Is Ulcerative Colitis an Autoimmune Disease? Understanding UC

Medically Reviewed By Saurabh Sethi, M.D., MPH
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While the exact cause of ulcerative colitis (UC) is unknown, the immune system plays a role in the development of the disease. Certain immune system cells and proteins affect the digestive tract, causing chronic inflammation and damage to the lining of the intestines.

While the immune system is responsible for finding and removing harmful substances from the body, in some cases, it may overreact and interfere with healthy cells and tissues.

Read on to learn more about ulcerative colitis and how the immune system influences its development.

Is ulcerative colitis an autoimmune disease?

A woman taking a pill
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UC is a disease related to immune system dysfunction. While experts do not yet know exactly what causes UC, there are a few main theories around why the immune system overreacts and triggers UC symptoms.

An atypical response to beneficial bacteria

The first theory is that the immune system mistakenly interferes with the helpful bacteria in the digestive system.

In a typical immune response, your immune system triggers a cascade of cells, chemicals, and proteins that find and remove antigens. Antigens may include substances such as bacteria, viruses, or fungi.

In UC, however, the immune system may mistake beneficial bacteria for harmful foreign substances and trigger an atypical response.

Learn more about the immune system.

An infection triggers the immune system

Another theory is that a bacterial or viral infection triggers a response from the immune system that continues to affect the body after the infection clears.

Other theories

Other possible causes of UC include a random immune system malfunction or an imbalance between beneficial and harmful bacteria in the digestive system.

More research is necessary to determine the exact cause of UC.

What role does the immune system play in ulcerative colitis?

Recent research identified several types of immune cells and substances that may affect how UC develops:

  • Innate immune response cells: These are the cells that contribute to the body’s initial broad response to antigens. They include neutrophils, dendritic cells, and innate lymphoid cells.
  • Adaptive immune response cells: These cells target specific antigens. They include T and B lymphocytes, which are white blood cells that remove antigens and produce antibodies.
  • Cytokines: Proteins known as cytokines affect the body’s inflammatory response. Inflammation helps the body heal by signaling the immune system to heal damaged tissue.

In people with UC, these immune system components overreact and interfere with the healthy tissues in the digestive tract. This overreaction leads to chronic inflammation and a weakening of the intestinal barrier, which causes ulcers to develop.

What immune system treatments are available for ulcerative colitis?

There are few treatments available that may mediate the immune system’s activity and relieve the symptoms of UC.

Thiopurines

Doctors may prescribe thiopurines, which are drugs that can help suppress the immune system. A 2018 research review showed that these drugs may help induce and maintain remission of the disease. Although, they can take a few months to begin working.

Examples of thiopurines include azathioprine, 6-mercaptopurine, and thioguanine.

Biologics

Biologics may help people with UC by working against certain inflammatory proteins like cytokines. Biologics are medications that come from biological sources instead of being fully synthetic.

Examples of biologics include adalimumab, golimumab, and infliximab.

Targeted synthetic small molecules

According to the Crohn’s and Colitis Foundation, medications called targeted synthetic small molecules affect specific parts of the immune system and reduce inflammation.

People with UC who experience difficult responses to other treatments may benefit from targeted synthetic small molecules due to their structure, which allows them to diffuse more efficiently in the body.

Examples of targeted synthetic small molecule drugs include tofacitinib, upadacitinib, and ozanimod.

Other treatments

Doctors may prescribe other medications, like corticosteroids or aminosalicylates, combined with immunosuppressive drugs to help you manage flare-ups or maintain remission.

Learn more about treatment options for ulcerative colitis.

Frequently asked questions

Here are a few other questions people commonly ask about ulcerative colitis and the immune system. Dr. Saurabh Sethi medically reviewed the answers.

Are people with ulcerative colitis considered immunocompromised?

People with UC are not necessarily immunocompromised. UC by itself does not cause immunosuppression. However, medications that treat UC and other autoimmune diseases can weaken part or all of the immune system.

UC can be a serious and debilitating disease. It is important to follow your doctor’s treatment plan to manage the symptoms and avoid potentially severe complications.

Can you cure ulcerative colitis?

There is currently no known cure for UC. Treatment for the disease focuses on relieving symptoms and inducing and maintaining remission.

Summary

UC is an autoimmune disease with unclear causes. Experts suspect that the immune system may mistake helpful gut bacteria for foreign invaders, or that an infection triggers an immune response that lasts beyond the infection.

Many components of the immune system play a role in inflammation and damage to the intestinal tract. Therefore, treatment for UC may include a few different approaches.

Immunosuppressive drugs and medications that mediate the body’s inflammatory response may be beneficial in people with UC.

Contact your doctor to discuss the treatment methods that may be right for you.

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Medical Reviewer: Saurabh Sethi, M.D., MPH
Last Review Date: 2022 Sep 28
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Chan, J. C. N., et al. (2017). Biologics and biosimilars: What, why and how? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5519784/
  2. Ghezala, I. B., et al. (2021). Small molecule drugs in inflammatory bowel diseases. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308576/
  3. Immunosuppressive medication for the treatment of autoimmune disease. (2020). https://www.aaaai.org/Conditions-Treatments/Related-Conditions/immunosuppressive
  4. Justiz Vaillant, A. A., et al. (2021). Physiology, immune response. https://www.ncbi.nlm.nih.gov/books/NBK539801/
  5. Kałużna, A., et al. (2022). The role of innate and adaptive immune cells in the pathogenesis and development of the inflammatory response in ulcerative colitis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8780689/
  6. Lim, S. Z., et al. (2018). Revisiting the role of thiopurines in inflammatory bowel disease through pharmacogenomics and use of novel methods for therapeutic drug monitoring. https://www.frontiersin.org/articles/10.3389/fphar.2018.01107/full
  7. Lynch, W. D., et al. (2022). Ulcerative colitis. https://www.ncbi.nlm.nih.gov/books/NBK459282/
  8. Medication options for ulcerative colitis. (n.d.). https://www.crohnscolitisfoundation.org/what-is-ulcerative-colitis/medication
  9. Ulcerative colitis. (2019). https://www.nhs.uk/conditions/ulcerative-colitis/