707

    Abstract

    Current methods that assay hemoglobin beta-globin chain variants can have limited clinical sensitivity when applied techniques identify only a predefined panel of mutations. Even sequence-based assays may be limited depending on which gene regions are investigated. We sought to develop a clinically practical yet inclusive molecular assay to identify beta-globin mutations in multicultural populations. We highlight the beta-globin mutation detection assay (beta-GMDA), an extensive gene sequencing assay. The polymerase chain reaction (PCR) primers are located to encompass virtually all hemoglobin beta locus (HBB) mutations. In addition, this assay is able to detect, by gap PCR, a common large deletion (Delta619 base pair), which would be missed by sequencing alone. We describe our 5-year experience with the beta-GMDA and indicate its capability for detecting homozygous, heterozygous, and compound heterozygous sequence changes, including previously unknown HBB variants. The beta-GMDA offers superior sensitivity and ease of use with comprehensive detection of HBB mutations that result in beta-globin chain variants.

    View details for DOI 10.1309/AJCP7HQ2KWGHECIO

    View details for Web of Science ID 000277476500004

    View details for PubMedID 20395516

  • Combined Use of PCR-Based TCRG and TCRB Clonality Tests on Paraffin-Embedded Skin Tissue in the Differential Diagnosis of Mycosis Fungoides and Inflammatory Dermatoses JOURNAL OF MOLECULAR DIAGNOSTICS Zhang, B., Beck, A. H., Taube, J. M., Kohler, S., Seo, K., Zwerner, J., Viakhereva, N., Sundram, U., Kim, Y. H., Schrijver, I., Arber, D. A., Zehnder, J. L. 2010; 12 (3): 320-327

    Abstract

    The distinction between mycosis fungoides (MF) and inflammatory dermatoses (ID) by clinicopathologic criteria can be challenging. There is limited information regarding the performance characteristics and utility of TCRG and TCRB clonality assays in diagnosis of MF and ID from paraffin-embedded tissue sections. In this study, PCR tests were performed with both TCRG and TCRB BIOMED-2 clonality methods followed by capillary electrophoresis and Genescan analysis using DNA samples from 35 MF and 96 ID patients with 69 and 133 paraffin-embedded specimens, respectively. Performance characteristics were determined for each test individually and in combination. TCRG and TCRB tests demonstrated identical sensitivity (64%) and specificity (84%) when analyzed as individual assays. The positive predictive value, negative predictive value, and change of posttest MF probability over a range of MF pretest probabilities were obtained. These data were used to construct an algorithm for sequential use of TCRG and TCRB. As single tests, commercially available BIOMED-2 PCR-based TCRG and TCRB clonality tests on paraffin-embedded tissue have no significant difference in terms of sensitivity and specificity. Combined use of the two tests in patients with intermediate pretest probabilities as proposed in the algorithm could improve test utility.

    View details for DOI 10.2353/jmoldx.2010.090123

    View details for Web of Science ID 000277531700009

    View details for PubMedID 20203005

  • Presentation of Extranodal Natural Killer T-Cell Lymphoma, Nasal Type, With Poorly Circumscribed Erythematous Patches JOURNAL OF CLINICAL ONCOLOGY Pincus, L. B., Zehnder, J. L., Neuhaus, I. M., Andreadis, C., McCalmont, T. H. 2010; 28 (6): E94-E95

    View details for DOI 10.1200/JCO.2009.24.3428

    View details for Web of Science ID 000274653200030

    View details for PubMedID 19933911

  • Design and Evaluation of a Real-Time PCR Assay for Quantification of JAK2 V617F and Wild-Type JAK2 Transcript Levels in the Clinical Laboratory JOURNAL OF MOLECULAR DIAGNOSTICS Merker, J. D., Jones, C. D., Oh, S. T., Schrijver, I., Gotlib, J., Zehnder, J. L. 2010; 12 (1): 58-64

    Abstract

    The somatic mutation JAK2 V617F is associated with BCR-ABL1-negative myeloproliferative neoplasms. Detection of this mutation aids diagnosis of these neoplasms, and quantification of JAK2 V617F may provide a method to monitor response to therapy. For these reasons, we designed a clinical assay that uses allele-specific PCR and real-time detection with hydrolysis probes for the quantification of JAK2 V617F, wild-type JAK2, and GAPDH transcripts. Mutant and wild-type JAK2 were quantified by using external plasmid standards that contain the relevant JAK2 V617F or JAK2 sequence, respectively. We tested 55 peripheral blood specimens from patients with suspected myeloproliferative neoplasms and 55 peripheral blood specimens from patients not known to have myeloproliferative neoplasms. Low-level, nonspecific amplification was detected in reactions containing a high copy number of plasmid standards and in specimens from patients not known to have myeloproliferative neoplasms, necessitating the use of a laboratory-established mutant to wild-type cutoff. The limit of detection established by using cell line dilutions is 0.1%, and this method identified three JAK2 V617F-positive patients who were not detected by a less sensitive method. The assay characteristics and our initial evaluation indicate this method can be used for the detection and quantification of JAK2 V617F, which should be useful for diagnosis of myeloproliferative neoplasms and potentially for monitoring minimal residual disease in future trials of therapies targeted to myeloproliferative neoplasms.

    View details for DOI 10.2353/jmoldx.2010.090068

    View details for Web of Science ID 000273664100009

    View details for PubMedID 19959796

  • Anti-Glycoprotein H Antibody Impairs the Pathogenicity of Varicella-Zoster Virus in Skin Xenografts in the SCID Mouse Model JOURNAL OF VIROLOGY Vleck, S. E., Oliver, S. L., Reichelt, M., Rajamani, J., Zerboni, L., Jones, C., Zehnder, J., Grose, C., Arvin, A. M. 2010; 84 (1): 141-152

    Abstract

    Varicella-zoster virus (VZV) infection is usually mild in healthy individuals but can cause severe disease in immunocompromised patients. Prophylaxis with varicella-zoster immunoglobulin can reduce the severity of VZV if given shortly after exposure. Glycoprotein H (gH) is a highly conserved herpesvirus protein with functions in virus entry and cell-cell spread and is a target of neutralizing antibodies. The anti-gH monoclonal antibody (MAb) 206 neutralizes VZV in vitro. To determine the requirement for gH in VZV pathogenesis in vivo, MAb 206 was administered to SCID mice with human skin xenografts inoculated with VZV. Anti-gH antibody given at 6 h postinfection significantly reduced the frequency of skin xenograft infection by 42%. Virus titers, genome copies, and lesion size were decreased in xenografts that became infected. In contrast, administering anti-gH antibody at 4 days postinfection suppressed VZV replication but did not reduce the frequency of infection. The neutralizing anti-gH MAb 206 blocked virus entry, cell fusion, or both in skin in vivo. In vitro, MAb 206 bound to plasma membranes and to surface virus particles. Antibody was internalized into vacuoles within infected cells, associated with intracellular virus particles, and colocalized with markers for early endosomes and multivesicular bodies but not the trans-Golgi network. MAb 206 blocked spread, altered intracellular trafficking of gH, and bound to surface VZV particles, which might facilitate their uptake and targeting for degradation. As a consequence, antibody interference with gH function would likely prevent or significantly reduce VZV replication in skin during primary or recurrent infection.

    View details for DOI 10.1128/JVI.01338-09

    View details for Web of Science ID 000272564300013

    View details for PubMedID 19828615

  • Measurement and Clinical Monitoring of Human Lymphocyte Clonality by Massively Parallel V-D-J Pyrosequencing SCIENCE TRANSLATIONAL MEDICINE Boyd, S. D., Marshall, E. L., Merker, J. D., Maniar, J. M., Zhang, L. N., Sahaf, B., Jones, C. D., Simen, B. B., Hanczaruk, B., Nguyen, K. D., Nadeau, K. C., Egholm, M., Miklos, D. B., Zehnder, J. L., Fire, A. Z. 2009; 1 (12)

    Abstract

    The complex repertoire of immune receptors generated by B and T cells enables recognition of diverse threats to the host organism. In this work, we show that massively parallel DNA sequencing of rearranged immune receptor loci can provide direct detection and tracking of immune diversity and expanded clonal lymphocyte populations in physiological and pathological contexts. DNA was isolated from blood and tissue samples, a series of redundant primers was used to amplify diverse DNA rearrangements, and the resulting mixtures of barcoded amplicons were sequenced using long-read ultra deep sequencing. Individual DNA molecules were then characterized on the basis of DNA segments that had been joined to make a functional (or nonfunctional) immune effector. Current experimental designs can accommodate up to 150 samples in a single sequence run, with the depth of sequencing sufficient to identify stable and dynamic aspects of the immune repertoire in both normal and diseased circumstances. These data provide a high-resolution picture of immune spectra in normal individuals and in patients with hematological malignancies, illuminating, in the latter case, both the initial behavior of clonal tumor populations and the later suppression or re-emergence of such populations after treatment.

    View details for DOI 10.1126/scitranslmed.3000540

    View details for Web of Science ID 000277263200001

    View details for PubMedID 20161664

  • Glycogen synthase kinase 3 beta missplicing contributes to leukemia stem cell generation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Abrahamsson, A. E., Geron, I., Gotlib, J., Dao, K. T., Barroga, C. F., Newton, I. G., Giles, F. J., Durocher, J., Creusot, R. S., Karimi, M., Jones, C., Zehnder, J. L., Keating, A., Negrin, R. S., Weissman, I. L., Jamieson, C. H. 2009; 106 (10): 3925-3929

    Abstract

    Recent evidence suggests that a rare population of self-renewing cancer stem cells (CSC) is responsible for cancer progression and therapeutic resistance. Chronic myeloid leukemia (CML) represents an important paradigm for understanding the genetic and epigenetic events involved in CSC production. CML progresses from a chronic phase (CP) in hematopoietic stem cells (HSC) that harbor the BCR-ABL translocation, to blast crisis (BC), characterized by aberrant activation of beta-catenin within granulocyte-macrophage progenitors (GMP). A major barrier to predicting and inhibiting blast crisis transformation has been the identification of mechanisms driving beta-catenin activation. Here we show that BC CML myeloid progenitors, in particular GMP, serially transplant leukemia in immunocompromised mice and thus are enriched for leukemia stem cells (LSC). Notably, cDNA sequencing of Wnt/beta-catenin pathway regulatory genes, including adenomatous polyposis coli, GSK3beta, axin 1, beta-catenin, lymphoid enhancer factor-1, cyclin D1, and c-myc, revealed a novel in-frame splice deletion of the GSK3beta kinase domain in the GMP of BC samples that was not detectable by sequencing in blasts or normal progenitors. Moreover, BC CML progenitors with misspliced GSK3beta have enhanced beta-catenin expression as well as serial engraftment potential while reintroduction of full-length GSK3beta reduces both in vitro replating and leukemic engraftment. We propose that CP CML is initiated by BCR-ABL expression in an HSC clone but that progression to BC may include missplicing of GSK3beta in GMP LSC, enabling unphosphorylated beta-catenin to participate in LSC self-renewal. Missplicing of GSK3beta represents a unique mechanism for the emergence of BC CML LSC and might provide a novel diagnostic and therapeutic target.

    View details for DOI 10.1073/pnas.0900189106

    View details for Web of Science ID 000264036900051

    View details for PubMedID 19237556

  • Clinical characterization of acute myeloid leukemia with myelodysplasia-related changes as defined by the 2008 WHO classification system BLOOD Weinberg, O. K., Seetharam, M., Ren, L., Seo, K., Ma, L., Merker, J. D., Gotlib, J., Zehnder, J. L., Arber, D. A. 2009; 113 (9): 1906-1908

    Abstract

    Although some studies have validated the 2001 World Health Organization (WHO) classification of acute myeloid leukemia (AML), including the importance of multilineage dysplasia, others have suggested that multilineage dysplasia correlates with unfavorable cytogenetics but has no independent impact on prognosis. In 2008, the revised WHO classification has expanded this category into "AML with myelodysplasia-related changes" (AML-MRC). We evaluated the clinical, pathologic, cytogenetic, and molecular features of 100 AML patients using the 2008 WHO criteria. Patients underwent genetic screening for NPM1, FLT3-ITD, FLT3-D835, and CEBPA mutations. Compared with patients with AML, not otherwise specified, patients with AML-MRC were significantly older (P= .014), presented with a lower hemoglobin (P= .044), more frequently expressed CD14 (P= .048), and exhibited a decreased frequency of CEBPA mutations (P= .001). Multivariate analysis indicated that patients with AML-MRC had a significantly worse overall survival, progression-free survival, and complete response compared with AML-not otherwise specified (all P< .001). These data support the clinical, morphologic, and cytogenetic criteria for this 2008 WHO AML category.

    View details for DOI 10.1182/blood-2008-10-182782

    View details for Web of Science ID 000263723700007

    View details for PubMedID 19131546

  • Laboratory Practice Guidelines for Detecting and Reporting BCR-ABL Drug Resistance Mutations in Chronic Myelogenous Leukemia and Acute Lymphoblastic Leukemia A Report of the Association for Molecular Pathology JOURNAL OF MOLECULAR DIAGNOSTICS Jones, D., Kamel-Reid, S., Bahler, D., Dong, H., Elenitoba-Johnson, K., Press, R., Quigley, N., Rothberg, P., Sabath, D., Viswanatha, D., Weck, K., Zehnder, J. 2009; 11 (1): 4-11

    Abstract

    The BCR-ABL tyrosine kinase produced by the t(9;22)(q34;q11) translocation, also known as the Philadelphia chromosome, is the initiating event in chronic myeloid leukemia (CML) and Ph+ acute lymphoblastic leukemia (ALL). Targeting of BCR-ABL with tyrosine kinase inhibitors (TKIs) has resulted in rapid clinical responses in the vast majority of patients with CML and Philadelphia chromosome+ ALL. However, long-term use of TKIs occasionally results in emergence of therapy resistance, in part through the selection of clones with mutations in the BCR-ABL kinase domain. We present here an overview of the current practice in monitoring for such mutations, including the methods used, the clinical and laboratory criteria for triggering mutational analysis, and the guidelines for reporting BCR-ABL mutations. We also present a proposal for a public database for correlating mutational status with in vitro and in vivo responses to different TKIs to aid in the interpretation of mutation studies.

