IL-17 and Its Receptor System: a New Target for Psoriatic Arthritis

Abstract

Th17 cells are one subset of T cells, which produce IL-17, a pro-inflammatory cytokine. A regulatory role of Th17 cells has been proposed in several autoimmune diseases including psoriasis, psoriatic arthritis, rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, and multiple sclerosis. Psoriatic disease is an autoimmune disease which mainly involves skin and joints. Until recently, psoriasis and psoriatic arthritis were thought to be Th1-mediated disease, but after the discovery of IL-17 and IL-17, knockout animal studies as well as human experimental data indicate the crucial role of the Th17 cells in the pathogenesis of psoriatic disease. Human studies have shown the presence of Th17 cells in the psoriatic plaques in excess. Moreover, our research group not only have found abundance of CD4+IL-17+ T cells, mainly the memory phenotype (CD4RO+CD45RA-CD11a+) in the synovial fluid, but also have shown the existence of functional IL-17 receptor in synovial fibroblast of psoriatic arthritis patients. In this review article, we have discussed the contributing role of the IL-23/IL-17 axis in psoriatic arthritis (PsA) and the prospective of IL-17 targeted therapies in PsA.Copyright © 2015, Springer International Publishing AG.