Parkinson’s disease (PD) is a progressive neurological disorder that affects movement as well as mental and emotional changes. The exact cause is unknown, but researchers are investigating if autoimmune factors may play a role.

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PD is a neurological disorder where nerve cells in your brain become damaged or begin to die. While the cause of PD is unknown, there’s evidence that the immune system might be involved.

Below, we’ll cover more about PD and how autoimmune activity could contribute to it. Keep reading to learn more.

Autoimmune diseases happen when your immune system mistakenly attacks healthy tissues. This can cause inflammation and tissue damage in the affected areas of your body.

There are many different types of autoimmune diseases. Some that you may be familiar with include:

The exact cause of PD is unknown, and it’s currently not considered an autoimmune disease. While there’s some evidence that immune factors might be associated with PD, there’s no evidence so far that these immune factors actually cause PD.

A 2017 study found that PD may have genetic factors in common with some autoimmune diseases such as diabetes, ulcerative colitis, rheumatoid arthritis, and others.

Studies suggest that different parts of the immune system may play a role in PD, such as:

Microglia

Microglia are cells that help control development, repair injury, and maintain neural networks in the brain. When they’re healthy, these cells contribute to immune responses and tissue repair in your central nervous system. But when they become impaired, researchers think they may be involved in autoimmune conditions.

These cells have been found in high numbers in parts of the brain of individuals with PD. A 2022 review notes that microglia have long been known to be linked with PD and increased inflammation in the brain.

T cells

In PD, clumps of abnormal alpha-synuclein protein build up in the brain. These structures are called Lewy bodies and are thought to contribute in some way to the death of nerve cells that occurs in PD.

A 2017 study found that T cells (a type of immune cell found in the blood) of people with PD can recognize and make an immune response to alpha-synuclein protein.

What’s more, 2020 research using blood from people with PD revealed that T-cell activity against alpha-synuclein was highest in the time shortly after a PD diagnosis before decreasing as PD progressed. In one individual, reactive T cells could be detected 10 years before their PD onset and diagnosis.

A 2022 study compared gene expression in T cells of healthy people and people with PD. It found that alpha-synuclein-reactive T cells in people with PD had increased expression of genes linked with inflammation and oxidative stress.

Autoantibodies

Autoantibodies are antibodies produced by your body that then attack tissues and cells in your body — instead of attacking external invading cells like typical antibodies do. Researchers have found an increased number of autoantibodies in the blood and cerebrospinal fluid of people who have PD.

It’s still unclear if these autoantibodies are a result of having PD or help to cause of PD. Researchers have found that the levels of some types of autoantibodies in people with mild or moderate PD have been connected with disease activity in those people.

Unclear significance

It’s not understood if these changes in the immune system are a cause of PD or if they happen during or after these immune system cells are damaged.

This is an important distinction since autoimmune diseases are treated with medications that suppress the immune system, and there’s currently no evidence that these types of treatments would help people with PD.

Clinical trials investigating the effectiveness of immunosuppression as a treatment for Parkinson’s are currently underway.

PD is a neurogenerative disorder. Neurogenerative disorders happen as a result of gradual damage to the nervous system. These disorders affect functions such as movement, thinking, and behavior.

Examples of other neurodegenerative disorders include:

PD mainly affects movement, and the primary symptoms include:

PD can also lead to other symptoms, which may include, but aren’t limited to:

In PD, nerve cells in the brain become damaged and start to die off. Most PD symptoms happen due to nerve cell loss in an area called the substantia nigra.

The nerve cells in this area make dopamine, a chemical messenger that’s important for movement. When nerve cells in this area decrease, the levels of dopamine do as well. This leads to increasing problems with movement.

As we mentioned earlier, the exact cause of PD isn’t known, but it’s generally believed that a combination of genetic and environmental factors are involved. Some of the risk factors for PD include:

PD is mainly treated with a medication called carbidopa-levodopa, which helps to increase dopamine levels in your brain and reduce PD symptoms. It’s possible that other medications may be prescribed as well.

Along with medications, treatment for PD may also include things such as:

There’s no cure for PD. While treatment can help to manage symptoms, PD is progressive, meaning it gets worse with time.

Every person with PD is different. Because of this, there’s no way to predict how PD may progress on an individual level.

Can Parkinson’s disease be prevented?

No. Since it’s still unclear what causes PD, there’s currently no known way to prevent it. Some research suggests that engaging in exercise and eating a healthy diet may help to reduce PD risk.

How common is Parkinson’s disease?

According to the Parkinson’s Foundation, close to one million people in the United States are living with PD.

The exact cause of PD remains unknown. Research suggests that the immune system may be involved, but it’s not clear whether it’s part of the cause of PD or whether there could be an underlying autoimmune process.

Autoimmune activity can lead to increased inflammation in the brain. It’s likely that multiple parts of the immune system are involved.

So far, there’s no cure for PD. Treatment focuses on reducing symptoms and improving quality of life. As we gain a greater understanding of the causes of PD, including the immune system’s role, better ways to manage it can be developed.