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What Are Autoimmune Diseases?
The word "auto" is the Greek word for self. The immune system is a complicated network of cells and cell components (called molecules) that normally work to defend the body and eliminate infections caused by bacteria, viruses, and other invading microbes. If a person has an autoimmune disease, the immune system mistakenly attacks self, targeting the cells, tissues, and organs of a person's own body. A collection of immune system cells and molecules at a target site is broadly referred to as inflammation.
The autoimmune reaction is directed against the brain in multiple sclerosis and the gut in Crohn's disease. In other autoimmune diseases such as systemic lupus erythematosus (lupus), affected tissues and organs may vary among individuals with the same disease. One person with lupus may have affected skin and joints whereas another may have affected skin, kidney, and lungs. Destruction of insulin-producing cells of the pancreas causes Type 1 diabetes mellitus.
Who Is Affected by Autoimmune Diseases?
Autoimmune diseases afflict millions of Americans, strike women more often than men; in particular, they affect women of working age and during their childbearing years.
Lupus is more common in African-American and Hispanic women. Rheumatoid arthritis and scleroderma affect Native American communities .