Is MS an Autoimmune Disease? What the Science Says
This article explains more about what autoimmune disorders are, theories about what causes and risk factors are involved in MS, types of MS, and treatments for the disease.
The National Institute of Environmental Health Sciences (NIEHS) explains that an autoimmune disease is one in which the immune system makes a mistake and reacts to the body’s healthy cells. The word “auto” is from the Greek word for “self.”
There are more than 80 known autoimmune diseases, including type 1 diabetes, lupus, and rheumatoid arthritis. It’s unknown why some people develop an autoimmune disease or disorder, but doctors think a combination of factors plays a role.
Autoimmune disease may result from a combination of:
- your genetic makeup
- hormones you have or are exposed to
- your environment
- your lifestyle
- your diet
The NIEHS names MS as a type of autoimmune disease. Although not proven by research, it is a widely accepted theory that MS may be an autoimmune disorder.
The scientific community has long debated whether MS should be classified as an official autoimmune disorder. They know that MS involves the immune system, but the exact mechanism — including if it is a true autoimmune disease — is not entirely clear.
Many autoimmune disorders have a known antigen associated with the disease. An antigen can be a protein, fat molecule (lipid), or other substance that induces the immune system. Clinicians use the term “autoantigen” to describe the antigen in autoimmune disease.
The National Multiple Sclerosis Society (NMSS) explains that researchers have not yet discovered a specific autoantigen for MS. However, a 2021 research review in Frontiers in Immunology indicates that several proteins are derived from myelin that likely serve as autoantigens.
In MS, researchers suspect specific T-cell lymphocytes target these myelin-derived antigens and recruit additional immune cells and inflammatory substances like cytokines. This “cascade” of inflammation is what damages the nerve cells. The review authors describe MS as a T-cell-mediated autoimmune disease.
There is evidence that a fault in the immune system allows autoreactive T cells to develop. This may have to do with a change in regulatory T-cells. Regulatory T-cells suppress inflammation. If they are not present or do not work correctly, inflammation continues.
While most experts consider MS an autoimmune disorder, at the very minimum, MS is an immune-mediated disease.
The immune system plays a central role in MS, but what makes this happen? As the National Institute of Neurological Disorders and Stroke (NINDS) explains, doctors have different theories about what causes MS.
Some of the theories include:
- a viral infection that “primes” the immune system to zero in on your proteins and cells
- genetic traits that are activated by another factor — a virus or toxin, for example
- the immune system may react to the presence of unhealthy cells in the brain or spinal cord
- a malfunction of the immune system
- a break in the blood-brain barrier that leads the immune system to see myelin, for example, as something foreign that it needs to eliminate
Also, the likelihood of MS is higher in association with these factors:
Ultimately, what causes MS is a combination of genetic and other factors. This means that MS can develop in people with genetic susceptibility.
Learn more about what causes MS.
There are two main forms of MS: Relapsing and progressive.
Relapsing, or relapsing-remitting MS (RRMS), is characterized by bouts of inflammation that disrupt myelin and cause a flare in symptoms. Relapses can occur years apart, and people may have long, symptom-free periods. About 80% of people who are first diagnosed with MS will develop RRMS.
Progressive, or primary progressive MS (PPMS), has relatively few or no symptom-free periods. Primary progressive MS is rarer, and symptoms are generally more severe than RRMS. Left untreated, most cases of RRMS will become progressive. This is secondary progressive MS (SPMS).
Doctors do not know if there are different causes for relapsing MS and progressive MS.
However, MS treatments are generally more effective for relapsing versus progressive MS, explains the NINDS. MS treatments generally cannot stop or slow down progressive MS, according to the National Health Service (NHS).
In general, treatments for MS calm or alter the immune response. MS can be a highly individual disease, so doctors will often try different treatments based on someone’s disease progression and symptoms.
Some of the risks of MS treatments can be considerable, so doctors may start with more low risk medications first.
Doctors can prescribe steroids to decrease overall inflammation for immediate symptoms, followed by treatments that modulate specific parts of the immune system for long-term use.
There are many treatments for MS that aim to stop or decrease the inflammation and immune system response involved with the disease. For example, some medications inhibit T-cell or B-cell activation. Learn about the immune system and the type of immune cells.
To learn more about MS medications, read 10 Drugs Commonly Prescribed for Multiple Sclerosis.
Heidi Moawad, M.D., reviewed the following questions.
Why is MS not an autoimmune disease?
MS might be an autoimmune disease, but doctors are not completely sure. Doctors know that MS involves the immune system and is an inflammatory disease.
Is MS autoimmune or inflammatory?
MS is an inflammatory disease that damages the protective coating of CNS nerve cells. MS may have an autoimmune component. MS is an immune-mediated inflammatory disease.
Can you diagnose MS with a blood test?
A blood test will not detect MS, but doctors usually order blood tests to rule out other causes of symptoms. MS requires several tests for diagnosis. An MRI of the brain will detect MS lesions from ongoing inflammation.
MS is a disease that involves the immune system, but the exact cause of the disorder is not known. Many doctors categorize MS as an autoimmune disorder, but unlike other types of autoimmune diseases, there is no specific autoantigen for MS.
It is thought that many factors play a role in the development of MS. These include gene variations and exposure to toxins or viruses.
Because MS is an immune-mediated condition, treatments for MS affect the immune system. Approved medications typically inhibit a certain immune pathway, cell, or substance to slow the progression of MS and prevent relapses.