ABSTRACT
The use of the autoantibodies family directed to Citrulline-containing peptides including antibodies to cyclic citrullinated peptides2 [Anti CCP2] and Anti Keratin Antibodies [AKA] test is growing worldwide in the diagnosis of rheumatoid arthritis [RA]. To determine the frequency of Anti CCP2 and AKA and their relation to activity and severity in patients with RA and Osteoarthritis [OA]. 60 patients were recruited for the study; they were equally divided into two groups according to their diagnosis [RA and OA groups]. The thirty patients with RA were diagnosed according to the Revised Criteria for Classification of Rheumatoid Arthritis by the ACR [Arnett et al, 1988]. The thirty Patients with OA were fulfilling the criteria for classification of OA proposed by Altman [1991]. Patients' charts were reviewed for demographic information, clinical diagnosis, and radiographic information. They all had their peripheral blood sampled for CRP, CBC, ESR, IgM RF titre, Anti CCP2 and AKA. The comparison between both studied groups showed significant difference between disease duration and patient's assessment of pain by Visual analog scale [VAS] [p<0.05], while there was no significant difference between both diseases as regard patient's and physician's global assessment of disease activity [p>0.05]. The comparison between both studied groups showed also highly significant differences regarding age, duration, as well as CRP, ESR, Anti CCP2, AKA and IgM RF [p<0.01]. The relation between Activity of RA and severity of OA showed significant relation between both, as regard to Patient's Assessment Of Physical Function [Pt Ass Ph F] in RA patients and OA severity assessed according to Lequesne and Samson, 1991 [p<0.05]. In RA patients, there were significant correlations between each of IgM RF and Anti CCP2 with joint erosions [p<0.05], while there was no significant correlation as regard AKA with joint erosions [p>0.05]. the correlation between each of the IgM RF, Anti-CCP2 and AKA with the clinical assessment items in RA patients [age, disease duration, TJC, SJC, patient's assessment of pain, patient's global assessment of disease activity and physician's global assessment of disease activity showed no significant correlation except for disease duration with AKA [p<0.05]. None of the laboratory assessment items [ESR, CRP, IgMRF, Anti CCP2, and AKA] showed any significant correlation, except for CRP, with both IgM RF and Anti CCP2 [p<0.05]. Also there was a significant correlation between IgM RF and Anti CCP2 [p<0.05]. We concluded that anti-CCP2 could be a very useful serological assay for the diagnosis of RA, because anti-CCP2 revealed higher diagnostic specificity than RF and AKA and could be performed with an easy technique. It also has an independent role in predicting disease activity and has a prognostic value as a marker of erosive disease in RA