ABSTRACT
To demonstrate the expression of OPN in the synovial fluid of patients with RA and to correlate it with high resolution ultrasonographic [HRUS] findings and disease activity. This study was conducted on 30 RA patients and 20 patients with osteoarthritis [OA]. For RA patients, disease activity was assessed using the modified disease activity score [DAS]. For all patients, plasma and synovial fluid OPN concentrations were quantified using ELISA system. HRUS with B-mode ultrasound supplemented with power Doppler [PDUS] using standardized technique, was done for joints from which synovial fluid was obtained, then the cartilage thickness was measured, synovial thickening and bone erosions were recorded, and the resistive index was calculated. OPN levels were elevated in plasma and synovial fluid of RA patients. Comparison of OPN synovial fluid between RA and OA patients showed a highly significant statistical difference [p<0.001], being higher in the RA patients. OPN synovial fluid level in RA correlated significantly with disease activity score as well as with HR US findings. OPN levels were elevated in plasma and synovial fluid of RA patients. OPN level correlated significantly with disease activity, also with increased synovial thickness and bone erosions, as detected by HRUS. OPN could serve as a useful biochemical marker of RA