IL10 and infectious disease: Regulatory B cells (Bregs), newly identified regulatory cells, exert immunoregulatory roles in the course of infectious diseases (11, 12), autoimmune diseases (13, 14), and cancer (15, 16) by secreting interleukin (IL)-10, transforming growth factor-β1 (TGF-β1), IL-35, and other inhibitory cytokines.