June 2022

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Understanding Autoimmune Diseases

When Your Body Turns Against You

Your body’s disease defense system, called the immune system, goes to battle every day. It helps keep you healthy by fighting off viruses and bacteria that sneak into your body. But sometimes, your immune system makes mistakes. If it sees your body’s healthy cells as a threat, it may attack them. This can cause an autoimmune disorder.

There are many different autoimmune diseases. Some involve only one type of tissue. For example, in a disease called vasculitis, your immune system attacks your blood vessels. Other autoimmune diseases involve many different parts of the body. Lupus, for example, can damage the skin, heart, lungs, and more.

Most autoimmune diseases cause inflammationHeat, swelling, and redness caused by the body’s protective response to injury or infection.. But the symptoms they cause depend on the body parts affected. You can have pain in your joints or muscles. Or you may experience skin rashes, fevers, or fatigue.

Researchers still don’t know what causes most autoimmune diseases. But they’ve made progress in understanding what puts you at risk and figuring out ways to diagnose and treat them.

What Are the Triggers?

Some autoimmune diseases are rare, but others are fairly common. About 1% of people in the U.S. have rheumatoid arthritis, explains Dr. Mariana Kaplan, an NIH specialist in autoimmune diseases. Rheumatoid arthritis damages the joints.

Certain genesStretches of DNA you inherit from your parents that defines features, like your risk for certain diseases. put you at higher risk for developing an autoimmune disorder. But genes alone aren’t usually enough, says Dr. Peter Grayson, an NIH expert on vasculitis. His team recently found a single gene change that can cause vasculitis in older men.

Most people who carry genes linked with autoimmune diseases still won’t develop one. Usually, one or more triggers are needed to set off the immune system.

Different things in your environment can serve as triggers, explains Dr. Andrew Mammen, an NIH expert on muscle diseases. His team studies myositis, a disease in which immune cells attack the muscles.

Too much sun exposure can trigger a type of myositis in people who have certain genetic risk factors, Mammen explains. But, he says, most people need other triggers as well to develop the condition. What they are aren’t always clear.

Certain viruses can also jump-start an autoimmune attack. A recent NIH-funded study found that a virus called Epstein-Barr may trigger some cases of multiple sclerosis, or MS. MS is an autoimmune disease that damages the nerves.

Other risk factors can be your age, sex, smoking history, and weight. Many autoimmune diseases are also more common in women than men.

Getting a Diagnosis

A diagnosis of an autoimmune disease can take time, says Grayson. Especially if it’s one that affects many parts of the body.

People often turn to different doctors for different symptoms. “If you’re seeing, for example, an eye doctor, a skin doctor, and a lung doctor separately, they may not see that your symptoms are connected,” says Grayson.

Symptoms of autoimmune diseases can also mimic those of many other conditions. “For example, we call lupus ‘the great imitator,’ because it can look like many other diseases,” Kaplan says.

Talk with your health care provider if you’re having muscle, bone, or joint pain that’s not related to an injury. Or if you’ve had pain in multiple areas or for long periods of time. They may refer you to a rheumatologist. This is a doctor who specializes in diseases that cause inflammation.

Your doctor may use blood tests to look for antibodiesGerm-fighting molecules made by the body’s immune system. that are attacking your own tissues. These are called autoantibodies. But having them in your blood isn’t enough to be diagnosed with an autoimmune disease. Many people have them in their blood but don’t get sick, Kaplan explains.

Imaging technologies can be used to look for signs of an autoimmune disorder, too. X-rays can show joint issues. MRIs can reveal damage deep in the body.

Researchers are trying to find new ways to use imaging to help diagnose or monitor autoimmune disease. Grayson’s lab is testing whether PET scans can find hidden inflammation in the blood vessels of people with vasculitis.

Tamping Down the Attack

There are no cures for autoimmune disorders yet. But researchers have made progress in managing symptoms.

Drugs called corticosteroids are often the first treatment for an autoimmune disease. “They work quickly, and they’re effective,” Mammen says.

But steroids suppress your entire immune system. So they can have serious side effects. These include high blood pressure, bone loss, and weight gain.

Other drugs suppress only parts of the immune system. These tend to have fewer side effects and can be used for longer. Some of these drugs get rid of cells that make certain antibodies. Others target specific immune-system proteins. One such drug was recently the first new drug approved for lupus in a decade.

You may need to try several different drugs to find the one that works best to control your symptoms, Grayson says. It’s important to work with your doctor to balance quality of life with treating the disease, he adds.

Lifestyle changes can also help control symptoms. Movement is especially important for autoimmune diseases that affect the muscles, like myositis and MS, Mammen says. “We actually prescribe exercise,” he says. “It’s not optional; it’s part of the treatment.”

Talk with your health care provider about different activities you can try. Low-impact workouts like yoga, water aerobics, or walking can be helpful for some people.

Quitting smoking can help those whose disease affects their blood vessels, Grayson says.

Researchers are working to develop better treatments. NIH projects are bringing together scientists, nonprofit groups, and drug companies to find new treatments and research tools for autoimmune diseases.

Researchers also want to find ways to detect autoimmune diseases before they cause symptoms, Mammen explains. “Maybe there’s a time period where early treatment could put the brakes on one developing,” he says.