im·​mu·​no·​de·​fi·​cien·​cy ˌi-myə-nō-di-ˈfi-shən(t)-sē How to pronounce immunodeficiency (audio)
: inability to produce a normal complement of antibodies or immunologically sensitized T cells especially in response to specific antigens
immunodeficient adjective

Example Sentences

Recent Examples on the Web His approach could be further applied in autism or immunodeficiency research. Charlotte Hu, Discover Magazine, 24 Jan. 2018 An antigen target which attacks all immune cells in the lineage—as CAR T cell therapy often does for all B cells—would cause life-threatening immunodeficiency. William A. Haseltine, Forbes, 13 Feb. 2023 Time of death: approximately 10:50 a.m. Thursday July 15; witnesses: two animal control officers, one vet tech, one reporter and a handful of quarantined kittens that had tested positive for feline immunodeficiency virus. James Whitlow,, 23 July 2021 According to a new study published in the New England Journal of Medicine , an autoimmune response---when your immune system attacks your own body---triggers the immunodeficiency. Sophie Bushwick, Discover Magazine, 24 Aug. 2012 In 2013, five cases of VDPV infection were reported in India, every case attributed to a person diagnosed with an immunodeficiency - specifically, conditions in which their immune system is unable to produce antibodies (8). Rebecca Kreston, Discover Magazine, 28 Apr. 2016 Before Jamison arrived, the staff sent all cats who were positive for feline immunodeficiency virus, commonly known as FIV, and feline leukemia virus to a specialized adoption center in Austin. Dallas News, 27 Dec. 2022 These viruses have uncanny similarities to the simian immunodeficiency viruses that gave rise to HIV and the AIDS pandemic. Simon Makin, Scientific American, 15 Nov. 2022 Sara Anne Willette, a data analyst in Ames, Iowa, has a condition called common variable immunodeficiency that keeps her from making certain types of protective antibodies. Katherine J. Wu, The Atlantic, 29 Oct. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'immunodeficiency.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


immuno- + deficiency

First Known Use

1969, in the meaning defined above

Time Traveler
The first known use of immunodeficiency was in 1969

Dictionary Entries Near immunodeficiency

Cite this Entry

“Immunodeficiency.” Dictionary, Merriam-Webster, Accessed 23 Mar. 2023.

Kids Definition


im·​mu·​no·​de·​fi·​cien·​cy ˌim-yə-(ˌ)nō-də-ˈfish-ən-sē How to pronounce immunodeficiency (audio)
: inability to produce the normal number of antibodies or T cells capable of acting in an immune system

Medical Definition


im·​mu·​no·​de·​fi·​cien·​cy -di-ˈfish-ən-sē How to pronounce immunodeficiency (audio)
plural immunodeficiencies
: inability to produce a normal complement of antibodies or immunologically sensitized T cells especially in response to specific antigens see aids
immunodeficient adjective

More from Merriam-Webster on immunodeficiency

Last Updated: - Updated example sentences
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