CTLA4 and autoimmune disease: Strategies for Treg-based therapy for autoimmune diseases are to enhance the Treg expansion to achieve maximal suppressive effect or to limit their locate presence, such as in cancer and other autoimmune disorders, including forkhead box protein 3 (Foxp3) disruption-based Treg removal and CTLA-4 antibody-based effector Treg blockade19–21.