Factors underlying chronic inflammation in rheumatoid arthritis.

Rheumatoid arthritis (RA)is a debilitating chronic inflammatory disease whose characteristic pathology includes swollen, painful, and deformed joints. In recent decades, both clinical and basic scientific research have tried to determine the factors involved in the pathogenesis of this common disease. Although the cause of RA is still unknown, several factors that contribute to RA have been identified. Among these are the discoveries of: susceptibility genes, disease-causing immune cells, and cytokine and signal transduction networks involved in promoting persistence of inflammation. Various therapeutic strategies, including anti-tumor necrosis factor therapy, have been developed to target one or more of these factors. Although none of these therapeutic strategies can actually cure the disease, some of these novel agents have proven to be more effective than others. This implies that the success of a therapy is very much dependent on the therapeutic targets chosen. Therefore, improved understanding of the cellular and molecular events occurring in the rheumatoid joint during the pathogenesis of the disease is particularly important if we are to better combined therapeutic strategies. In this article we summarize current understanding of the factors that contribute to disease pathogenesis in RA and identify cellular and molecular events that could drive the development of the disease and represent potential new therapeutic targets.