The balance of Th1/Th2 cytokines in rheumatoid arthritis

It has been suggested that rheumatoid inflammation is mediated by activated pro-inflammatory T helper type I cells. In contrast, immunomodulatory T helper type 2 cells and their cytokines, in particular interleukin-4, are rarely found. This chapter reviews the concept of the Th1/Th2 dichotomy and summarizes the functions of the signature cytokines of the T helper subsets. We discuss current knowledge of the immunopathogenesis of rheumatoid arthritis and its related animal model, collagen induced arthritis, with regard to the Th1/Th2 paradigm. The accumulating evidence for a T helper type 1 driven inflammation and the implications for future therapy are delineated.