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

Menopause and autoimmune conditions such as rheumatoid arthritis and lupus can also accelerate collagen loss, according to the Arthritis Foundation. —Stacey Colino, Time, 8 June 2026

Multiple sclerosis is a chronic autoimmune disease that affects about 1 million Amerians. —Cynthia Littleton, Variety, 7 June 2026

For a small subset of people with severe, treatment-resistant autoimmune or hypersensitivity conditions, there may be a short-term clinical rationale worth exploring under medical supervision. —Scott Travers, Forbes.com, 6 June 2026

Her daughter Morgan had spent more than a decade battling a debilitating autoimmune disorder. —Elizabeth Dwoskin, Washington Post, 4 June 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