Diverse effects of infliximab and etanercept on T lymphocytes.

The tumor necrosis factor (TNF) antagonists infliximab and etanercept have proven to be useful additions to the armamentarium of agents used to manage patients with inflammatory disorders. However, as discussed in detail elsewhere in this supplement, these agents have different mechanisms of action and distinct safety and efficacy profiles in the clinical setting. Of particular interest are differing effects on T lymphocytes, thymocyte-derived cells that are responsible for cell-mediated immunity. Recent studies in 2 disease states, ankylosing spondylitis and Crohn's disease, have assessed the effects of TNF antagonists on T lymphocytes and reported differences that could partially explain some of the clinical disparities that have been reported.