    View details for DOI 10.2353/jmoldx.2009.080095

    View details for Web of Science ID 000262419500002

    View details for PubMedID 19095773

  • Molecular stratification of patients with normal karyotype acute myeloid leukemia based on initial assessment of FLT3-internal tandem duplication status at first complete remission LEUKEMIA & LYMPHOMA Medeiros, B. C., Gotlib, J., Zehnder, J. 2009; 50 (5): 851-853

    View details for DOI 10.1080/10428190902838400

    View details for Web of Science ID 000266201800029

    View details for PubMedID 19452323

  • Superficial venous thrombosis associated with congenital absence of the inferior vena cava and previous episode of deep venous thrombosis AMERICAN JOURNAL OF HEMATOLOGY Evanchuk, D. M., Von Gehr, A., Zehnder, J. L. 2008; 83 (3): 250-252

    Abstract

    Congenital malformations of the inferior vena cava (IVC) are uncommon and may be associated with an increased risk of venous thrombosis. We report the case of a man with congenital absence of the IVC and remote history of deep venous thrombosis who now presents with severe abdominal wall superficial thrombophlebitis. To our knowledge, this is the first report of a patient with IVC absence who has developed both deep and superficial venous thromboses.

    View details for DOI 10.1002/ajh.21089

    View details for Web of Science ID 000253559700018

    View details for PubMedID 17918250

  • Interlaboratory performance of a microarray-based gene expression test to determine tissue of origin in poorly differentiated and undifferentiated cancers JOURNAL OF MOLECULAR DIAGNOSTICS Dumur, C. I., Lyons-Weiler, M., Sciulli, C., Garrett, C. T., Schrijver, I., Holley, T. K., Rodriguez-Paris, J., Pollack, J. R., Zehnder, J. L., Price, M., Hagenkord, J. M., Rigl, C. T., Buturovic, L. J., Anderson, G. G., Monzon, F. A. 2008; 10 (1): 67-77

    Abstract

    Clinical workup of metastatic malignancies of unknown origin is often arduous and expensive and is reported to be unsuccessful in 30 to 60% of cases. Accurate classification of uncertain primary cancers may improve with microarray-based gene expression testing. We evaluated the analytical performance characteristics of the Pathwork tissue of origin test, which uses expression signals from 1668 probe sets in a gene expression microarray, to quantify the similarity of tumor specimens to 15 known tissues of origin. Sixty archived tissue specimens from poorly and undifferentiated tumors (metastatic and primary) were analyzed at four laboratories representing a wide range of preanalytical conditions (eg, personnel, reagents, instrumentation, and protocols). Cross-laboratory comparisons showed highly reproducible results between laboratories, with correlation coefficients between 0.95 to 0.97 for measurements of similarity scores, and an average 93.8% overall concordance between laboratories in terms of final tissue calls. Bland-Altman plots (mean coefficients of reproducibility of 32.48+/-3.97) and kappa statistics (kappa >0.86) also indicated a high level of agreement between laboratories. We conclude that the Pathwork tissue of origin test is a robust assay that produces consistent results in diverse laboratory conditions reflecting the preanalytical variations found in the everyday clinical practice of molecular diagnostics laboratories.

    View details for DOI 10.2353/jmoldx.2008.070099

    View details for Web of Science ID 000252521200009

    View details for PubMedID 18083688

  • Gene expression and pathway analysis of immune thrombocytopenic purpura BRITISH JOURNAL OF HAEMATOLOGY Sood, R., Wong, W., Gotlib, J., Jeng, M., Zehnder, J. L. 2008; 140 (1): 99-103

    Abstract

    A global expression profile of peripheral blood from patients with immune thrombocytopenic purpura (ITP) was performed that identified an ITP-specific signature, which also included interferon (IFN)-induced genes. Several genes correlated with ITP have been shown to be associated with expression signatures in systemic lupus erythematosis and rheumatoid arthritis, indicating an overlap with other autoimmune disorders. Pathway analysis demonstrated that IFN signalling, death receptor and protein ubiquitination pathways were associated with ITP. These results provide the first glimpse of the genes and pathways consistently aberrant in ITP, identifying new targets for investigations of pathogenesis and treatment of ITP.

    View details for DOI 10.1111/j.1365-2141.2007.06881.x

    View details for Web of Science ID 000251502700011

    View details for PubMedID 18005267

  • Laboratory testing for heparin-induced thrombocytopenia is inconsistent in North America: A survey of North American specialized coagulation laboratories THROMBOSIS AND HAEMOSTASIS Price, E. A., Hayward, C. R., Moffat, K. A., Moore, J. C., Warkentin, T. E., Zehnder, J. L. 2007; 98 (6): 1357-1361

    Abstract

    Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy. As HIT is considered a clinico-pathologic entity, laboratory practices have an important role in diagnosing or excluding HIT. It was the objective of this study to assess the current status of laboratory testing for HIT in North America. An online survey consisting of 67 questions related to laboratory testing for HIT was developed by the North American Specialized Coagulation Laboratory Association (NASCOLA), and distributed to its 59 members. The survey included queries about HIT test ordering practices, HIT immunoassay and activation assays performed, and reporting practices. Data was collected from the 44 NASCOLA laboratories who responded. Of these sites, 88% performed immunoassays for HIT, commonly using commercial assays. However, sites varied in practices related to use of controls, immunoglobulin class of antibody detected, and in result interpretation and reporting. Platelet activation assays for HIT were performed by 36% of sites, commonly using assays of serotonin release (50%) or heparin-induced platelet aggregation (43%). Sites varied in the use of washed platelets versus platelet-rich plasma, controls, and heparin concentrations. This survey is the first comprehensive assessment of patterns of practice in HIT testing among diagnostic coagulation laboratories in North America. We observed site-specific variability of testing methods encompassing all stages of testing, including pre-analytical handling, testing methodologies, and result interpretation and reporting. The variability in HIT platelet activation assay methods among institutions indicates a need for proficiency testing to assess assay performance, and for consensus guidelines on HIT laboratory testing.

    View details for DOI 10.1160/TH07-06-0401

    View details for Web of Science ID 000251687400031

    View details for PubMedID 18064336

  • Effect of Ginkgo biloba (EGb 761) aggregation and platelet and aspirin on platelet analysis among older adults at risk of cardiovascular disease: a randomized clinical trial BLOOD COAGULATION & FIBRINOLYSIS Gardner, C. D., Zehnder, J. L., Rigby, A. J., Nicholus, J. R., Farquhar, J. W. 2007; 18 (8): 787-793

    Abstract

    Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size.

    View details for Web of Science ID 000251271200012

    View details for PubMedID 17982321

  • T-cell clonality analysis in biopsy specimens from two different skin sites shows high specificity in the diagnosis of patients with suggested mycosis fungoides JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Thurber, S. E., Zhang, B., Kim, Y. H., Schrijver, I., Zehnder, J., Kohler, S. 2007; 57 (5): 782-790

    Abstract

    The diagnosis of mycosis fungoides (MF) is often difficult because of significant clinical and histopathologic overlap with inflammatory dermatoses. T-cell receptor (TCR)gamma chain rearrangement by polymerase chain reaction (PCR) (TCR-PCR) is a helpful adjuvant tool in this setting, but several of the inflammatory dermatoses in the differential diagnosis of MF may contain a clonal T-cell proliferation.We examined whether analysis for T-cell clonality and comparison of the clones with the standardized BIOMED-2 PCR multiplex primers for the TCRgamma chain from two anatomically distinct skin sites improves diagnostic accuracy.We examined two biopsy specimens each from 10 patients with unequivocal MF, from 18 patients with inflammatory dermatoses, and from 18 patients who could initially not be definitively given a diagnosis based on clinical and histopathologic criteria.Eight of 10 patients with unequivocal MF had an identical clone in both biopsy specimens. Two of 18 patients with inflammatory dermatoses were found to have a clone in one of the biopsy specimens. On further follow-up of the 18 patients with morphologically nondiagnostic biopsy specimens, 13 of 18 were later confirmed to have MF and 5 of 18 had inflammatory dermatoses. Eleven of 13 patients with MF had an identical clone in both biopsy specimens; two of 13 had a polyclonal amplification pattern in both biopsy specimens. Four of 5 patients with inflammatory dermatoses had no clone in either biopsy specimen. One patient with an inflammatory dermatosis had an identical clone in both specimens. The sensitivity of TCR-PCR analysis to evaluate for an identical clone at different anatomic skin sites (dual TCR-PCR) is 82.6% and the specificity is 95.7%.The number of patients in the study group was limited.These data suggest that dual TCR-PCR is a very promising technique with high specificity in distinguishing MF from inflammatory dermatoses.

    View details for DOI 10.1016/j.jaad.2007.06.004

    View details for Web of Science ID 000250387100004

    View details for PubMedID 17646032

  • Identification of an intronic single nucleotide polymorphism leading to allele dropout during validation of a CDH1 sequencing assay: implications for designing polymerase chain reaction-based assays GENETICS IN MEDICINE Mullins, F. M., Dietz, L., Lay, M., Zehnder, J. L., Ford, J., Chun, N., Schrijver, I. 2007; 9 (11): 752-760

    Abstract

    The CDH1 gene encodes the cell adhesion protein E-cadherin, and CDH1 germline mutations are associated with hereditary diffuse gastric cancer. Identification of individuals at high risk of developing diffuse gastric cancer affords the opportunity for endoscopic screening or elective prophylactic gastrectomy. We set out to develop a CDH1 sequencing assay for clinical use.All exons of the CDH1 gene were amplified and sequenced with published and modified primers.While validating the assay, we encountered a case in which a single nucleotide polymorphism located in intron 15 led to allele dropout and therefore to a false-negative result. The polymorphism leading to allele dropout was located within a primer-binding sequence, five bases away from the 3' end of the primer. A frameshift mutation in exon 15 was detected by an alternative primer that binds away from the polymorphic site. A search of the University of California Santa Cruz single nucleotide polymorphism database revealed other polymorphisms located within primer-binding sites. A total of 12 primers in nine primer sets were modified to minimize allele dropout risk.The approach of designing primers to avoid known single nucleotide polymorphisms can be generalized to the design of any polymerase chain reaction-based assay and should be employed whenever possible.

    View details for DOI 10.1097/GIM.0b013e318159a369

    View details for Web of Science ID 000251233500004

    View details for PubMedID 18007144

  • Antithrombotic therapy and pregnancy: consensus report and recommendations for prevention and treatment of venous thromboembolism and adverse pregnancy outcomes AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY Duhl, A. J., Paidas, M. J., Ural, S. H., Branch, W., Casele, H., Cox-Gill, J., Hamersley, S. L., Hyers, T. M., Katz, V., Kuhlmann, R., Nutescu, E. A., Thorp, J. A., Zehnder, J. L. 2007; 197 (5)

    Abstract

    Venous thromboembolism and adverse pregnancy outcomes are potential complications of pregnancy. Numerous studies have evaluated both the risk factors for and the prevention and management of these outcomes in pregnant patients. This consensus group was convened to provide concise recommendations, based on the currently available literature, regarding the use of antithrombotic therapy in pregnant patients at risk for venous thromboembolic events and adverse pregnancy outcomes.

    View details for DOI 10.1016/j.ajog.2007.04.022

    View details for Web of Science ID 000250915500004

    View details for PubMedID 17980177

  • Aberrant infection and persistence of varicella-zoster virus in human dorsal root ganglia in vivo absence of glycoprotein I PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Zerboni, L., Reichelt, M., Jones, C. D., Zehnder, J. L., Ito, H., Arvin, A. M. 2007; 104 (35): 14086-14091

    Abstract

    Varicella-zoster virus (VZV) causes varicella, establishes latency in sensory ganglia, and reactivates as herpes zoster. Human dorsal root ganglia (DRGs) xenografts in immunodeficient mice provide a model for evaluating VZV neuropathogenesis. Our investigation of the role of glycoprotein I (gI), which is dispensable in vitro, examines the functions of a VZV gene product during infection of human neural cells in vivo. Whereas intact recombinant Oka (rOka) initiated a short replicative phase followed by persistence in DRGs, the gI deletion mutant, rOkaDeltagI, showed prolonged replication with no transition to persistence up to 70 days after infection. Only a few varicella-zoster nucleocapsids and cytoplasmic virions were observed in neurons, and the major VZV glycoprotein, gE, was retained in the rough endoplasmic reticulum in the absence of gI. VZV neurotropism was not disrupted when DRG xenografts were infected with rOka mutants lacking gI promoter elements that bind cellular transactivators, specificity factor 1 (Sp1) and upstream stimulatory factor (USF). Because gI is essential and Sp1 and USF contribute to VZV pathogenesis in skin and T cells in vivo, these DRG experiments indicate that the genetic requirements for VZV infection are less stringent in neural cells in vivo. The observations demonstrate that gI is important for VZV neurotropism and suggest that a strategy to reduce neurovirulence by deleting gI could prolong active infection in human DRGs.

    View details for DOI 10.1073/pnas.0706023104

    View details for Web of Science ID 000249187500042

    View details for PubMedID 17709745

  • Testing for maternal cell contamination in prenatal samples - A comprehensive survey of current diagnostic practices in 35 molecular diagnostic laboratories JOURNAL OF MOLECULAR DIAGNOSTICS Schrijver, I., Cherny, S. C., Zehnder, J. L. 2007; 9 (3): 394-400

    Abstract

    The potential presence of maternal cell contamination (MCC) in chorionic villus or amniotic fluid samples poses a serious preanalytical risk for prenatal misdiagnosis. The aim of this study was to identify current diagnostic practices in the absence of comprehensive practice guidelines. Thirty-five clinical molecular laboratories that conduct prenatal testing agreed to participate in a clinical practice survey. The survey included questions about sample requirements, test indications, assay type, test performance and limitations, criteria and management of uninformative test results, reporting, and billing. Sixty percent of participating laboratories performed testing on direct and cultured amniotic fluid, whereas forty percent tested cultured cells only. Most also accepted chorionic villus samples. Although MCC testing of fetal samples is recommended in guidelines by the American College of Medical Genetics, only 60% of surveyed laboratories performed it without exception. Commercially available assays were used by 75% of participating laboratories, and at least five identity markers were evaluated at 87% of the laboratories. The reported lower limit of MCC detection ranged from 1 to 20% but was not determined in all laboratories. MCC testing was performed in the majority of molecular diagnostic laboratories, but guidelines for standardization are needed to ensure optimal and accurate prenatal patient care.

