Ken Takase

Monitoring of cytomegalovirus reactivation after allogeneic stem cell transplantation: comparison of an antigenemia assay and quantitative real-time polymerase chain reaction.

Cytomegalovirus (CMV) antigenemia and quantitative real-time polymerase chain reaction (PCR) were compared for monitoring of CMV reactivation after allogeneic stem cell transplantation. The number of CMV antigen-positive cells by the antigenemia assay and the level of CMV DNA by real-time PCR correlated well. The sensitivity and specificity of the antigenemia assay was 55.4% and 95.5%, respectively, using real-time PCR as the reference standard. The probability of positive antigenemia at day 100 was 76.5%, with a median of first detection at day 37 in 51 patients, compared with a positive PCR of 84.3% and day 33, respectively. When HLA-identical sibling donor transplant recipients and other donor transplant recipients were analyzed separately, there was no difference between the two tests. However, temporal patterns of first detection of CMV antigen-positive cells and CMV DNA differed between HLA-identical and alternative recipients; patients without CMV (29%) or with sporadic positive PCR results (14%) were more common in HLA-identical sibling transplants, whereas patients with simultaneous antigenemia and positive PCR occurred more in alternative transplants (48%). Two of 51 patients (4%) developed CMV colitis despite antigenemia-guided prophylaxis, but both were successfully treated with ganciclovir. Although PCR is more sensitive than antigenemia, both tests are useful in the early detection of CMV after allogeneic stem cell transplantation.

A phase I-II trial of autologous peripheral blood stem cell transplantation in the treatment of refractory autoimmune disease

Objectives: To carry out a phase I-II trial to elucidate the feasibility and efficacy of high dose cyclophosphamide (CY) supported by autologous peripheral blood stem cell transplantation (PBSCT) in the treatment of severe and refractory autoimmune disease (AD). Methods: Peripheral blood stem cells (PBSCs) were mobilised during haematological recovery after relatively high dose CY (2 g/m2) for 2 days, followed by administration of granulocyte colony stimulating factor. After collecting PBSCs—more than 2×106 CD34+ cells/kg—by apheresis, CD34+ cells were immunologically selected and cryopreserved. Eight patients were enrolled—five had systemic sclerosis (SSc) alone, one had SSc with systemic lupus erythematosus, one amyopathic dermatomyositis (ADM), and one Wegener’s granulomatosis (WG). All of the patients were treated with high dose CY (50 mg/kg) for 4 days and autologous PBSCT. Results: Haematopoietic reconstitution was rapid and sustained. Toxicity due to the regimen included various infections such as pneumonia, sepsis, cystitis, herpes zoster, and acute heart failure. However, there was no treatment related mortality. Encouraging results were obtained after autologous PBSCT. Sclerosis of the skin was markedly improved in all of the patients with SSc. Interstitial pneumonia (IP), evaluated by Pao2, serum KL-6 levels, and pulmonary high resolution computed tomography, improved significantly. In a patient with ADM, severe and progressive IP also improved markedly. In a patient with WG, the size of the left orbital granuloma decreased substantially, resulting in reduction of the exophthalmos. Conclusions: These observations suggest that high dose CY with autologous PBSCT is feasible and may be effective in the treatment of severe and refractory AD.

Association of MBL gene polymorphisms with major bacterial infection in patients treated with high-dose chemotherapy and autologous PBSCT

A growing body of evidence indicates that genetic factors are involved in an increased risk of infection. We investigated whether mannose-binding lectin (MBL) gene polymorphisms that cause low levels of MBL are associated with the occurrence of major infections in patients, mainly bearing hematological malignancies, after high-dose chemotherapy (HDT) rescued by autologous peripheral blood stem cell transplantation (auto-PBSCT). A retrospective evaluation of 113 patients treated with HDT and auto-PBSCT revealed that the low-producing genotypes, B/B and B/LXA, were associated with major bacterial infection (P=0.0016, OR 7.9). We next performed a nation-wide large-scale study to assess the allele frequency of the MBL coding mutation in a total of 2623 healthy individuals in Japan. The frequency of allele B was estimated to be ∼0.2, almost the same in seven different areas of Japan. This common occurrence suggests that MBL deficiency may play an important role in the clinical settings of immunosuppression.

