autoimmune

adjective

au·​to·​im·​mune ˌȯ-tō-im-ˈyün 

: of, relating to, or caused by autoantibodies or T cells that attack molecules, cells, or tissues of the organism producing them

autoimmune diseases

autoimmunity

ˌȯ-tō-im-ˈyü-nə-tē 

noun

autoimmunization

ˌȯ-tō-ˌim-yə-nə-ˈzā-shən 

also -im-ˌyü-

noun

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Any healthy body produces a variety of antibodies, proteins in the blood whose job is to protect the body from unwanted bacteria, viruses, and cancer cells. The cells and organs that deal with such infections make up the immune system. In some people and animals, for various reasons, the antibodies become overactive and turn on the body's healthy tissues as well; the result is an autoimmune disease—an immune response directed against one's own self. More than eighty autoimmune diseases have been identified, the best-known being type 1 diabetes, multiple sclerosis, lupus, and rheumatoid arthritis.

Examples of autoimmune in a Sentence

Recent Examples on the Web

This loss is often the result of an autoimmune process in which the body's immune system mistakenly attacks those cells. — Daryl Austin, USA Today, 8 July 2026

According to his parents, Ryan was diagnosed with Addison’s disease, an autoimmune disease in which the body doesn’t produce cortisol and aldosterone. — Edie Peffley, NBC news, 8 July 2026

For people managing chronic or autoimmune conditions like lupus, the same continuous-monitoring approach could flag the haematological shifts that precede a flare, prompting further testing before symptoms escalate. — Dr. Shaheena Janjuha-Jivraj, Forbes.com, 8 July 2026

The disease in question is autoimmune gastritis, a chronic inflammatory condition in which antibodies destroy acid-producing cells in the stomach, which prevents people from absorbing iron. — Sarah Todd, STAT, 8 July 2026

Word History

Etymology

auto- + immune, after autoimmunity, borrowed from French auto-immunité

First Known Use

1952, in the meaning defined above

Kids Definition

autoimmune

adjective

au·​to·​im·​mune ˌȯt-ō-im-ˈyün 

: relating to or caused by an abnormal condition in which an organism's immune system attacks and destroys parts of its own cells or tissues

multiple sclerosis is an autoimmune disease

Medical Definition

autoimmune

adjective

au·​to·​im·​mune -im-ˈyün 

: of, relating to, or caused by antibodies or T cells that attack molecules, cells, or tissues of the organism producing them

autoimmune diseases