Autoimmune Diseases

Crohn's Disease | Diabetes | Lupus | Multiple Sclerosis | Myasthenia Gravis-Als | Rheumatoid Arhritis | Scleroderma

An autoimmune disease is a malfunction of the body's immune system that causes the body to attack its own tissues.

• Autoimmune diseases can be triggered in many ways
• Symptoms vary depending on which disease develops and which part of the body is affected
• Several blood tests are usually needed to confirm the presence of an autoimmune disease
• Autoimmune diseases are treated with drugs that suppress the activity of the immune system.

The immune system defends the body against what it perceives to be foreign or dangerous substances. Such substances include microorganisms, parasites (such as worms), cancer cells, and even transplanted organs and tissues. Substances that can stimulate an immune response are called antigens. Antigens are molecules that may be contained within cells or on the surface of cells (such as bacteria, viruses, or cancer cells). Some antigens, such as pollen or food molecules, exist on their own.

Even cells in a person's own tissues can have antigens. But, normally, the immune system reacts only to antigens from foreign or dangerous substances, not to antigens from a person's own tissues. However, the immune system sometimes malfunctions, interpreting the body's own tissues as foreign and producing antibodies (called autoantibodies) or immune cells that target and attack particular cells or tissues of the body. This response is called an autoimmune reaction. It results in inflammation and tissue damage. Such effects may constitute an autoimmune disease, but some people produce such small amounts of autoantibodies that an autoimmune disease does not occur.

Some of the more common autoimmune diseases include systemic sclerosis (scleroderma), rheumatoid arthritis, systemic lupus erythematosus (lupus), and crohn's disease, among others. Additional diseases that are believed to be due to autoimmunity include hyperthyroidism (graves disease), glomerulonephritis, addison's disease, mixed connective tissue disease, polymyositis, Sjögren's syndrome, and some cases of infertility.

Causes

Autoimmune reactions can be triggered in several ways:

• A substance in the body that is normally confined to a specific area (and thus is hidden from the immune system) is released into the bloodstream. For example, a blow to the eye can cause the fluid in the eyeball to be released into the bloodstream. The fluid stimulates the immune system to recognize the eye as foreign and attack it
• A normal body substance is altered, for example, by a virus, a drug, sunlight, or radiation. The altered substance may appear foreign to the immune system. For example, a virus can infect and thus alter cells in the body. The virus-infected cells stimulate the immune system to attack
• A foreign substance that resembles a natural body substance may enter the body. The immune system may inadvertently target the similar body substance as well as the foreign substance. For example, the bacteria that cause strep throat have some antigens that are similar to those in human heart cells. Rarely, the immune system may attack a person's heart after strep throat (this reaction is part of rheumatic fever)
• The cells that control antibody production—for example, B lymphocytes (a type of white blood cell)—may malfunction and produce abnormal antibodies that attack some of the body's cells.

Heredity may be involved in some autoimmune diseases. Susceptibility to the disease, rather than the disease itself, may be inherited. In susceptible people, a trigger, such as a viral infection or tissue damage, may cause the disease to develop. Hormonal factors may also be involved, because many autoimmune diseases are more common among women.

Symptoms and Diagnosis

Autoimmune diseases may cause a fever. However, symptoms vary depending on the disease and the part of the body affected. Some autoimmune diseases affect certain types of tissue throughout the body—for example, blood vessels, cartilage, or skin. Other autoimmune diseases affect a particular organ. Virtually any organ, including the kidneys, lungs, heart, and brain, can be affected. The resulting inflammation and tissue damage can cause pain, deformed joints, weakness, jaundice, itching, difficulty breathing, accumulation of fluid (edema), delirium, and even death.

Blood tests that indicate the presence of inflammation may suggest an autoimmune disease. For example, the erythrocyte sedimentation rate (ESR) is often increased, because proteins that are produced in response to inflammation interfere with the ability of red blood cells (erythrocytes) to remain suspended in blood. Frequently, the number of red blood cells is decreased (anemia) because inflammation decreases their production. However, inflammation has many causes, many of which are not autoimmune. Thus, doctors often obtain blood tests to detect different antibodies that can occur in people who have particular autoimmune diseases. Examples of these antibodies are antinuclear antibodies, which are typically present in systemic lupus erythematosus, and rheumatoid factor or anti-cyclic citrullinated peptide (anti-CCP) antibodies, which are typically present in rheumatoid arthritis. But even these antibodies may sometimes occur in people who do not have an autoimmune disease, so doctors usually use a combination of test results and the person's signs and symptoms to decide whether an autoimmune disease is present.

Treatment

Individual treatment of an autoimmune disease may vary depending upon the patient and their desire to receive tradition treatment, alternative treatment or integrative treatment for the disease.  It is vital that persons diagnosed with, or suspected of having an autoimmune disease consult with their health care provider to assure proper evaluation, treatment and interpretation of information contained on this site.