Serum Levels of Soluble Fas in Rheumatoid Arthritis Patients Treated With Infliximab

Background. Anti-TNF-alpha therapy is effective in certain inflammatory arthritides and inflammatory bowel diseases. The therapeutic effect of TNF-alpha blockade is associated with both anti-inflammatory potential and interference with cell apoptosis. Rheumatoid arthritis (RA) is characterized by deregulated apoptosis of synovial cells and peripheral blood mononuclear cells. Objectives. The aim of this study was to assess the influence of a monoclonal chimeric anti-TNF-alpha antibody, infliximab, on the serum levels of soluble Fas, which is able to inhibit Fas-induced apoptosis. Material and Methods. The study group consisted of 18 RA patients treated with infliximab at a dose of 3 mg/kg intravenously according to the standard protocol. Serum samples were obtained before therapy and after infusion at weeks 0, 6, 22, and 30. Patient response to the therapy was evaluated at weeks 6 and 54 using the DAS28 index. Serum sFas levels were measured by a commercial ELISA test. Results. There was a statistically significant decrease in sFas levels after infliximab infusion (p = 0.0089, Wilcoxon test). Patients regarded as responders at week 54 had significantly higher baseline sFas levels than non-responders (sFas 0-1, p = 0.0164, Mann-Whitney test). Serum sFas level at baseline correlated with DAS28 index (Spearman's correlation coefficient R = 0.747, p < 0.001). Conclusions. Treatment with infliximab resulted in a significant decrease in sFas level, which may exert a therapeutic effect by removing the soluble inhibitor of cell apoptosis. Pre-treatment serum levels of sFas were significantly higher in patients who responded to the therapy, which can make it a potential prognostic marker for treatment response (Adv Clin Exp Med 2008, 17, 4, 411-414).