Rheumatoid arthritis (RA) is an autoimmune disease in which the immune system attacks the tissues in and around joints. This disease destroys cartilage and bone causing inflammation, stiffness, pain, and disability. Although the cause of RA is not known, it affects approximately 1.3 million patients in the United States and it is more common in women and patients who are 40 to 60 years of age. Since there is no cure for RA, treatment is focused on relieving inflammation and pain and preventing joint destruction. RA therapy usually begins with nonsteroidal antiinflammatory agents (NSAIDs) such as aspirin and corticosteroids such as prednisone. For more advanced disease, treatment options include disease-modifying antirheumatic drugs (DMARDs) such as the antiinflammatory drug sulfasalazine and the immunosuppressant methotrexate. In addition, a new
class of genetically engineered biologic agents has been developed to inhibit specific mediators of inflammation, particularly the tumor