Autoimmunity is the failure of an organism in recognizing its own constituent parts as self, which allows an immune response against its own cells and tissues. Any disease that results from such an aberrant immune response is termed an autoimmune disease. Autoimmunity is often caused by a lack of germ development of a target body and as such the immune response acts against its own cells and tissues. Prominent examples include Coeliac disease, diabetes mellitus type 1 (IDDM), systemic lupus erythematosus (SLE), Sjögren's syndrome, Churg-Strauss Syndrome, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's Disease, rheumatoid arthritis (RA) and allergies. Autoimmune diseases are very often treated with steroids.
The misconception that an individual's immune system is totally incapable of recognizing self antigens is not new. Paul Ehrlich, at the beginning of the twentieth century, proposed the concept of horror autotoxicus, wherein a 'normal' body does not mount an immune response against its own tissues. Thus, any autoimmune response was perceived to be abnormal and postulated to be connected with human disease. Now, it is accepted that autoimmune responses are an integral part of vertebrate immune systems (sometimes termed 'natural autoimmunity'), normally prevented from causing disease by the phenomenon of immunological tolerance to self-antigens. Autoimmunity should not be confused with alloimmunity.Wikipedia
Wikipedia's article on autoimmunity.ACES Autoimmune Support Group
Support, stories, and resources.American Autoimmune Related Diseases Association (AARDA)
The American Autoimmune Related Diseases Association is dedicated to the eradication of autoimmune diseases and the alleviation of suffering and the socioeconomic impact of autoimmunity through fostering and facilitating collaboration in the areas of education, research, and patient services in an effective, ethical and efficient manner.National Institute of Allergies and Infectious Diseases
A short article discussing autoimmunity.Polyarteritis Nodosa Research and Support Network
Large page of links for more resources.