    View details for DOI 10.2353/jmoldx.2007.070017

    View details for Web of Science ID 000247691200015

    View details for PubMedID 17591939

  • International standardized approach for flow cytometric residual disease monitoring in chronic lymphocytic leukaemia LEUKEMIA Rawstron, A. C., Villamor, N., Ritgen, M., Boettcher, S., Ghia, P., Zehnder, J. L., Lozanski, G., Colomer, D., Moreno, C., Geuna, M., Evans, P. A., Natkunam, Y., Coutre, S. E., Avery, E. D., Rassenti, L. Z., Kipps, T. J., Caligaris-Cappio, F., Kneba, M., Byrd, J. C., Hallek, M. J., Montserrat, E., Hillmen, P. 2007; 21 (5): 956-964

    Abstract

    The eradication of minimal residual disease (MRD) in chronic lymphocytic leukaemia (CLL) predicts for improved outcome. However, the wide variety of MRD techniques makes it difficult to interpret and compare different clinical trials. Our aim was to develop a standardized flow cytometric CLL-MRD assay and compare it to real-time quantitative allele-specific oligonucleotide (RQ-ASO) Immunoglobulin heavy chain gene (IgH) polymerase chain reaction (PCR). Analysis of 728 paired blood and marrow samples demonstrated high concordance (87%) for patients off-therapy. Blood analysis was equally or more sensitive than marrow in 92% of samples but marrow analysis was necessary to detect MRD within 3 months of alemtuzumab therapy. Assessment of 50 CLL-specific antibody combinations identified three (CD5/CD19 with CD20/CD38, CD81/CD22 and CD79b/CD43) with low inter-laboratory variation and false-detection rates. Experienced operators demonstrated an accuracy of 95.7% (specificity 98.8%, sensitivity 91.1%) in 141 samples with 0.01-0.1% CLL. There was close correlation and 95% concordance with RQ-ASO IgH-PCR for detection of CLL above 0.01%. The proposed flow cytometry approach is applicable to all sample types and therapeutic regimes, and sufficiently rapid and sensitive to guide therapy to an MRD-negativity in real time. These techniques may be used as a tool for assessing response and comparing the efficacy of different therapeutic approaches.

    View details for DOI 10.1038/sj.leu.2404584

    View details for Web of Science ID 000245999900014

    View details for PubMedID 17361231

  • Severe coagulation factor V deficiency associated with an interstitial deletion of chromosome 1q JOURNAL OF THROMBOSIS AND HAEMOSTASIS Caudill, J. S., Sood, R., Zehnder, J. L., Pruthi, R. K., Steensma, D. P. 2007; 5 (3): 626-628

    View details for Web of Science ID 000244277800034

    View details for PubMedID 17166249

  • Safety and efficacy of a ginkgo biloba-containing dietary supplement on cognitive function, quality of life, and platelet function in healthy, cognitively intact older adults JOURNAL OF THE AMERICAN DIETETIC ASSOCIATION Carlson, J. J., Farquhar, J. W., Dinucci, E., Ausserer, L., Zehnder, J., Miller, D., Berra, K., Hagerty, L., Haskell, W. L. 2007; 107 (3): 422-432

    Abstract

    To determine if a ginkgo biloba-containing supplement improves cognitive function and quality of life, alters primary hemostasis, and is safe in healthy, cognitively intact older adults.Four-month, randomized, double-blind, placebo-controlled parallel design.Ninety men and women (age range 65 to 84 years) were recruited to a university clinic. Eligibility included those without dementia or depression, not taking psychoactive medications or medications or supplements that alter hemostasis.Ninety subjects were randomly assigned to placebo or a ginkgo biloba-based supplement containing 160 mg ginkgo biloba, 68 mg gotu kola, and 180 mg decosahexaenoic acid per day for 4 months.Assessments included: six standardized cognitive function tests, the SF-36 Quality of Life questionnaire, the Platelet Function Analyzer-100 (Dade Behring, Eschbom, Germany), and the monitoring of adverse events.Baseline characteristics and study hypotheses were tested using analysis of covariance. Tests were two-tailed with a 0.05 significance level.Seventy-eight subjects (87%) completed both baseline and 4-month testing (n=36 in placebo group, n=42 in ginkgo biloba group). At baseline, the participants' cognitive function was above average. One of six cognitive tests indicated significant protocol differences at 4 months (P=0.03), favoring the placebo. There were no significant differences in quality of life, platelet function, or adverse events.These finding do not support the use of a ginkgo biloba-containing supplement for improving cognitive function or quality of life in cognitively intact, older, healthy adults. However, high baseline scores may have contributed to the null findings. The ginkgo biloba product seems safe and did not alter platelet function, though additional studies are needed to evaluate the interaction of varying doses of ginkgo biloba and ginkgo biloba-containing supplements with medications and supplements that alter hemostasis.

    View details for DOI 10.1016/j.jada.2006.12.011

    View details for Web of Science ID 000244551100016

    View details for PubMedID 17324660

  • Molecular characterization and subcellular localization of Tyr478del: a pathogenic in-frame deletion in coagulation factor V JOURNAL OF THROMBOSIS AND HAEMOSTASIS Jones, C. D., Yeung, C., Negro, F., Zehnder, J. L. 2007; 5 (2): 431-433

    View details for Web of Science ID 000243563000038

    View details for PubMedID 17269939

  • Gene expression profile of idiopathic thrombocytopenic purpura (ITP) PEDIATRIC BLOOD & CANCER Sood, R., Wong, W., Jeng, M., Zehnder, J. L. 2006; 47 (5): 675-677

    Abstract

    To search for novel mechanisms that contribute to the pathophysiology of idiopathic thrombocytopenic purpura (ITP), we determined the whole blood gene expression profile in five ITP patients and five control samples. Using DNA microarrays that contained 24,473 unique putative genes, we found 176 cDNAs that were strongly correlated with ITP. These included a cluster of interferon-regulated genes and TLR7, as well many less-well characterized genes which are candidates for further study. We believe this approach is likely to yield new insights into our understanding of the molecular pathophysiology of ITP.

    View details for DOI 10.1002/pbc.20981

    View details for Web of Science ID 000240405600010

    View details for PubMedID 16933260

  • Maintenance rituximab following induction chemoimmunotherapy may prolong progression-free survival in mantle cell lymphoma: a pilot study from the Wisconsin Oncology Network ANNALS OF ONCOLOGY Kahl, B. S., Longo, W. L., Eickhoff, J. C., Zehnder, J., Jones, C., Blank, J., McFarland, T., Bottner, W., Rezazedeh, H., Werndli, J., Bailey, H. H. 2006; 17 (9): 1418-1423

    Abstract

    There is no standard first line treatment for mantle cell lymphoma.This was a multicenter phase II pilot study of rituximab and modified hyper-fractionated cyclophosphamide, vincristine doxorubicin, dexamethasone (modified R-hyperCVAD) administered every 28 days for four to six cycles followed by rituximab maintenance therapy consisting of four weekly doses every 6 months for 2 years. Unlike traditional hyperCVAD regimens, no methotrexate or cytarabine was administered.Of 22 patients, the overall response rate was 77% and the complete response rate was 64%. With a median follow-up time of 37 months in surviving patients, the median PFS was 37 months and the median OS was not reached. The achievement of a molecular remission did not correlate with improved outcome. The major toxicity was expected myelosuppression. Two patients died during induction treatment. There were no major adverse effects during maintenance therapy.In a multicenter trial, modified R-hyperCVAD was tolerable and effective induction therapy for untreated MCL. Maintenance rituximab appeared to prolong PFS without increasing toxicity.

    View details for DOI 10.1093/annonc/mdl127

    View details for Web of Science ID 000240587900012

    View details for PubMedID 16766582

  • Detection of the JAK2 V617F mutation by LightCycler PCR and probe dissociation analysis JOURNAL OF MOLECULAR DIAGNOSTICS Lay, M., Mariappan, R., Gotlib, J., Dietz, L., Sebastian, S., Schrijver, I., Zehnder, J. L. 2006; 8 (3): 330-334

    Abstract

    A point mutation in the JAK2 gene, a member of the tyrosine kinase family, was recently identified and shown to be associated with several myeloproliferative disorders. Several studies identified the same JAK2 point mutation (1,849G>T), resulting in the substitution of a valine to phenylalanine at codon 617 (V617F). We developed a simple and sensitive method to detect this mutation via polymerase chain reaction and probe dissociation analysis using the LightCycler platform, and we compared this method to existing restriction fragment-length polymorphism, direct sequencing, and amplification refractory mutation system methods. We found that the LightCycler method offered advantages of speed, reliability, and more straightforward interpretation over the restriction fragment-length polymorphism and sequencing approaches.

    View details for DOI 10.2353/jmoldx.2006.050130

    View details for Web of Science ID 000239106800006

    View details for PubMedID 16825505

  • First molecular characterization of a patient with combined factor V and factor VII deficiency THROMBOSIS AND HAEMOSTASIS Traynis, I., Jones, C. D., Gibb, C. B., Acharya, S. S., Zehnder, J. L. 2006; 95 (6): 1031-1032

    View details for DOI 10.1160/TH06-03-0177

    View details for Web of Science ID 000238557200019

    View details for PubMedID 16732384

  • Mast cells can promote the development of multiple features of chronic asthma in mice JOURNAL OF CLINICAL INVESTIGATION Yu, M., Tsai, M., Tam, S., Jones, C., Zehnder, J., Galli, S. J. 2006; 116 (6): 1633-1641

    Abstract

    Bronchial asthma, the most prevalent cause of significant respiratory morbidity in the developed world, typically is a chronic disorder associated with long-term changes in the airways. We developed a mouse model of chronic asthma that results in markedly increased numbers of airway mast cells, enhanced airway responses to methacholine or antigen, chronic inflammation including infiltration with eosinophils and lymphocytes, airway epithelial goblet cell hyperplasia, enhanced expression of the mucin genes Muc5ac and Muc5b, and increased levels of lung collagen. Using mast cell-deficient (Kit(W-sh/W-sh) and/or Kit(W/W-v)) mice engrafted with FcRgamma+/+ or FcRgamma-/- mast cells, we found that mast cells were required for the full development of each of these features of the model. However, some features also were expressed, although usually at less than wild-type levels, in mice whose mast cells lacked FcRgamma and therefore could not be activated by either antigen- and IgE-dependent aggregation of Fc epsilonRI or the binding of antigen-IgG1 immune complexes to Fc gammaRIII. These findings demonstrate that mast cells can contribute to the development of multiple features of chronic asthma in mice and identify both Fc Rgamma-dependent and Fc Rgamma-independent pathways of mast cell activation as important for the expression of key features of this asthma model.

    View details for DOI 10.1172/JCI25702

    View details for Web of Science ID 000237979700025

    View details for PubMedID 16710480

  • The JAK2 V617F mutation occurs in hematopoietic stem cells in polycythemia vera and predisposes toward erythroid differentiation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Jamieson, C. H., Gotlib, J., Durocher, J. A., Chao, M. P., Mariappan, M. R., Lay, M., Jones, C., Zehnder, J. L., Lilleberg, S. L., Weissman, I. L. 2006; 103 (16): 6224-6229

    Abstract

    Although a large proportion of patients with polycythemia vera (PV) harbor a valine-to-phenylalanine mutation at amino acid 617 (V617F) in the JAK2 signaling molecule, the stage of hematopoiesis at which the mutation arises is unknown. Here we isolated and characterized hematopoietic stem cells (HSC) and myeloid progenitors from 16 PV patient samples and 14 normal individuals, testing whether the JAK2 mutation could be found at the level of stem or progenitor cells and whether the JAK2 V617F-positive cells had altered differentiation potential. In all PV samples analyzed, there were increased numbers of cells with a HSC phenotype (CD34+CD38-CD90+Lin-) compared with normal samples. Hematopoietic progenitor assays demonstrated that the differentiation potential of PV was already skewed toward the erythroid lineage at the HSC level. The JAK2 V617F mutation was detectable within HSC and their progeny in PV. Moreover, the aberrant erythroid potential of PV HSC was potently inhibited with a JAK2 inhibitor, AG490.

    View details for DOI 10.1073/pnas.0601462103

    View details for Web of Science ID 000236999000031

    View details for PubMedID 16603627

  • Gene expression patterns in human placenta PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Sood, R., Zehnder, J. L., Druzin, M. L., Brown, P. O. 2006; 103 (14): 5478-5483

    Abstract

    The placenta is the principal metabolic, respiratory, excretory, and endocrine organ for the first 9 months of fetal life. Its role in fetal and maternal physiology is remarkably diverse. Because of the central role that the placenta has in fetal and maternal physiology and development, the possibility that variation in placental gene expression patterns might be linked to important abnormalities in maternal or fetal health, or even variations in later life, warrants investigation. As an initial step, we used DNA microarrays to analyze gene expression patterns in 72 samples of amnion, chorion, umbilical cord, and sections of villus parenchyma from 19 human placentas from successful full-term pregnancies. The umbilical cord, chorion, amnion, and villus parenchyma samples were readily distinguished by differences in their global gene-expression patterns, many of which seemed to be related to physiology and histology. Differentially expressed genes have roles that include placental trophoblast secretion, signal transduction, metabolism, immune regulation, cell adhesion, and structure. We found interindividual differences in expression patterns in villus parenchyma and systematic differences between the maternal, fetal, and intermediate layers. A group of genes that was expressed in both the maternal and fetal villus parenchyma sections of placenta included genes that may be associated with preeclampsia. We identified sets of genes whose expression in placenta was significantly correlated with the sex of the fetus. This study provides a rich and diverse picture of the molecular variation in the placenta from healthy pregnancies.

    View details for DOI 10.1073/pnas.0508035103

    View details for Web of Science ID 000236636400044

    View details for PubMedID 16567644

  • Successful transduction of liver in hemophilia by AAV-factor IX and limitations imposed by the host immune response NATURE MEDICINE Manno, C. S., Arruda, V. R., Pierce, G. F., Glader, B., Ragni, M., Rasko, J., Ozelo, M. C., Hoots, K., Blatt, P., Konkle, B., Dake, M., Kaye, R., Razavi, M., Zajko, A., Zehnder, J., Nakai, H., Chew, A., Leonard, D., Wright, J. F., Lessard, R. R., Sommer, J. M., TIGGES, M., Sabatino, D., Luk, A., Jiang, H. Y., Mingozzi, F., Couto, L., Ertl, H. C., High, K. A., Kay, M. A. 2006; 12 (3): 342-347

    Abstract

    We have previously shown that a single portal vein infusion of a recombinant adeno-associated viral vector (rAAV) expressing canine Factor IX (F.IX) resulted in long-term expression of therapeutic levels of F.IX in dogs with severe hemophilia B. We carried out a phase 1/2 dose-escalation clinical study to extend this approach to humans with severe hemophilia B. rAAV-2 vector expressing human F.IX was infused through the hepatic artery into seven subjects. The data show that: (i) vector infusion at doses up to 2 x 10(12) vg/kg was not associated with acute or long-lasting toxicity; (ii) therapeutic levels of F.IX were achieved at the highest dose tested; (iii) duration of expression at therapeutic levels was limited to a period of approximately 8 weeks; (iv) a gradual decline in F.IX was accompanied by a transient asymptomatic elevation of liver transaminases that resolved without treatment. Further studies suggested that destruction of transduced hepatocytes by cell-mediated immunity targeting antigens of the AAV capsid caused both the decline in F.IX and the transient transaminitis. We conclude that rAAV-2 vectors can transduce human hepatocytes in vivo to result in therapeutically relevant levels of F.IX, but that future studies in humans may require immunomodulation to achieve long-term expression.

