IL17A and autoimmune disease: In a mouse model, Th17 cells generated with TGF‐β1 and IL‐6 produce IL‐17 but do not readily induce autoimmune disease without further exposure to IL‐23, whilst Th17 generated in the presence of IL‐23 or TGF‐β3 and IL‐6 induced severe EAE 28, 38, 39, 40.