Bio

Clinical Focus


  • Cutaneous T-Cell Lymphoma
  • Myeloma
  • Medical Oncology
  • Cancer > Lymphoma
  • Cancer > Blood and Marrow Transplant

Academic Appointments


Administrative Appointments


  • Scientific Advisory Board, Lymphoma Research Foundation (2011 - Present)

Honors & Awards


  • Translational Research Grant, Stanford Cancer Institute (2014-2015)
  • Division Teaching Award, BMT, Stanford University (2012)
  • Developmental Research Award, Stanford Cancer Institute (2012-2013)
  • ITI Seed Grant Award, Institute for Immunity, Transplantation and Infection, Stanford University (2011-2012)
  • Division Teaching Award, BMT, Stanford University (2010)
  • Developmental Research Award, Stanford University Cancer Center (2009-2010)
  • Division Teaching Award, BMT, Stanford University (2009)
  • K08 Clinical Scientist Career Development Award, NIH/NCI (2005-2009)
  • Fellowship, Lymphoma Research Foundation (2002-2004)
  • Charles and Dorothy Andrew Bird Award, Sigma Xi Scientific Research Society (1996)
  • Doctoral Dissertation Award, University of Minnesota Graduate School (1995)
  • Predoctoral National Research Service Award, NIH/NIAID (1994-1995)

Professional Education


  • Medical Education:Chungshan Medical College (1988)
  • University of Minnesota (1996) MN
  • Internship:University of Texas Medical School (1997) TX
  • Residency:University of Texas Medical School (1999) TX
  • Fellowship:Stanford University School of Medicine (2002) CA
  • Board Certification: Internal Medicine, American Board of Internal Medicine (2007)
  • Board Certification: Medical Oncology, American Board of Internal Medicine (2008)

Research & Scholarship

Current Research and Scholarly Interests


My clinical focus is non-Hodgkin's lymphoma (NHL) and am currently conducting clinical trials with novel therapies on these patients. My basic research interest is immunotherapy for lymphoma, with two components: tumor vaccines and allogeneic transplant. For the tumor vaccine, I am working with my colleagues in Oncology to conduct a clinical trial using a CpG-activated tumor vaccine in mantel cell NHL patients who undergo autologous transplantation. The goal is to sensitize the autologous T cells to recognize the malignant lymphoma cells and to expand these tumor-specific T cells immediate after autologous transplant.

Second, I am conducting a study using a novel non-myeloablative preparative regimen prior to allogeneic transplant in patients with mycosis fungoides/Sezary syndrome, a cutaneous T cell NHL. While these patients exhibit little sensitivity to traditional chemotherapy, graft-versus-lymphoma effect provided by allogeneic transplant seems to have an excellent disease control effect. I also use high throughput sequencing technology to assess the minimal residual disease and the immune reconstitution after allogeneic transplant.

Clinical Trials


  • Pilot Study of Brentuximab Vedotin (SGN-35) in Patients With MF With Variable CD30 Expression Level Recruiting

    The purpose of this study is to learn the effects of an investigational medication, SGN 35, on patients with cutaneous T cell lymphoma (CTCL), specifically mycosis fungoides (MF) and Sezary syndrome (SS). Despite a wide range of therapeutic options, the treatments are associated with short response duration, thus this condition is largely incurable. This investigational drug may offer less toxicity than standard treatments and have better tumor specific targeting. The primary objective is to explore the biologic activity of brentuximab vedotin (SGN-35) in patients with mycosis fungoides (MF) and Sézary syndrome (SS), the most common types of cutaneous T-cell lymphoma (CTCL), where expression of CD30 is variable. SGN-35 has significant biologic activity in Hodgkin's disease (HD) where only a small numbers of CD30 positive tumor cells are present, as well as in lymphomas with large numbers of CD30-expressing tumor cells such as systemic anaplastic large cell lymphoma (sALCL). This phase II exploratory study will evaluate the clinical response of brentuximab vedotin (SGN-35) in MF and SS where tumor cells express variable levels of CD30 target molecule. The grouping by CD30 expression levels (low, intermediate, high) is for accrual purposes only to ensure a wide range of CD30 expression. Given the exploratory nature of this study, it will be open-label, single-arm, and non-randomized trial. One centers will be involved to complete the accrual, a total of 24 patients with MF and SS. Enrollment will be based on CD30 expression levels by tissue immunohistochemistry (IHC), defined as low, intermediate or high expressers. The investigators will target 8 patients in each group for total of 24 patients. Of these 8 patients per group, up to 3 may be patients with SS. Each patient regardless of CD30 expression level will receive 1.8 mg/kg of SGN-35 IV every 21 days, up to 8 cycles of therapy. Patients with CR may receive 2 additional cycles. Patients who have PR may receive up to a maximum of 16 doses IF they are continuing to improve after 8 cycles. Patients who relapse within 6 months after CR maybe eligible for retreatment.

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  • Ph II of Non-myeloablative Allogeneic Transplantation Using TLI & ATG In Patients w/ Cutaneous T Cell Lymphoma Recruiting

    Non-myeloablative approach for allogeneic transplant is a reasonable option, especially given that the median age at diagnosis is 55-60 years and frequently present compromised skin in these patients, which increases the risk of infection. Therefore, we propose a clinical study with allogeneic HSCT using a unique non-myeloablative preparative regimen, TLI/ATG, to treat advanced MF/SS.

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  • Post T-plant Infusion of Allogeneic Cytokine Induced Killer Cells as Consolidative Therapy in Myelodysplastic Syndromes/Myeloproliferative Disorders Recruiting

    This study examines CIK (Cytokine Induced Killer Cells) as Consolidative Therapy after Non-Myeloablative Allogeneic Transplantation.

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  • Acute Graft-versus-Host Disease Treatment (BMT CTN 0802) Not Recruiting

    The study is a Phase III, randomized double blind, placebo controlled, and trial evaluating the addition of MMF vs. placebo to systemic corticosteroids as initial therapy for acute GVHD. The primary endpoint will be GVHD free survival at Day 56 post randomization.

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • Nilotinib and Imatinib Mesylate After Donor Stem Cell Transplant in Treating Patients With Acute Lymphoblastic Leukemia or Chronic Myelogenous Leukemia Not Recruiting

    This phase I/II trial is studying the side effects and best way to give nilotinib when given together with imatinib mesylate after donor stem cell transplant in treating patients with acute lymphoblastic leukemia or chronic myelogenous leukemia. Nilotinib and imatinib mesylate may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth.

