CD4 and autoimmune disease: Concurrent with these publications, Sakaguchi and his colleagues reported that a critical subset of CD4+ T cells that express the IL-2R α-chain, ~10% of mature peripheral CD4+ T cells, could prevent autoimmune diseases of immunodeficient nu/nu mice injected with immunocompetent CD4+ T cells depleted of IL-2Rα+ cells (Sakaguchi et al., 1995).