Autoimmune diseases can affect almost every part of the body and impact tens of millions of people. While they are most common in women, these diseases can affect anyone, adults or children, and their prevalence is rising.
New research is offering hope for treatments that go beyond relieving symptoms. Dozens of clinical trials are testing ways to reprogram a misbehaving immune system, with early successes reported for lupus, myositis, and other illnesses.
Researchers are also exploring ways to delay the onset of autoimmune diseases, such as Type 1 diabetes, before symptoms appear.
“This is probably the most exciting time that we’ve ever had to be in autoimmunity,” said Dr Amit Saxena, a rheumatologist at NYU Langone Health.
What are autoimmune diseases?
Autoimmune diseases are chronic conditions that range from mild to life-threatening. There are more than 100 types, each named based on how and where they cause damage.
Rheumatoid arthritis and psoriatic arthritis attack joints. Sjögren’s disease is known for dry eyes and mouth. Myositis and myasthenia gravis weaken muscles in different ways, with myasthenia gravis disrupting nerve signalling.
Lupus has varied symptoms, including a butterfly-shaped facial rash, joint and muscle pain, fevers and damage to the kidneys, lungs, and heart.
These diseases can be unpredictable. Even patients doing well for long periods can suddenly experience a “flare” for no apparent reason.
Why are autoimmune diseases hard to diagnose?
Many start with vague symptoms that come and go or mimic other illnesses. Some have overlapping symptoms; for example, rheumatoid arthritis and Sjögren’s can also harm major organs
Diagnosis may require multiple tests, including blood tests to detect antibodies that attack healthy tissue.
Doctors typically rely on symptoms and a process of elimination. Depending on the disease, diagnosis can take years and involve seeing multiple specialists.
How the immune system gets out of whack
The human immune system is a complex army with sentinels to detect threats like germs or cancer cells, a variety of soldiers to attack them, and peacemakers to calm things down once the danger is over.
Normally, the system can distinguish between foreign invaders and the body itself, a process called tolerance.
Sometimes, confused immune cells or antibodies slip through, or the peacemakers can not calm things down after a battle. If the system cannot spot and fix the problem, autoimmune diseases gradually develop.
Triggers of autoimmune diseases
Most autoimmune diseases, especially in adults, are not caused by a specific gene defect. Instead, a variety of genes that affect immune functions can make people susceptible.
Scientists say it then takes some “environmental” trigger, such as an infection, smoking or pollutants, to set the disease into motion. For example, the Epstein-Barr virus is linked to multiple sclerosis (MS).
Scientists are zeroing in on the earliest molecular triggers. For example, white blood cells called neutrophils are first responders to signs of infection or injury.
However, abnormally overactive ones are suspected of playing a key role in lupus, rheumatoid arthritis, and other diseases.
Women are at higher risk
Women make up about four out of five autoimmune patients, many of them young. Hormones may play a role, and women’s two X chromosomes may increase vulnerability if cell mechanisms fail to properly switch off one X.
However, men can also develop autoimmune diseases. For example, VEXAS syndrome, discovered in 2020, mainly affects men over 50 and can cause blood clots, shortness of breath, and night sweats.
Certain populations are at higher risk: lupus is more common in Black and Hispanic women, while northern Europeans have a higher risk of MS.
Treatment is complex
The global market for autoimmune disease treatments is estimated at $100 billion a year, not including doctor visits and lost work time. Treatments are lifelong and, while usually covered by insurance, can be expensive.
Historically, treatment relied on high-dose steroids and broad immunosuppressing drugs, which carry risks of infections and cancer. Newer treatments target specific molecules and are somewhat less suppressive.
However, for many autoimmune diseases, treatment remains a trial-and-error process with limited guidance for patients.
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