    Stanford is currently not accepting patients for this trial. For more information, please contact Physician Referrals, (650) 723 - 0822.

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  • Phase II Poor Risk Diffuse Large B-cell Lymphoma (DLBCL) of Total Lymphoid Irradiation (TLI) and Antithymocyte Globulin (ATG) Followed by Matched Allogeneic Hematopoietic Transplantation as Consolidation to Autologous Hematopoietic Cell Transplantation (AHCT) Not Recruiting

    The purpose of this study is to develop an alternative treatment for patients with relapsed diffuse large B cell lymphoma who are not likely to be cured by the conventional transplantation regimen.

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • Cyclosporine Eye Drops in Preventing Graft-Versus-Host Disease of the Eye in Patients Who Have Undergone Donor Stem Cell Transplant for Hematologic Cancer or Bone Marrow Failure Disorder Not Recruiting

    RATIONALE: Cyclosporine eye drops may prevent graft-versus-host disease of the eye in patients who have undergone donor stem cell transplant for hematologic cancer or bone marrow failure disorder. PURPOSE: This randomized phase I trial is studying how well cyclosporine eye drops work in preventing graft-versus-host disease of the eye in patients who have undergone donor stem cell transplant for hematologic cancer or bone marrow failure disorder.

    Stanford is currently not accepting patients for this trial. For more information, please contact Joanne Otani, (650) 721 - 2372.

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  • A Phase 3 Study of Brentuximab Vedotin (SGN-35) in Patients at High Risk of Residual Hodgkin Lymphoma Following Stem Cell Transplant (The AETHERA Trial) Not Recruiting

    This is a randomized, double-blind, placebo-controlled, multicenter phase 3 trial to evaluate the efficacy and safety of brentuximab vedotin (SGN-35) and best supportive care (BSC) compared to placebo and BSC in treatment of residual Hodgkin lymphoma (HL) following autologous stem cell transplant (ASCT).

    Stanford is currently not accepting patients for this trial. For more information, please contact Sarah Robeson, (650) 725 - 1647.

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  • Allogeneic HCT Using Nonmyeloablative Host Conditioning With TLI & ATG vs SOC in AML Not Recruiting

    Acute myeloid leukemia (AML) is a cancer of the bone marrow that mostly affects older adults. Even with the best chemotherapy, two-year disease-free survival is achieved in a minority of patients. Bone marrow transplantation from a sibling donor may improve cure rates; however, patients over 50 years of age have a high risk of complications and therefore generally are excluded from this treatment option. Recently our group developed a transplantation strategy for older cancer patients that protects against transplant-associated complications, yet does not interfere with the ability of the transplanted donor cells to destroy cancer cells. With this new method, we can now safely evaluate transplantation as a curative therapy for AML patients over the age of 50. We have assembled clinical and scientific researchers throughout the state of California to study and compare bone marrow transplantation using our new approach with the best standard of care chemotherapy in AML patients over the age of 50. The results of this study have the potential to establish a new treatment standard that will improve survival of older AML patients.

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, 650-725-1647.

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  • Safety and Efficacy Study of an Anti-CD20 Monoclonal Antibody (AME-133v) to Treat Non-Hodgkin's Lymphoma Not Recruiting

    The protein engineering of AME-133v is hypothesized to result in an anti-CD20 therapy with greater potency and efficacy in all patients, but particularly in genetically defined subpopulations that respond poorly to rituximab because they express a low affinity version of the Fc receptor on their immune effector cells. A monoclonal antibody that has increased binding for this receptor should be more effective in stimulating effector cell killing and thus improve response to the antibody. This study is designed to provide evidence of the safety and a preliminary understanding of the efficacy of AME 133v.

    Stanford is currently not accepting patients for this trial. For more information, please contact Maria Ahern, (650) 493 - 5000.

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  • Intravenous Administration of RGI-2001 in Patient Undergoing Allogenic Hematopoietic Stem Cell Transplantation (AHSCT) Recruiting

    The clinical trial is a Phase 1/2a, open-label, multi-center, dose-escalation study to evaluate the safety, tolerability and pharmacokinetic profile of RGI-2001 in patients undergoing AHSCT, with radiation or non-radiation myeloablative preparative treatment. The study will be separated into two parts; a dose escalation phase to assess safety, followed by a large expansion phase to further evaluate the pharmacologic effects of either a Maximum Tolerated Dose, Maximum Feasible Dose or optimal pharmacologically active dose of RGI-2001. The initial dose escalation safety portion of the study (Part 1) will include higher risk patients and limit the unrelated donor transplants. After safety is established in part 1 of the study, the second portion of the study will expand the enrollment criteria and allow transplantation by either related or unrelated donors. This study will endeavor to identify the dose range at which RGI-2001 has an acceptable safety profile, at which biologic activity is observed, and to guide possible dose levels to utilize in later phase studies based on biological activity.

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  • Phase I/II of a CpG-Activated Whole Cell Vaccine Followed by Autologous Immunotransplant for MCL Recruiting

    While autologous hematopoietic stem cell transplant (AHCT) has been shown to cure some subtypes of non-Hodgkin's lymphoma (NHL), mantle cell lymphoma (MCL) still has a prognosis marked by relapse. This study will evaluate the safety and efficacy of treating newly diagnosed MCL patients with an autologous, tumor-derived vaccine followed by re-infusion of vaccine-primed T cells combined with standard autologous hematopoietic stem cell transplant (AHCT). CpG-MCL vaccine is derived from each patient's own tumor, treated in vitro with the immunostimulatory CpG-enriched oligodeoxynucleotide - PF-3512676 - and irradiated. The overall treatment schema is that patients receive: induction chemotherapy, priming vaccinations, leukapheresis to harvest vaccine-primed T cells, preparative myeloablative chemotherapy followed by AHCT, re-infusion of vaccine-primed T-cells ('immunotransplant') and repeat vaccinations zero and three months post-AHCT.

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  • Vaccine Therapy and GM-CSF in Treating Patients With Progressive Non-Hodgkin's Lymphoma Not Recruiting

    RATIONALE: Vaccines made from a person's cancer cells may make the body build an effective immune response to kill cancer cells. Colony-stimulating factors, such as GM-CSF, may increase the number of immune cells found in bone marrow or peripheral blood and may stimulate the immune system in different ways and stop cancer cells from growing. PURPOSE: This phase II trial is studying how well giving vaccine therapy together with GM-CSF works in treating patients with progressive B-cell non-Hodgkin's lymphoma.

    Stanford is currently not accepting patients for this trial. For more information, please contact Mayita Romero, (650) 725 - 6452.

