Doctor of Philosophy, University Of Tokyo (2008)
Doctor of Medicine, Tsukuba University (2001)
Gastric antral vascular ectasia (GAVE) is an angiodysplastic disorder that causes gastric bleeding. GAVE can develop as a complication of hematopoietic stem cell transplantation (HSCT-GAVE), and it has been suggested that it may be associated with oral administration of busulfan. We report two cases of HSCT-GAVE after a conditioning regimen containing intra-venous busulfan (ivBu), not oral busulfan. The first case, a 42-year-old woman with blastic plasmacytoid dendritic cell neoplasm, underwent second allogeneic HSCT with conditioning regimen consisting of cyclophosphamide (120 mg/kg) and ivBu (12.8 mg/kg). HSCT-GAVE developed on day 84 post-transplant, and argon plasma coagulation (APC) was performed successfully. The second case, a 60-year-old woman with acute myelogenous leukemia, underwent allogeneic HSCT with the conditioning regimen consisting of ivBu (12.8 mg/kg) and fludarabine (150 mg/kg). She developed melena and was diagnosed with GAVE by endoscopy on day 145 post-transplant. Although complete hemostasis was not achieved despite four administrations of APCs, the melena spontaneously terminated on day 235 post-transplant. To our knowledge, this is the first report describing HSCT-GAVE after ivBU-based HSCT. Although there is no established therapy for HSCT-GAVE, APC may be an option for HSCT-GAVE.
View details for DOI 10.1007/s12185-013-1342-8
View details for Web of Science ID 000321769400020
View details for PubMedID 23632949
Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and it has several morphologic and clinicopathologic variants. The prognosis of DLBCL can vary according to specific genetic and immunophenotypic abnormalities. The aim of this study was to investigate the prognostic impact of previously identified prognostic factors, such as activated B cell-like immunophenotype, CD5, BCL2 and MYC rearrangement (MYC-R), in patients treated with rituximab. We retrospectively analyzed the prognosis of 100 patients with DLBCL (median age, 66.5 years) treated with rituximab-containing chemotherapy. The 3-year overall survival (OS) and progression-free survival (PFS) were 66% and 62%. Outcomes were significantly worse in patients with MYC-R in 3-year OS (50% vs. 67.8%, p = 0.043) and PFS (30% vs. 57.8%, p = 0.003), and multivariate analysis showed that this finding was independent of the International Prognostic Index (IPI). Immunostaining by Muris algorithm had the highest predictive power among the three algorithms. However, other previously reported prognostic factors, such as BCL2 and CD5, were not good predictors of outcomes in these patients. In conclusion, our data suggest that fluorescence in situ hybridization (FISH) analysis for MYC-R can predict outcomes in response to rituximab-containing chemotherapy in Japanese patients with DLBCL.
View details for PubMedID 23363269
Single-nucleotide polymorphism genotyping microarray (SNP array) analysis provides detailed information on chromosomal copy number aberrations. To obtain detailed information on genomic abnormalities related to pathogenesis or prognosis of multiple myeloma (MM), we performed 250K SNP array analysis in 39 MM patients and 11 cell lines. We identified an accumulation of deletions and uniparental disomies at 22q12.1. Among the hyperdiploid MM cases, chromosomal imbalance at this locus was associated with poor prognosis. On sequencing, we also found a mutation in the seizure-related 6 homolog (mouse)-like (SEZ6L) gene located at ch.22q12.1 in an MM cell line, NOP1. We further found isolated deletions in 17 genes, five of which are known tumor suppressor genes. Of these, deletion of protein tyrosine phosphatase, receptor type D (PTPRD) was found in three samples, including two patients. Consistent with previous reports, non-hyperdiploid MM, deletion of 13q (del13q) and gain of 1q in non-hyperdiploid MMs were predictive of poor prognosis (p = 0.039, p = 0.049, and p = 0.013, respectively). However, our analysis revealed that unless accompanied by gain of 1q, the prognosis of non-hyperdiploid MM was as good as that of hyperdiploid MM. Thus, SNP array analysis provides significant information useful to understanding the pathogenesis and prognosis of MM.
