Clinical Significance of IgA Rheumatoid Factor, Anti-Myeloperoxidase, and Anti-Proteinase 3 Antibodies in Patients with Rheumatoid Arthritis

According to the variable progression of rheumatoid arthritis(RA) determination of factors related with poor prognosis is necessary for appropriate treatment of these patients. In this cross section analytical study the aim was to determine the correlation between IgA RF, anti-MPO, anti-PR3 antibodies and clinical, radiological severity in patients with RA. Patients and Serum samples from 48 patients with RA, who were seen regularly in this clinic were tested. IgA RF, anti-MPO, anti-PR3 titers were estimated by enzyme linked immunoabsorbent assay(ELISA). Hand radiographs were read using the Larsen method as modified by Rau and Herborn also carpometacarpal ratio was calculated. For statistical analysis frequency, percent of frequency indices, mean, median, mode, standard deviation, standard error and for analytic analysis, pearson's correlation coefficient have been used. IgA RF was detected in 33.3% of patients[24.4% of RF(agglutination test) negative patients] and was significantly correlated with low blood hemoglobin(r=-0.311, p=0.02), but not with radiologic damage(r=-0.078). Anti-MPO, and anti-PR3 antibodies were detected in 4.16%, and 2.08% of patients respectively. According to small number of positive sera no correlation was assessed. IgA RF is significantly associated with disease activity and more sensitive in detecting serpositive patients.