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  • Clinical and Pathologic Studies in Non-Hodgkin's Lymphoma Patients Receiving Antibody Treatment Not Recruiting

    To characterize the molecular and cell biology of the tumor cells in lymphoma. The mechanism of monoclonal antibody treatment by rituximab or epratuzumab will also be examined.

    Stanford is currently not accepting patients for this trial. For more information, please contact Mayita Romero, (650) 725 - 6452.

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  • Stem Cell Transplant With Lenalidomide Maintenance in Patients With Multiple Myeloma (BMT CTN 0702) Not Recruiting

    The study is designed as a Phase III, multicenter trial of tandem autologous transplants plus maintenance therapy versus the strategy of single autologous transplant plus consolidation therapy with lenalidomide, bortezomib and dexamethasone (RVD) followed by maintenance therapy or single autologous transplant plus maintenance therapy as part of upfront treatment of multiple myeloma (MM). Lenalidomide will be used as maintenance therapy for three years in all arms.

    Stanford is currently not accepting patients for this trial. For more information, please contact Physician Referrals, (650) 723 - 0822.

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  • Autologous Followed by Non-myeloablative Allogeneic Transplantation for Non-Hodgkin's Lymphoma Recruiting

    The purpose of this trial is to develop an alternative treatment for patients with poor risk non-Hodgkin's lymphoma. This trial uses a combination of high dose chemotherapy with stem cell transplant using the patient's own cells. This is followed with non-myeloablative transplant using stem cells from a related or unrelated donor to try and generate an anti-lymphoma response from the new immune system.

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  • High Dose Chemotherapy and Allogeneic Hematopoietic Cell Transplant for Non-Hodgkin's Lymphoma Not Recruiting

    To evaluate the role of allogeneic hematopoietic cell transplantation in the treatment of NHL.

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • A Pilot Study of Imatinib Mesylate in Steroid Refractory Chronic Graft Versus Host Disease Not Recruiting

    To determine if subjects with steroid refractory cGVHD can tolerate imatinib mesylate and whether their cGVHD responds to imatinib mesylate.

    Stanford is currently not accepting patients for this trial. For more information, please contact Joanne Otani, (650) 721 - 2372.

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  • Chronic Graft-versus-Host Disease Treatment (BMT CTN 0801) Not Recruiting

    This study is designed as a combined Phase II/III, randomized, open label, multicenter, prospective comparative study of sirolimus plus prednisone versus sirolimus/calcineurin-inhibitor plus prednisone for the treatment of chronic GVHD. Patients will be stratified by transplant center and will be randomized to an experimental arm of one of the two pre-specified experimental arms (sirolimus + prednisone or the comparator arm of sirolimus + calcineurin inhibitor + prednisone) in a 1:1 ratio.

    Stanford is currently not accepting patients for this trial. For more information, please contact Physician Referrals, 650-723-0822.

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  • Sirolimus & Mycophenolate Mofetil as GVHD Prophylaxis in Myeloablative, Matched Related Donor HCT Not Recruiting

    GVHD prophylaxis of sirolimus and mycophenolate mofetil for patients undergoing matched related allogeneic transplant for acute and chronic leukemia, MDS, high risk NHL and HL

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • Ph II of Autologous Followed by Nonmyeloablative Allogeneic Transplantation Using TLI & ATG Not Recruiting

    To evaluate the toxicity and tolerability of this tandem autologous/allogeneic transplant approach for patients with advanced stage multiple myeloma.

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • Comparing Peripheral Blood Stem Cell Transplantation Versus Bone Marrow Transplantation in Individuals With Hematologic Cancers Not Recruiting

    The study is designed as a Phase III, randomized, open label, multicenter, prospective, comparative trial of granulocyte colony stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSC) versus marrow from unrelated donors for transplantation in patients with hematologic malignancies. Recipients will be stratified by transplant center and disease risk and will be randomized to either the PBSC or marrow arm in a 1:1 ratio.

    Stanford is currently not accepting patients for this trial. For more information, please contact Kate Tierney, (650) 725 - 7063.

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  • Mixed Chimera Allo Transplantation in Multiple Myeloma Not Recruiting

    To determine toxicity and feasibility of mixed chimera allogeneic hematopoietic cell transplants for multiple myeloma; prepare and vaccinate patients with allogenic dendritic cell vaccinations following mixed chimera allogeneic hematopoietic cell transplants

    Stanford is currently not accepting patients for this trial. For more information, please contact BMT Referrals, (650) 723 - 0822.

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  • Fluticasone Propionate, Azithromycin, and Montelukast Sodium in Treating Patients With Bronchiolitis Obliterans Who Previously Underwent Stem Cell Transplant Not Recruiting

    This phase II trial studies how well giving fluticasone propionate, azithromycin, and montelukast sodium (FAM) together works in treating patients with bronchiolitis obliterans who previously underwent stem cell transplant. FAM may be an effective treatment for bronchiolitis obliterans

    Stanford is currently not accepting patients for this trial. For more information, please contact Physician Referrals, 650-723-0822.

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Teaching

2013-14 Courses


Graduate and Fellowship Programs


Publications

Journal Articles


  • Minimal residual disease monitoring with high-throughput sequencing of T cell receptors in cutaneous T cell lymphoma SCIENCE TRANSLATIONAL MEDICINE Weng, W. K., Armstrong, R., Arai, S., Desmarais, C., Hoppe, R., Kim, Y. H. 2013; 5 (214): 214ra171
  • Cancer Vaccines and T Cell Therapy BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Rezvani, K., Brody, J. D., Kohrt, H. E., Logan, A. C., Advani, R., Czerwinski, D. K., Weng, W., Negrin, R. S., Carlton, V., Faham, M., Levy, R., Barrett, J. 2013; 19 (1): S97-S101

    View details for DOI 10.1016/j.bbmt.2012.09.020

    View details for Web of Science ID 000313998100024

    View details for PubMedID 23041602

  • 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

  • The histone deacetylase inhibitor, romidepsin, suppresses cellular immune functions of cutaneous T-cell lymphoma patients AMERICAN JOURNAL OF HEMATOLOGY Kelly-Sell, M. J., Kim, Y. H., Straus, S., Benoit, B., Harrison, C., Sutherland, K., Armstrong, R., Weng, W., Showe, L. C., Wysocka, M., Rook, A. H. 2012; 87 (4): 354-360

