CD4+Foxp3+ Tregs are indispensable in immune tolerance to self-tissues, which is evident by the fact that deficiency of a functional Foxp3, the master regulator of Treg development and function, leads to severe autoimmunity and early mortality in both humans and mice.[28] All T cell subsets require cytokine signals for survival and function, and Tregs are no exception. Here, FOXP3 is linked to Autoimmunity.