delayed hypersensitivity reaction
- delayed hypersensitivity reaction
- a reaction of cell-mediated immunity, named in contrast to immediate hypersensitivity reactions because its onset is 24 to 72 hours after the antigenic challenge; the term is usually used to denote the subset of type IV hypersensitivity reactions (Gell and Coombs classification) involving cytokine release and macrophage activation, as opposed to direct cytolysis, but can be used more broadly, even sometimes being used synonymously with type IV hypersensitivity r. The classic delayed hypersensitivity reaction is the tuberculin reaction observed in skin testing.
Medical dictionary.
2011.
Look at other dictionaries:
immediate hypersensitivity reaction — 1. type I hypersensitivity r. 2. occasionally, any hypersensitivity reaction mediated by antibodies and developing rapidly, generally in minutes to hours (i.e., type I, II, or III hypersensitivity r.), as distinguished from those mediated by T… … Medical dictionary
reaction — 1. The response of a muscle or other living tissue or organism to a stimulus. 2. The color change effected in litmus and certain other organic pigments by contact with substances such as acids or alkalies; also the property that such substances… … Medical dictionary
hypersensitivity — Abnormal sensitivity, a condition in which there is an exaggerated response by the body to the stimulus of a foreign agent. See allergy. contact h. 1. SYN: contact dermatitis. 2. SYN: delayed reaction. delayed h. 1 … Medical dictionary
hypersensitivity — In immunology, a state of excessive and potentially damaging immune responsiveness as a result of previous exposure to antigen. If the hypersensitivity is of the immediate type (antibody mediated), then the response occurs in minutes; in delayed… … Dictionary of molecular biology
Delayed sleep phase syndrome — Classification and external resources ICD 10 G47.2 ICD 9 327.31 … Wikipedia
reversal reaction — a type 1 lepra reaction usually occurring during chemotherapy in borderline leprosy. It is a type of delayed hypersensitivity reaction with “upgrading†of cell mediated immunity to Mycobacterium leprae; this process tends to move the disease… … Medical dictionary
type IV hypersensitivity — hypersensitivity initiated by antigen specific T lymphocytes; unlike forms mediated by antibodies, it takes one or more days to develop and can be transferred by lymphocytes but not by serum. The term is often equated with delayed… … Medical dictionary
lepra reaction — n one of the acute episodes of chills and fever, malaise, and skin eruption occurring in the chronic course of leprosy * * * an aggravation of lumps on the skin caused by leprosy, accompanied by fever and malaise. * * * an acute or subacute… … Medical dictionary
allergic reaction — noun hypersensitivity reaction to a particular allergen; symptoms can vary greatly in intensity • Syn: ↑allergy • Derivationally related forms: ↑allergic (for: ↑allergy), ↑allergist (for: ↑ … Useful english dictionary
Type IV hypersensitivity — Classification and external resources MeSH D006968 Type IV hypersensitivity is often called delayed type hypersensitivity as the reaction takes two to three days to develop. Unlike the other types, it is not antibody mediated but rather is a type … Wikipedia
