IL10 and Autoimmunity: CD8+CD122+ T cells contain an abundant subset of PD-1+ cells that are CD8+ Treg cells; these Treg cells (CD8+CD122+PD-1+) are capable of suppressing autoimmunity and alloimmunity mainly through their secretion of IL-10, and are largely CD127 (encoded by IL-7Rα) negative (31, 32).