    Abstract

    Romidepsin is the second histone deacetylase inhibitor (HDACi) approved for the treatment of advanced stages of cutaneous T-cell lymphoma (CTCL). Recent in vitro data suggest that HDACis suppress immune function although these findings have not been confirmed in patients. Thus, we serially examined the cellular immune function of eight CTCL patients undergoing treatment with three cycles of romidepsin. We measured the patients' natural killer (NK) and dendritic cell (DC) function and performed an in vitro terminal deoxynucleotidyl transferase dUTP nick end labeling assay to measure cellular apoptosis. Patients' NK cell cytolytic activity decreased from baseline to the third cycle of treatment (P = 0.018) but stimulation with a toll-like receptor (TLR) agonist increased this activity (P = 0.018). At baseline, a TLR agonist could both activate patients' DC (P = 0.043) and stimulate interleukin-12 protein production (P = 0.043) but both were suppressed after the first cycle of romidepsin. Finally, we observed increased specificity for romidepsin-induced CD4+ tumor cell apoptosis and dose-dependent increases in cellular apoptosis of healthy cells in multiple lineages (P < 0.05). These findings raise concern that HDACis suppress immune function in CTCL patients and they support the concurrent use of multiple immune stimulatory agents to preserve the host immune response.

    View details for DOI 10.1002/ajh.23112

    View details for Web of Science ID 000301429300003

    View details for PubMedID 22367792

  • Tandem chemo-mobilization followed by high-dose melphalan and carmustine with single autologous hematopoietic cell transplantation for multiple myeloma BONE MARROW TRANSPLANTATION Chen, A. I., Negrin, R. S., McMillan, A., Shizuru, J. A., JOHNSTON, L. J., Lowsky, R., Miklos, D. B., Arai, S., Weng, W., Laport, G. G., Stockerl-Goldstein, K. 2012; 47 (4): 516-521

    Abstract

    Single autologous hematopoietic cell transplant (AHCT) with high-dose melphalan prolongs survival in patients with multiple myeloma but is not curative. We conducted a study of intensive single AHCT using tandem chemo-mobilization with CY and etoposide followed by high-dose conditioning with melphalan 200 mg/m(2) plus carmustine 15 mg/kg. One hundred and eighteen patients in first consolidation (CON1) and 58 patients in relapse (REL) were transplanted using this intensified approach. Disease response improved from 32% very good PR (VGPR)+CR pre-mobilization to 76% VGPR+CR post transplant in CON1. With a median follow-up of 4.7 years, the median EFS was 2.8 years, and the median OS was 5.1 years in CON1. OS from time of transplant was significantly shorter for REL (3.4 years) compared with CON1 (5.1 years; P=0.02). However, OS from time of diagnosis was similar in REL (6.1 years) and CON1 (6.0 years; P=0.80). The 100-day non-relapse mortality in the CON1 and REL groups was 0% and 7%, respectively. In summary, intensified single AHCT with tandem chemo-mobilization and augmented high-dose therapy is feasible in multiple myeloma and leads to high-quality response rates.

    View details for DOI 10.1038/bmt.2011.106

    View details for Web of Science ID 000302576700008

    View details for PubMedID 21602899

  • Stimulation of natural killer cells with a CD137-specific antibody enhances trastuzumab efficacy in xenotransplant models of breast cancer JOURNAL OF CLINICAL INVESTIGATION Kohrt, H. E., Houot, R., Weiskopf, K., Goldstein, M. J., Scheeren, F., Czerwinski, D., Colevas, A. D., Weng, W., Clarke, M. F., Carlson, R. W., Stockdale, F. E., Mollick, J. A., Chen, L., Levy, R. 2012; 122 (3): 1066-1075

    Abstract

    Trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2; also known as HER-2/neu), is indicated for the treatment of women with either early stage or metastatic HER2(+) breast cancer. It kills tumor cells by several mechanisms, including antibody-dependent cellular cytotoxicity (ADCC). Strategies that enhance the activity of ADCC effectors, including NK cells, may improve the efficacy of trastuzumab. Here, we have shown that upon encountering trastuzumab-coated, HER2-overexpressing breast cancer cells, human NK cells become activated and express the costimulatory receptor CD137. CD137 activation, which was dependent on NK cell expression of the Fc?RIII receptor, occurred both in vitro and in the peripheral blood of women with HER2-expressing breast cancer after trastuzumab treatment. Stimulation of trastuzumab-activated human NK cells with an agonistic mAb specific for CD137 killed breast cancer cells (including an intrinsically trastuzumab-resistant cell line) more efficiently both in vitro and in vivo in xenotransplant models of human breast cancer, including one using a human primary breast tumor. The enhanced cytotoxicity was restricted to antibody-coated tumor cells. This sequential antibody strategy, combining a tumor-targeting antibody with a second antibody that activates the host innate immune system, may improve the therapeutic effects of antibodies against breast cancer and other HER2-expressing tumors.

    View details for DOI 10.1172/JCI61226

    View details for Web of Science ID 000301021500029

    View details for PubMedID 22326955

  • Prophylactive Transcriptome sequencing in Sezary syndrome identifies Sezary cell and mycosis fungoides-associated IncRNAs and novel transcripts BLOOD Lee, C. S., Ungewickell, A., Bhaduri, A., Qu, K., Webster, D. E., Armstrong, R., Weng, W. K., Aros, C. J., Mah, A., Chen, R. O., Lin, M., Sundram, U., Chang, H. Y., Kretz, M., Kim, Y. H., Khavari, P. A. 2012; 120: 3288-3297
  • Adoptive Immunotherapy with Cytokine-Induced Killer Cells for Patients with Relapsed Hematologic Malignancies after Allogeneic Hematopoietic Cell Transplantation BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Laport, G. G., Sheehan, K., Baker, J., Armstrong, R., Wong, R. M., Lowsky, R., Johnston, L. J., Shizuru, J. A., Miklos, D., Arai, S., Benjamin, J. E., Weng, W., Negrin, R. S. 2011; 17 (11): 1679-1687

