It has been demonstrated that the pathogenetic mediators of many autoimmune diseases, such as MS, T1D, rheumatoid arthritis and psoriasis, are Th17 sub-populations beyond Th1 cells that are notably involved in autoimmunity [16,17].Th17 produce cytokines IL-17, IL-21, IL-22 and IL-23 [18]. The gene discussed is IL17A; the disease is rheumatoid arthritis.