To evaluate frequency of anti-cyclic citrullinated peptide antibodies (anti-CCP) in long-standing rheumatoid arthritis (LsRA) patients and their relationship with extra-articular manifestations of rheumatoid arthritis (RA), in addition to comparing frequency of anti-CCP antibodies in early RA (ERA) and LsRA group.
One hundred and fifteen consecutive RA patients were included in the study as having LsRA because their disease duration was longer than 3 years. Thirty-nine consecutive patients with RA were included in the study as having ERA (<3 years). Also, 64 individuals were included in the study as healthy controls to verify the specificity and sensitivity of anti-CCP antibodies. Anti-CCP antibody and rheumatoid factor (RF) were evaluated with enzyme-linked immunosorbent assay kits and standard nephelometry methods, respectively. Extra-articular manifestations were diagnosed by relevant criteria.
The total number of patients with extra-articular manifestations was found to be 45 (39%). No significant difference was found between LsRA group and ERA group in terms of extra-articular manifestations. There were no differences between both groups regarding the number of patients with positive anti-CCP antibodies and the levels of anti-CCP antibodies. In LsRA group, there was a positive correlation between erosion and disease duration (r=0.24, p<0.01), between erosion and RF (r=0.29, p<0.002), and between erosion and anti-CCP antibody (r=0.21, p<0.02). Positive correlations between RF and anti-CCP antibody (r=0.32, p<0.0001), as well as between subcutaneous nodule and lung involvement (r=0.24, p<0.008), were found in the LsRA group. However, no positive correlation could be found between anti-CCP antibody positivity and extra-articular organ involvement, either cumulatively or separately.
Although anti-CCP antibodies are associated with the severity of the disease and erosion, they do not seem to have much linkage with extra-articular manifestations of RA.