    Abstract

    Donor leukocyte infusions induce remissions in some patients with hematologic malignancies who relapse after allogeneic hematopoietic cell transplantation (HCT); however, graft-versus-host disease (GVHD) remains the major complication of this strategy. Cytokine-induced killer (CIK) cells are a unique population of cytotoxic T lymphocytes that express the CD3(+)CD56(+) phenotype and show marked up-regulation of the natural killer cell receptor NKG2D (CD314). CIK cells are non-major histocompatibility complex-restricted and NKG2D-dependent in target recognition and cytotoxicity. We explored the feasibility of ex vivo expansion of allogeneic CIK cells in patients with relapsed hematologic malignancies after allogeneic HCT. Eighteen patients (median age, 53 years; range, 20-69 years) received CIK cell infusions at escalating doses of 1 × 10(7) CD3(+) cells/kg (n = 4), 5 × 10(7) CD3(+) cells/kg (n = 6), and 1 × 10(8) CD3(+) cells/kg (n = 8). The median expansion of CD3(+) cells was 12-fold (range, 4- to 91-fold). CD3(+)CD56(+) cells represented a median of 11% (range, 4%-44%) of the harvested cells, with a median 31-fold (range, 7- to 515-fold) expansion. Median CD3(+)CD314(+) cell expression was 53% (range, 32%-78%) of harvested cells. Significant cytotoxicity was demonstrated in vitro against a panel of human tumor cell lines. Acute GVHD grade I-II was seen in 2 patients, and 1 patient had limited chronic GVHD. After a median follow-up of 20 months (range, 1-69 months) from CIK infusion, the median overall survival was 28 months, and the median event-free survival was 4 months. All deaths were due to relapsed disease; however, 5 patients had longer remissions after infusion of CIK cells than from allogeneic HCT to relapse. Our findings indicate that this form of adoptive immunotherapy is well tolerated and induces a low incidence of GVHD, supporting further investigation as an upfront modality to enhance graft-versus-tumor responses in high-risk patient populations.

    View details for DOI 10.1016/j.bbmt.2011.05.012

    View details for Web of Science ID 000296829000016

    View details for PubMedID 21664472

  • Phase I/II Trial of GN-BVC, a Gemcitabine and Vinorelbine-Containing Conditioning Regimen for Autologous Hematopoietic Cell Transplantation in Recurrent and Refractory Hodgkin Lymphoma BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Arai, S., Letsinger, R., Wong, R. M., Johnston, L. J., Laport, G. G., Lowsky, R., Miklos, D. B., Shizuru, J. A., Weng, W., Lavori, P. W., Blume, K. G., Negrin, R. S., Horning, S. J. 2010; 16 (8): 1145-1154

    Abstract

    Autologous hematopoietic cell transplantation with augmented BCNU regimens is effective treatment for recurrent or refractory Hodgkin lymphoma (HL); however, BCNU-related toxicity and disease recurrence remain challenges. We designed a conditioning regimen with gemcitabine in combination with vinorelbine in an effort to reduce the BCNU dose and toxicity without compromising efficacy. In this phase I/II dose escalation study, the gemcitabine maximum tolerated dose (MTD) was determined at 1250 mg/m(2), and a total of 92 patients were treated at this dose to establish safety and efficacy. The primary endpoint was the incidence of BCNU-related toxicity. Secondary endpoints included 2-year freedom from progression (FFP), event-free survival (EFS), and overall survival (OS). Sixty-eight patients (74%) had 1 or more previously defined adverse risk factors for transplant (stage IV at relapse, B symptoms at relapse, greater than minimal disease pretransplant). The incidence of BCNU-related toxicity was 15% (95% confidence interval, 9%-24%). Only 2% of patients had a documented reduction in diffusing capacity of 20% or greater. With a median follow-up of 29 months, the FFP at 2 years was 71% and the OS at 2 years was 83%. Two-year FFP was 96%, 72%, 67%, and 14% for patients with 0 (n = 24), 1 (n = 37), 2 (n = 23), or 3 (n = 8) risk factors, respectively. Regression analysis identified PET status pretransplant and B symptoms at relapse as significant prognostic factors for FFP. This new transplant regimen for HL resulted in decreased BCNU toxicity with encouraging FFP and OS. A prospective, risk-modeled comparison of this new combination with other conditioning regimens is warranted.

    View details for DOI 10.1016/j.bbmt.2010.02.022

    View details for Web of Science ID 000280137800013

    View details for PubMedID 20197102

  • The IgG Fc Receptor FcγRIIIa 158 V/F Polymorphism is Correlated with Rituximab-Induced Neutropenia after Autologous Transplantation in Patients with Non-Hodgkin Lymphoma JOURNAL OF CLINICAL ONCOLOGY Weng, W. K., Negrin, R., Lavori, P., Horning, S. J. 2010; 28: 279-284
  • TLI and ATG conditioning with low risk of graft-versus-host disease retains antitumor reactions after allogeneic hematopoietic cell transplantation from related and unrelated donors BLOOD Kohrt, H. E., Turnbull, B. B., Heydari, K., Shizuru, J. A., Laport, G. G., Miklos, D. B., Johnston, L. J., Arai, S., Weng, W., Hoppe, R. T., Lavori, P. W., Blume, K. G., Negrin, R. S., Strober, S., Lowsky, R. 2009; 114 (5): 1099-1109

    Abstract

    A hematopoietic cell transplantation regimen was adapted from a preclinical model that used reduced-intensity conditioning (RIC) and protected against graft-versus-host disease (GVHD) by skewing residual host T-cell subsets to favor regulatory natural killer T cells. One hundred eleven patients with lymphoid (64) and myeloid (47) malignancies received RIC using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) followed by the infusion of granulocyte colony-stimulating factor-mobilized grafts. Included were 34 patients at least 60 years of age, 32 patients at high risk of lymphoma relapse after disease recurrence following prior autologous transplantation, and 51 patients at high risk of developing GVHD due to lack of a fully human leukocyte antigen (HLA)-matched related donor. Durable chimerism was achieved in 97% of patients. Cumulative probabilities of acute GVHD (grades II-IV) were 2 and 10% of patients receiving related and unrelated donor grafts. Nonrelapse mortality (NRM) at 1 year was less than 4%. Cumulative incidence of chronic GVHD was 27%. The 36-month probability of overall and event-free survival was 60% and 40%, respectively. Disease status at start of conditioning and the level of chimerism achieved after transplantation significantly impacted clinical outcome. The high incidence of sustained remission among patients with active disease at time of transplantation suggests retained graft-versus-tumor reactions. Active trial registration currently at clinicaltrials.gov under IDs of NCT00185640 and NCT00186615.

