Naturally-occurring, thymus derived T-regs (nT-regs) are defined by the master transcription factor forkhead box P3 (FOXP3) (100, 101) and provide essential control of autoimmunity through: absorption of pro-inflammatory IL-2; CTLA-4-mediated masking of CD80 and CD86 co-stimulatory ligands on APCs; expression of immune-inhibitory molecules (IL-10, IL-35, TGF-β); and granzyme-mediated killing of APCs (102). Here, FOXP3 is linked to Autoimmunity.