Biochemical Analysis of C-X-C Motif Chemokine Ligand 10 (CXCL10) as a Biomarker in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by chronic inflammation and synovial hyperplasia that eventually leads to the destruction of the joints. CXCL10 has been originally identified as a pro-inflammatory chemokine that mediate leukocyte trafficking and modulate innate and adaptive immune responses. It plays a critical role in the inflammatory response and is involved in several biological processes. The aim of the study was to assess the diagnostic efficacy of serum CXCL10 levels in early RA patients. Patients and methods: The study included 60 RA patients; 30 of them were early diagnosed, and 30 longstanding RA and 30 healthy controls. Clinical examination was done for all patients. Measurement of serum CXCL10 level was done by ELISA, while assessment of disease activity in patients was done using disease activity score (DAS-28). Serum levels of CXCL10 were significantly higher in RA patients than controls (P < 0.001), and was more elevated in early diagnosed than longstanding RA patients, with a a significant positive correlation with DAS-28 ESR (r=0.361, P=0.005), number of tender joint (r=0.319, P=0.013), and number of swollen joint (r=0.280, P=0.030). A cutoff at 470.0 pg/ml was able to recognize longstanding RA with a sensitivity of 88.3% and a specificity of 90% , while a cutoff of 793 pg/ml was able to diagnose early RA with 65% sensitivity and 77% specificity (P=0.009). in conclusion, serum CXCL10 may be a useful biomarker for diagnosis of early RA and determination of disease activity.