    View details for DOI 10.1038/nm1358

    View details for Web of Science ID 000235802900035

    View details for PubMedID 16474400

  • Characterization of a novel prothrombin variant, Prothrombin C20209T, as a modifier of thrombotic risk among African-Americans JOURNAL OF THROMBOSIS AND HAEMOSTASIS Itakura, H., Telen, M. J., Hoppe, C. C., White, D. A., Zehnder, J. L. 2005; 3 (10): 2357-2359

    View details for Web of Science ID 000232443200036

    View details for PubMedID 16194213

  • A comparison study of different PCR assays in measuring circulating plasma Epstein-Barr virus DNA levels in patients with nasopharyngeal carcinoma CLINICAL CANCER RESEARCH Le, Q. T., Jones, C. D., Yau, T. K., Shirazi, H. A., Wong, P. H., Thomas, E. N., Patterson, B. K., Lee, A. W., Zehnder, J. L. 2005; 11 (16): 5700-5707

    Abstract

    To compare the performance of three PCR assays in measuring circulating Epstein-Barr virus (EBV). DNA levels in nasopharyngeal carcinoma patients and to confirm its prognostic significance.Plasma from 58 newly diagnosed nasopharyngeal carcinoma patients were collected before, during, and every 3 to 6 months after radiotherapy. EBV DNA levels were determined by real-time quantitative PCR using primer/probe sets for polymerase-1 (Pol-1), latent membrane protein 2 (Lmp2), and BamHI-W. Pretreatment levels from the three assays were correlated with each other and serial measurements from the Pol-1 assay were correlated with clinical variables.Pol-1 was more accurate than BamHI-W in predicting EBV DNA concentrations in cell lines. Of the three assays, BamHI-W yielded the highest concentrations followed by Pol-1 in plasmas (n = 23). The correlation coefficient was 0.99 (P < 0.0001) for Pol-1 and Lmp2, 0.66 (P < 0.0001) for Pol-1 and BamHI-W, and 0.55 (P < 0.0001) for BamHI-W and Lmp2. Elevated pretreatment DNA levels as detected by Pol-1 were correlated with advanced nodal stage (P = 0.04) and overall stage (P = 0.028). There was no correlation between pretreatment EBV DNA levels and freedom-from-relapse or overall survival; however, there was a significant correlation between posttreatment levels and these variables. The 2-year freedom-from-relapse and overall survival rates were 92% and 94% for patients with undetectable, and 37% and 55% for those with detectable, posttreatment levels (P < 0.0001 and P < 0.002).The three PCR assays yielded similar results in detecting EBV DNA in plasmas. The Pol-1-detected posttreatment EBV DNA level was the strongest predictor for treatment outcomes.

    View details for DOI 10.1158/1078-0432.CCR-05-0648

    View details for Web of Science ID 000231320000009

    View details for PubMedID 16115906

  • Identification of mislabeled specimen by molecular methods: Case report and review INTERNATIONAL JOURNAL OF SURGICAL PATHOLOGY Mariappan, M. R., Zehnder, J., Arber, D. A., Lay, M., Fadare, O., Schrijver, R. 2005; 13 (3): 253-258

    Abstract

    Specimen misidentification is a common cause of errors in surgical pathology. We report a case where bone-marrow biopsies from patients of different genders were mislabeled and molecular methods were applied to resolve the identity. A short tandem repeat (STR)-polymerase chain reaction-based assay, commonly used in paternity testing, was employed in an attempt to assign the correct identity to the specimens. However, the specimens had been processed by decalcification and the DNA yield was poor. One of the markers in the assay is the non-STR amelogenin locus that distinguishes the X and Y chromosomes. This amelogenin marker results in a product of low molecular weight, enabling unequivocal resolution of identity despite a poor DNA yield. The prevalence of errors in pathology due to specimen misidentifications is reviewed.

    View details for Web of Science ID 000231185700004

    View details for PubMedID 16086080

  • Varicella-zoster virus infection of human dorsal root ganglia in vivo PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Zerboni, L., Ku, C. C., Jones, C. D., Zehnder, J. L., Arvin, A. M. 2005; 102 (18): 6490-6495

    Abstract

    Varicella-zoster virus (VZV) causes varicella and establishes latency in sensory ganglia. VZV reactivation results in herpes zoster. We developed a model using human dorsal root ganglion (DRG) xenografts in severe combined immunodeficient (SCID) mice to investigate VZV infection of differentiated neurons and satellite cells in vivo. DRG engrafted under the kidney capsule and contained neurons and satellite cells within a typical DRG architecture. VZV clinical isolates infected the neurons within DRG. At 14 days postinfection, VZ virions were detected by electron microscopy in neuronal cell nuclei and cytoplasm but not in satellite cells. The VZV genome copy number was 7.1 x 10(7) to 8.0 x 10(8) copies per 10(5) cells, and infectious virus was recovered. This initial phase of viral replication was followed within 4-8 weeks by a transition to VZV latency, characterized by the absence of infectious virus release, the cessation of virion assembly, and a reduction in VZV genome copies to 3.7 x 10(5) to 4.7 x 10(6) per 10(5) cells. VZV persistence in DRG was achieved without any requirement for VZV-specific adaptive immunity and was associated with continued transcription of the ORF63 regulatory gene. The live attenuated varicella vaccine virus exhibited the same pattern of short-term replication, persistence of viral DNA, and prominent ORF63 transcription as the clinical isolates. VZV-infected T cells transferred virus from the circulation into DRG, suggesting that VZV lymphotropism facilitates its neurotropism. DRG xenografts may be useful for investigating neuropathogenic mechanisms of other human viruses.

    View details for DOI 10.1073/pnas.0501045102

    View details for Web of Science ID 000228918400045

    View details for PubMedID 15851670

  • High frequency of premature termination mutations in the factor V gene: Three factor V deficiency case reports and a mutation review THROMBOSIS AND HAEMOSTASIS Schrijver, I., Hong, D. W., Mandle, L., Jones, C. D., DiMichele, D., Monahan, P. E., Zehnder, J. L. 2005; 93 (3): 610-611

    View details for Web of Science ID 000227808200034

    View details for PubMedID 15735818

  • Granulocyte-macrophage progenitors as candidate leukemic stem cells in blast-crisis CML NEW ENGLAND JOURNAL OF MEDICINE Jamieson, C. H., Ailles, L. E., Dylla, S. J., Muijtjens, M., Jones, C., Zehnder, J. L., Gotlib, J., Li, K., Manz, M. G., Keating, A., Sawyers, C. L., Weissman, I. L. 2004; 351 (7): 657-667

    Abstract

    The progression of chronic myelogenous leukemia (CML) to blast crisis is supported by self-renewing leukemic stem cells. In normal mouse hematopoietic stem cells, the process of self-renewal involves the beta-catenin-signaling pathway. We investigated whether leukemic stem cells in CML also use the beta-catenin pathway for self-renewal.We used fluorescence-activated cell sorting to isolate hematopoietic stem cells, common myeloid progenitors, granulocyte-macrophage progenitors, and megakaryocyte-erythroid progenitors from marrow during several phases of CML and from normal marrow. BCR-ABL, beta-catenin, and LEF-1 transcripts were compared by means of a quantitative reverse-transcriptase-polymerase-chain-reaction assay in normal and CML hematopoietic stem cells and granulocyte-macrophage progenitors. Confocal fluorescence microscopy and a lymphoid enhancer factor/T-cell factor reporter assay were used to detect nuclear beta-catenin in these cells. In vitro replating assays were used to identify self-renewing cells as candidate leukemic stem cells, and the dependence of self-renewal on beta-catenin activation was tested by lentiviral transduction of hematopoietic progenitors with axin, an inhibitor of the beta-catenin pathway.The granulocyte-macrophage progenitor pool from patients with CML in blast crisis and imatinib-resistant CML was expanded, expressed BCR-ABL, and had elevated levels of nuclear beta-catenin as compared with the levels in progenitors from normal marrow. Unlike normal granulocyte-macrophage progenitors, CML granulocyte-macrophage progenitors formed self-renewing, replatable myeloid colonies, and in vitro self-renewal capacity was reduced by enforced expression of axin.Activation of beta-catenin in CML granulocyte-macrophage progenitors appears to enhance the self-renewal activity and leukemic potential of these cells.

    View details for Web of Science ID 000223225500008

    View details for PubMedID 15306667

  • Rapid combined genotyping assay for four achondroplasia and hypochondroplasia mutations by real-time PCR with multiple detection probes GENETIC TESTING Schrijver, I., Lay, M. J., Zehnder, J. L. 2004; 8 (2): 185-189

    Abstract

    Achondroplasia (ACH) and hypochondroplasia (HYCH) are the most prevalent genetic short-stature syndromes. Whereas the diagnosis of ACH can be established on clinical and radiologic grounds alone in the majority of cases, HYCH is more difficult to confirm. Molecular genetic analysis of both skeletal dysplasias can be especially helpful for the purpose of prenatal diagnosis, in early childhood to differentiate definitively between the largely overlapping phenotypes, and in atypical presentations. The two most prevalent mutations for each syndrome cause substitution of a single respective nucleotide. These mutations can be identified by a variety of molecular methods, including PCR with restriction enzyme digestion or direct DNA sequencing. We have developed a single-step, real-time PCR assay in which two detection probes are applied in combination with a single anchor probe at each mutation position. Because the two most prevalent mutations for each syndrome cause substitution of a single respective nucleotide, this approach guarantees optimal differentiation during probe dissociation analysis after amplification. This assay, which is performed on the LightCycler thermocycler, enables the rapid and reliable detection of the two most common FGFR3 mutations associated with ACH (1138G --> A and 1138G --> C; G380R) and HYCH (1620C --> A and 1620 C --> G; N540K) in a single test.

    View details for Web of Science ID 000223513900019

    View details for PubMedID 15345118

  • CyclinD1/CyclinD3 ratio by real-time PCR improves specificity for the diagnosis of mantle cell lymphoma JOURNAL OF MOLECULAR DIAGNOSTICS Jones, C. D., Darnell, K. H., Warnke, R. A., Zehnder, J. L. 2004; 6 (2): 84-89

    Abstract

    We developed a real-time, quantitative, reverse transcription PCR assay for cyclin D1 (CCND1) expression to aid in the diagnosis of mantle cell lymphoma (MCL). The diagnosis of MCL can be problematic, and existing CCND1 expression assays show a lack of specificity, with elevated expression also detected in other lymphoproliferative disorders. We postulated that evaluating CCND1 expression relative to CCND3 expression by quantitative PCR could offer an improved specificity over an evaluation of CCND1 alone. This method quantitates both CCND1 and CCND3, each normalized to a housekeeping gene (GADPH), using the 5'-exonuclease technique. We analyzed 107 clinical specimens: MCL (17), chronic lymphocytic leukemias (CLL) (10), other non-MCL hematolymphoid disorders (41), non-malignant tissues with an epithelial component (7) and other normal samples (32). This method correctly identified 16 of 17 MCLs, and there were no false positives among any of the other diagnostic groups tested including CLL. CLL presents the major diagnostic dilemma at this institution when diagnosing MCL. Sensitivity studies showed that this method could detect an elevated CCND1/CCND3 ratio when the tumor infiltrate is at least 10% of the cells. We compared the specificity of CCND1 expression alone against the CCND1/CCND3 ratio to demonstrate the increased specificity for the latter. We conclude that the CCND1/CCND3 ratio is a sensitive and specific test for the diagnosis of MCL.

    View details for Web of Science ID 000221002500002

    View details for PubMedID 15096562

  • Randomized trial of folic acid for prevention of cardiovascular events in end-stage renal disease JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Wrone, E. M., Hornberger, J. M., Zehnder, J. L., McCann, L. M., Coplon, N. S., Fortmann, S. P. 2004; 15 (2): 420-426

    Abstract

    High serum total homocysteine (tHcy) is gaining scrutiny as a risk factor for cardiovascular disease in the general population. The relationship between tHcy and mortality and cardiovascular events in patients with end-stage renal disease (ESRD) is unsettled. This randomized trial evaluates the efficacy of high-dose folic acid in preventing events in ESRD. A total of 510 patients on chronic dialysis were randomized to 1, 5, or 15 mg of folic acid contained in a renal multivitamin with a median follow-up of 24 mo. Mortality, cardiovascular events, and homocysteine levels were assessed. There were 189 deaths, and 121 patients experienced at least one cardiovascular event. Composite rates of mortality and cardiovascular events among the folic acid groups did not differ (at 24 mo: 43.7% in 1 mg group, 38.6% in 5 mg group, 47.1% in 15 mg group; log-rank P = 0.47). Unexpectedly, high baseline tHcy was associated with lower event rates. From lowest to highest quartile, event rates at 24 mo were 54.5% for Q1, 41.8% for Q2, 41.2% for Q3, and 34.7% for Q4 (log-rank P = 0.033). In contrast to some studies describing tHcy as a risk factor for mortality and cardiovascular events, this study found a reverse relationship between tHcy and events in ESRD patients. Administration of high-dose folic acid did not affect event rates.

    View details for DOI 10.1097/01.ASN.0000110181.64655.6C

    View details for Web of Science ID 000188604600020

    View details for PubMedID 14747389

  • Congenital and acquired thrombocytopenia. Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program Cines, D. B., Bussel, J. B., McMillan, R. B., Zehnder, J. L. 2004: 390-406

    Abstract

    The diagnosis and management of thrombocytopenia is a growing component in the practice of hematology. The frequency with which hematologists are called in consultation for thrombocytopenia continues to increase with the advent of routine automated platelet determinations and the introduction of new medications. For most patients, such as those with inherited and auto-immune thrombocytopenia, emphasis is focused on efforts to treat or forestall bleeding without excess drug-induced toxicity or burden to the patient. However, in disorders such as heparin-induced thrombocytopenia (HIT), avoidance of thrombotic complications is the key to management. In this chapter, we provide the pediatric and adult hematologist with new insights into the pathogenesis and recognition of congenital inherited thrombocytopenias (CTP), a hitherto difficult to comprehend constellation of clinical entities. We also highlight new approaches to the diagnosis and treatment of two of the more common thrombocytopenic conditions encountered in practice, autoimmune or idiopathic thrombocytopenic purpura (ITP) and HIT. In Section I, Dr. James Bussel discusses CTPs and their distinction from childhood ITP. He emphasizes the clinical features that enable the pediatrician and hematologist to suspect the diagnosis of CTP and those that are of use to subcategorize the various entities, where possible. He also emphasizes newer molecular markers that afford definitive diagnosis in some cases and provide insight into platelet production. This section highlights the characteristic associated findings and differences in the natural history and approaches to management of the various entities. In Section II, Dr. Robert McMillan discusses adult chronic ITP. He revisits the utility of platelet antibody determination in diagnosis and review new insights into pathogenesis. The role of Helicobacter pylori infection and the timing of splenectomy in the management of acute and emergent ITP are examined. New insights into the natural history of ITP post-splenectomy and management strategies for patients with severe, chronic, refractory ITP are discussed. In Section III, Dr. James Zehnder updates us on HIT. He emphasizes new insights into the clinical presentation and pathogenesis of this condition. He critically reviews the utility of laboratory testing for heparin-dependent antibodies. Recent studies on the use of direct thrombin inhibitors are examined and the management of cardiopulmonary bypass surgery in patients with HIT is discussed.

