Antibodies against cyclic citrullinated peptide and IgA rheumatoid factor predict the development of rheumatoid arthritis

Anti-CCP antibody and RFs of all isotypes predated the onset of RA by several years. The presence of anti-CCP and IgA-RF predicted the development of RA, with anti-CCP antibody having the highest predictive value. This indicates that citrullination and the production of anti-CCP and RF autoantibodies are early processes in RA.