immunodeficiency

American  

[im-yuh-noh-di-fish-uhn-see, ih-myoo-] / ˌɪm yə noʊ dɪˈfɪʃ ən si, ɪˌmyu- /

noun

immunodeficiencies plural

1. impairment of the immune response, predisposing to infection and certain malignancies.

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immunodeficiency British  

/ ˌimjʊnəʊdɪˈfɪʃənsɪ /

noun

1. a deficiency in or breakdown of a person's immune system

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immunodeficiency Scientific  

/ ĭm′yə-nō-dĭ-fĭsh′ən-sē,ĭ-myo̅o̅′- /

1. The inability to produce a normal immune response, caused by an acquired or inherited disease.

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Other Word Forms

Derived Forms

• immunodeficient
  adjective

Inflected Forms

noun

• immunodeficiencies
  plural

Etymology

Origin of immunodeficiency

First recorded in 1970–75; immuno- + deficiency

Explanation

When someone's body can't protect itself from infection the way it should, they suffer from an immunodeficiency. Many patients being treated for cancer have immunodeficiencies. Your immune system is the network of cells that works to fight infection throughout your body, and when it isn't functioning well, the result is immunodeficiency. The word is rooted in the Latin immunis, "exempt," and deficere, "to fail." In other words, immunodeficiency is a failure of the system that keeps you free from infections and illness. Various diseases, genetic conditions, and medications can result in this risky situation.

Example Sentences

The growth was driven by strong sales of products for treatment of HIV, or human immunodeficiency virus, which rose 10% to $5 billion, as well as the drugs Trodelvy and Livdelzi.

From The Wall Street Journal • May 7, 2026

HIV, or human immunodeficiency virus, spreads through unprotected sex, unsafe medical practices, infected blood transfusions, or from mother to child during pregnancy, childbirth or breastfeeding.

From BBC • Dec. 19, 2025

"Heavy metal exposure has been linked to degenerative heart disease, immunodeficiency and increased parasite infestations, among other disease risks."

From Science Daily • Feb. 21, 2024

The legal dispute centered on who devised the idea of using a Gilead medication for people at high risk of contracting H.I.V., or the human immunodeficiency virus, which causes AIDS.

From New York Times • May 9, 2023

The 58-year-old lawyer who lives in Phoenix has an immunodeficiency disease that increases his risk of severe outcomes from COVID-19 and other infections.

From Seattle Times • Apr. 27, 2023