Michihiro Hidaka

Allogeneic hematopoietic stem cell transplantation for adult T-cell leukemia-lymphoma with special emphasis on preconditioning regimen: a nationwide retrospective study.

Adult T-cell leukemia-lymphoma (ATL) is an intractable mature T-cell neoplasm. We performed a nationwide retrospective study of allogeneic hematopoietic stem cell transplantation (HSCT) for ATL in Japan, with special emphasis on the effects of the preconditioning regimen. This is the largest study of ATL patients receiving HSCT. Median overall survival (OS) and 3-year OS of bone marrow or peripheral blood transplantation recipients (n = 586) was 9.9 months (95% confidence interval, 7.4-13.2 months) and 36% (32%-41%), respectively. These values for recipients of myeloablative conditioning (MAC; n = 280) and reduced intensity conditioning (RIC; n = 306) were 9.5 months (6.7-18.0 months) and 39% (33%-45%) and 10.0 months (7.2-14.0 months) and 34% (29%-40%), respectively. Multivariate analysis demonstrated 5 significant variables contributing to poorer OS, namely, older age, male sex, not in complete remission, poor performance status, and transplantation from unrelated donors. Although no significant difference in OS between MAC and RIC was observed, there was a trend indicating that RIC contributed to better OS in older patients. Regarding mortality, RIC was significantly associated with ATL-related mortality compared with MAC. In conclusion, allogeneic HSCT not only with MAC but also with RIC is an effective treatment resulting in long-term survival in selected patients with ATL.

Allogeneic Hematopoietic Stem Cell Transplantation Using Reduced-Intensity Conditioning for Adult T Cell Leukemia/Lymphoma: Impact of Antithymocyte Globulin on Clinical Outcome

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for adult T cell leukemia/lymphoma (ATLL), but shows high mortality. We evaluated the feasibility of reduced-intensity transplantation using fludarabine and busulfan, with particular focus on the clinical impact of antithymocyte globulin (ATG) in the conditioning regimen. Fourteen elderly patients with aggressive ATLL were enrolled in the current study without ATG, and were compared to those in 15 patients who were treated similarly, but with ATG, in our previous study. Engraftment was prompt, and treatment was tolerable. Overall (OS) and progression-free survival (PFS) at 3 years were 36% and 31%, respectively. HTVL-1 proviral load became undetectable by the polymerase chain reaction in 62% of patients. Compared to the previous study with ATG, complete donor chimera was significantly delayed. Although early relapse tended to be decreased, OS or PFS was not improved significantly. Analysis of combined data from both our current and previous studies disclosed that grade I-II acute GVHD was the only factor that favorably affected OS and PFS. These data suggested the presence of a graft-versus-ATLL effect and the feasibility of a transplant procedure without ATG in elderly ATLL patients, but could not demonstrate the clinical benefit of incorporating ATG.

A Vascular Gene Trap Screen Defines RasGRP3 as an Angiogenesis-Regulated Gene Required for the Endothelial Response to Phorbol Esters

ABSTRACT We identified Ras guanine-releasing protein 3 (RasGRP3) as a guanine exchange factor expressed in blood vessels via an embryonic stem (ES) cell-based gene trap screen to identify novel vascular genes. RasGRP3 is expressed in embryonic blood vessels, down-regulated in mature adult vessels, and reexpressed in newly formed vessels during pregnancy and tumorigenesis. This expression pattern is consistent with an angiogenic function for RasGRP3. Although a loss-of-function mutation in RasGRP3 did not affect viability, RasGRP3 was up-regulated in response to vascular endothelial growth factor (VEGF) stimulation of human umbilical vein endothelial cells, placing RasGRP3 regulation downstream of VEGF signaling. Phorbol esters mimic the second messenger diacylglycerol (DAG) in activating both protein kinase C (PKC) and non-PKC phorbol ester receptors such as RasGRP3. ES cell-derived wild-type blood vessels exposed to phorbol myristate acetate (PMA) underwent extensive aberrant morphogenesis that resulted in the formation of large endothelial sheets rather than properly branched vessels. This response to PMA was completely dependent on the presence of RasGRP3, as mutant vessels were refractory to the treatment. Taken together, these findings show that endothelial RasGRP3 is up-regulated in response to VEGF stimulation and that RasGRP3 functions as an endothelial cell phorbol ester receptor in a pathway whose stimulation perturbs normal angiogenesis. This suggests that RasGRP3 activity may exacerbate vascular complications in diseases characterized by excess DAG, such as diabetes.

