Current therapeutic strategies against
rheumatoid arthritis (RA) employ increasingly aggressive regimens from an early stage of the disease ; thus, serological markers more specific than
IgM-
rheumatoid factor (
IgM-RF) are desirable. Anti-
cyclic citrullinated peptide (
anti-CCP) antibody has been reported as a useful and highly specificity marker for the diagnosis of RA. To clarify the diagnostic utility of
anti-CCP antibody in early RA, we measured serum concentrations of
anti-CCP antibody, IgM-RF, anti-
agalactosyl IgG antibody and
matrix metalloproteinase (MMP)-3 in 184
polyarthritis patients who showed onset symptoms within the previous 2 years. The diagnostic sensitivity of
anti-CCP antibody in early RA was 60.0%, equivalent to
IgM-RF (66.3%) and anti-
agalactosyl IgG antibody (66.0%). Specificity, positive predictive values and diagnostic accuracy of
anti-CCP antibody were the best among the four tested makers. In 38 patients who initially did not meet the ACR criteria for RA, but were diagnosed with RA during the course, the diagnostic sensitivity of
anti-CCP antibody was 55.3%. On the other hand, the disease activity score (
DAS) 28 of
anti-CCP antibody positive and the negative patients was 5.16 and 5.34, respectively. Our data indicated that determination of
anti-CCP antibody was useful for early diagnosis of RA.