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

Objectives The routine biomarkers for RA, including anti-CCP, RF, IgM, ESR and CRP, have limited sensitivity and specificity. Scavenger receptor-A (SR-A) is a novel RA biomarker identified recently by our group, 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.Methods 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 three 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 curve, sensitivity, specificity and clinical association.Results 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.Conclusion SR-A and anti-CCP dual combination could potentially improve early diagnosis of RA, thus improving the prognosis and reducing mortality.