IL10 and inflammation: Tregs’ roles in maintaining self-tolerance and prevention of autoimmune responses and chronic inflammation are mediated by various mechanisms including: a) Treg killing of target cells (38); b) modulation of target cells via cell-cell contact; c) inhibition of target cells by exosome-carried microRNAs (28); and d) secretion of anti-inflammatory/immunosuppressive cytokines (13) including interleukin-10 (IL-10), IL-35 (1, 43, 44), and transforming growth factor-β (TGF-β).