    View details for DOI 10.1182/blood-2009-03-211441

    View details for Web of Science ID 000268491100025

    View details for PubMedID 19423725

  • Genetic polymorphism of the inhibitory IgG Fc receptor FcRIIb is not associated with clinical outcome in patients with follicular lymphoma treated with rituximab LEUKEMIA & LYMPHOMA Weng, W. K., Levy, R. 2009; 50 (5:723-727)
  • Immunoglobulin G Fc Receptor Polymorphisms Do Not Correlate with Response to Chemotherapy or Clinical Course in Patients with Follicular Lymphoma LEUKEMIA & LYMPHOMA Weng, W. K., Levy, R. 2009; 50 (9): 1494-1500
  • Tumor-specific recombinant idiotype immunisation after chemotherapy as initial treatment for follicular non-Hodgkin lymphoma LEUKEMIA & LYMPHOMA Timmerman, J. M., Vose, J. M., Czerwinski, D. K., Weng, W., Ingolia, D., Mayo, M., Denney, D. W., Levy, R. 2009; 50 (1): 37-46

    Abstract

    Tumor-specific variable regions of the clonal immunoglobulin (idiotype, Id) expressed by B cell non-Hodgkin lymphoma (NHL) can be targeted by active immunotherapy. We conducted a phase I/II trial to determine the safety and immunogenicity of a patient-specific, recombinant, mammalian cell-derived Id protein conjugated to keyhole limpet hemocyanin (Id-KLH; MyVax personalised immunotherapy) in 22 patients with follicular NHL in first remission after chemotherapy. Subjects received five subcutaneous immunisations with MyVax plus locally administered granulocyte-macrophage colony-stimulating factor (GM-CSF). Among 21 evaluable patients, 62% mounted Id-specific immune responses. Evoked anti-Id antibodies recognised both recombinant Id and native Id, and could specifically stain autologous tumor cells. At median follow-up of more than 6 years, median progression-free survival is 38 months. Immunisation of follicular lymphoma patients with MyVax Id-KLH is safe and patients often mount tumor-specific immune responses. These results form the basis of a pivotal phase 3 trial of MyVax in follicular NHL.

    View details for DOI 10.1080/10428190802563355

    View details for Web of Science ID 000262789000009

    View details for PubMedID 19125383

  • A Polymorphism in the Complement Component C1qA Correlates with Prolonged Response Following Rituximab Therapy of Follicular Lymphoma CLINICAL CANCER RESEARCH Racila, E., Link, B. K., Weng, W., Witzig, T. E., Ansell, S., Maurer, M. J., Huang, J., Dahle, C., Halwani, A., Levy, R., Weiner, G. J. 2008; 14 (20): 6697-6703

    Abstract

    Complement may play a role in the clinical response to rituximab and other monoclonal antibody-based therapies of cancer. The purpose of this study was to explore the relationship between the C1qA([276]) polymorphism and the clinical response to rituximab in patients with follicular lymphoma.Genotyping for C1qA([276A/G]) was done in 133 subjects with follicular lymphoma treated with single-agent rituximab, and correlation with clinical response was done using Cox regression analysis.Prolonged remission was observed among subjects that responded clinically to rituximab therapy and were carriers of the A allele compared with homozygous G subjects. Homozygous G subjects had a time to progression of 282 days, whereas A-allele carriers had a time to progression of 708 days [hazard ratio, (HR), 2.5; 95% confidence interval (95% CI), 2.0-3.1; P = 0.02]. Among subjects who achieved complete remission, homozygous G subjects had a time to progression of 250 days, whereas A-allele carriers had a time to progression of 1,118 days (HR, 4.5; 95% CI, 4.1-4.8, P = 0.04). The difference persisted after controlling for CD32 and CD16 polymorphisms. In patients who responded to rituximab used as first-line agent, a linear trend was observed among the C1qA([276]) genotypes, with homozygous A subjects achieving complete response at a higher rate compared with heterozygous or homozygous G subjects.Our findings indicate that polymorphisms in the C1qA gene may affect the clinical response and duration of response to rituximab therapy of follicular lymphoma. These results could have direct implications on designing antibodies with improved efficiency and enhance our understanding of the role of complement in monoclonal antibody therapy.

    View details for DOI 10.1158/1078-0432.CCR-08-0745

    View details for Web of Science ID 000260359600042

    View details for PubMedID 18927313

  • The antileukemia activity of a human anti-CD40 antagonist antibody, HCD122, on human chronic lymphocytic leukemia cells BLOOD Luqman, M., Klabunde, S., Lin, K., Georgakis, G. V., Cherukuri, A., Holash, J., Goldbeck, C., Xu, X., Kadel, E. E., Lee, S. H., Aukerman, S. L., Jallal, B., Aziz, N., Weng, W., Wierda, W., O'Brien, S., Younes, A. 2008; 112 (3): 711-720

    Abstract

    B-cell chronic lymphocytic leukemia (B-CLL) is a lymphoproliferative disorder characterized by the surface expression of CD20, CD5 antigens, as well as the receptor CD40. Activation of CD40 by its ligand (CD40L) induces proliferation and rescues the cells from spontaneous and chemotherapy-induced apoptosis. CD40 activation also induces secretion of cytokines, such as IL-6, IL-10, TNF-alpha, IL-8, and GM-CSF, which are involved in tumor cell survival, migration, and interaction with cells in the tumor microenvironment. Here we demonstrate that in primary B-CLL tumor cells, the novel antagonist anti-CD40 monoclonal antibody, HCD122, inhibits CD40L-induced activation of signaling pathways, proliferation and survival, and secretion of cytokines. Furthermore, HCD122 is also a potent mediator of antibody-dependent cellular cytotoxicity (ADCC), lysing B-CLL cells more efficiently than rituximab in vitro, despite a significantly higher number of cell surface CD20 binding sites compared with CD40. Unlike rituximab, however, HCD122 (formerly CHIR-12.12) does not internalize upon binding to the cells. Our data suggest that HCD122 may inhibit B-CLL growth by blocking CD40 signaling and by ADCC-mediated cell lysis.

