IL17A and rheumatoid arthritis: Although the causes of RA are unclear, infiltration of T and B cells into the joints leads to induction of inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, and IL-17A and autoantibodies and drives the proliferation of fibroblast-like synoviocytes and destruction of bone [3, 4].