Autoimmune Disorders
"An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue.
In patients with an autoimmune disorder, the immune system can't tell the difference between healthy body tissue and antigens. The result is an immune response that destroys normal body tissues. The response is a hypersensitivity reaction similar to allergies, where the immune system reacts to a substance that it normally would ignore. In allergies, the immune system reacts to an external substance that would normally be harmless. With autoimmune disorders, the immune system reacts to normal body tissues.
What causes the immune system to no longer distinguish between healthy body tissues and antigens is unknown. One theory holds that various microorganisms and drugs may trigger some of these changes, particularly in persons who are genetically prone to autoimmune disorders.
An autoimmune disorder may result in:
- The destruction of one or more types of body tissue
- Abnormal growth of an organ
- Changes in organ function"
From a MedlinePlus Article (opens in new tab or window)