title: Targeting interleukin-21 in rheumatoid arthritis.
abstract: Interleukin-21 (IL-21) is a new member of the type I cytokine superfamily, which binds to a composite receptor that consists of a private receptor (IL-21R) and the common cytokine receptor γ chain. Recently, increasing evidence has shown that IL-21 contributes to the pathogenesis of chronic inflammatory and autoimmune diseases because of its pro-inflammatory and immune-mediated properties. IL-21 induced T-cell activation and pro-inflammatory cytokine secretion in rheumatoid arthritis (RA). IL-21R RNA transcripts were found in synovial tissue samples of patients with RA. In addition, blockade of the IL-21/IL-21R pathway ameliorated disease in animal models of RA and significantly inhibited inflammatory cytokine production in vitro. Moreover, IL-21R deficiency in the K/BxN mouse model of inflammatory arthritis was sufficient to block arthritis initiation completely. All theses findings suggest that IL-21 has important biological effects in autoimmunity that might be a promising therapeutic target for RA. In this review, we discuss the biological features of IL-21 and summarize recent advances in the role of IL-21 in the pathogenesis and treatment of RA.
authors.affiliation: The Third Hospital Affiliated to Nantong University, Wuxi, 214041 Jiangsu, People's Republic of China.
authors.forename: Feng-Lai
authors.initials: FL
authors.lastname: Yuan
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Lu
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Li
authors.forename: Rui-Sheng
authors.initials: RS
authors.lastname: Xu
authors.forename: Cheng-Wan
authors.initials: CW
authors.lastname: Li
authors.forename: Fei-Hu
authors.initials: FH
authors.lastname: Chen
authors.forename: Cheng
authors.initials: C
authors.lastname: Jin
mesh_terms: D000818:Animals; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000628:therapy; D006801:Humans; D007378:Interleukins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D053655:Receptors, Interleukin-21 / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D000098546:Interleukin-21
chemical_list: D007378:Interleukins; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21