Interleukin-21 receptor might be a novel therapeutic target for the treatment of rheumatoid arthritis

Abstract

Background: Rheumatoid 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. Methods: Surface 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. Results: IL-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. Conclusion: Our 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. © 2014