Value of Anti-PeptidylArginine Deiminase4Antibodies in Rheumatoid Arthritis Patients Compared to Anti-cyclic CitrullinatedPeptide

Background:Rheumatoid arthritis (RA) as a chronic multisystem disease isdistinguished by chronic polyarthritis and can lead to deformities and disabilities [1] .Antibodies to anti-cyclic citrullinated peptidewere found to be specific for RA, including the early form, demonstrating a possible prognostic value [2] .In addition to the widely used RF and ACCP autoantibody assay, several tests have emerged to help in RA diagnosis, such as serum anti PADI4[3] , which is the enzyme that causescitrullination of proteins leading to production of autoantibodies[4] . Objectives:To assess the role of serum Anti-PADI4 Ab. in patients with RA and its relation with clinical parameters, disease activity and comparing it with ACCP level in RA patients.Subjects and Methods:A case-control study comprising 100 subjects, 50 RA patients and 50 apparently healthy subjects asa control was carried out at Department of Physical Medicine, Rheumatology and Rehabilitation, Zagazig University Hospitals. All included patients underwent detailed history taking, clinical examination, and disease activity assessment using DAS-28, CRP and ESR. Serum Anti-PADI4 and ACCP were determined in RA patients and healthy controls utilizing quantitative ELISA technique. Results:We found a significant positive correlation between Anti-PADI4 and ACCP level (P = 0.02). We found no correlations between serum Anti-PADI4, ACCP and DAS28, number of tenders, swollen joints, and ESR. Conclusion: Significant increase existed in Anti-PADI4 serum level of RA patients over healthy controls subjects. Sensitivity and specificity of Anti-PADI4 increased in the presence of ACCP, indicating that Anti-PADI4 may helpto diagnoseRA patients lacking ACCP.