Anti-cyclic citrullinated peptide antibody is associated with radiographic erosion in rheumatoid arthritis independently of shared epitope status.

Shared epitope (SE) and anti-cyclic citrullinated peptide (CCP) antibody are known to be associated with rheumatoid arthritis (RA). The authors investigated their adjusted effects on RA from Korean population. Clinical features were evaluated in 226 RA patients; 164 healthy controls were enrolled. HLA-DRB1 typing for SE was done by polymerase chain reaction. Anti-CCP antibody levels were determined by enzyme linked immunosorbent assay. Logistic regression analysis method was used for adjusted effects. SE and anti-CCP antibody were associated with RA susceptibility. Anti-CCP antibody was associated with RA susceptibility independent of SE [odds ratio, OR 179.9 (95% confidence interval, CI 40.8-792.2), P < 0.001]. Anti-CCP antibody was associated with radiographic erosive changes independent of SE or rheumatoid factor [OR 3.9 (95% CI 1.1-13.3), P = 0.032]. Anti-CCP antibody was strongly associated with RA susceptibility and radiographic erosion of RA patients, independent of SE in Korean.