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Question: What Do These Diseases Have In Common?

American Autoimmune Related Diseases Association
About Autoimmunity
Autoimmune Diseases
Ordering Information
Newsletter Subscriptions & Contributions

Lupus

Insulin Dependent Diabetes Mellitus

Multiple Sclerosis

Crohn's Disease

Pernicious Anemia

Scleroderma

Rheumatoid Arthritis

Graves' Disease

Anti-TBM Nephritis

Cardiomyopathy

Polymyositis

Antiphospholipid (APL) Syndrome

Rheumatic Fever

Addison's Disease

Myasthenia Gravis

Chronic Active Hepatitis

Sjogren's

Psoriasis

Raynaud's

Click here to get more info on these and other diseases.

Answer: Autoimmunity

Questions And Answers About Autoimmunity

Common Autoimmune Diseases
What is Autoimmunity?
What Causes Autoimmunity?
Different Types of Autoimmunity
What About Treatment?
Family Connection
Autoimmune Facts

What is Autoimmunity?

Autoimmune diseases are a broad category of related diseases in which the person's immune system attacks his/her own tissue.

One of the functions of the immune system is to respond to invading microorganisms, such as viruses or bacteria, by producing antibodies or sensitized lymphocytes (types of white blood cells) that will recognize and destroy the invaders. Autoimmune disease occur when these reactions take place against the body's own cells and tissues, producing a variety of diseases.

The disease-producing mechanisms in autoimmunity are called hypersensitivity reactions. These reactions also occur in allergies, which are a related phenomenon. Both are inappropriate responses of the immune system except that, with allergy, the response is to invading substances (antigens) from outside the body.

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What Causes Autoimmunity?

The immune system normally can distinguish "self" from "nonself". Some lymphocytes are capable of reacting against self, but these lymphocytes are usually suppressed. Autoimmune diseases occur when there is some interruption of the usual control process, allowing lymphocytes to avoid suppression, or when there is an alteration in some body tissue so that it is no longer recognized as self and is thus attacked.

The exact mechanisms causing these changes are not completely understood; but bacteria, viruses, toxins, and some drugs may play a role in triggering an autoimmune process in someone who already has a genetic (inherited) predisposition to develop such a disorder. It is theorized that the inflammation initiated by these agents, toxic or infectious, somehow provokes in the body a "sensitization," an autoimmune reaction, in the involved tissue.

Are There Different Types of Autoimmunity?

Autoimmune processes can have various results, for example, slow destruction of a specific type of cells or tissue, stimulation of an organ into excessive growth, or interference in its function. Organs and tissues frequently affected include the endocrine gland (such as thyroid, pancreas, and adrenal glands), components of the blood (such as red blood cells), and the connective tissues, skin, muscles, and joints.

Particular autoimmune disorders are frequently classified into organ-specific disorders and non-organ-specific types.

In organ-specific disorders, the autoimmune process is directed mostly against one organ. Examples, with the organ affected, include Hashimoto's thyroiditis (thyroid gland), pernicious anemia (stomach), Addison's disease (adrenal glands), and insulin-dependent diabetes mellitus (pancreas).

In non-organ-specific disorders, autoimmune activity is widely spread throughout the body. Examples include rheumatoid arthritis, systemic lupus erythematosus (SLE, or lupus), and dermatomyositis. Some autoimmune diseases fall between the two types. Patients may experience several organ-specific diseases at the same time. There is, however, little overlap between the two ends of the spectrum.

What About Treatment?

Of first importance in treating any autoimmune disease is the correction of all major deficiencies. An example would be replacing hormones that are not being produced by the gland, such as thyroxin in autoimmune thyroid disease or insulin in type one diabetes. In autoimmune blood disorders, it may be necessary to replace components of the blood by transfusion.

Second in importance is to diminish the activity of the immune system. This necessitates a delicate balance, controlling the disorder while maintaining the body's ability to fight disease in general. The drugs most commonly used are corticosteroid drugs. More severe disorders can be treated with other more powerful immunosuppressant drugs, such as methotrexate, azathioprine and cyclophosphamide. All of these drugs, however, can damage rapidly dividing tissues, such as the bone marrow, and so are used with caution.

Intravenous immunoglobulin therapy is used in the treatment of various autoimmune diseases to reduce circulating immune complexes. Some mild forms of rheumatic autoimmune diseases are treated by relieving the symptoms with nonsteroidal anti-inflammatory medications.

Drugs that act more specifically on the immune system, for example, by blocking a particular hypersensitivity reaction, are being researched.

Is There a Family Connection?

The ability to develop an autoimmune disease is determined by a dominant genetic trait that is very common (20 percent of the population) and may present in families as different autoimmune diseases within the same family. However, the genetic predisposition alone does not cause the development of autoimmune diseases. It seems that other factors need to be present as well in order to initiate the disease process. It is important for families with members who have autoimmune diseases to mention this fact when another member of the family is experiencing medical problems that appear to be difficult to diagnose.

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Autoimmune Facts

There are more than 80 known autoimmune diseases.
1 in 5 Americans or twenty percent of the population has an autoimmune disease.
Approximately seventy five percent of those affected are women.
Autoimmunity is not related to AIDS (in which an acquired virus attacks the immune system), nor is it a form of cancer.
Researchers have found "family clusters" of autoimmunity; persons with autoimmune diseases often find that many members of their family also have an autoimmune disease.
Autoimmune diseases are not contagious or infectious, but they can cause major organ damage and be life threatening.

Last updated April 09, 1997

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