IL17A and autoimmune disease: Anomalous autoreactive responses of CD4+ T helper cells, such as Th1 cells producing IFNγ 2 and Th17 cells producing IL‐17,47, 48, 49, 50, 51, 52 are tightly correlated with the clinical severity and progression of several autoimmune diseases, clinically and experimentally.11, 12, 53, 54