Gene therapy for rheumatoid arthritis

Gene therapy was initially conceived of as a means of replacing defective genes in monogenic disorders such as cystic fibrosis or hemophilia, but has rapidly progressed into areas of medicine that involve a wide range of diseases including cancer, neurodegenerative disorders and autoimmunity. Elucidation of some of the cellular and molecular mechanisms implicated in the pathogenesis of joint inflammation and cartilage and bone destruction in inflammatory joint diseases such as rheumatoid arthritis (RA) have revealed novel targets for gene therapy. Strategies include the inhibition of pro-inflammatory cytokines, blockade of cartilage-degrading enzymes, inhibition of synovial cell activation or apoptosis of synovial cells, and manipulation of the Th1-Th2 cytokine balance. Both viral and non-viral gene transfer vector systems have been used to deliver therapeutic genes systemically or directly to arthritic joints by ex vivo as well as in vivo administration. Animal models of RA have been essential not only for better understanding the mechanisms of RA but also in serving as basic experimental tools to evaluate candidate gene products with anti-arthritic properties and develop therapeutic strategies.