Despite developing autoimmune signs in the absence of detectable IL-17 levels, as in case of choriomeningitis-virus-induced model of type 1 diabetes [12], a key role of TH17 cells and their related molecules was underscored in many previously assigned “TH1-mediated” AD including rheumatoid arthritis (RA), psoriasis, systemic lupus erythematosus (SLE), and multiple sclerosis (MS), as well as, the experimental autoimmune encephalomyelitis—EAE [7, 9, 13–15]. Here, IL17A is linked to rheumatoid arthritis.