C-X-C Chemokine Receptor-3 as a Diagnostic Biomarker in Patients with Rheumatoid Arthritis

Abstract

Background: Rheumatoid Arthritis (RA) is a chronic and systemic inflammatory disease characterized by synovial inflammation and the progressive destruction of joint ligaments and bones. CXCR3 is a seven-transmembrane G-protein-coupled chemokine receptor that has been appeared to play a vital role in a variety of inflammatory and immunological responses. We aimed to evaluate the utility of serum C-X-C chemokine receptor 3 (CXCR3) levels in the diagnosis, monitor, and follow-up of RA patients. Methods: Sixty RA patients were divided into 30 early RA patients with disease duration < 2 years and 30 longstanding RA patients with disease duration ≥ 2 years. Thirty healthy subjects were recruited as a control group. Medical history and clinical data were taken. All the patients were assessed for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and CXCR3 serum levels. Results: Serum CXCR3 level was significantly elevated in RA patients compared to healthy normal controls with a highly statistically significant difference (p< 0.001). The serum levels of CXCR3 were elevated in long-standing RA more than early RA. Serum level of CXCR3 was only positively correlated with the duration of disease (r= 0.540, p= >0.001) and combined treatment (r= 0.296, p= 0.022). Receiver operating characteristic (ROC) curves were plotted for the prediction of serum CXCR3 in RA patients. The best cut-off value that indicates the presence of early RA disease is 4.026 ng/mL serum CXCR3 with 71.7% sensitivity and 70% specificity (p= 0.005). Conclusion: Serum CXCR3 is an imperative predictive biomarker for the diagnosis of RA, an indicator for early RA disease, and endorses the established RA disease.