Related transplantation with HLA-1 Ag mismatch in the GVH direction and HLA-8/8 allele-matched unrelated transplantation: a nationwide retrospective study

To clarify which is preferable, a related donor with an HLA-1 Ag mismatch at the HLA-A, HLA-B, or HLA-DR loci in the graft-versus-host (GVH) direction (RD/1AG-MM-GVH) or an HLA 8/8-allele (HLA-A, HLA-B, HLA-C, and HLA-DRB1)-matched unrelated donor (8/8-MUD), we evaluated 779 patients with acute leukemia, chronic myelogenous leukemia, or myelodysplastic syndrome who received a T cell-replete graft from an RD/1AG-MM-GVH or 8/8-MUD. The use of an RD/1AG-MM-GVH donor was significantly associated with a higher overall mortality rate than the use of an 8/8-MUD in a multivariate analysis (hazard ratio, 1.49; P < .001), and this impact was statistically significant only in patients with standard-risk diseases (P = .001). Among patients with standard-risk diseases who received transplantation from an RD/1AG-MM-GVH donor, the presence of an HLA-B Ag mismatch was significantly associated with a lower overall survival rate than an HLA-DR Ag mismatch because of an increased risk of treatment-related mortality. The HLA-C Ag mismatch or multiple allelic mismatches were frequently observed in the HLA-B Ag-mismatched group, and were possibly associated with the poor outcome. In conclusion, an 8/8-MUD should be prioritized over an RD/1AG-MM-GVH donor during donor selection. In particular, an HLA-B Ag mismatch in the GVH direction has an adverse effect on overall survival and treatment-related mortality in patients with standard-risk diseases.

Rituximab for the treatment of corticosteroid-refractory chronic graft-versus-host disease

We prospectively evaluated the safety and efficacy of the anti-CD20 chimeric monoclonal antibody rituximab for the treatment of corticosteroid-refractory chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. Seven patients were treated with 375 mg/m2 rituximab weekly for 4 consecutive weeks. Rituximab was well tolerated with no severe toxicity observed during treatment. At 1 year, 3 patients showed a partial response to rituximab therapy, 3 had stable disease, and 1 had progressive disease. Rituximab allowed a reduction in the dose of steroids in 4 patients. Responsive manifestations included mild to moderate skin and oral lesions, and immune hemolytic anemia, and thrombocytopenia. Severe manifestations involving the skin, fascia, and eye did not respond to treatment. These observations suggest that rituximab therapy may be effective for select patients with corticosteroid-refractory chronic GVHD that is not advanced.

Characteristic mode of action of gangliosides in selective modulation of CD4 on human T lymphocytes

We have explored the possible mechanisms for selective modulation by gangliosides of CD4 on human T lymphocytes and subsequent re-expression of CD4. Indirect immunofluorescence staining with anti-CD4 antibodies revealed newly internalized CD4 in ganglioside-treated cells after membrane permeabilization with 0.1% saponin. Cycloheximide and other metabolic inhibitors did not alter the modulation but inhibited significantly the re-expression of CD4. These results suggest both selective modulation of CD4 by a process of endocytosis and re-expression of CD4 through de novo protein synthesis.

Japan Clinical Oncology Group (JCOG) prognostic index and characterization of long-term survivors of aggressive adult T-cell leukaemia-lymphoma (JCOG0902A)

This study evaluated the clinical features of 276 patients with aggressive adult T‐cell leukaemia‐lymphoma (ATL) in 3 Japan Clinical Oncology Group (JCOG) trials. We assessed the long‐term survivors who survived >5 years and constructed a prognostic index (PI), named the JCOG‐PI, based on covariates obtained by Cox regression analysis. The median survival time (MST) of the entire cohort was 11 months. In 37 patients who survived >5 years, no disease‐related deaths in 10 patients with lymphoma‐type were observed in contrast to the 10 ATL‐related deaths in other types. In multivariate analysis of 193 patients, the JCOG‐PI based on corrected calcium levels and performance status identified moderate and high risk groups with an MST of 14 and 8 months respectively (hazard ratio, 1·926). The JCOG‐PI was reproducible in an external validation. Patients with lymphoma‐type who survived >5 years might have been cured. The JCOG‐PI is valuable for identifying patients with extremely poor prognosis and will be useful for the design of future trials combining new drugs or investigational treatment strategies.

