An autoimmune disease is a condition that results from an anomalous
response of the adaptive immune system, wherein it mistakenly targets and
attacks healthy, functioning parts of the body as if they were foreign
organisms. It is estimated that there are more than 80 recognized autoimmune
diseases, with recent scientific evidence suggesting the existence of
potentially more than 100 distinct conditions. Nearly any body part can be
involved.
Autoimmune diseases are a separate class from autoinflammatory diseases. Both
are characterized by an immune system malfunction which may cause similar
symptoms, such as rash, swelling, or, fatigue, but the cardinal cause or
mechanism of the diseases are different.