IL17A and rheumatoid arthritis: First of all, being an inflammatory disease, it involves several inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), and interleukin-17 (IL-17), which are overexpressed in RA joints and play an important role in its pathogenesis [4,5].