T cells: Pathogenic cells and therapeutic targets in rheumatoid arthritis

Objectives: To provide: 1) a brief review of current thought on the role of T cells in the pathogenesis of rheumatoid arthritis (RA); and 2) To provide an overview of RA therapies directed against T cells. Methods: The following papers in relevant American and European medical journals were reviewed. Those related to: the role of T cells in the pathogenesis of RA; to biological therapy directed against cell surface markers specific to T cell populations implicated in RA; and to treatment of RA with cyclosporin A and leflunomide, pharmacological agents known to interfere with the T cell response to antigens. Results: Although a variety of cell types are now recognized as contributors to the progressive joint destruction that is a hallmark of RA, T cell activation is still thought to be a central event in the initiation and progression of this disease. As a result, various therapeutic options directed against T cells have been developed. These include biological agents directed against specific populations of activated T cells and pharmacological agents that have specific T cell-modulatory actions. Conclusions: Use of T cell-directed biological therapies for RA has been disappointing, as a result of both lack of efficacy and serious toxicity. Treatment of RA with pharmacological agents that interfere with antigen-driven T cell proliferation has been more successful.