Gene trapping of two novel genes, Hzf and Hhl, expressed in hematopoietic cells

Using an expression gene trapping strategy, we have identified and characterized two novel hematopoietic genes, Hzf and Hhl. Embryonic stem (ES) cells containing a gene trap vector insertion were cultured on OP9 stromal cells to induce hematopoietic differentiation and screened for lacZ reporter gene expression. Two ES clones displaying lacZ expression within hematopoietic cells in vitro were used to generate mice containing the gene trap integrations. Paralleling this in vitro expression pattern, both Hzf and Hhl were expressed in a tissue-specific manner during hematopoietic development in vivo. Hzf encodes a novel protein containing three C(2)H(2)-type zinc fingers predominantly expressed in megakaryocytes and CFU-GEMM. Hhl encodes a novel protein containing a putative phosphotyrosine binding (PTB) domain expressed in megakaryocytes, CFU-GEMM and BFU-E. These results demonstrate the utility of expression trapping to identify novel hematopoietic genes. Future studies of Hzf and Hhl should provide valuable information on the role these genes play during megakaryocytopoiesis.

Evaluation of the Function of Human Invariant NKT Cells from Cancer Patients Using α-Galactosylceramide-Loaded Murine Dendritic Cells

NKT cells play a role in immunological regulation of certain diseases, and their frequency and/or function may be related to disease prognosis. However, it is often difficult to evaluate NKT cell function in patients with malignancies due to reduced numbers of NKT cells as well as the dysfunction of the APCs used as stimulators. We found that NKT cell function could not be evaluated by conventional ELISPOT assays, confirming the impaired function of APCs in chronic myelogenous leukemia (CML)-chronic phase patients. To overcome this problem, we have established a sensitive assay using murine dendritic cells to evaluate the function of small numbers of human NKT cells independent of autologous APCs. We found that imatinib-treated CML-chronic phase patients showing a complete cytogenetic response had NKT cells capable of producing IFN-γ, whereas NKT cells from patients who were only partially responsive to imatinib treatment did not produce IFN-γ. Functional NKT cells found in imatinib-treated, CML-complete cytogenetic response patients may offer the promise of effective immunotherapy with ex vivo-generated α-galactosylceramide-pulsed dendritic cells. This new approach should be available for evaluating the functions of NKT cells and APCs in cancer patients.

Impact of graft-versus-host disease on allogeneic hematopoietic cell transplantation for adult T cell leukemia-lymphoma focusing on preconditioning regimens: nationwide retrospective study.

Allogeneic hematopoietic cell transplantation (HCT), but not autologous HCT, can provide long-term remission in some patients with adult T cell leukemia-lymphoma (ATL). We retrospectively analyzed the effects of acute graft-versus-host disease (GVHD) among the 616 patients with ATL who survived at least 30 days after allogeneic HCT with other than cord blood grafts. Multivariate analyses treating the occurrence of GVHD as a time-varying covariate demonstrated an association between grade I-II acute GVHD and favorable overall survival (OS) (hazard ratio [HR], 0.634; 95% confidence interval [CI], 0.477 to 0.843), whereas grade III-IV acute GVHD showed a trend toward unfavorable OS (HR, 1.380; 95% CI, 0.988 to 1.927) compared with nonacute GVHD. In subsequent multivariate analyses of patients who survived at least 100 days after HCT (n = 431), the presence of limited chronic GVHD showed a trend toward favorable OS (HR, 0.597; 95% CI, 0.354 to 1.007), and extensive chronic GVHD had a significant effect on OS (HR, 0.585; 95% CI, 0.389 to 0.880). There were no significant interactions between myeloablative conditioning or reduced-intensity conditioning with OS even when acute GVHD was absent or present at grade I-II or grade III-IV or when chronic GVHD was absent, limited, or extensive. This study demonstrates the actual existence of graft-versus-ATL effects in patients with ATL regardless of whether myeloablative conditioning or reduced-intensity conditioning is used.