    View details for DOI 10.1182/blood-2007-04-084756

    View details for Web of Science ID 000258257900039

    View details for PubMedID 18497318

  • Humoral immune response and immunoglobulin G Fc receptor genotype are associated with better clinical outcome following idiotype vaccination in follicular lymphoma patients regardless their response to induction chemotherapy. BLOOD Weng, W. K., Czerwinski , D., Levy, R. 2007; 109: 951-3
  • Immune-mediated antitumor effects with antibody therapy. American Society of Clinical Oncology Educational Book Weng WK 2005: 200-4
  • Clinical outcome of lymphoma patients after idiotype vaccination is correlated with humoral immune response and immunoglobulin G Fc receptor genotype. JOUNRAL OF CLINICAL ONCOLOGY Weng, W. K., Czerwinski , D., Timmerman, J., Hsu, F. J., Levy, R. 2004; 22: 4717
  • Two immunoglobulin G fragment C receptor polymorphisms independently predict response to rituximab in patients with follicular lymphoma JOURNAL OF CLINICAL ONCOLOGY Weng, W. K., Levy, R. 2003; 21 (21): 3940-3947

    Abstract

    Although rituximab is now routinely used in the treatment of B-cell non-Hodgkin's lymphoma, the mechanism of its antitumor effect is not clear. One potential mechanism of action involves antibody-dependent cellular cytotoxicity (ADCC). Two aspects of ADCC influence the effectiveness of this process: the susceptibility of tumor cells and the activation of effector cells via their immunoglobulin G fragment C receptors (Fc gamma Rs). Several Fc gamma R polymorphisms have been identified that may affect the killing function of natural killer cells and macrophages.The pretreatment tumor cells from 43 patients with follicular lymphoma were tested for their intrinsic susceptibility to rituximab-mediated ADCC. In addition, the Fc gamma RIIIa (CD16) and Fc gamma RIIa (CD32) polymorphisms were determined in an expanded group of 87 patients. The results were then correlated with clinical outcome of these patients.No difference was found between the susceptibility of tumors from patients who clinically responded to rituximab versus those who did not respond. Conversely, both the Fc gamma RIIIa 158 valine/valine and the Fc gamma RIIa 131 histidine/histidine genotypes were found to be independently associated with the response rate and freedom from progression.These data support the hypothesis that ADCC plays an important role in the clinical effect of rituximab at the level of the effector cell. It will be important to include information on Fc receptor polymorphisms in future trials of rituximab therapy.

    View details for DOI 10.1200/JCO.2003.05.013

    View details for Web of Science ID 000186295500010

    View details for PubMedID 12975461

  • Hepatitis C virus (HCV) and lymphomagenesis LEUKEMIA & LYMPHOMA Weng, W. K., Levy, S. 2003; 44 (7): 1113-1120

    Abstract

    Hepatitis C virus (HCV) is the major cause for non-A, non-B hepatitis. Most HCV-infected individuals do not clear the virus resulting in a chronic infection that may potentially lead to liver cirrhosis and hepatocellular carcinoma. In addition to hepatic manifestations, HCV infection is associated with B cell lymphoproliferative disorders, including mixed cryoglobulinemia, usually a benign condition, and overt B cell lymphoma. A direct role of HCV infection in the genesis of these B cell lymphoproliferative disorders has been suggested initially by epidemiological studies and is supported by recent studies, which analyzed the monoclonal B cells that proliferate in these disorders. How HCV induces B cell lymphoproliferative disorders is still unclear, it is probably not due to direct change of phenotype in B cells after viral infection, but may be due to an HCV-antigen driven process. Support for this hypothesis comes from the analysis of monoclonal B cells found in these disorders, which use a restricted repertoire of immunoglobulin variable region genes that are similar to those used by B cells that secrete anti-HCV antibodies. The fact that monoclonal IgM is resolved in HCV-infected patients who responded to anti-viral treatment supports the linkage between antigen persistence and B cell proliferation. Finally, the linkage between benign B cell proliferation and overt lymphoma is supported by the identification of a pre-malignant B cell clone that subsequently converted to an overt B cell lymphoma. The molecular basis for viral induced B cell proliferation is still unknown. One possibility is that HCV stimulates the proliferation of monoclonal B cells via their HCV-specific B cell receptor (BCR) on the cell surface. Binding of the HCVenvelope proteins to a cellular ligand, CD81, may also enhance this antigen-driven process. A recent report on regression of splenic marginal zone lymphoma after anti-viral treatment with interferon and ribavirin has significantly strengthened the cause-effect relationship between HCV infection and lymphoma. Further studies should determine whether BCRs expressed on HCV-associated lymphomas, particularly those that regress in response to anti-viral therapy, bind HCV antigens that stimulate their proliferation.

    View details for DOI 10.1080/1042819031000076972

    View details for Web of Science ID 000182775000003

    View details for PubMedID 12916862

  • Expression of complement inhibitors CD46, CD55, and CD59 on tumor cells does not predict clinical outcome after rituximab treatment in follicular non-Hodgkin lymphoma BLOOD Weng, W. K., Levy, R. 2001; 98 (5): 1352-1357

    Abstract

    Rituximab is a chimeric monoclonal antibody that targets B-cell-specific antigen CD20 and an effective treatment for B-cell non-Hodgkin lymphoma. Although it is readily used in clinical practice, the exact mechanism of its antitumor effect is unclear. One potential mechanism involves complement-mediated cytotoxicity. It has been shown that rituximab induces complement-mediated cytotoxicity in follicular lymphoma cells in vitro, and complement inhibitors CD55 and CD59 may regulate this process. To determine whether complement inhibitors play a role in regulating the antitumor effect of rituximab, the expression of complement inhibitors CD46, CD55, and CD59 was analyzed in pretreatment tumor cells from 29 rituximab-treated follicular lymphoma patients. Among them, 8 patients achieved complete responses, 11 patients achieved partial responses, and 10 patients showed no or minimal responses to rituximab treatment. Expression of surface CD20, CD46, CD55, and CD59 was determined by 2-color flow cytometry. Although the CD59 level was slightly lower in the complete response group, there was no statistically significant difference in the expression of individual complement inhibitor CD46 (mean channel fluorescence [MCF]: NR, 26.4; PR, 21.9; CR, 29.9), CD55 (MCF: NR, 16.4; PR, 14.9; CR, 23.2), or CD59 (MCF: NR, 41.6; PR, 40.6; CR, 30.6), the combination of any 2 inhibitors, or all 3 on tumor cells from 3 response groups. In addition, there was no difference in the rituximab-induced complement-mediated cytotoxicity in an in vitro assay using tumor cells from 3 response groups. Thus, CD46, CD55, and CD59 expression on pretreatment tumor cells, or their susceptibility to in vitro complement-mediated killing, does not predict clinical outcome after rituximab treatment.

