Immunosuppressive Tregs and Bregs are also remarkably increased in MM bone marrow microenvironment, and they maintain immune tolerance through the secretion of immunosuppressive cytokines such as TGF-β and IL-10, as well as the expression of immune inhibitory molecules, such as PD1, TIM3, and CD38 (93). Here, CD38 is linked to Miyoshi myopathy.