Interleukin-21 Receptor Might be a Novel Therapeutic Target for the Treatment of Rheumatoid Arthritis

BackgroundRheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the synovial inflammation of the joints. Various cells and cytokines have been identified that may contribute to RA pathology. Interleukin (IL)-21 is a proinflammatory cytokine mediating pleiotropic functions through the IL-21 receptor (IL-21R). Blockade of IL-21R may represent a hopeful therapeutic approach in RA. The aim of this study was to determine the percentage of IL-21R expressing CD4+ cells and IL-21 mRNA expression in peripheral blood of RA patients.MethodsSurface expression of IL-21R on CD4+ cells in peripheral blood of RA patients (n = 32 compared to healthy control participants (n = 20) was evaluated by flow cytometry. Simultaneously, mononuclear cells were taken apart from the peripheral blood of individuals on a density gradient. The expression of IL-21 mRNA was assessed by real-time polymerase chain reaction.ResultsIL-21R-expressing CD4+ cells from RA patients showed a significantly higher percentage of IL-21R compared with healthy controls (p < 0.05). Moreover, real-time polymerase chain reaction showed that there was no significant difference between patients and healthy controls.ConclusionOur results indicate higher expression of IL-21R in RA patients and suggest that targeting of the IL-21R may be a novel therapeutic idea for the treatment of RA.