What Are Autoimmune Diseases?

Autoimmune Diseases 101

Young woman has a cold, sitting in a kitchen wrapped in blanket and using a digital tablet.
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Your immune system is on duty, protecting you 24-hours per day, every day of your life. Always on alert, the molecules and cells of your immune system sort, sift, attack, and destroy foreign germs, or rogue cells, that could hurt you. Unfortunately, sometimes things go wrong in translation.

An autoimmune disease occurs when the immune system confuses your own body for a dangerous molecule. The prefix “auto,” refers to self, so an autoimmune disorder is one where the immune system reacts against itself—rather than a bonafide intruder.

If you are injured, or become sick, your body mounts an immune response. That means your body targets the invader, or the wounded area of your body, and directs cells, chemicals, and liquids to the area to fight, defend, and heal. A collection of cells directed at a particular area in the body is called inflammation. With an autoimmune disease, your own tissue and glands are the target of a mistaken immune response.

Autoimmune diseases affect the body in different ways. With multiple sclerosis, an autoimmune response is directed against the brain. With Crohn’s disease,the attack is directed against the digestive tract. Still other autoimmune disorders, like systemic lupus erythematosus (lupus), can provoke varying symptoms—like damage to skin and joints in one patient—while another person suffers kidney and lung damage. Hashimoto's disease affects the thyroid, and causes destruction of the gland. And Graves' disease causes antibodies that stimulate the thyroid gland to overproduce thyroid hormone.

For many, damage to tissue and cells from autoimmune diseases is permanent, as with the destruction of insulin-producing cells in the pancreas that lead to Type 1 diabetes mellitus.

Who Is Affected by Autoimmune Diseases?

Many autoimmune diseases are rare. Despite that, autoimmune diseases afflict millions of Americans. Autoimmune diseases strike women more often than men, and frequently affect women of working age, during childbearing years.

Some minority populations are more susceptible to certain autoimmune disease. Lupus is more common in African-American and Hispanic women than in Caucasian women of European ancestry. Rheumatoid arthritis and scleroderma affect higher percentage of residents in some Native American communities than in the general U.S. population. The social, economic, and health impact of autoimmune diseases is far-reaching and felt by family, friends, employers, and co-workers.

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