In RA, Interleukin-17 (IL-17) released from T helper 17 cells (Th17) stimulated various pathogenic cells through activating pro-inflammatory mediators Interleukin-23 (IL-23), Interleukin- 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) [61]. Here, IL17A is linked to rheumatoid arthritis.