one of a number of otherwise unrelated disorders caused by inflammation and destruction of tissues by the body's own immune response. These disorders include acquired haemolytic anaemia, pernicious anaemia, rheumatic fever, rheumatoid arthritis, glomerulonephritis, systemic lupus erythematosus, myasthenia gravis, Sjögren's syndrome, and several forms of thyroid dysfunction, including Hashimoto's disease. It is not known why the body should lose the ability to distinguish between substances that are 'self' and those that are 'non-self'.
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a disorder caused by an immune response directed against self antigens. The usual characteristics are demonstrable circulating autoantibodies or cell-mediated immunity against autoantigens, inflammatory lesions caused by immunologically competent cells or immune complexes in tissues containing the autoantigens, and clinical or experimental evidence that the autoimmune process is pathogenic and not secondary to other tissue damage. However, some diseases, such as systemic lupus erythematosus and rheumatoid arthritis are often classified as autoimmune diseases even though their pathogenesis is unclear.Medical dictionary. 2011.