Background: Targeted anti-tumor necrosis factor-alpha (TNFα) therapy in patients with rheumatoid arthritis (RA) has resulted in dramatic improvement in the course of the disease and prognosis. One of the features of RA is hyperplasia of synovial cells, particularly RA synovial fibroblasts (RA-SF), caused partially by impaired apoptosis of RA-SF cells. It has been shown that TNFα may inhibit apoptosis in RA-SF cells and this process may be reversed by the use of TNFα antagonists.

Objectives: To determine the influence of etanercept, an anti-TNFα agent, on sFas (CD 95) receptor.

Methods: We analyzed serum levels of sFaS and TNFα in a group of 26 patients with high RA disease activity who were selected to start treatment with etanercept. Assessment of sFas receptor and TNFα levels was performed before and 6 months after treatment with etanercept.

Results: Treatment with etanercept resulted in increased TNFα levels (log TNFα 0.602 vs. 1.17, P < 0.05) but no change in sFas levels (log sFas 3.17 vs. 3.11, P = 0.37). As expected, treatment resulted in significant reduction in both disease activity and levels of inflammatory markers.

Conclusions: Etanercept may increase TNFα levels in patients with RA. We also speculate that the Fas pathway is not the main apoptotic pathway in patients with RA treated with etenercept, since sFas, a marker of apoptotic activity, remained unchanged and was not influenced by disease activity and concomitant treatment.