Association of cell-free DNA, micro-RNA 21, and micro-RNA 146a levels with rheumatoid arthritis activity

Rheumatoid arthritis (RA) is a progressive systemic autoimmune disease characterized by chronic inflammation of synovial joints and impaired immunological tolerance. It ultimately results in irreversible joint degeneration. This study aimed to measure Cell-Free DNA (cf-DNA), miR-21, and miR-146a and assess their disease activity levels in RA.

This case-control trial was conducted on 80 subjects (patients and control groups). Cases were categorised into two groups: Group I: 20 cases with active disease and Group II: 20 cases with inactive disease. Group III (control): 40 healthy subjects with matched age and sex. The DAS-28 score was used to assess the RA disease activity. This study demonstrated that miRNA21, miRNA 146a, and cf-DNA significantly increased in both active and inactive groups compared to controls (P-value < 0.001). In addition, there was a significant increase in the active group compared to the inactive group (P-value < 0.001). In the active group, miRNA 146a and cf-DNA exhibited a significant positive correlation with the DAS-28 score and clinical manifestations, including morning stiffness, joint tenderness, and swelling. The linear regression analysis revealed that the primary predictors of miRNA21, miRNA 146a, and cf-DNA levels are the DAS-28 score, ESR, and disease duration.

miRNA 146a can be considered a valuable marker for disease activity in RA patients. Furthermore, cf-DNA is suggested to indicate inflammatory conditions; however, MiR21 did not show a significant association with disease activity.