Department of Internal Medicine, Division of Rheumatology and Rheumatic Diseases Core Center, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA.
Recent findings have substantiated the importance of T lymphocytes to the pathogenesis of rheumatoid arthritis (RA). Here, we review emerging data regarding genetic predisposition, spontaneous animal models of arthritis, and cell-cell interactions that implicate T cells as driving synovial inflammation and joint destruction. Information regarding the proinflammatory role of interleukin-17-producing T cells and the functional state of regulatory T cells both in animal models and in patients with RA is also discussed. In light of the overwhelming evidence that disrupted T-cell homeostasis greatly contributes to joint pathology in RA, the therapeutic potential of targeting activators of pro-inflammatory T cells or their products is compelling.