IL2 and Autoimmunity: There is no issue more critical in autoimmunity than the dissection of mechanisms that are critical for immune tolerance.10, 18, 19, 20, 21, 22, 23, 24, 25, 26 Previous work have focused on the regulation of Treg cells, which are of crucial importance in preventing autoimmunity, by the cytokines TGF-β and IL-2.