    View details for PubMedID 15561694

  • Prothrombin gene variants in non-Caucasians with fetal loss and intrauterine growth retardation JOURNAL OF MOLECULAR DIAGNOSTICS Schrijver, I., Lenzi, T. J., Jones, C. D., Lay, M. J., Druzin, M. L., Zehnder, J. L. 2003; 5 (4): 250-253

    Abstract

    Thrombotic predisposition may affect pregnancy outcome, but in non-Caucasians the contributing genetic factors are poorly characterized. Two recently identified prothrombin gene mutations (20209C>T and 20221C>T) have been observed in non-Caucasian patients with thrombosis. The mutations are located near the commonly identified variant 20210G>A and have not been reported in Caucasian patients. The authors report a novel connection with pregnancy complications. The identification of sequence variants other than 20210G>A in the 3'-untranslated region of the prothrombin gene suggests that additional nucleotide substitutions may contribute to the development of thrombotic events and adverse pregnancy outcomes, especially in less well-characterized populations.

    View details for Web of Science ID 000186292700009

    View details for PubMedID 14573785

  • Lymphomatoid papulosis associated with mycosis fungoides: A study of 21 patients including analyses for clonality JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Zackheim, H. S., Jones, C., LeBoit, P. E., Kashani-Sabet, M., McCalmont, T. H., Zehnder, J. 2003; 49 (4): 620-623

    Abstract

    Although an association of lymphomatoid papulosis (LyP) with mycosis fungoides (MF) is recognized, our understanding of this relation is limited.We sought to document the clinical experience at the University of California, San Francisco, in 21 patients who had both LyP and MF and to do clonality studies in 7 of those patients in whom this was possible.We conducted chart review of the 21 patients and analysis for T-cell receptor-gamma gene rearrangements by the polymerase chain reaction.Of 54 patients, 21 (39%) with LyP had associated MF. LyP preceded MF in 14 (67%), MF preceded LyP in 4 (19%), and there was concurrent appearance in 3 (14%). Of the 21 patients, 20 (95%) were type A and only 1 (5%) was type B. An identical clone was found in lesions of both LyP and MF in all 7 patients in whom analysis was possible.Findings of this study strengthen the idea that LyP and MF are related T-cell lymphoproliferative disorders.

    View details for DOI 10.1067/S0190-9622(03)01577-9

    View details for Web of Science ID 000185606500006

    View details for PubMedID 14512906

  • Heterozygous prothrombin G20210A gene mutation in a patient with livedoid vasculitis ARCHIVES OF DERMATOLOGY Gotlib, J., Kohler, S., Reicherter, P., Oro, A. E., Zehnder, J. L. 2003; 139 (8): 1081-1083

    View details for Web of Science ID 000184692700021

    View details for PubMedID 12925402

  • Comprehensive validation of a real-time quantitative bcr-abl assay for clinical laboratory use AMERICAN JOURNAL OF CLINICAL PATHOLOGY Jones, C. D., Yeung, C., Zehnder, J. L. 2003; 120 (1): 42-48

    Abstract

    We developed and extensively validated a real-time PCR assay for the quantitation of bcr-abl to determine residual disease in patients with chronic myelogenous leukemia. This method quantitates the p210 and the p190 bcr-abl RNA fusion transcripts with results normalized to a housekeeping gene, using the 5'-exonuclease technique and the ABI PRISM 7700 Sequence Detection System (Applied Biosystems, Foster City, CA). We parallel tested 372 clinical specimens and 50 peripheral blood samples from patients not known to have any myeloproliferative disorders. The results were 100% specific. Sensitivity studies showed that this method can detect bcr-abl in cell lines diluted to 0.0001% and can detect a single bcr-abl plasmid spiked into negative RNA. The between-run reproducibility showed a coefficient of variance (CV) of 12.3%, and within-run reproducibility showed a CV of 13.8%. This method can be used to reliably monitor the disease load in patients with bcr-abl-positive diseases.

    View details for DOI 10.1309/60A9C8WGEGHRNXEE

    View details for Web of Science ID 000183730300005

    View details for PubMedID 12866371

  • Diagnostic single nucleotide polymorphism analysis of factor V Leiden and prothrombin 20210G > A - A comparison of the nanogen electronic microarray with restriction enzyme digestion and the Roche LightCycler AMERICAN JOURNAL OF CLINICAL PATHOLOGY Schrijver, I., Lay, M. J., Zehnder, J. L. 2003; 119 (4): 490-496

    Abstract

    Genetic thrombosis risk factors include a sequence variant in the prothrombin gene (20210G > A) and factor V Leiden (1691G > A). These single nucleotide polymorphisms can be diagnosed with restriction fragment length polymorphism (RFLP) analysis, fluorescent genotyping on the LightCycler (Roche Diagnostics, Indianapolis, IN), and microarray-based testing on the novel NanoChip electronic microarray (NanoChip Molecular Biology Workstation, Nanogen, San Diego, CA). We compared these methods for accuracy, time to results, throughput, and interpretation. Results from 789 of 800 individual amplicons analyzed on the NanoChip were in complete agreement with the other assays. Eleven were "no calls" (uninterpreted by the NanoChip system) resulting from failed polymerase chain reaction amplifications. Although the NanoChip System, when used in a low-throughput setting, requires more overall time than the LightCycler, it is nearly equivalent per genotyping call. Owing to minimal sample handling, assay results are more reliable on the NanoChip platform and on the LightCycler than with RFLP. The NanoChip assay is reliable and may be especially valuable to laboratories with a large volume of thrombophilia test requests.

    View details for DOI 10.1309/3VTR7TL2X7TXL0XY

    View details for Web of Science ID 000181872500002

    View details for PubMedID 12710121

  • Lack of human herpesvirus 8 and Epstein-Barr virus in Kikuchi's histiocytic necrotizing lymphadenitis HUMAN PATHOLOGY George, T. I., Jones, C. D., Zehnder, J. L., Warnke, R. A., Dorfman, R. F. 2003; 34 (2): 130-135

    Abstract

    Kikuchi's histiocytic necrotizing lymphadenitis is a self-limited disorder that typically involves the cervical lymph nodes of young women. Although a viral etiology has been postulated, a definitive viral agent has not been identified. Recent reports have suggested that human herpesvirus 8 (HHV 8) or Epstein-Barr virus (EBV) may play an etiologic role. We investigated the presence of HHV 8 and EBV in archival tissue from 34 cases of Kikuchi's histiocytic necrotizing lymphadenitis. We examined 29 cases for HHV 8 using a nested polymerase chain reaction (PCR) on paraffin-embedded or frozen tissue, and 24 cases for EBV RNA using in situ hybridization (ISH) for EBER1. Controls included reactive lymph nodes from 8 adult women presenting with cervical or axillary lymphadenopathy. The study patients included 7 men and 27 women with a mean age of 28 years. All patients were previously healthy without evidence of immunocompromise and presented with cervical, axillary, or inguinal lymphadenopathy. Two cases exhibited EBV RNA by ISH; this was confirmed by PCR for EBV DNA. HHV 8 DNA was not amplified by nested PCR in any of the cases of Kikuchi's histiocytic necrotizing lymphadenitis or reactive lymph nodes; control PCR demonstrated the presence of amplifiable DNA in all cases. These findings suggest that HHV 8 and EBV do not play causative roles in Kikuchi's histiocytic necrotizing lymphadenitis.

    View details for DOI 10.1053/hupa.2003.11

    View details for Web of Science ID 000181275500005

    View details for PubMedID 12612880

  • Psoriasiform mycosis fungoides with fatal outcome after treatment with cyclosporine JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Zackheim, H. S., Koo, J., LeBoit, P. E., McCalmont, T. H., Bowman, P. H., Kashani-Sabet, M., Jones, C., Zehnder, J. 2002; 47 (1): 155-157

    View details for DOI 10.1067/mjd.2002.120571

    View details for Web of Science ID 000176560400023

    View details for PubMedID 12077599

  • Homozygous factor V splice site mutation associated with severe factor V deficiency BLOOD Schrijver, I., Koerper, M. A., Jones, C. D., Zehnder, J. L. 2002; 99 (8): 3063-3065

    Abstract

    We investigated a family whose proband has a severe bleeding disorder and factor V antigenic and functional levels of 8% and less than 1% of control values, respectively. Molecular analysis of the factor V gene revealed a novel homozygous mutation in the last nucleotide of exon 10. 1701G>T causes activation of a cryptic exonic splice site in exon 10, which encodes part of the factor V heavy chain (A2 domain). This leads to the deletion of 35 nucleotides and results in a frameshift with a premature stop codon at amino acid position 498. The G1701 and corresponding Gln509 are conserved in murine, bovine, and porcine factor V and in human factor VIII. Few factor V deficiency mutations have been identified as yet. Several are present in the heterozygous form in combination with factor V Leiden (Arg506Gln). This is the first reported homozygous splice site mutation in a patient with factor V deficiency.

    View details for Web of Science ID 000174866500055

    View details for PubMedID 11929802

  • Novel factor VC2-domain mutation (R2074H) in two families with factor V deficiency and bleeding THROMBOSIS AND HAEMOSTASIS Schrijver, I., Houissa-Kastally, R., Jones, C. D., Garcia, K. C., Zehnder, J. L. 2002; 87 (2): 294-299

    Abstract

    The molecular basis of Factor V deficiency has been defined in few patients only. We report a homozygous nucleotide change (G6395A) in two Tunisian probands with Factor V deficiency and bleeding episodes. This substitution results in the replacement of an arginine (R) by a histidine (H) in amino acid position 2074, located in the Factor V C2-domain. Mutations in this protein domain have not previously been described. Several lines of evidence support that this sequence variant is indeed disease causing: 1) Crystal structures of Factor V and molecular C2-domain modeling studies of H2074 suggest that the conserved R2074 is required for correct folding; 2) Structure-function studies of selective Factor V mutants (R2074A) demonstrate the importance of R2074 for structural stability of the Factor V C2-domain and for cofactor activity (1); 3) In Factor VIII, point mutations in codon 2209, which corresponds to position 2074 in Factor V, cause hemophilia A.

    View details for Web of Science ID 000173869300020

    View details for PubMedID 11858490

  • Immunological consequences of topical bovine thrombin AMERICAN JOURNAL OF PATHOLOGY Zehnder, J. L., Leung, L. L. 2001; 159 (6): 2371-2371

    View details for Web of Science ID 000172457400040

    View details for PubMedID 11733385

  • A polymorphism in the BCL-6 gene is associated with follicle center lymphoma LEUKEMIA & LYMPHOMA Lossos, I. S., Jones, C. D., Zehnder, J. L., Levy, R. 2001; 42 (6): 1343-1350

    Abstract

    Follicle center lymphoma (FCL) accounts for approximately 40% of all non-Hodgkin's lymphomas (NHL). The genetic-environmental interactions involved in the etiology and pathogenesis of this disease are unknown. In our previous study a single nucleotide polymorphism (SNP) (397C) in the regulatory untranslated first intron region of the BCL-6 gene was found in four of the eight FCL patients but in none of the 10 healthy controls. To further evaluate the potential association between the 397C allele of the BCL-6 gene and FCL, we performed a case-control study. Genomic DNA was isolated from 85 FCL patients, from 98 control cases without a previous history of malignancy, treated at Stanford University Medical Center for non-malignant disorders and from 90 samples from the DNA Polymorphism Discovery Resource. The 397G and the 397C polymorphic alleles were identified by a PCR-RFLP method. To evaluate the possible effect of this polymorphism on gene expression, BCL-6 mRNA levels in nine FCL tumors with the 397G-G genotype and in nine FCL tumors with the 397G-C genotype were measured by quantitative real-time RT-PCR. The 397C polymorphic allele was found in 32 FCL cases (37.6%), in 20 controls (20.4%) and in 17 (18.9%) samples from the DNA Polymorphism Discovery Resource. The prevalence of the 397G-C and 397C-C genotypes was significantly higher in FCL cases than in control group (p = 0.01). No difference in BCL-6 gene expression was observed between FCL cases with 397G-G and 397G-C genotypes. The present study demonstrates a possible association between the 397C allele of the BCL-6 proto-oncogene and FCL. The similar levels of BCL-6 mRNA expression in 397G-G and in 397G-C FCL cases suggests that any possible oncogenic effect of the polymorphic allele would not simply be related to a direct effect on BCL-6 gene expression and suggests the existence of other FCL susceptibility genes that are in linkage disequilibrium with the 397C allele of the BCL-6 gene.

