Novel molecular diagnostic marker in the evaluation of cartilage destruction in patients with rheumatoid arthritis

Aim The aim of this study was to evaluate the serum levels of cartilage oligomeric matrix protein (COMP) in rheumatoid patients in correlation with disease severity and cartilage destruction and to evaluate the therapeutic effectiveness of slow‑remitting agents such as leflunomid on this marker of cartilage destruction. Patients and methods Fifty patients with rheumatoid arthritis (RA) diagnosed on the basis of the 2010 ACR/EULAR Rheumatoid Arthritis Classification Criteria and 20 age‑matched and sex‑matched controls were enrolled in the study. C‑reactive protein, erythrocyte sedimentation rate (ESR), rheumatoid factor, anti‑ cyclic citrullinated peptide, and COMP were determined. Patients were classified into two groups according to Disease Activity Score‑28: group 1 (29 patients) included patients with severe activity with a score of greater than 5.1; and group 2 (21 patients) included patients with moderate activity with a score of greater than 3.2 and less than and equal to 5.1. The studied patients were classified into two groups on the basis of the time of receiving leflunomid therapy (20 mg daily after initial therapy 100 mg daily for 3 days) for 3 months: group 3 received before treatment and group 4 received after treatment. Results Serum COMP was significantly higher in patients with RA when compared with controls (P = 0.000). The COMP levels were found to be positively correlated with Joint space narrowing score (JSN) (r = 0.832, P = 0.000) and erosion score (r = 0.863, P = 0.000) of radiography and negatively correlated with rheumatoid factor (r=−0.313, P = 0.027); however, COMP levels did not correlate with age (r = 0.231, P = 0.106), duration of disease (r = −0.060, P = 0.678), Disease Activity Score‑28 (r = −0.098, P = 0.498), C‑reactive protein (r = −0.242, P = 0.090), ESR first hour (r = −0.096, P = 0.509), ESR second hour (r = −0.101, P = 0.484), or anti‑cyclic citrullinated peptide (r = 0.041, P = 0.775). Conclusion COMP could be a useful biomarker for the detection of early cartilage and bone destruction and in the follow‑up of disease severity and treatment in RA.