∞ generated and posted on 2016.03.20 ∞

Defects in immune system functioning that can be due to disease, drugs, injury, or genetics.

Also known simply as an immune deficiency or immune insufficiency, an immunodeficiency is a defect in either innate or adaptive immunity. For immunodeficiencies in adaptive immunity, this can be in terms of B cell or T cell function or, indeed, both (i.e., severe combined immunodeficiency, or SCID).

Acquired immunodeficiencies are due to injuries or diseases, or can be drug induced. The latter can either be as a side effect (e.g., of anti-cancer chemotherapy) or as the intended effect (such as is the case with anti-rejection drugs used following transplantation). Acquired immunodeficiencies are also known as secondary immunodeficiencies.

Secondary immunodeficiencies contrast with primary immunodeficiencies, which are also known as congenital immunodeficiencies. Such inborn immunodeficiencies include but are not limited to immunodeficiencies that are of genetic origin.

See similarly immunocompromised, which can be defined as an individual that possesses an immunodeficiency.