Previously, we showed that variants in IL2RA that predispose to type 1 diabetes reduce the level of IL-2RA/CD25 on Tregs and memory Teff cells [20, 22], thereby potentially increasing the amount of homeostatic IL-2 production required for Treg survival and function, and limiting Tfh differentiation. This evidence concerns the gene IL2RA and type 1 diabetes mellitus.