View details for DOI 10.1007/s12185-012-1171-1
View details for Web of Science ID 000309954300014
View details for PubMedID 22972171
Retinoic acid related orphan receptor gamma-t (ROR?t) is known to be a master regulator of Th17-cell development. In this study, we generated ROR?t-overexpressing transgenic (ROR?t Tg) mice in which transgene expression was driven by the CD2 promoter, and found that these mice developed polyclonal plasmacytosis and autoantibody production. ROR?t Tg mice were generated on a C57BL/6 background, and also were intercrossed with BALB/c mice. BALB/c F1 (BALB/F1) ROR?t Tg mice developed massive polyclonal plasma-cytosis, and had shorter life spans. Splenomegaly and infiltration of plasma cells into the lung were observed. Hyperglobulinemia, anti-double-stranded DNA antibodies, anti-erythrocyte antibodies, and anti-platelet antibodies were detected in BALB/F1 ROR?t Tg mice. In the present study, polyclonal plasmacytosis in BALB/F1 ROR?t Tg mice appeared to be due to the induction of excessive IL-6 production by IL-17. We detected increased numbers of CD11b(+) cells that produced IL-6. We also generatedIL-6-deficient ROR?t Tg BALB/F1 background mice, which displayed high levels of serum IL-17, but did not develop severe hyperglobulinemia. Excessive IL-6 production by several cell types, including macrophages, in BALB/F1 ROR?t Tg mice, might effect the development of plasma-cytosis. These results suggest that ROR?t plays important roles in the development of plasmacytosis and autoantibody production.
View details for DOI 10.1002/eji.201142250
View details for Web of Science ID 000307119600012
View details for PubMedID 22623033
Bronchiolitis obliterans (BO) is one of the serious, noninfectious pulmonary complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Early diagnosis of BO is usually difficult because patients are often asymptomatic at an initial stage of the disease and pathologic findings are available mostly at the late stages. Therefore, the diagnosis of the disease is based on the pulmonary function test using the National Institute of Health consensus criteria. Here, we report a case of slowly progressive BO. A biopsy specimen at an early stage demonstrated alveolar destruction with lymphocyte infiltration in bronchial walls and mild narrowing of bronchioles without fibrosis, those were strongly indicative of initial pathologic changes of BO. Definitive BO followed, which was proven by both clinical course and autopsy. While alloreactive lymphocytes associated with chronic graft-versus-host disease are believed to initiate BO, we present a rare case that directly implies such a scenario.
View details for DOI 10.1155/2012/957612
View details for PubMedID 22957280
The prognosis of adult Burkitt lymphoma (BL) has improved in western countries since the introduction of high-dose methotrexate (HD-MTX)-containing chemotherapy. Here we analyzed nine consecutive Japanese patients diagnosed with BL at our institution. All except for the three elderly (> 70 years) patients were treated with a regimen including 13 g/m(2) HD-MTX in total, divided into 3 cycles. The median follow-up period was 56 months (range 38-118). All the nine patients achieved complete remission and have not shown any disease progression, including the three elderly patients who received reduced doses or alternative treatments. These observations suggest that chemotherapy including 13 g/m(2) HD-MTX in total is tolerable and effective in Japanese adult BL patients aged < 70 and that BL is curable even if developed in those who are > 70 years.
View details for PubMedID 22104309
B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma (iDLBCL/BL) is a newly categorized lymphoma in the WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues v4. This lymphoma has characteristics of both DLBCL and BL, morphologically and genetically. We report a case with therapy-resistant iDLBCL/BL, which used to be categorized as BL in the WHO Classification v3. This case showed strong BCL2 staining, otherwise exhibiting features of BL. The case was treated with intensive chemotherapy containing high-dose methotrexate, cyclophosphamide, and cytarabine. However, soon after the chemotherapy, the lymphoma relapsed in the central nervous system and was resistant to whole-brain radiation therapy and allogeneic stem cell transplantation. The patient died 37 days after the transplantation. The clinical course was different from that of typical BL in terms of resistance to intensive chemotherapy, in agreement with the characteristics of iDLBCL/BL.
View details for PubMedID 21628859
The nature of the in vivo cellular events underlying thrombus formation mediated by platelet activation remains unclear because of the absence of a modality for analysis. Lymphocyte adaptor protein (Lnk; also known as Sh2b3) is an adaptor protein that inhibits thrombopoietin-mediated signaling, and as a result, megakaryocyte and platelet counts are elevated in Lnk-/- mice. Here we describe an unanticipated role for Lnk in stabilizing thrombus formation and clarify the activities of Lnk in platelets transduced through integrin alphaIIbbeta3-mediated outside-in signaling. We equalized platelet counts in wild-type and Lnk-/- mice by using genetic depletion of Lnk and BM transplantation. Using FeCl3- or laser-induced injury and in vivo imaging that enabled observation of single platelet behavior and the multiple steps in thrombus formation, we determined that Lnk is an essential contributor to the stabilization of developing thrombi within vessels. Lnk-/- platelets exhibited a reduced ability to fully spread on fibrinogen and mediate clot retraction, reduced tyrosine phosphorylation of the beta3 integrin subunit, and reduced binding of Fyn to integrin alphaIIbbeta3. These results provide new insight into the mechanism of alphaIIbbeta3-based outside-in signaling, which appears to be coordinated in platelets by Lnk, Fyn, and integrins. Outside-in signaling modulators could represent new therapeutic targets for the prevention of cardiovascular events.