    View details for Web of Science ID 000173558700022

    View details for PubMedID 11911418

  • Expression of a single gene, BCL-6, strongly predicts survival in patients with diffuse large B-cell lymphoma BLOOD Lossos, I. S., Jones, C. D., Warnke, R., Natkunam, Y., Kaizer, H., Zehnder, J. L., Tibshirani, R., Levy, R. 2001; 98 (4): 945-951

    Abstract

    Diffuse large B-cell lymphoma (DLBCL) is characterized by a marked degree of morphologic and clinical heterogeneity. Establishment of parameters that can predict outcome could help to identify patients who may benefit from risk-adjusted therapies. BCL-6 is a proto-oncogene commonly implicated in DLBCL pathogenesis. A real-time reverse transcription-polymerase chain reaction assay was established for accurate and reproducible determination of BCL-6 mRNA expression. The method was applied to evaluate the prognostic significance of BCL-6 expression in DLBCL. BCL-6 mRNA expression was assessed in tumor specimens obtained at the time of diagnosis from 22 patients with primary DLBCL. All patients were subsequently treated with anthracycline-based chemotherapy regimens. These patients could be divided into 2 DLBCL subgroups, one with high BCL-6 gene expression whose median overall survival (OS) time was 171 months and the other with low BCL-6 gene expression whose median OS was 24 months (P =.007). BCL-6 gene expression also predicted OS in an independent validation set of 39 patients with primary DLBCL (P =.01). BCL-6 protein expression, assessed by immunohistochemistry, also predicted longer OS in patients with DLBCL. BCL-6 gene expression was an independent survival predicting factor in multivariate analysis together with the elements of the International Prognostic Index (IPI) (P =.038). By contrast, the aggregate IPI score did not add further prognostic information to the patients' stratification by BCL-6 gene expression. High BCL-6 mRNA expression should be considered a new favorable prognostic factor in DLBCL and should be used in the stratification and the design of risk-adjusted therapies for patients with DLBCL. (Blood. 2001;98:945-951)

    View details for Web of Science ID 000170364100008

    View details for PubMedID 11493437

  • CD31 mismatching affects marrow transplantation outcome BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION GRUMET, F. C., Hiraki, D. D., Brown, B. W., Zehnder, J. L., Zacks, E. S., Draksharapu, A., Parnes, J., Negrin, R. S. 2001; 7 (9): 503-512

    Abstract

    Graft-versus-host disease (GVHD) complicating allogeneic bone marrow transplantation (BMT) is often attributed to mismatched minor histocompatibility antigens (mHags), which are poorly defined in humans. CD31 is a candidate human mHag relevant to acute GVHD, but reports disagree about its level of significance, the role of HLA restriction, and the relative importance of different polymorphic codons within the molecule. We therefore examined in greater detail the impact of CD31-matching on BMT outcome in a prospective study from a single institution. Samples of recipient and donor DNA were collected pretransplantation for all patients receiving unmanipulated bone marrow from an HLA-identical sibling over a 45-month period at our institution. CD31 DNA typing of alleles at the 3 polymorphic codons 125 (L or V), 563 (N or S), and 670 (R or G) was performed for 118 patient-donor pairs plus 2 additional pairs who had codon 125 typing only. Donor-recipient CD31 nonidentity was tested for correlation with BMT clinical outcome measures of severe acute GVHD, chronic GVHD, relapse, and survival. Gene frequencies of approximately 0.5 for each allele at all 3 codons were comparable to previous reports. Because complete association was seen for 563N with 670G and for 563S with 670R, nonidentity for those codons was analyzed as a single genetic marker designated codon 563/670. Donor-recipient CD31 nonidentity was a significant risk factor for overall survival, both at codon 563/670 (hazard ratio [hr] = 2.58, P = .005) and at codon 125 (hr = 1.07, P = .036). Similar results held for disease-free survival. Nonidentity at codon 563/670 was also a significant risk factor (odds ratio [OR] = 11.15, P = .011) for severe (grades III, IV) versus no (grade 0) acute GVHD. Nonidentity at codon 125 posed less but still significant risk (OR = 9.30, P = .030). When the comparison group without severe acute GVHD was expanded to include grade I as well as grade 0 patients, the risk from CD31 nonidentity increased for both codon 563/670 (OR = 12.31, P = .010) and codon 125 (OR = 11.24, P = .011). CD31 nonidentity remained a significant independent risk factor for survival and for severe acute GVHD when tested in multivariate analysis with the covariates of adulthood, recipient-donor sex difference, ethnic group, disease, pretransplantation risk category, HLA-A2 type, B44-like types, and GVHD prophylactic regimen. CD31 nonidentity showed a trend but failed to achieve statistical significance as a risk factor for relapse and for chronic GVHD. In conclusion, donor-recipient CD31 nonidentity is a significant risk factor for survival and for severe acute GVHD in HLA-identical sibling BMT. The stronger associations with codon 563/670 suggest that polymorphism may be more important than the linked polymorphism at codon 125.

    View details for Web of Science ID 000171449200004

    View details for PubMedID 11669217

  • Sensitive detection of clonal immunoglobulin rearrangements in frozen and paraffin embedded tissues by polymerase chain reaction heteroduplex analysis DIAGNOSTIC MOLECULAR PATHOLOGY Ranheim, E. A., Jones, C. D., Zehnder, J. L. 2000; 9 (4): 177-183

    Abstract

    Molecular detection of a clonal population of B or T cells through analysis of rearranged antigen receptor genes is an essential adjunct to the morphologic, flow cytometric, and immunohistochemical evaluation of tissue specimens for the presence of leukemia or lymphoma. Combining polymerase chain reaction (PCR) with heteroduplex annealing and polyacrylamide gel electrophoresis (PAGE) has been used to detect clonal T-cell receptor rearrangements, particularly in skin biopsy specimens. The authors have developed a similar PCR heteroduplex assay for detection of clonal VDJ immunoglobulin gene rearrangements using two sets of primers based on relatively conserved consensus regions in the J(H) and framework I and 2 regions of the immunoglobulin heavy chain V region gene. This method is able to detect a clonal rearrangement when the clone comprises as little as 1% of the population in a polyclonal B-cell background. It may be used on fresh, frozen, or paraffin-embedded tissue and detects a clonal population in a majority of lymphoma subtypes. Compared with conventional PCR analysis, this method requires only a short additional cycle of denaturation and slow renaturation before PAGE. Interpretation is simplified as the clonal PCR product migrates away from the polyclonal background products.

    View details for Web of Science ID 000165556700001

    View details for PubMedID 11129440

  • PCR-heteroduplex analysis of T-cell receptor gamma gene rearrangement in paraffin-embedded skin biopsies AMERICAN JOURNAL OF DERMATOPATHOLOGY Kohler, S., Jones, C. D., Warnke, R. A., Zehnder, J. L. 2000; 22 (4): 321-327

    Abstract

    We developed a rapid, simple, and sensitive method for the detection of T-cell receptor-gamma (TCRgamma) gene rearrangements in paraffin-embedded skin biopsies. Available techniques often require either fresh tissue, several primer pairs, nested amplifications, or specialized electrophoresis steps such as denaturing gradient gel electrophoresis. Our method is based on heteroduplex analysis of polymerase chain reaction (PCR) products of the TCRgamma in a nondenaturing modified polyacrylamide gel using a single pair of primers and is adapted for paraffin-embedded tissue. When tested against Southern blot analysis, the PCR results correlated in 8 of 9 cases. Six mature cutaneous B-cell lymphomas and 29 inflammatory skin disorders all resulted in a polyclonal amplification pattern. When analyzing 3-mm or 4-mm punch biopsies of 51 cases of cutaneous T-cell lymphoma, 37 (72.5%) showed a clonal rearrangement with this technique. For 7 cases of patch stage mycosis fungoides, frozen tissue and formalin-fixed and paraffin-embedded tissue was available, and in 5 of 7 cases (71%), the results in frozen and paraffin-embedded tissue were concordant. One case showed a clonal pattern in frozen tissue but not in paraffin-embedded tissue, and one case was polyclonal in frozen tissue but monoclonal in paraffin-embedded tissue. Using serial dilutions of DNA from a T-cell ALL in a polyclonal background (tonsil), we established a sensitivity of 0.5%. Heteroduplex PCR of the TCRgamma is a rapid, sensitive, and inexpensive screening procedure as well as a useful adjunct to histologic analysis and immunophenotyping of cutaneous T-cell proliferations.

    View details for Web of Science ID 000088565400005

    View details for PubMedID 10949457

  • Blastic/blastoid transformation of follicular lymphoma - Immunohistologic and molecular analyses of five cases AMERICAN JOURNAL OF SURGICAL PATHOLOGY Natkunam, Y., Warnke, R. A., Zehnder, J. L., Jones, C. D., Milatovich-Cherry, A., Cornbleet, P. J. 2000; 24 (4): 525-534

    Abstract

    Progression of follicular lymphoma to a higher-grade malignancy frequently heralds a poor prognosis. Clinical transformation is variably accompanied by a spectrum of histologic changes characterized by alteration in growth and cytology. Although several cytogenetic events and potential oncogenes have been documented in this progression, the underlying molecular mechanisms are largely unknown. We present five patients with an unusual histologic transformation of follicular lymphoma manifested by blastic/blastoid morphology. This transformation is histologically distinct from other types of transformation of follicular lymphoma. All five cases exhibited the t(14;18) translocation and expressed the BCL-2 protein. In addition, two of the five patients showed increased levels of the p53 protein within neoplastic cells implicating a possible role for this oncogene in blastic/blastoid transformation. The lack of BCL-1 and myeloid antigens by immunohistochemistry and flow cytometry studies served to distinguish blastic/blastoid transformation of follicular lymphoma from its morphologic mimics. This distinction is clinically important because lymphoblastic and myeloid leukemias require significantly different therapeutic modalities and show better prognosis. Moreover, the lack of Epstein-Barr virus-specific mRNA suggests that this virus is unlikely to participate in blastic/blastoid transformation of follicular lymphoma.

    View details for Web of Science ID 000086211700006

    View details for PubMedID 10757399

  • Antibodies against the first Ig-like domain of human platelet endothelial cell adhesion molecule-1 (PECAM-1) that inhibit PECAM-1-dependent homophilic adhesion block in vivo neutrophil recruitment JOURNAL OF IMMUNOLOGY Nakada, M. T., Amin, K., Christofidou-Solomidou, M., O'Brien, C. D., Sun, J., Gurubhagavatula, I., Heavner, G. A., Taylor, A. H., Paddock, C., Sun, Q. H., Zehnder, J. L., Newman, P. J., Albelda, S. M., DeLisser, H. M. 2000; 164 (1): 452-462

    Abstract

    Platelet endothelial cell adhesion molecule (PECAM-1), a member of the Ig superfamily, is found on endothelial cells and neutrophils and has been shown to be involved in the migration of leukocytes across the endothelium. Adhesion is mediated, at least in part, through binding interactions involving its first N-terminal Ig-like domain, but it is still unclear which sequences in this domain are required for in vivo function. Therefore, to identify functionally important regions of the first Ig-like domain of PECAM-1 that are required for the participation of PECAM-1 in in vivo neutrophil recruitment, a panel of mAbs against this region of PECAM-1 was generated and characterized in in vitro adhesion assays and in an in vivo model of cutaneous inflammation. It was observed that mAbs that disrupted PECAM-1-dependent homophilic adhesion in an L cell aggregation assay also blocked TNF-alpha-induced intradermal accumulation of neutrophils in a transmigration model using human skin transplanted onto SCID mice. Localization of the epitopes of these Abs indicated that these function-blocking Abs mapped to specific regions on either face of domain 1. This suggests that these regions of the first Ig-like domain may contain or be close to binding sites involved in PECAM-1-dependent homophilic adhesion, and thus may represent potential targets for the development of antiinflammatory reagents.

    View details for Web of Science ID 000084321200060

    View details for PubMedID 10605042

  • Real-time t(11;14) and t(14;18) PCR assays provide sensitive and quantitative assessments of minimal residual disease (MRD) LEUKEMIA Olsson, K., Gerard, C. J., Zehnder, J., Jones, C., Ramanathan, R., Reading, C., Hanania, E. G. 1999; 13 (11): 1833-1842

    Abstract

    Non-Hodgkin's lymphoma (NHL) arises as a clonal transformation of normal B and T cell differentiation and is often characterized by a higher incidence of specific chromosomal translocations. We have developed real-time TaqMan PCR assays directed toward two of these tumor-associated DNA markers, the t(14;18)(q32;q21.3) at the major breakpoint region of the bcl-2 gene and the t(11;14)(q13;q32) at the bcl-1 major translocation cluster. During analysis of serial dilutions of t(14;18)-positive DNA, the t(14;18) real-time PCR was at least as sensitive as nested PCR and demonstrated enhanced quantitative potential. Moreover, in a blinded comparison of the t(14;18) real-time PCR and a clinically validated nested PCR protocol using 134 cell line and patient DNA samples, the real-time PCR detected the translocation in 30.0% more cases than nested PCR. Both the t(14;18) and t(11;14) real-time PCR assays were used to quantitate minimal residual disease (MRD) in an NHL clinical trial assessing the safety and efficacy of a tumor-purging protocol in autologous stem cell transplantation. The assays were also used to evaluate disease depletion in an ex vivo tumor spiking model in which normal peripheral blood was spiked with tumor cell lines and processed according to the clinical purging method. PCR data from both the clinical trial and the ex vivo model demonstrated a 4 to 6 log reduction in tumor cells during CD34+ and CD34+ Thy-1+ enrichment. Because the t(14;18) and t(11;14) real-time PCR assays are very sensitive, quantitative, rapid, and require no post-PCR manipulation, they may serve as practical alternatives to nested PCR.

    View details for Web of Science ID 000083664000023

    View details for PubMedID 10557059

  • Familial coagulation factor V deficiency caused by a novel 4 base pair insertion in the factor V gene: factor V Stanford [erratum]. Thrombosis and haemostasis Zehnder, J. L., Hiraki, D. D., Jones, C. D., Gross, N., GRUMET, F. C. 1999; 82 (5): XII-?

    View details for PubMedID 10681265

  • Variability of polymerase chain reaction detection of the bcl-2-IgH translocation in an international multicentre study ANNALS OF ONCOLOGY Johnson, P. W., Swinbank, K., MacLennan, S., Colomer, D., Debuire, B., Diss, T., Gabert, J., Gupta, R. K., Haynes, A., Kneba, M., Lee, M. S., MacIntyre, E., Mensink, E., Moos, M., MORGAN, G. J., NERI, A., Johnson, A., Reato, G., Salles, G., van 't Veer, M. B., Zehnder, J. L., Zucca, E., Selby, P. J., Cotter, F. E. 1999; 10 (11): 1349-1354

    Abstract

    The capacity of the polymerase chain reaction (PCR) to detect very low numbers of cells bearing a t(14;18) translocation has led to its application in assessment of the results of treatment for follicular lymphoma, and suggestions that therapy might be guided by molecular studies. To test the reliability of PCR a collaborative study was undertaken to compare results from different laboratories in Europe and North America.Twenty laboratories with records of publication in molecular diagnostics were sent blood from normal donors with varying numbers of t(14;18)-bearing cells added from a cell line with a translocation in the major breakpoint region (MBR) of the bcl-2 gene. Samples contained 1000, 100, 10, 1 or 0 cells per ml of whole blood and were sent blinded in duplicate. PCR methodology varied widely, with the total number of amplification cycles between 30 and 70, and 13 different primers used for the MBR region. Twelve laboratories used nested PCR and eight single round amplification.The sensitivity of nested and single round PCR was similar at 100 cells/ml but below this the nested method proved significantly more sensitive. The false positive rate was 28%, with 11 samples from 9 laboratories reported as positive when no t(14;18) cells were added. PCR product size and sequence analysis showed that false positives were due to contamination from cell-line DNA rather than background translocations in the donors. There was no significant difference in false positive rates between nested and single round techniques.The polymerase chain reaction to detect bcl-2-IgH rearrangements is presently carried out with widely disparate results. Further effort is required to bring forward a standard PCR protocol which can be re-tested in different laboratories to improve accuracy and reproducibility. The application of quantitative techniques such as real-time PCR may resolve many of the problems presently encountered.

