TGFB1 and systemic lupus erythematosus: Since IL-2 and TGF-β production and/or signaling can be deficient in autoimmune diseases including SLE (11, 12), rheumatoid arthritis (13, 14), type 1 diabetes (15, 16), multiple sclerosis (17, 18) and inflammatory bowel disease (19, 20), these abnormalities can contribute to Treg instability.