anti-cyclic citrullinated peptide antibody and rheumatoid factor isotypes in iranian patients with rheumatoid arthritis: evaluation of clinical value and association with disease activity.

in  this  study  we  determined  the  frequency,  sensitivity  and  specificity  of  anti  cyclic citrullinated peptides (anti-ccp) igg antibody, total rheumatoid factor (rf-t), and rf isotypes in iranian patients with rheumatoid arthritis (ra) and their association with age, clinical and serological parameters. anti-ccp and rf-t and rf isotypes level were measured in 418 patients and 399 healthy controls by enzyme-linked immunosurbant assay (elisa). additionally, serum c-reactive protein (crp), erythrocyte sedimentation rate (esr), visual analog scale (vas) and disease activity score (das28) were evaluated in ra patients. the anti-ccp was positive in 53.1% of ra patients and 4.7% of controls. the frequency of rf-t was 61.87% and 17.66% in ra patients and controls respectively. the prevalence of rf isotypes in ra patients was 46.52% for rf-igm, 23.47% for rf-iga and 21.74% for rf-igg. 31.39% of ra patients were rf-igm positive without rf-iga and rf-igg and 21.9% were positive for all three rf classes. the anti-ccp positive patients showed increased number of swollen joints. on the other hand, rf-t positive patients exhibited a longer disease duration, lower age of onset and also higher esr, crp level and increased swollen joints. rf-t titer was significantly higher in ra patients with active disease compared to remission, low and moderate active groups. the sensitivity and specificity were 53.1, 95.3 for anti-ccp antibody and 61.8, 82.3 for rf-t. our results support that anti-ccp and rf titer maybe valuable in estimation of disease activity and other inflammatory parameters in ra patients.