Assessment of synovitis in early rheumatoid arthritis by CXCL13 serum levels and power Doppler ultrasonography: Correlation with disease activity

Aim of the workAssessment of synovitis in rheumatoid arthritis (RA) is a major issue for proper treatment; it has been proven that high resolution ultrasound (US) examination could be of valuable help. The B-cell chemokine, CXCL13, is a proposed serum biomarker of synovitis in RA. We aimed to find out the presence of synovitis in patients with recent-onset RA and its correlation with disease activity.Patients and methodsWe evaluated 30 patients with early RA for the presence and degree of synovitis by performing high resolution US and obtaining serum CXCL13 levels. In addition, we correlated these results with disease activity score 28 (DAS 28). Results of high resolution US and serum CXCL13 were also obtained for 20 healthy age- and sex-matched volunteers and served as controls.ResultsSerum CXCL13 level was significantly increased in early RA patients vs. controls (p < 0.001). High resolution US revealed that RA patients had a significant increased synovial thickness and high power Doppler US score. In RA patients, DAS 28 had a significant correlation with serum CXCL13 (r = 0.42, p = 0.02), synovial thickness (r = 0.39, p = 0.03) and power Doppler US score (r = 0.43, p = 0.02). Serum CXCL13 level correlated with synovial thickness (r = 0.63, p = 0.001) and power Doppler US score (r = 0.69, p = 0.001).ConclusionRecent-onset RA patients suffer from synovitis as evidenced by significantly increased serum CXCL13 and by high resolution US. Serum CXCL13 is a reliable marker of synovial inflammation which correlates better with synovial thickening and power Doppler US scores than DAS28.