IL-2 signals through its high-affinity IL-2R (consisting of the IL-2Rα (CD25), IL-2Rβ, and common γ-chain (γc) subunits) and is essential for the expansion of activated effector T (Teff) cells.[3] Therefore, it was somewhat unexpected that mice deficient in IL-2, IL-2Rα, or IL-2Rβ developed lethal autoimmune diseases. Here, IL2RB is linked to autoimmune disease.