TNFSF13 and plasma cell myeloma: Recently, a member of the TNF receptor superfamily, B-cell maturation antigen (BCMA), which binds to B-cell activating factor and a proliferation-inducing ligand (APRIL) [65,66], was found to express on primary human CD34+ hematopoietic cells and are commonly expressed in plasma cells and primary myeloma cells [67,68].