    View details for Web of Science ID 000170685000014

    View details for PubMedID 11520782

  • Differential induction of DNA-binding activities following CD19 cross-linking in human B lineage cells JOURNAL OF IMMUNOLOGY Weng, W. K., Shah, N., O'Brien, D., Van Ness, B., LeBien, T. W. 1997; 159 (11): 5502-5508

    Abstract

    The B cell-specific cell surface molecule CD19 is expressed at all stages of B cell development, including normal plasma cells, and mediates signal transduction via interaction with cytoplasmic effector proteins. Cross-linking CD19 on early human B lineage cells induces the formation of a CD19/Vav/phosphatidylinositol-3 kinase complex, tyrosine phosphorylation of CD19 and Vav, and activation of the Ras pathway. To further explore the ramifications of CD19 signaling, the current study examined whether phosphorylation of Elk-1, activation of activator protein-1 (AP-1), or activation of nuclear factor-kappaB (NF-kappaB) transcription factors occurred following CD19 cross-linking. The cells used were the BLIN-1 pre-B cell line expressing low levels of cell surface mu heavy chain associated with surrogate light chain and the 1E8 immature B cell line expressing cell surface mu/kappa. Lysates from CD19 cross-linked 1E8 cells induced robust phosphorylation of an Elk-1 fusion protein in vitro, whereas no phosphorylation of Elk-1 fusion protein occurred using lysates from CD19 cross-linked BLIN-1 cells. An electrophoretic mobility shift assay employing AP-1 and NF-kappaB consensus oligonucleotides was used to demonstrate that AP-1 -binding activity increased, while constitutive NF-kappaB-binding activity was not enhanced, following 2 h of CD19 cross-linking in 1E8 cells. Supershift experiments revealed that JunD and c-Fos proteins mediated anti-CD19 induced AP-1-binding activity in 1E8 cells. In contrast, CD19 cross-linking in BLIN-1 cells resulted in the induction of NF-kappaB, but had no apparent effect on AP-1-binding activity. These data suggest that CD19-mediated signal transduction activates different transcription factors at juxtaposed stages of B cell development that may culminate in the activation or suppression of distinct sets of genes.

    View details for Web of Science ID 000071914800039

    View details for PubMedID 9548490

  • SIGNALING THROUGH CD19 ACTIVATES VAV MITOGEN-ACTIVATED PROTEIN-KINASE PATHWAY AND INDUCES FORMATION OF A CD19/VAV/PHOSPHATIDYLINOSITOL 3-KINASE COMPLEX IN HUMAN B-CELL PRECURSORS JOURNAL OF BIOLOGICAL CHEMISTRY Weng, W. K., Jarvis, L., LeBien, T. W. 1994; 269 (51): 32514-32521

    Abstract

    The B cell-specific cell surface molecule CD19 plays a role in regulating immunoglobulin (Ig) receptor signaling, and cross-linking CD19 activates several signaling molecules in mature human B cells. In surface Ig-negative B cell precursors, a protein tyrosine kinase (PTK)-dependent homotypic aggregation response can be triggered by cross-linking CD19. In the current study, we examined the outcome of PTK-mediated signal transduction following CD19 cross-linking on surface Ig negative and surface Ig positive B cell lines, as well as freshly isolated surface Ig-negative B cell precursors. PTK activation resulted in the tyrosine phosphorylation of multiple protein substrates and peaked at 0.5-1 min following CD19 cross-linking in all B-lineage cells examined. One of the tyrosine-phosphorylated substrates was identified as the hematopoietic-specific protein Vav, a guanine nucleotide exchange factor that activates the Ras pathway. Evidence consistent with Ras pathway activation was also demonstrated by MEK activation and subsequent phosphorylation of a MAP kinase fusion protein. CD19 cross-linking, sequential immunoprecipitation, and Western blotting revealed that: (a) Vav becomes associated with CD19, (b) phosphatidylinositol 3-kinase (PI 3-kinase) becomes associated with CD19, and (c) PI 3-kinase becomes associated with Vav. No such physical interaction occurred following control IgG1 cross-linking or cross-linking of class I major histocompatability complex cell surface molecules. Coupled with a previous report (Tuveson, D.A., Carter, R.H., Soltoff, S.P., and Fearon, D.T. (1993) Science 260, 986-988), our data support a model in which CD19 cross-linking induces the formation of a signaling complex that leads to the activation of two pathways involving Ras and PI 3-kinase.

    View details for Web of Science ID A1994PX30400074

    View details for PubMedID 7528218

  • FUNCTIONAL EFFECT OF IL-7-ENHANCED CD19 EXPRESSION ON HUMAN B-CELL PRECURSORS JOURNAL OF IMMUNOLOGY Wolf, M. L., Weng, W. K., STIEGLBAUER, K. T., Shah, N., LeBien, T. W. 1993; 151 (1): 138-148

    Abstract

    We have previously demonstrated that IL-7 can sustain the growth of normal human B cell precursors (BCP) for several weeks on bone marrow-derived stromal cells. Flow cytometric analysis of BCP recovered from IL-7 supplemented cultures revealed two- to threefold higher levels of cell surface CD19, compared with BCP maintained without IL-7. Short term culture of BCP showed that IL-7 enhancement of CD19 was dose-dependent, with increases detected by day 1 and plateauing by days 3 to 4. IL-7 increased cell-surface CD19 on small lymphoid cells, and to a greater degree on lymphoblasts, whereas cell-surface CD10 was unchanged. The CD34+/CD19+ pro-B cell population showed a greater increase in cell-surface CD19 compared with pre-B and immature B cells. IL-1, IL-3, IL-4, IL-6, and stem-cell factor had no effect on CD19. The potential functional significance of IL-7-enhanced cell-surface CD19 was examined using a F(ab')2 fragment of anti-CD19. This reagent had no effect on [3H]TdR incorporation in BCP cultured in the absence or presence of IL-7 for 5 days, but homotypic adhesion of BCP was induced at a concentration as low as 1.0 ng/ml F(ab')2 anti-CD19. IL-7 enhanced the F(ab')2 anti-CD19 induced homotypic adhesion of BCP in a dose-dependent manner. Blocking antibody studies indicated that members of the beta 1 or beta 2 integrin families did not mediate anti-CD19-induced homotypic adhesion, even though the adhesion was completely ablated by 10 mM EDTA. The pre-B and immature leukemic B cell lines NALM-6 and 1E8 expressed comparable levels of cell-surface CD19, and exhibited comparable increases after IL-7 stimulation. However, their homotypic adhesion responses to anti-CD19 were different. NALM-6 cells exhibited a strong homotypic adhesion response to anti-CD19 that was EDTA-resistant, and beta 1/beta 2 integrin independent. 1E8 cells only responded to anti-CD19 after IL-7 stimulation; this response was EDTA-sensitive and beta 1/beta 2 integrin independent. These collective results indicate that IL-7 not only acts as a growth factor for human BCP, but also regulates signal transduction through cell-surface CD19.

    View details for Web of Science ID A1993LM57900015

    View details for PubMedID 7686930

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