Autoimmune Definition

Normally the immune system recognizes the tissues in the body that are not "foreign" and does not attack them. Autoimmune disorders are diseases caused by the body producing an immune response against its own tissues. The cause of autoimmune diseases is unknown, but it appears that there is a genetic predisposition to develop autoimmune disease in many cases (i.e. they are passed down through families). In a few types of autoimmune disease (such as rheumatic fever), a bacteria or virus triggers an immune response, and the antibodies or T-cells attack normal cells because they have some part of their structure that resembles a part of the infecting germ.



Autoimmune disorders fall into two general types: those that damage many organs ('systemic'), and those where only a single organ or tissue is directly damaged by the autoimmune process ('localized').