title: IL-17 receptor and its functional significance in psoriatic arthritis.
abstract: To delineate the functional significance of IL-17 Receptor (IL-17RA) and characterize the IL-17 producing T cell (Th17) subpopulation in psoriatic arthritis (PsA). Mononuclear cells from blood and synovial fluid (SF) were obtained from PsA (n=20), rheumatoid arthritis (RA, n=20) and osteoarthritis (OA, n=20) patients. Synoviocytes (FLS) were isolated from the synovium of RA (n=5), PsA (n=5) and OA (n=5) patients. IL-17RA expression in FLS was identified by western blotting (WB) and flowcytometry. T lymphocytes derived from the SF of these patients were studied to identify and phenotype the Th17 cells. The functional significance of IL-17RA was determined by evaluating its regulatory role on the production of proinflammatory cytokines and endopeptidase. IL-17RA expression was found to be significantly higher in FLS of RA (15.7%±4.9) and PsA (4.5%±0.9) in comparison to OA (1.14%±0.9). Western blot analyses showed that the relative intensity (RI) of IL-17RA protein was higher in RA and PsA compared to OA (Fisher exact, P<0.01). A significant enrichment of IL-17-producing CD4+ T cells (7.9%±2.8) was observed in the SF of PsA patients compared to that of OA patients (P<.001). Compared to OA-FLS, recombinant IL-17 induced higher levels of IL-6, IL-8, and MMP-3 production in PsA-FLS. Blockage of IL-17RA with an anti-IL-17RA antibody inhibited the production of IL-6, IL-8, and MMP-3. This is the first report to demonstrate the functional significance of IL-17RA in PsA. Results of this study support the hypothesis that IL-17RA blocking antibodies have the potential to be a therapeutic option for psoriatic arthritis.
authors: Division of Rheumatology, Allergy & Clinical Immunology, University of California Davis School of Medicine & VA Medical Center Sacramento, 1911 Geneva Place, Davis, CA 95618, USA. sraychaudhuri@ucdavis.edu
authors: Siba P
authors: SP
authors: Raychaudhuri
authors: Smriti K
authors: SK
authors: Raychaudhuri
authors: Mark C
authors: MC
authors: Genovese
mesh_terms: D019138:Antibodies, Blocking / Q000494:pharmacology; D015535:Arthritis, Psoriatic / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D001172:Arthritis, Rheumatoid / Q000209:etiology / Q000276:immunology; D016022:Case-Control Studies; D006801:Humans; D015850:Interleukin-6; D016209:Interleukin-8; D019278:Matrix Metalloproteinase 3; D053722:Receptors, Interleukin-17 / Q000276:immunology*; D013582:Synovial Fluid / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology
chemical_list: D019138:Antibodies, Blocking; D015850:Interleukin-6; D016209:Interleukin-8; D053722:Receptors, Interleukin-17; D019278:Matrix Metalloproteinase 3