    View details for Web of Science ID 000084979300018

    View details for PubMedID 10631464

  • Familial coagulation factor V deficiency caused by a novel 4 base pair insertion in the factor V gene: Factor v Stanford THROMBOSIS AND HAEMOSTASIS Zehnder, J. L., Hiraki, D. D., Jones, C. D., Gross, N., GRUMET, F. C. 1999; 82 (3): 1097-1099

    Abstract

    An index patient with pseudohomozygosity for factor V Leiden was identified. Each of his two children inherited a different paternal factor V allele; a daughter was heterozygous for factor V Leiden, with 100% factor V activity, and a son was heterozygous for factor V deficiency, with 50% factor V activity. Genomic DNA was obtained from family members, and the 25 factor V exons and flanking intronic regions were sequenced in the proband and confirmed in the children. Within exon 13 of factor V, a 4 base insertion was found at NT 2856 in the proband and son. but not the daughter. This mutation, here designated factor V Stanford, results in a frameshift with loss of a thrombin activation site (R1545V) and premature termination of translation at amino acid 1560.

    View details for Web of Science ID 000082421100018

    View details for PubMedID 10494770

  • Mast-cell heparin demystified. Nature Zehnder, J. L., GALLI, S. J. 1999; 400 (6746): 714-715

    View details for PubMedID 10466718

  • Use of the polymerase chain reaction in the evaluation of cutaneous T-cell infiltrates DERMATOLOGIC CLINICS Kohler, S., Zehnder, J. L. 1999; 17 (3): 657-?

    Abstract

    Histologic evaluation of suspected cutaneous T-cell neoplasia is challenging. There is significant overlap with features of benign condition, and neoplastic cells often occur in a reactive background. Recently, molecular techniques using paraffin-embedded tissue have been applied to the diagnosis of cutaneous T-cell infiltrates. These methods are useful for determining whether a clonal population of T-cells is present. The advantages and limitation of molecular diagnostic methods in the diagnosis of cutaneous T-cell infiltrates are discussed.

    View details for Web of Science ID 000081318700015

    View details for PubMedID 10410865

  • Aggressive natural killer-like T-cell malignancy with leukemic presentation following solid organ transplantation AMERICAN JOURNAL OF CLINICAL PATHOLOGY Natkunam, Y., Warnke, R. A., Zehnder, J. L., Cornbleet, P. J. 1999; 111 (5): 663-671

    Abstract

    NK-like T-cell malignancies are part of a spectrum of lymphoproliferative diseases that complicate immunosuppression associated with solid organ transplantation. We describe 2 patients with long-standing immunosuppression following solid organ transplantation. Both patients had systemic symptoms that included fever, myalgia, and weight loss. Organ involvement and lymphadenopathy were not initially observed. Unique to these 2 cases are the initial leukemic symptoms, which led to further characterization and identification of NK-like T-cell malignancies. Both patients exhibited an anomalous T/NK phenotype, CD56 positivity, and atypical blastic architecture of the large granular lymphocytes. Clonal rearrangement of T-cell receptor genes was detected in both patients. In 1 patient, a cytogenetic abnormality involving 8q24 was demonstrated. The disease course in both patients was aggressive, with involvement of multiple sites and rapid demise. This study emphasizes the importance of including NK-like T-cell malignancies in the differential diagnosis of lymphoproliferative disorders associated with immunosuppression and recognizing that an aggressive clinical course may follow leukemic presentation of disease.

    View details for Web of Science ID 000079920500011

    View details for PubMedID 10230357

  • Aggressive cutaneous NK and NK-like T-cell lymphomas - Clinicopathologic, immunohistochemical, and molecular analyses of 12 cases AMERICAN JOURNAL OF SURGICAL PATHOLOGY Natkunam, Y., SMOLLER, B. R., Zehnder, J. L., Dorfman, R. F., Warnke, R. A. 1999; 23 (5): 571-581

    Abstract

    Natural killer (NK) and NK-like T-cell lymphomas are rare hematolymphoid malignancies that predominate in the upper aerodigestive system. They also involve other extranodal sites, including the skin. Primary cutaneous manifestations of NK and NK-like T-cell lymphomas are uncommon, and the clinicopathologic features are poorly understood. We have studied 12 patients of varied ethnic backgrounds with CD56-positive lymphomas in the skin. Six patients subsequently progressed to disseminated disease. These lymphomas showed the following immunophenotype: CD56+, CD43+, TCRb-, CD3-/+, CD20-, CD30-/+, CD4-, and CD8-. Two cases exhibited T-cell receptor gene rearrangements supporting a T-cell origin for these lymphomas, whereas the remaining 10 cases were likely derived from NK cells. Our results show inconsistent association of these lymphomas with Epstein-Barr virus (EBV), the multidrug resistance phenotype, and expression of P53. In addition, we found a previously unreported correlation between lymphomas harboring EBV mRNA and the expression of the multidrug resistance phenotype. These lymphomas were aggressive and were associated with rapid clinical progression, treatment failure, multiple relapses, and an average survival of 15 months from the time of diagnosis. Our results indicate the importance of recognizing this disease as a distinct subset of aggressive cutaneous lymphomas that may be diagnosed on the basis of morphology, immunophenotype, and gene rearrangement studies.

    View details for Web of Science ID 000080178200012

    View details for PubMedID 10328090

  • The international normalized ratio during concurrent warfarin and argatroban anticoagulation: Differential contributions of each agent and effects of the choice of thromboplastin used CLINICAL CHEMISTRY Hursting, M. J., Zehnder, J. L., Joffrion, J. L., Becker, J. C., Knappenberger, G. D., Schwarz, R. P. 1999; 45 (3): 409-412

    View details for Web of Science ID 000078979100015

    View details for PubMedID 10053045

  • Mesenteric artery thrombosis: A case report of combined protein S and protein C deficiency AMERICAN JOURNAL OF HEMATOLOGY Atkins, K. A., Zehnder, J. L. 1998; 58 (3): 246-247

    Abstract

    Individuals with more than one defect in natural coagulant/anticoagulant systems have been postulated to be at an increased risk for thrombotic events. We report a case of combined protein S and C deficiency in a young woman, which resulted in fatal arterial mesenteric thrombosis. The role of coagulation defects in arterial thrombosis is discussed.

    View details for Web of Science ID 000074510000017

    View details for PubMedID 9662280

  • Factor V Leiden and the risk of proximal venous thrombosis after total hip arthroplasty JOURNAL OF ARTHROPLASTY Woolson, S. T., Zehnder, J. L., Maloney, W. J. 1998; 13 (2): 207-210

    Abstract

    Deep vein thrombosis (DVT) remains a major cause of morbidity in patients undergoing total hip arthroplasty (THA). Despite postoperative DVT prophylaxis, 20-50% of THA patients still develop DVT. Currently, there is no accurate way of predicting which patients will develop DVT despite standard prophylaxis. The presence of factor V Leiden is the most common cause of inherited DVT risk. It has been postulated that patients who have factor V Leiden and are subjected to thrombogenic stressors such as THA would have an increased risk of thrombosis. The factor V Leiden genotype of 36 patients who developed proximal DVT after surgery and 45 control patients who had THA but did not develop DVT was determined. All patients had had prophylaxis against thrombosis using intermittent pneumatic compression alone or in combination with warfarin or aspirin. Surveillance for proximal DVT was performed on all patients prior to discharge by duplex ultrasound. The 2 groups were similar in age, sex, and type of operation. Three of 36 study patients who had developed DVT (8%) and 2 of 45 control patients who had not developed DVT (4%) were heterozygotes for factor V Leiden; these prevalences were not statistically different. Heterozygosity for factor V Leiden is not associated with DVT prophylaxis failure in patients undergoing THA.

    View details for Web of Science ID 000072498700014

    View details for PubMedID 9526216

  • A microplate allele-specific oligonucleotide hybridization assay for detection of factor V Leiden DIAGNOSTIC MOLECULAR PATHOLOGY Zehnder, J. L., Benson, R. C., Cheng, S. 1997; 6 (6): 347-352

    Abstract

    Factor V Leiden is the most common genetic risk factor for thrombosis. Currently, the determination of factor V Leiden genotype is limited to laboratories with expertise in molecular methods to develop "home brew" assays using polymerase chain reaction (PCR) to amplify genomic DNA, followed by analysis of Mnl I restriction fragments. These methods are not standardized, are labor intensive, and have low throughput. We describe a method for determination of factor V Leiden genotype using allele-specific oligonucleotide capture probes coated onto 96 well plates, requiring only a thermal cycler and a microplate spectrophotometer to perform. With an automated strip washer and plate reader, genotypes could be determined in 80 min from completion of PCR. Within-run and between-run coefficients of variation for the assay were < 10%. In all 160 cases studied, the microplate assay correctly identified the factor V genotype. The microplate oligonucleotide hybridization assay is a simple and reliable system for determination of factor V Leiden genotype. The assay offers an automatable, high-throughput alternative to current testing methodologies.

    View details for Web of Science ID 000072819400007

    View details for PubMedID 9559295

  • Heparin-induced platelet aggregation vs platelet factor 4 enzyme-linked immunosorbent assay in the diagnosis of heparin-induced thrombocytopenia-thrombosis AMERICAN JOURNAL OF CLINICAL PATHOLOGY Look, K. A., Sahud, M., Flaherty, S., Zehnder, J. L. 1997; 108 (1): 78-82

    Abstract

    Thrombosis occurs in an unpredictable subset of patients with heparin-induced thrombocytopenia (HIT). The diagnosis of HIT requires clinical suspicion and laboratory confirmation. Although the "gold-standard" diagnostic test is considered to be the serotonin release assay (SRA), most laboratories use heparin-induced platelet aggregation (HIPA), which is highly specific but reported to be less sensitive than the SRA. Recently, the heparin-platelet factor 4 (PF4) enzyme-linked immunosorbent assay (ELISA) has been reported to have comparable sensitivity to the SRA. We compared the HIPA and PF4 ELISA in serum samples from 146 patients examined for HIT and assessed whether either test predicted thrombotic risk. Results for 81 patients were positive for HIPA, PF4 ELISA, or both. Of these, 91% were HIPA-positive, while only 60% were PF4 ELISA-positive. Clinical information was available on 63 patients, 17 of whom had thrombotic events (10 venous, 6 arterial, and 1 both). Neither the HIPA nor the PF4 ELISA predicted thrombotic risk, but the HIPA proved to be a more sensitive test for laboratory confirmation.

    View details for Web of Science ID A1997XG01600013

    View details for PubMedID 9208982

  • Administration of a CD31-derived peptide delays the onset and significantly increases survival from lethal graft-versus-host disease BLOOD Chen, Y. F., Schlegel, P. G., Tran, N. P., Thompson, D., Zehnder, J. L., Chao, N. J. 1997; 89 (4): 1452-1459

    Abstract

    The CD31 monoclonal antibody, LYP21, binds to the CD31 domain 6 and inhibits the human mixed-lymphocyte reaction (MLR) in a specific and dose-dependent fashion. A synthetic CD31 peptide based on human CD31 epitope (amino acids 551 to 574) recognized by LYP21 is equally effective in inhibiting the MLR. In this study, we used the murine homolog of CD31 peptide 551 to 574 and a control peptide to study the role of CD31 molecule on T-cell activation. In vitro, CD31 peptide inhibited the MLR across several major and minor histocompatibility differences in a specific and dose-dependent fashion, similar to the results observed in the human system. Maximal inhibition was achieved at a dose of 200 microg/mL. In the cytotoxic T-lymphocyte (CTL) assay, CD31 peptide inhibited CTL responses by 97%. To study the in vivo effect of this peptide, graft-versus-host disease (GVHD) across minor histocompatibility barriers was induced in the B10.D2 (H-2d) --> BALB/c (H-2d) model. BALB/c recipients received CD31 peptide (100 microg/d), or phosphate-buffered saline (PBS), or control peptide (100 microg/d) intraperitoneally (IP) for the first 5 weeks. CD31 peptide delayed onset of graft-versus-host disease and significantly increased long-term survival. Twelve of 14 mice receiving CD31 peptide survived more than 100 days after transplantation, as compared with none of 10 mice receiving PBS and none of five mice receiving control peptide (P = .0001). Long-term engraftment of allogeneic bone marrow was documented in all transplanted mice by polymerase chain reaction (PCR) analysis of microsatellite region in the interleukin (IL)-1beta gene. Our data suggest that the CD31 molecule has an important functional role in T-cell activation in vitro and in vivo.

    View details for Web of Science ID A1997WG79700038

    View details for PubMedID 9028970

  • Sensitivity and specificity of the APC resistance assay in detection of individuals with factor V Leiden AMERICAN JOURNAL OF CLINICAL PATHOLOGY Zehnder, J. L., Benson, R. C. 1996; 106 (1): 107-111

    Abstract

    Resistance to activated protein C (APC) is the most common cause of familial thrombophilia. The partial thromboplastin time (PTT)-based test for resistance to APC has been widely employed as a screening test for this disorder. However, the utility of this test for screening is not well characterized. More than 90% of patients with resistance to APC have the G1691A mutation in factor V (factor V Leiden). The authors studied the ability of a commercial APC resistance assay to correctly identify the factor V Leiden genotype in 130 individuals. At the recommended assay cut-off value of 2, the sensitivity of the APC resistance assay was 50%, with a specificity of 98%. Increasing the cut-off value increased the sensitivity but decreased the specificity of the test. Receiver operating characteristic (ROC) curve analysis indicated that the test was of intermediate utility. There was considerable overlap in APC ratios in the range of 2 to 3 between subjects with a normal factor V genotype and heterozygotes for factor V Leiden. The authors conclude that the APC resistance assay in its present form is not a useful screening test for factor V Leiden heterozygotes. Until the performance of this assay is improved, patients should have molecular diagnostic testing performed to determine their factor V Leiden status.

    View details for Web of Science ID A1996UW50500018

    View details for PubMedID 8701918

  • Recurrent thrombosis due to compound heterozygosity for factor V Leiden and factor V deficiency BLOOD COAGULATION & FIBRINOLYSIS Zehnder, J. L., Jain, M. 1996; 7 (3): 361-362

    Abstract

    A point mutation in the factor V gene (factor V Leiden) is the most common cause of familial thrombophilia. Patients with factor V Leiden have an increased risk of thrombosis, particularly those homozygous for the mutation. However, the phenotype in individuals with the mutation is variable, suggesting that other factors influence thrombotic risk. We describe for the first time a family in which two independent defects in factor V co-exist: heterozygosity for factor V Leiden and factor V deficiency. Compound heterozygosity for these two defects results in a phenotype similar to a homozygous factor V Leiden state with profound resistance to APC and recurrent thrombosis.

