Serum Soluble Cd86, Still A Prognostic Factor In The Novel Agent Era In Multiple Myeloma Patients, Is Produced By Myeloma Cells With High Cd86 Variant 3 Expression

Introduction: We previously reported that CD86 expressed on tumor cells from multiple myeloma (MM) patients is associated with a proliferative advantage of tumor cells and suppresses the antitumor immune response by inducing the immunosuppressive cytokine IL-10 from CD4+ T cells via CD86-CD28 interaction [Yamashita T, Clin Cancer Res 2009]. Furthermore, CD28 expressed on MM cells can mediate pro-survival signaling through CD86-CD28 interaction, resulting in chemotherapeutic resistance [Murray ME, Blood 2014]. Hock et al. reported that serum soluble CD86 levels (sCD86) were a significant independent prognostic marker in MM patients treated with conventional chemotherapy [Br J Haematol 2006]. However, it is unknown whether serum soluble CD86 is still a prognostic marker in the novel agent era and how sCD86 is produced in serum. In this study, we investigated the association of clinical characteristics and prognosis with serum sCD86 and elucidated the mechanism by which sCD86 is produced in MM patients.