Is there an importance of CD200 during an activation of rheumatoid arthritis?

Rheumatoid arthritis is a systemic autoimmune disease primarily affecting synovial joints. CD200 is a type I transmembrane glycoprotein that has an effects on immune system. Previous animal studies have established the inhibitory role of CD200 in collagen induced arthritis models. The goal of this study is to demonstrate whether change of plasma and synovial fluid CD200 level exist at active Rheumatoid arthritis patients with knee effusion during activation of rheumatoid arthritis. Eleven active rheumatoid arthritis patients with knee effusion and as a control 5 patients with knee effusion due to trauma were included in this study. Plasma and synovial fluid CD200, TNFα and IFNγ levels are measured by ELİSA. Disease activity was determined by erythrocyte sedimentation rate (ESR), C reactive protein (CRP), disease activity score 28 (DAS28)-ESR and DAS28-CRP respectively. There was no difference between rheumatoid arthritis patients and controls in terms of plasma and synovial fluid CD200, TNFα and synovial fluid IFNγ levels. Plasma IFNγ level was higher in control group and this was statistically significant (p =0.047). Plasma and synovial fluid CD200, TNFα and synovial fluid IFNγ levels were not statistically different between biological agents treated rheumatoid arthritis patients and controls whereas plasma IFNγ level was higher in controls compare to treatment group (p= 0.028). In this study, levels of plasma and synovial fluid CD200 were not found statistically different between rheumatoid arthritis patients and controls. Further studies with more patients are needed to explore the importance of CD200 role in rheumatoid arthritis.