IL-6, together with transforming growth factor- (TGF-) β, induces differentiation of IL-17-producing T helper cells (Th17) [6] that play a crucial role in the development of various autoimmune diseases including systemic lupus erythematosus [7], Behçet's disease [8], or rheumatoid arthritis [9]. Here, IL6 is linked to rheumatoid arthritis.