SCIENCE IN THE NEWS - Autoimmune Diseases: When the Body Sta（在线收听）

SCIENCE IN THE NEWS - Autoimmune Diseases: When the Body Starts to Attack Its Own Cells
By Dana Demange

Broadcast: Tuesday, June 21, 2005

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VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm Barbara Klein.

VOICE TWO:

And I'm Bob Doughty. On our program this week, we talk about a sickness called lupus and other autoimmune diseases. Autoimmune diseases affect the immune system – the body's natural defenses for fighting disease.

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VOICE ONE:

The immune system normally protects the body against foreign materials, such as viruses and bacteria. Autoimmune diseases result from a failure of the body's own defenses against disease. The immune system loses its ability to tell the difference between foreign materials and its own cells. So, the body starts attacking its own organs and tissues.

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There are three kinds of lupus. Discoid lupus affects only the skin and can be identified by red marks on the face or neck. These marks on the skin can be a sign of another form of lupus called systemic lupus. Systemic lupus can affect almost any organ or organ system of the body. When people talk about lupus, they usually mean the systemic form of the disease.

Some kinds of medicines can cause what is called drug-induced lupus. This form of lupus usually goes away when the patient stops using the medicines.

VOICE ONE:

High body temperature and pain in the elbows or knees are common signs of lupus. Other signs are red marks on the skin, feelings of extreme tiredness and a lack of iron in the body.

At different times, the effects of lupus can be either mild or serious. The signs of the disease can come and go. This makes identifying the disease difficult. Many people with lupus also suffer from depression.

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VOICE TWO:

Experts are not sure what causes lupus. Genetics or environmental influences seem to be involved. Lupus has been known to attack members of the same family. Yet, the genes responsible have yet to be identified. Also, many women with lupus give birth to healthy babies.

Many scientists believe infections may cause lupus. So can extreme bodily or mental tension, commonly known as stress. Two other suspected causes are antibiotic drugs and hormones produced by the body.

In fact, hormones might explain why lupus affects women far more often than men. The Lupus Foundation of America says ninety percent of the people with lupus are women. Also, persons of African American, American Indian or Asian ancestry get infected more often than white women.

Scientists do not know why women are more at risk than men. They think it might have to do with female hormones, like estrogen. Another idea is that it could involve the foreign cells left in a woman's body after a pregnancy.

VOICE ONE:

There is currently no cure for lupus. Yet doctors have developed ways of treating the disease. Treatments are based on the condition and needs of each patient. No two individuals have the exact same problems. A treatment could include a combination of exercise, stress-reduction and drugs such as painkillers or steroids. Anti-malaria drugs also have been effective.

It has been thirty years since the United States Food and Drug Administration approved a drug especially for treating lupus. Several companies are working to make drugs that can help lupus patients. Organizations like the Lupus Foundation of America are working to increase public understanding of the disease.

Lupus can be life threatening if left untreated. Yet, many patients can lead a normal and healthy life if they follow their doctor's advice. Patients must take their medicines and keep looking for side effects or any new signs of the disease.

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VOICE TWO:

Lupus is not the only autoimmune disease. Doctors and scientists have identified at least eighty other such diseases in which the body attacks its own organs and cells. Some of the diseases attack just one area of the body, like the skin, eye or muscles. Others affect an organ system or even the whole body.

Some of the diseases are well known, such as rheumatoid arthritis, multiple sclerosis and type-one diabetes. Others are less well known and more difficult to identify.

For example, celiac disease is difficult to identify because the signs of the disease are so common. Patients may have low iron levels and experience stomach pain. The uncontrolled expulsion of bodily wastes also is a problem.

Doctors might treat those signs and not know they are caused by celiac disease. Some people develop celiac disease after eating gluten, a protein found in all wheat products. It is not always clear that eating something as harmless as wheat can be bad for a person's health. For some patients, it can be years before the problem is correctly identified.

VOICE ONE:

The United States National Institutes of Health says autoimmune diseases affect an estimated five to eight percent of the country's population. That represents between fourteen million and twenty-two million Americans.

The physical, emotional, and financial cost of autoimmune diseases is huge. Most of those affected are women. While people of all ages are affected, women who are old enough to have children are especially at risk. This can have an effect on birth rates.

Also, some autoimmune diseases like lupus and scleroderma are more common in African Americans. Diseases such as multiple sclerosis and type-one diabetes are more common among whites. Doctors do not yet know why this is true.

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VOICE TWO:

New drugs are being tested to help treat autoimmune diseases. Some drugs can be a problem because they suppress the immune system. This means the body is less able to defend itself against infections. The side effects of the drugs can end up being as dangerous as the disease itself.

Newer drugs attempt to suppress only one small part of the immune system, not all of it. For example, drugs like Enbrel and Remicade block tumor necrosis factor. This is a protein that causes inflammation, a physical reaction to infection, injury or other causes. These drugs have been useful in treating autoimmune diseases like rheumatoid arthritis, psoriasis, and Crohn's disease. However, the drugs are very costly. Some cost more than ten thousand dollars a year.

The drugs also have also been found to increase the risk of cancer. One such drug, called Tysabri, was used to treat multiple sclerosis. But the drug was removed from the market after it was linked to brain infections.

VOICE ONE:

Scientists continue searching for other methods of treatment. For example, some scientists hope to use stem cells to replace tissues damaged by disease. Stem cells have the ability to grow into other cells, such as heart, nerve or brain cells.

Some medical experts are working together to improve the way autoimmune diseases are identified and treated. A few years ago, the Johns Hopkins Autoimmune Disease Research Center was formed in the American state of Maryland. The aim of the Center is to bring together experts to improve the study of autoimmune diseases.

Private groups like the Center show how important it is for scientists to share information about such diseases. Because each disease often affects different organs, many experts might be needed to treat the disorder. Experts need to know about the most recent medical research and technology. By sharing information about their patients, doctors also can learn from other cases.

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Government organizations also are working to increase knowledge about autoimmune diseases. In the United States, the National Institutes of Health created an autoimmune disease research plan two years ago. The plan urges agencies from different areas to work together.

American lawmakers have approved four hundred and fifty million dollars for the project. It is the first national effort to study the causes and treatments of autoimmune diseases.

Both private and government organizations are working to increase public understanding of such diseases. This can help individuals better understand what to do should they develop a health problem. At the same time, medical researchers continue working to help patients have a better quality of life.

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VOICE ONE:

This SCIENCE IN THE NEWS program was written by Dana Demange. Our producer was Cynthia Kirk. I'm Barbara Klein.

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And I'm Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.