ABSTRACT
To assess the diagnostic value of anti-cycle citrullinated peptide [anti-CCP] antibodies in patients with rheumatoid arthritis [RA] and its relation to disease activity and severity of erosions and to determine whether the combined measurements of rheumatoid factor[RF] and [anti-CCP] antibodies add to diagnosis of RA. In this cross sectional study, serum samples from 60 patients with RA, 40 patients with other rheumatic diseases and 30 healthy subjects were tested for anti-CCP antibodies by enzyme linked immunosorbent assay [ELISA] and IgM rheumatoid factor [IgM RF] with Latex Fixation Test [LFT] and then titrated with Rose Waaler test [RW]. Radiographs of hands and wrists were taken then the joint destructions were quantified using Larsen's score. Sensitivity was higher for IgM RF [76.6%] but the specificity was higher for [anti-CCP] antibodies [95% and 96.6% versus other rheumatic disease patients and control subjects, respectively]. The combination of both IgM RF and anti-CCP measurements improve both sensitivity and specificity. Positivity of anti-CCP and RF were associated significantly with constitutional symptoms and extra-articular manifestations. Significant differences were found between RA positive and negative cases of anti-CCP or RF as regards degree of disease activity and radiological changes. While no significant differences were found when positive and negative cases of anti-CCP or RF were compared as regards duration of disease and duration of morning stiffness. RF test has a high sensitivity and weak specificity but anti-CCP has a moderate sensitivity and excellent specificity. So combined RF and anti-CCP tests are useful in establishing the diagnosis of RA especially in RA patients with negative RF