Combination of scavenger receptor-A with anti-cyclic citrullinated peptide antibody for the diagnosis of rheumatoid arthritis

The routine biomarkers for rheumatoid arthritis (RA), including anticyclic citrullinated peptide antibody (anti-CCP), rheumatoid factor (RF), immunoglobulin M (IgM), erythrocyte sedimentation rate (ESR), and C-reaction protein (CRP) have limited sensitivity and specificity. Scavenger receptor-A (SR-A) is a novel RA biomarker identified by our group recently, especially for seronegative RA. Here, we performed a large-scale multicentre study to further assess the diagnostic value of SR-A in combination with other biomarkers for RA. The performance of SR-A in combination with other biomarkers for RA diagnosis was first revealed by a pilot study, and was further elucidated by a large-scale multicentre study. A total of 1129 individuals from 3 cohorts were recruited in the study, including RA patients, healthy controls, and patients with other common rheumatic diseases. Diagnostic properties were evaluated by the covariate-adjusted receiver-operating characteristic (AROC) curve, sensitivity, specificity and clinical association, respectively. Large-scale multicentre analysis showed that SR-A and anti-CCP dual combination was the optimal method for RA diagnosis, increasing the sensitivity of anti-CCP by 13% (87% vs 74%) while maintaining a specificity of 90%. In early RA patients, SR-A and anti-CCP dual combination also showed promising diagnostic value, increasing the sensitivity of anti-CCP by 7% (79% vs 72%) while maintaining a specificity of 94%. Moreover, SR-A and anti-CCP dual combination was correlated with ESR, IgM, and autoantibodies of RA patients, further revealing its clinical significance. SR-A and anti-CCP dual combination could potentially improve early diagnosis of RA, thus improving the prognosis and reducing mortality.