Title: immediate-type hypersensitivity
Long Title: IUPAC Gold Book - immediate-type hypersensitivity
DOI: 10.1351/goldbook.13255
Status: current

Definition
Reaction provoked by re-exposure to an antigen (allergen) that causes plasma cells to secrete immunoglobulin E (IgE) which binds to Fc receptors on the surface of tissue mast cells and blood basophils, sensitizing them, so that later exposure to the same allergen cross-links the bound IgE, leading to degranulation and the secretion of pharmacologically active mediators such as histamine, leukotriene, and prostaglandin that act immediately on the surrounding tissues.

Note
The principal effects of these products are vasodilation and smooth-muscle contraction. The reaction may be either local or systemic. Symptoms vary from mild irritation to sudden death from anaphylactic shock.

Related Terms
- Fc receptors: https://goldbook.iupac.org//terms/view/13138
- allergen: https://goldbook.iupac.org//terms/view/12857
- anaphylactic shock: https://goldbook.iupac.org//terms/view/12871
- basophils: https://goldbook.iupac.org//terms/view/12943
- degranulation: https://goldbook.iupac.org//terms/view/13084
- immunoglobulin E (IgE): https://goldbook.iupac.org//terms/view/13288
- leukotriene: https://goldbook.iupac.org//terms/view/13384
- mast cells: https://goldbook.iupac.org//terms/view/13442
- plasma cells: https://goldbook.iupac.org//terms/view/13576
- systemic: https://goldbook.iupac.org//terms/view/13708

Source
- PAC, 2012, 84, 1113. 'IUPAC glossary of terms used in immunotoxicology (IUPAC Recommendations 2012)' on page 1182 (https://doi.org/10.1351/PAC-REC-11-06-03)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/13255/html
- json: https://goldbook.iupac.org/terms/view/13255/json
- xml: https://goldbook.iupac.org/terms/view/13255/xml

Citation: Citation: 'immediate-type hypersensitivity' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.13255
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
Collection: If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .
Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-07-13T05:10:40+00:00