Autoreactive T cells are part of the normal immune system and are kept under control by mechanisms known as anergy. Autoimmune diseases are caused by the breakdown of this tolerance, and T cell activation leads to severe inflammation and tissue damage. For example, in rheumatoid arthritis, synovial joints will be destroyed whereas in insulin-dependent diabetes mellitus (IDDM, type 1 diabetes), insulin-producing beta cells in the pancreatic islets of Langerhans will be the focus of the attack. The genetic makeup of susceptible individuals and the environmental factors leading to autoimmunity are complex and largely unknown. In many instances, the main genetic locus ... Read more