Miki Furukawa

Autocrine and paracrine interactions between multiple myeloma cells and bone marrow stromal cells by growth arrest-specific gene 6 crosstalk with interleukin-6

The pathogenesis of multiple myeloma (MM) has not yet been fully elucidated. Our microarray analysis and immunohistochemistry revealed significant up-regulation of growth arrest-specific gene 6 (Gas6), a vitamin K-dependent protein with a structural homology with protein S, in bone marrow (BM) cells of MM patients. ELISA showed that the serum levels of soluble Gas6 were significantly increased in the MM patients when compared with healthy controls. Gas6 was overexpressed in the human CD138-positive MM cell line RPMI-8226. Exogenous Gas6 suppressed apoptosis induced by serum deprivation and enhanced cell proliferation of the MM cells. The conditional medium from the human BM stromal cell line HS-5 induced cell proliferation and anti-apoptosis of the MM cells with extracellular signal-regulated kinase, Akt, and nuclear factor-κB phosphorylation, which were reversed by the neutralizing antibody to Gas6 or IL-6. The TAM family receptor Mer, which has been identified as a Gas6 receptor, was overexpressed in BM cells of MM patients. The knockdown of Mer by siRNA inhibited cell proliferation, anti-apoptosis, and up-regulation of intercellular cell adhesion molecule-1 (ICAM-1) in MM cells stimulated by an HS-5 cell-conditioned medium. Furthermore, the Gas6-neutralizing antibody reduced the up-regulation of IL-6 and ICAM-1 induced by a HS-5 cell-conditioned medium in MM cells. The present study provides new evidence that autocrine and paracrine stimulation of Gas6 in concert with IL-6 contributes to the pathogenesis of MM, suggesting that Gas6-Mer-related signaling pathways may be a promising novel target for treating MM.

Erratum to: Persistent complete remission of acute leukemic-phase CCR4-positive gamma–delta peripheral T-cell lymphoma by autologous stem cell transplantation with mogamulizumab

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), frequently shows a poor outcome. Especially, expressions of CC chemokine receptor 4 (CCR4) and γδ T-cell receptor (TCR) are associated with worse prognosis in PTCL-NOS. We here report successful treatment with autologous peripheral blood stem cell transplantation (auto-PBSCT) combined with anti-CCR4 antibody mogamulizumab for a very rare case of CCR4+γδTCR+ PTCL-NOS that coexisted with Hodgkin’s lymphoma. PTCL-NOS in this patient progressed to leukemic phase, whereas Hodgkin’s lymphoma disappeared with standard chemotherapies within 4 years of the initial diagnosis. Leukemic-phase PTCL-NOS was refractory to several chemotherapies. However, auto-PBSCT following high-dose chemotherapy combined with pre- and post-transplant mogamulizumab, which is a humanized monoclonal antibody to CCR4, provided persistent complete remission of PTCL-NOS, despite residual γδTCR+ in the transplanted stem cell product, suggesting a purging effect of mogamulizumab. At 15 months after transplantation, we also found markedly fewer effector regulatory T cells, which may have contributed to prolonged remission. This case suggests that autologous stem cell transplantation combined with mogamulizumab may have a potential to cure T-cell neoplasms that express CCR4 including leukemic-phase PTCL-NOS.

Post‐engraftment blood transfusion and outcomes of bone marrow transplantation

Red blood cell (RBC) transfusion prior to allogeneic hematopoietic stem cell transplantation (allo‐HSCT) is linked to poor outcomes, but outcomes related to post‐transplant, especially postengraftment transfusions, have not been fully investigated. We investigated allo‐HSCT outcome in association with early postengraftment transfusion.

A Japanese case of chronic lymphocytic leukemia with t (1;6)

Chronic lymphocytic leukemia (CLL) rarely exhibits an aggressive clinical course and its patients often have chromosomal deletions or additions. Furthermore, reciprocal translocations are barely observed in CLL. There have only been a few reports of CLL with t(1;6), and here we report the first Asian case of CLL with reciprocal translocation t(1;6). Since our case and previously reported CLL patients with t(1;6) consistently showed aggressive clinical course, t(1;6) may define a distinct type of CLL.