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

While some diseases, like seasonal allergies, asthma, and autoimmune diseases, are known to cause eosinophilia, or an abnormally high number of these cells, the role of eosinophilia in chronic pain hasn’t been well explored. —New Atlas, 13 Oct. 2025

These findings have transformed the understanding of autoimmune diseases, cancer immunotherapy, and organ transplant science, leading to over 200 clinical trials worldwide. —Shane Croucher, MSNBC Newsweek, 10 Oct. 2025

The goal is to learn how Treg cells and other immune cells can be kept in equilibrium – strong enough to defend against infections and cancer yet restrained enough to prevent autoimmune and inflammatory diseases. —Mitzi Nagarkatti, The Conversation, 10 Oct. 2025

Scleroderma is a rare and often life-threatening autoimmune condition that can cause fibrosis in the skin and other vital organs. —Paul Grein, Billboard, 8 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