IL17A and rheumatoid arthritis: Th17 cells and Th17 cytokines are important for the pathogenesis of several autoimmune and inflammatory diseases, including psoriasis, psoriatic arthritis, multiple sclerosis, rheumatoid arthritis, Crohn’s disease, systemic lupus erythematosus, etc. Therefore, inhibiting the IL-17/IL-17R pathway is suggested as a useful method for treating autoimmune inflammatory disorders (Yamagata et al., 2015; Yasuda et al., 2019).