The specificity of anti-cyclic citrullinated peptide antibodies in the diagnosis of rheumatoid arthritis from a large cohort study in the Chinese / 中华内科杂志

ABSTRACT

Objective To determine the sensitivity and specificity of anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies) in the diagnosis of rheumatoid arthritis. Method A total of 1018healthy donors, 212 patients with rheumatoid arthritis, 435 patients with other connective tissue disease were recruited to this study. Anti-CCP antibodies and IgM-rheumatoid factor (RF) were determined by ELISA according to manufacturer instructions, with a cut-off of 20U. Result The frequency of positive anti-CCP antibodies in patients with rheumatoid arthritis is 48.1% (n = 102 ), higher than healthy donors (2.6%,n = 26) and patients with other connective tissue diseases (3.7%, n = 16). The specificity of anti-CCP antibodies is 97.4%. The titer of anti-CCP antibodies in patients with rheumatoid arthritis (429. 7 U) is much higher than that in healthy donors (29. 3 U ) and patients with other connective tissue diseases (36. 5 U). The frequency of positive IgM-RF in patients with rheumatoid arthritis is 94. 3% whilst only21.5% in healthy donors. The false positivity rate of IgM-RF is higher than anti-CCP antibody. Conclusion Anti-CCP antibodies is a highly specific autoantibody in the diagnosis of rheumatoid arthritis.