Autoimmune Disorders: When the Body Attacks

The human body was designed with a number of highly evolved, specialized systems that perform such functions as circulating oxygen-rich blood, metabolizing food into energy, and firing nerves that let us think, walk, sleep and dream. It even has its own security force - the immune system - to detect and defend us against foreign intruders, such as bacteria and viruses that can weaken us and make us ill.

Sometimes our immune system gets its signals crossed and begins to attack healthy tissue instead of protecting us. And when the immune system targets itself as the enemy, it releases antibodies that attack its own cells, tissues or organs. That, in turn, "can unleash a torrent of disorders, including allergic diseases, arthritis and a form of diabetes (type 1)," according to the National Institute of Allergy and Infectious Diseases (NIAID) - the primary government organization for research on autoimmune diseases.

In a consumer publication titled "Understanding the Immune System," NIAID says: "No one knows exactly what causes an autoimmune disease, but multiple factors are likely to be involved. These include elements in the environment, such as viruses, certain drugs, and sunlight, all of which may cause inflammation and tissue damage." Genes and hormones may also be a causal factor in some diseases.

Autoimmune Disorders Differ Widely
The National Institutes of Health (NIH) currently classifies more than 80 disorders as autoimmune diseases. Their effects can differ widely, from mild to disabling and potentially life-threatening. They affect a wide range of organs, including the thyroid, joints, skin, kidneys, liver, heart, lungs, blood vessels, nerves and brain.

Estimates of how many suffer from autoimmune disorders also vary widely. The NIH estimates that 5% to 8% of Americans - between 15 million and 24 million people - have an autoimmune disorder. The American Autoimmune Related Diseases Association (AARDA) claims as many as 50 million Americans suffer from some type of autoimmune disease. Among the most common:

• Hashimoto's thyroiditis
• Lupus
• Multiple sclerosis (MS)
• Rheumatoid arthritis (RA)

Women at Greater Risk
Women are at greatest risk of developing an autoimmune disorder, according to the web site of the National Women's Health Information Center:

"Most autoimmune diseases occur in women, and most often during their childbearing years. Some of these diseases also affect African-American, American-Indian and Latina women more than white women. These diseases tend to run in families, so your genes, along with the way your immune system responds to certain triggers or things in the environment, affect your chances of getting one of these diseases."

Although women are at greater risk than men for many autoimmune disorders, the ratio of women to men varies widely among the diseases. For instance, with Hashimoto's disease, women are more likely to be affected by a ratio of as much as 10 to 1 compared with men. With lupus, the female-to-male ratio is estimated at 9 to 1. With rheumatoid arthritis, it's 3 to 1 (with African-American women three times more likely to acquire lupus than Caucasian women). With multiple sclerosis, the ratio of women to men is 2 to 1.

The reasons women are more prone to these conditions than men are not well understood, but likely comprise hormonal and genetic factors.

Difficult to Diagnose and Treat
Autoimmune disorders can be difficult to diagnose, in part because their symptoms are often common to a wide range of other conditions. Some autoimmune diseases are characterized by "flares," during which symptoms increase, followed by periods of remission. Many autoimmune disorders damage organs by promoting an inflammatory process, and newer treatments often aim at curbing that inflammation.

Multiple Sclerosis
In people with MS, the immune system attacks the myelin (the tissue that insulates nerves), causing inflammation. In the past dozen years, the treatment of choice for MS has been immunomodulators, which help regulate the inflammatory process and therefore decrease the frequency and severity of relapses. The goal of this treatment is to slow down any further disability.

Systemic Lupus Erythematosus (Lupus)
Symptoms of lupus can vary widely. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), "One person with lupus may have swollen knees and fever. Another person may be tired all the time or have kidney trouble. Someone else may have rashes. Lupus can involve the joints, the skin, the kidneys, the lungs, the heart or the brain. It may affect two or three parts of the body." Because of this complexity, treatments span a broad range, and may include steroids and corticosteroids to suppress inflammation; or drugs that suppress the immune system.

Rheumatoid Arthritis
Rheumatoid arthritis is characterized by swelling of the lining of the joints, progressing to the total joint. When the tissue that normally cushions the joint becomes inflamed, it becomes thick and makes the joint red, swollen, painful and puffy. Like lupus, a variety of treatments may be tried to relieve pain and inflammation. In some cases, surgery might be indicated.

Hashimoto's Thyroiditis
With Hashimoto's hypothyroidism, the production of thyroid hormone decreases below what the body normally needs. Every organ in the body slows down, making it difficult to concentrate. The bowels become sluggish and constipation occurs. Metabolism slows down, causing weight gain. Hashimoto's is diagnosed by measuring the patient's levels of thyroid-stimulating hormone. If the levels are low, the patient is tested for antibodies associated with disease. If appropriate, patients are put on thyroid hormone replacement therapy.

Although autoimmune disorders are not curable, some, like Hashimoto's, can be fairly well controlled by medication. Others, like lupus, multiple sclerosis and rheumatoid arthritis, can be progressive and more difficult to manage. New combination treatments, however, can many times offer hope of symptom relief.

Barbara Abel
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.