Cutting Edge: Tyk2 Is Required for the Induction and Nuclear Translocation of Daxx Which Regulates IFN-α-Induced Suppression of B Lymphocyte Formation

IFN-α inhibits B lymphocyte development, and the nuclear protein Daxx has been reported to be essential for this biological activity. We show in this study that IFN-α inhibits the clonal proliferation of B lymphocyte progenitors in response to IL-7 in wild-type, but not in tyk2-deficient, mice. In addition, the IFN-α-induced up-regulation and nuclear translocation of Daxx are completely abrogated in the absence of tyk2. Therefore, tyk2 is directly involved in IFN-α signaling for the induction and translocation of Daxx, which may result in B lymphocyte growth arrest and/or apoptosis.

Signal Transducers and Activators of Transcription 3 Augments the Transcriptional Activity of CCAAT/Enhancer-binding Protein α in Granulocyte Colony-stimulating Factor Signaling Pathway

The Janus kinase (Jak)-Stat pathway plays an essential role in cytokine signaling. Granulocyte colony-stimulating factor (G-CSF) promotes granulopoiesis and granulocytic differentiation, and Stat3 is the principle Stat protein activated by G-CSF. Upon treatment with G-CSF, the interleukin-3-dependent cell line 32D clone 3(32Dcl3) differentiates into neutrophils, and 32Dcl3 cells expressing dominant-negative Stat3 (32Dcl3/DNStat3) proliferate in G-CSF without differentiation. Gene expression profile and quantitative PCR analysis of G-CSF-stimulated cell lines revealed that the expression of C/EBPα was up-regulated by the activation of Stat3. In addition, activated Stat3 bound to CCAAT/enhancer-binding protein (C/EBP)α, leading to the enhancement of the transcription activity of C/EBPα. Conditional expression of C/EBPα in 32Dcl3/DNStat3 cells after G-CSF stimulation abolishes the G-CSF-dependent cell proliferation and induces granulocytic differentiation. Although granulocyte-specific genes, such as the G-CSF receptor, lysozyme M, and neutrophil gelatinase-associated lipocalin precursor (NGAL) are regulated by Stat3, only NGAL was induced by the restoration of C/EBPα after stimulation with G-CSF in 32Dcl3/DNStat3 cells. These results show that one of the major roles of Stat3 in the G-CSF signaling pathway is to augment the function of C/EBPα, which is essential for myeloid differentiation. Additionally, cooperation of C/EBPα with other Stat3-activated proteins are required for the induction of some G-CSF responsive genes including lysozyme M and the G-CSF receptor.

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.

Long-term outcomes of autologous PBSCT for peripheral T-cell lymphoma: retrospective analysis of the experience of the Fukuoka BMT group

Peripheral T-cell lymphoma (PTCL) is generally characterized by poor prognosis after conventional chemotherapy compared with aggressive B-cell lymphoma. To elucidate the role of high-dose chemotherapy (HDCT) with auto-SCT, we retrospectively analyzed the outcomes of 39 patients with PTCL who received HDCT and auto-SCT between 1990 and 2005. Eleven patients were histologically typed as angioimmunoblastic, nine as anaplastic large-cell lymphoma, seven as natural killer/T-cell lymphoma and twelve as PTCL unspecified. Clinical conditions at transplantation were complete response (CR) in 27 patients and non-CR in 12 patients. Thirty-two patients received a pre-transplant conditioning regimen (MCEC) comprising ranimustine, carboplatin, etoposide and CY, and seven did other TBI-based regimens. Rapid engraftment was obtained in all cases, and transplant-related death was not seen. An estimated 5-year OS was 62.1% with a median follow-up of 78 months. The 5-year OS was significantly higher in patients transplanted during complete response than in those during other disease status (71.4% vs 27.3%, P=0.046). HDCT supported by auto-SCT may therefore be effective as consolidation in CR for PTCL treatment.