    View details for Web of Science ID A1996UL37900012

    View details for PubMedID 8735145

  • Polymorphism of adhesion molecule CD31 and its role in acute graft-versus-host disease NEW ENGLAND JOURNAL OF MEDICINE Behar, E., Chao, N. J., Hiraki, D. D., Krishnaswamy, S., Brown, B. W., Zehnder, J. L., GRUMET, F. C. 1996; 334 (5): 286-291

    Abstract

    Graft-versus-host disease (GVHD) caused by poorly defined minor (i.e., other than HLA) histocompatibility antigens remains a serious problem in recipients of bone marrow transplants. We sought to determine whether the CD31 adhesion molecule is a minor alloantigen.We directly sequenced samples of complementary DNA (cDNA) encoding CD31 molecules from 21 unrelated normal subjects. Sequence-specific primers were then designed to amplify alleles by the polymerase chain reaction, thereby permitting CD31 typing of genomic DNA from additional normal subjects. To assess the relevance of CD31 matching to bone marrow transplantation, we performed CD31 typing of 46 recipients of bone marrow (32 without GVHD and 14 with severe [grade III or IV] acute GVHD) and their HLA-identical sibling donors. The immunoreactivity of CD31 phenotypes with anti-CD31 monoclonal antibodies was compared by flow cytometry.Direct sequencing of cDNA for CD31 from the 21 normal subjects identified a single polymorphism, CTG-->GTG (Leu-->Val), at codon 125; we designated the resulting alleles CD31.L and CD31.V, respectively. The CD31 genotypes of these and 142 other unrelated subjects were of the expected frequencies. Among the transplant recipients, 71 percent of those with acute GVHD had CD31 genotypes that were not identical to the donor's genotype, as compared with 22 percent of the recipients without GVHD (P = 0.004). The binding of anti-CD31 monoclonal antibodies as measured by fluorescence-activated cell sorting correlated with the CD31 types of homozygous cell lines.The adhesion molecule CD31 is polymorphic. When donor and recipient genotypes are not identical, the risk of GVHD increases. Prospective CD31 typing may reduce the risk of acute GVHD.

    View details for Web of Science ID A1996TV69500002

    View details for PubMedID 8532023

  • HISTIDINE-RICH GLYCOPROTEIN - IS THERE A ROLE IN HEMOSTASIS OR IMMUNE FUNCTION JOURNAL OF LABORATORY AND CLINICAL MEDICINE Zehnder, J. L., Leung, L. L. 1995; 125 (6): 682-683

    View details for Web of Science ID A1995RB44500004

    View details for PubMedID 7769360

  • INVOLVEMENT OF CD31 IN LYMPHOCYTE-MEDIATED IMMUNE-RESPONSES - IMPORTANCE OF THE MEMBRANE-PROXIMAL IMMUNOGLOBULIN DOMAIN AND IDENTIFICATION OF AN INHIBITING CD31 PEPTIDE BLOOD Zehnder, J. L., Shatsky, M., Leung, L. L., BUTCHER, E. C., McGregor, J. L., Levitt, L. J. 1995; 85 (5): 1282-1288

    Abstract

    CD31 (PECAM-1) is an immunoglobulin gene superfamily cell adhesion molecule found on vascular endothelium, platelets, and leukocytes. Lymphocyte expression of CD31 is most closely associated with the CD45RA+CD8+ naive T phenotype. CD31 has recently been shown to play a role in leukocyte egress to inflammatory sites. The mechanism of CD31 adhesion remains under investigation. Several investigators have reported evidence for a heterotypic ligand. We have previously shown that CD31 is phosphorylated with cell activation, which suggests a possible role for CD31 in cell activation events. We therefore studied the effects of CD31 antibodies on in vitro assays of lymphocyte activation. One CD31 antibody, LYP21, inhibited the mixed lymphocyte reaction (MLR) in a specific and dose-dependent fashion. An LYP21 epitope was localized to the sixth Ig domain of CD31. This peptide and a scrambled control peptide were synthesized and used to study effects of this epitope on lymphocyte activation. The CD31 peptide strongly inhibited the MLR. Because CD31 is expressed on both stimulator and responder populations, stimulator peripheral blood leukocytes and responder lymphocyte populations were separately incubated with CD31 peptide or control peptide and then washed before mixing. The CD31 peptide inhibited the MLR equally when either stimulator or responder cells were preincubated with the CD31 peptide. We further sorted responder cells into CD31-high and CD31-low populations and separately incubated these subsets with peptides. The CD31 peptide strongly inhibited MLRs, regardless of level of responder-cell CD31 expression. Examination of MLR reactions involving the CD31 peptide showed dispersed small aggregates of cells, rather than the single large aggregate observed in control MLRs. The CD31 peptide did not affect activation of lymphocytes by phorbol myristate acetate (PMA) and ionomycin. These results suggest that a surface CD31-ligand interaction may have a functional role in alloimmune lymphocyte activation and identify a functionally important domain of CD31.

    View details for Web of Science ID A1995QJ43500018

    View details for PubMedID 7858258

  • THE CELL-ADHESION MOLECULE CD31 IS PHOSPHORYLATED AFTER CELL ACTIVATION - DOWN-REGULATION OF CD31 IN ACTIVATED LYMPHOCYTES-T JOURNAL OF BIOLOGICAL CHEMISTRY Zehnder, J. L., Hirai, K., Shatsky, M., McGregor, J. L., Levitt, L. J., Leung, L. L. 1992; 267 (8): 5243-5249

    Abstract

    We report the independent cloning of the cDNA for CD31, a recently described cell adhesion molecule of the immunoglobulin gene superfamily present on platelets, granulocytes, monocytes, lymphocytes, and endothelial cells. Northern analysis revealed three major mRNA transcripts in Jurkat (a human T cell line) and K562 and HEL (leukemia cell lines) cells with an additional 5.3-kilobase transcript seen in cultured human umbilical vein endothelial cells. Following T cell activation, CD31 mRNA was down-regulated by Northern analysis, and decreased CD31 protein expression was confirmed by immunoblots. The down-regulation of CD31 was partially mediated by decreased transcription as demonstrated by nuclear run-on studies. CD31 became rapidly phosphorylated in platelets, Jurkat cells, and endothelial cells after cell activation. We were unable to demonstrate the presence of a phosphotyrosine in CD31 using monoclonal and polyclonal phosphotyrosine antibodies. In addition, CD31 phosphorylation in platelets was induced by phorbol ester and was blocked by staurosporin, a protein kinase C inhibitor, suggesting that CD31 phosphorylation is mediated by protein kinase C and involves serine and/or threonine residues. The phosphorylation of CD31 following cell activation may modulate its cellular adhesiveness, and the down-regulation of its expression may serve to impart target specificity and to localize effector lymphocytes to areas of inflammation.

    View details for Web of Science ID A1992HH74700040

    View details for PubMedID 1544907

  • DEVELOPMENT OF ANTIBODIES TO THROMBIN AND FACTOR-V WITH RECURRENT BLEEDING IN A PATIENT EXPOSED TO TOPICAL BOVINE THROMBIN BLOOD Zehnder, J. L., Leung, L. L. 1990; 76 (10): 2011-2016

    Abstract

    A 65 year old patient who was exposed to topical bovine thrombin during cardiac surgery developed markedly prolonged clotting times and a severe bleeding diathesis. Mixing studies with normal plasma failed to correct the clotting times. Platelet transfusions, immunosuppressive and immunomodulatory therapies were ineffective, but plasmapheresis was effective in decreasing clotting times and in the resolution of clinical bleeding events. The patient's purified IgG reacted with bovine thrombin by immunoblotting and enzyme-linked immunosorbent assay (ELISA). However, the IgG reacted minimally with human thrombin. In view of the severe bleeding, a coexisting inhibitor was sought. The patient's factor V activity was 1% of normal and was not corrected by mixing with normal plasma, demonstrating the presence of an inhibitor against factor V. The patient's IgG reacted with both bovine and human factor V. Immunoblotting localized the site of antibody binding to the light chain of activated bovine factor V. Detectable amounts of bovine factor V were found in commercial bovine thrombin preparations by ELISA. The data suggest that patients exposed to topical bovine thrombin may develop antibodies to thrombin and factor V. Anti-thrombin antibodies may mask coexisting factor V inhibitors responsible for clinical bleeding.

    View details for Web of Science ID A1990EJ39100016

    View details for PubMedID 2242423

  • TORSADES-DE-POINTES PRECIPITATED BY A CHINESE HERBAL REMEDY AMERICAN JOURNAL OF CARDIOLOGY Bryerash, M., Zehnder, J., ANGELCHIK, P., Maisel, A. 1987; 60 (14): 1186-1187

    View details for Web of Science ID A1987K936300016

    View details for PubMedID 3687752

  • REINVESTIGATION OF THE REACTION OF CHYMOTRYPSIN WITH N-FURYLACRYLOYLTRYPTOPHAN DERIVATIVES AT ACIDIC PH BIOCHEMICAL JOURNAL Fink, A. L., Feldman, R., Zehnder, J. 1979; 181 (3): 733-736

    Abstract

    The reaction of alpha-chymotrypsin with N alpha-3-(2-furyl)acryloyl-L-tryptophan methyl ester (FA-Trp-OMe) and amide has been investigated in aqueous and dimethylsulphoxide cryosolvent solutions from pH2 to 7 and over a wide temperature range. Previous reports have suggested that an intermediate preceding the acyl-enzyme can be detected spectrophotometrically in the reaction with methyl esters of FA-Trp and FA-Tyr at low pH [Yu & Viswanatha (1969) Eur. J. Biochem. 11, 347--352), and that this intermediate is an oxazolinone [Coletti-Previero et al. (1970) FEBS Lett. 11, 213--217]. We show that the previous interpretations of the time-dependent spectral changes were incorrect, and that the only detected intermediate is the acyl-enzyme. This may be isolated by gel filtration at pH less than 2.5, 1 degree C, owing to its relative stability. The pH-dependence of the rates of acylation and deacylation from pH 8.5 to 2.0 are consistent with a single ionization of pK congruent to 7.0 in both aqueous and cryosolvent solutions.

    View details for Web of Science ID A1979HL98500027

    View details for PubMedID 42387

Conference Proceedings


  • An MTHFR variant, homocysteine, and cardiovascular comorbidity in renal disease Wrone, E. M., Zehnder, J. L., Hornberger, J. M., McCann, L. M., Coplon, N. S., Fortmann, S. P. NATURE PUBLISHING GROUP. 2001: 1106-1113

    Abstract

    It is unclear whether total serum homocysteine (tHcy) and the C677T mutation of methylenetetrahydrofolate reductase (MTHFR) are associated with cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD).A cross-sectional sample of 459 patients with ESRD on chronic dialysis was assessed to determine whether tHcy and the C677T mutation are associated with CVD prevalence in multiple logistic regression. As CVD mortality is high, we examined the relationship between homozygosity and duration of dialysis.Mean tHcy was higher in patients without a history of CVD (35.2 micromol/L vs. 30.4 micromol/L, P = 0.02). In multivariate models, CVD was negatively associated with tHcy and positively associated with TT genotype, male gender, and body mass index. Mean tHcy levels were higher among those with the TT genotype compared with those with the CC genotype when adjusted for age, folate, creatinine, and albumin (37.9 micromol/L vs. 31.9 micromol/L, P = 0.005). Among whites, the prevalence of the TT genotype was higher in those having undergone less than one year of dialysis (P = 0.002).The C677T genotype of MTHFR is associated with CVD in ESRD and may be a more meaningful marker than tHcy for abnormal homocysteine metabolism in ESRD. Prospective data from ongoing clinical trials are needed to improve our understanding of these findings. Screening for this polymorphism may help guide prevention measures.

    View details for Web of Science ID 000170668100029

    View details for PubMedID 11532106

  • Peripheral T-cell lymphoma complicated by a proliferation of large B cells Higgins, J. P., van de Rijn, M., Jones, C. D., Zehnder, J. L., Warnke, R. A. AMER SOC CLINICAL PATHOLOGY. 2000: 236-247

    Abstract

    We studied 14 cases that showed a morphologic appearance of peripheral T-cell lymphoma and contained substantial numbers of CD20+ large B cells. In all but 2 cases, the CD20+ large cells showed a mix of kappa and lambda light chain expression. Two cases showed a focal predominance of kappa expression. In situ hybridization using the EBER1 probe for detection of Epstein-Barr virus (EBV) RNA was performed on every case. EBV RNA was present in 10 cases. Of 8 cases with EBV RNA stained by immunohistochemistry for the latent membrane protein of EBV, 6 were positive. Double-labeling immunohistochemistry and in situ hybridization confirmed that EBV was present in the large B cells. Polymerase chain reaction (PCR) analysis showed a clonal rearrangement of the T-cell receptor (TCR)-gamma chain gene in 12 of 13 cases tested. One additional case showed a clonal rearrangement of the TCR-beta chain gene by Southern blot hybridization. PCR analysis showed a clonal immunoglobulin gene rearrangement in 5 cases, a suggestion of a clonal rearrangement in 1, an oligoclonal pattern in 4, and a polyclonal pattern in 4. The finding of large B and T cells may result in a misdiagnosis of a reactive process or of T-cell-rich B-cell lymphoma. The presence of EBV in some cases could cause further confusion with the reactive T- and B-immunoblastic proliferation of infectious mononucleosis.

    View details for Web of Science ID 000088460700010

    View details for PubMedID 10941339

  • Cross-linking hybridization assay for direct detection of factor V Leiden mutation Zehnder, J., VANATTA, R., Jones, C., Sussman, H., Wood, M. AMER ASSOC CLINICAL CHEMISTRY. 1997: 1703-1708

    Abstract

    A nucleic acid photocross-linking technology was used in the development of a direct assay for factor V Leiden, a point mutation in the factor V gene (G1691A) that is the most common inherited risk factor for thrombosis. This cross-linking hybridization assay included two allele-specific capture probes and six signal-generating reporter probes; all were modified with a photoactivated cross-linking compound. By using two different capture probes complementary to a 16-base sequence at the factor V Leiden mutation site, but differing in the nucleotide opposite the mutation site (C vs T), wild-type and factor V Leiden alleles were differentiated in purified DNA specimens. The assay was also successfully applied to genomic DNA in leukocytes isolated from whole blood; the factor V status of 122 patients as determined by this method was in complete concordance with a standard PCR-based assay and clearly discriminated between healthy individuals and factor V Leiden heterozygotes.

    View details for Web of Science ID A1997XV89700033

    View details for PubMedID 9299963

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