Drug targets in immunological diseases: Focus on rheumatoid arthritis

Extract: There are a large number of diseases involving inappropriate activation of the immune system. These are often classified as immune-mediated diseases and include autoimmune diseases such as rheumatoid arthritis (RA), multiple sclerosis, and type I diabetes mellitus, allergic diseases such as asthma, and immune-mediated graft/organ rejection. RA is a chronic systemic inflammatory disease involving the destruction of articular cartilage and bone in joints. Despite the advances in our understanding of RA, the cause remains elusive. It is now recognized that there are two arms to the disease, namely an inflammatory arm and a destructive arm. The inflammation causes many of the symptoms of pain and swelling whereas the joint destruction is the major cause of long term disability associated with this disease. It is clear that the joint destruction occurs early in the course of the disease and mediators, such as cytokines (non-antibody proteins that act as intracellular mediators), are important in this process.