Autoinflammatory diseases are a relatively new category of immune disorders that arise from problems with the innate immune system--the body's nonspecific defenses that are inborn and primed at all times to fight infection.  Whereas the adaptive immune system selectively targets and fights infectious agents using antibodies, the innate immune system fights anything in the body that it recognizes as foreign or non-self with a general and immediate response.  The hallmark of innate immunity is inflammation, or swelling of tissues accompanied by redness and pain. 

     When the innate and adaptive immune systems are working together correctly, they present an effective defense against disease.  However, sometimes the body attacks its own tissues by mistake.  For disorders of the adaptive immune system, this is referred to as autoimmunity.  For disorders of the innate immune system, the term autoinflammatory has become the gold standard.

     The science of autoinflammatory diseases has progressed rapidly since the term was first coined in the late 1990s in an effort to distinguish this distinct group of illnesses from the more well-defined autoimmune diseases, such as rheumatoid arthritis and lupus.  Advances in genetic technologies have expanded the understanding of the molecular and cellular basis of autoinflammatory diseases and have broadened the field to include disorders that no longer fit within the original classification.  In line with other similar diseases,  autoinflammatory disorders were defined by episodes of seemingly unprovoked inflammation with high-titer autoantibodies or antigen-specific T lymphocytes.  Both are indicators of autoimmune diseases, which involve the adaptive immune system. 

     In an effort to converge the clinical concept of autoinflammatory diseases with advances in the basic science of immunity, researchers suggest a revised classification that focuses on abnormally increased inflammation mediated predominately by the innate immune system, with a significant host predisposition.  The host predisposition could result from genetic factors or could be triggered by gene-environment interactions.

     Daniel L. Kastner, M.D., Ph.D., of the National Institutes of Health's National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), is lead author of the study which was published in the March 19, 2010, issue of Cell as "Autoinflammatory Disease Reloaded: A Clinical Perspective."

--Source: NIH News, National Institutes of Health, NIAMS, March 22, 2010