CXCL8 and rheumatoid arthritis: It is an important immunosuppressive protein because it regulates expression of several inflammatory cytokines/chemokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), and CCL2, which have been reported in the pathogenesis of rheumatoid arthritis, psoriasis, and multiple sclerosis (10, 11).