Objective: Anti-cyclic citrullinated peptide (anti-CCP) antibody has been known to be a specific autoantibody of rheumatoid arthritis (RA). The objective of this study was to examine the availability of anti-CCP antibody in early RA. Methods: 109 patients with RA were included in this study, and thirty of them had early RA, that was within one year of onset. Anti-CCP antibody and rheumatoid factor (RF) were measured in all serum samples, and their sensitivity as RA markers was analyzed during

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... e time from onset of the disease. Results: Anti-CCP antibody was found in 79% of all RA patients, but in only 70% of early RA patients, which was almost the same sensitivity as for RF, In addition, 12% of all patients were positive for anti-CCP antibody, but negative for RF. Conclusion: Taking into consideretion the high specificity, anti-CCP antibody seems useful in the diagnosis of early RA.