From Wikipedia, the free encyclopedia
Hypersensitivity refers to undesirable (damaging, discomfort-producing and sometimes fatal) reactions produced by the normal immune system. Hypersensitivity reactions require a pre-sensitized (immune) state of the host. The four-group classification was expounded by P. H. G. Gell and Robin Coombs in 1963.[1]
[edit] Comparison table: Types 1-4
[edit] Type 5 and 6
This is an additional type that is sometimes (often in Britain) used as a distinction from Type 2.[3]
Instead of binding to cell surface components, the antibodies recognize and bind to the cell surface receptors, which either prevents the intended ligand binding with the receptor or mimics the effects of the ligand, thus impairing cell signalling.
Some clinical examples:
(There is also a type 6 hypersensitivity reaction in which natural killer cells lyse cells that have been coated in antibody and this reaction is thought to be implicated with certain autoimmune diseases, tumour rejection and parasite rejection.)
[edit] See also
[edit] References
- ^ Gell PGH, Coombs RRA, eds. Clinical Aspects of Immunology. 1st ed. Oxford, England: Blackwell; 1963.
- ^ a b c Unless else specified in boxes, then ref is: Lippincott's Illustrated Reviews: Immunology. Paperback: 384 pages. Publisher: Lippincott Williams & Wilkins; (July 1, 2007). Language: English. ISBN-10: 0781795435. ISBN-13: 978-0781795432. Page 195
- ^ Rajan TV. The Gell-Coombs classification of hypersensitivity reactions: a re-interpretation. Trends Immunol. 2003 Jul;24(7):376-9. PMID 12860528
[edit] External links
