Biologic therapies in rheumatoid arthritis.

Our growing understanding of the immune response mechanism has created a wave of novel biologic agents for the treatment of rheumatoid arthritis. The domain of biologic agents includes: 1) Recombinant regulatory cytokines; 2) engineered molecules and monoclonal antibodies that target proinflammatory cytokines; 3) monoclonal antibodies against lymphocyte cell-surface proteins; 4) fusion proteins and monoclonal antibodies that block the second signal and induce anergy; 5) vaccines comprised of specific proteins from lymphocytes and antigen presenting cells; 6) monoclonal antibodies that block intercellular adhesion; and 6) gene therapy whereby antiarthritis genes are introduced directly into the joint. Most treatments remain under investigation; however, in 1998 two antagonists of tumor necrosis factor were approved marking the first approvals of antirheumatic biologic agents. For the first time anti-rheumatic therapies are being designed instead of borrowed.