Mobilization of Human Lymphoid Progenitors after Treatment with Granulocyte Colony-Stimulating Factor

Hemopoietic stem and progenitor cells ordinarily residing within bone marrow are released into the circulation following G-CSF administration. Such mobilization has a great clinical impact on hemopoietic stem cell transplantation. Underlying mechanisms are incompletely understood, but may involve G-CSF-induced modulation of chemokines, adhesion molecules, and proteolytic enzymes. We studied G-CSF-induced mobilization of CD34+CD10+CD19−Lin− and CD34+CD10+CD19+Lin− cells (early B and pro-B cells, respectively). These mobilized lymphoid populations could differentiate only into B/NK cells or B cells equivalent to their marrow counterparts. Mobilized lymphoid progenitors expressed lymphoid- but not myeloid-related genes including the G-CSF receptor gene, and displayed the same pattern of Ig rearrangement status as their bone marrow counterparts. Decreased expression of VLA-4 and CXCR-4 on mobilized lymphoid progenitors as well as multipotent and myeloid progenitors indicated lineage-independent involvement of these molecules in G-CSF-induced mobilization. The results suggest that by acting through multiple trans-acting signals, G-CSF can mobilize not only myeloid-committed populations but a variety of resident marrow cell populations including lymphoid progenitors.

Intracellular signal transduction of interferon on the suppression of haematopoietic progenitor cell growth

Summary. Interferon (IFN)‐α and IFN‐γ suppress the growth of haematopoietic progenitor cells. IFN‐α activates Janus kinase‐1 (Jak1) and Tyrosine kinase‐2 (Tyk2), followed by the phosphorylation of the signal transducers and activators of transcription, Stat1 and Stat2. IFN‐γ activates Jak1 and Jak2, followed by the activation of Stat1. Activated Stats bind the promoter regions of IFN‐inducible genes. We evaluated the role of Tyk2 and Stat1 in the IFN‐mediated inhibition of haematopoietic progenitor cell growth. While IFN‐α (1000 U/ml) suppressed the number of granulocyte‐macrophage colony‐forming units (CFU‐GM) or erythroid burst‐forming units (BFU‐E) from wild‐type mouse bone marrow cells, this suppression was partially inhibited by a deficiency in Tyk2 and completely inhibited by a deficiency in Stat1. High levels of IFN‐α (10 000 U/ml) suppressed the CFU‐GM or BFU‐E obtained from Stat1‐deficient mice, but did not suppress this growth in cells from Tyk2‐deficient mice. Stat1 was phosphorylated by IFN‐α in Tyk2‐deficient cells, although the level of phosphorylation was weaker than that observed in wild type mice. Thus, the inhibitory signal on haematopoietic progenitor cells mediated by IFN‐α may be transduced by two signalling pathways, one regulated by Tyk2 and the other dependent on Stat1. IFN‐γ also suppressed the number of CFU‐GM or BFU‐E, and this pathway was mediated by IFN‐γ in a Stat1‐dependent manner, independently of Tyk2.

FLT3 mutations in normal karyotype acute myeloid leukemia in first complete remission treated with autologous peripheral blood stem cell transplantation.

Summary:We retrospectively analysed the significance of FLT3 mutations in patients with acute myeloid leukemia (AML) having a normal karyotype, who were treated with high-dose chemotherapy and autologous peripheral blood stem cell transplantation (auto-PBSCT). In all, 34 patients with normal karyotype AML in first complete remission receiving high-dose chemotherapy and auto-PBSCT were analysed based on the presence or absence of FLT3/ITDs and FLT3/D835. They were 16 males and 18 females and with a median age of 41.5 years. FLT3/ITDs were detected in eight of 34 patients (23.5 %), and FLT3 D835 mutations in two of 34 patients (5.9%). White blood cell count (P=0.0087), serum concentration of lactate dehydrogenase (P=0.005), and percentages of peripheral blood (P=0.0131) and bone marrow (BM) blasts (P=0.0312) were significantly higher in patients showing the FLT3 mutations. Overall survival (OS) and disease-free survival (DFS) were similar between patients with or without FLT3 mutations (5 year DFS, 67.5 vs 68.55%, P=0.819; 5 year OS, 64.81 vs 78.88%, P=0.4457, by the log-rank test). FLT3 mutations demonstrate no further prognostic impact in patients with normal karyotype AML in first CR treated with high-dose chemotherapy and auto-PBSCT. Myeloablative chemotherapy supported by auto-PBSCT may overcome any poor prognostic implications of FLT3 mutations.