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

Type 1 diabetes is an autoimmune disease (typically arising in younger people) that occurs when your immune system attacks the cells in the pancreas that are responsible for producing insulin, leaving you with little to no insulin at all, per NIDDK. —Caroline C. Boyle, USA Today, 3 Nov. 2025

Over time, this can promote autoimmune disorders, contribute to disease progression and decrease longevity. —Melissa Rudy, FOXNews.com, 3 Nov. 2025

Scalp Psoriasis Scalp psoriasis is an autoimmune condition that makes skin cells grow faster, resulting in thick, scaly patches of skin (plaques). —Lindsay Curtis, Health, 30 Oct. 2025

There are currently two clinical programs underway, with one being led by its partner Eli Lilly for an autoimmune and inflammatory disorder treatment called Ocadusertib. —Michelle Fox, CNBC, 30 Oct. 2025

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