View details for DOI 10.1172/JCI39503
View details for Web of Science ID 000273495700023
View details for PubMedID 20038804
Embryonic stem cells (ESCs) could potentially compensate for the lack of blood platelets available for use in transfusions. Here, we describe a new method for generating mouse ESC-derived platelets (ESPs) that can contribute to hemostasis in vivo. Flow cytometric sorting of cells from embryoid bodies on day 6 demonstrated that c-Kit(+) integrin alpha IIb (alpha IIb)(+) cells, but not CD31(+) cells or vascular endothelial cadherin(+) cells, are capable of megakaryopoiesis and the release of platelet-like structures by day 12. alpha IIb beta 3-expressing ESPs exhibited ectodomain shedding of glycoprotein (GP)Ibalpha, GPV, and GPVI, but not alpha IIb beta 3 or GPIb beta. ESPs showed impaired alpha IIb beta 3 activation and integrin-mediated actin reorganization, critical events for normal platelet function. However, the administration of metalloproteinase inhibitors GM6001 or TAPI-1 during differentiation increased the expression of GPIb alpha, improving both thrombogenesis in vitro and posttransfusion recovery in vivo. Thus, the regulation of metalloproteinases in culture could be useful for obtaining high-quality, efficacious ESPs as an alternative platelet source for transfusions.
View details for DOI 10.1084/jem.20071482
View details for Web of Science ID 000258528500020
View details for PubMedID 18663123
Human embryonic stem cells (hESCs) could potentially represent an alternative source for blood transfusion therapies and a promising tool for studying the ontogeny of hematopoiesis. When we cultured hESCs on either C3H10T1/2 or OP-9 cells to facilitate hematopoiesis, we found that exogenous administration of vascular endothelial growth factor promoted the emergence of sac-like structures, which we named embryonic stem cell-derived sacs (ES-sacs). These ES-sacs consisted of multiple cysts demarcated by cellular monolayers that retained some of the properties of endothelial cells. The spherical cells inside ES-sacs expressed primarily CD34, along with VE-cadherin, CD31, CD41a, and CD45, and were able to form hematopoietic colonies in semisolid culture and to differentiate into mature megakaryocytes by day 24 in the presence of thrombopoietin. Apparently, ES-sacs provide a suitable environment for hematopoietic progenitors. Relatively large numbers of mature megakaryocytes could be induced from the hematopoietic progenitors within ES-sacs, which were then able to release platelets that displayed integrin alpha IIb beta 3 activation and spreading in response to ADP or thrombin. This novel protocol thus provides a means of generating platelets from hESCs, which could serve as the basis for efficient production of platelets for clinical transfusion and studies of thrombopoiesis.
View details for DOI 10.1182/blood-2007-10-117622
View details for Web of Science ID 000256336500011
View details for PubMedID 18388179
Actin polymerization is crucial in throm-bopoiesis, platelet adhesion, and mega-karyocyte (MK) and platelet spreading. The Wiskott-Aldrich syndrome protein (WASp) homolog WAVE functions downstream of Rac and plays a pivotal role in lamellipodia formation. While MKs and platelets principally express WAVE1 and WAVE2, which are associated with Abi1, the physiologic significance of WAVE isoforms remains undefined. We generated WAVE2(-/-) embryonic stem (ES) cells because WAVE2-null mice die by embryonic day (E) 12.5. We found that while WAVE2(-/-) ES cells differentiated into immature MKs on OP9 stroma, they were severely impaired in terminal differentiation and in platelet production. WAVE2(-/-) MKs exhibited a defect in peripheral lamellipodia on fibrinogen even with phorbol 12-myristate 13-acetate (PMA) costimulation, indicating a requirement of WAVE2 for integrin alpha(IIb)beta(3)-mediated full spreading. MKs in which expression of Abi1 was reduced by small interfering RNA (siRNA) exhibited striking similarity to WAVE2(-/-) MKs in maturation and spreading. Interestingly, the knockdown of IRSp53, a Rac effector that preferentially binds to WAVE2, impaired the development of lamellipodia without affecting proplatelet production. In contrast, thrombopoiesis in vivo and platelet spreading on fibrinogen in vitro were intact in WAVE1-null mice. These observations clarify indispensable roles for the WAVE2/Abi1 complex in alpha(IIb)beta(3)-mediated lamellipodia by MKs and platelets through Rac and IRSp53, and additionally in thrombopoiesis independent of Rac and IRSp53.
View details for DOI 10.1182/blood-2007-04-085860
View details for Web of Science ID 000250946300030
View details for PubMedID 17664349