Furthermore, recent studies have uncovered novel subsets of Treg cells that have a pathogenic role, notably through the secretion of the cytokine IL17A, in the setting of the autoimmune diseases, including SLE and arthritis (61, 62), which could also explain why the role of Treg cells in human SLE remains contradictory. The gene discussed is IL17A; the disease is systemic lupus erythematosus.