Hypersensitivity 335058 225387819 2008-07-13T12:19:16Z 192.89.123.41 {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | DiseasesDB = 28827 | ICD10 = {{ICD10|T|78|4|t|66}} | ICD9 = {{ICD9|995.3}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D006967 | }} '''Hypersensitivity''' (also called hypersensitivity reaction) 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 [[Philip George Houthem Gell|P. H. G. Gell]] and [[Robin Coombs]] in 1963.<ref>Gell PGH, Coombs RRA, eds. Clinical Aspects of Immunology. 1st ed. Oxford, England: Blackwell; 1963.</ref> ==Comparison table: Types 1-4== {|Class="wikitable" |+ Comparison of hypersensitivity types |- ! Type !! Alternative names <ref name=Immunology195Unless> 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 </ref> !! Often mentioned disorders<ref name=Immunology195Unless/> !! Mediators<ref name=Immunology195Unless/> |- ! [[Type I hypersensitivity|1]] | [[Allergy]] (immediate)|| *[[Atopy]] *[[Anaphylaxis]] *[[Asthma]] || *[[Immunoglobulin E|IgE]] |- ! [[Type II hypersensitivity|2]] | Cytotoxic, antibody-dependent || *[[Erythroblastosis fetalis]] *[[Goodpasture's syndrome]] *[[Autoimmune hemolytic anemia]] || *[[Immunoglobulin M|IgM]] or [[Immunoglobulin G|IgG]] *([[Complement system|Complement]]) |- ! [[Type III hypersensitivity|3]] | [[Immune complex]] disease || *[[Serum sickness]] *[[Arthus reaction]] *[[Systemic lupus erythematosus|SLE]] || *[[Immunoglobulin G|IgG]] *([[Complement system|Complement]]) |- ! [[Type IV hypersensitivity|4]] | Delayed-type hypersensitivity<ref>Black, CA. Delayed Type Hypersensitivity: Current Theories with an Historic Perspective ''Dermatol. Online J.'' (May 1999) 5(1):7 at http://dermatology.cdlib.org/DOJvol5num1/reviews/black.html</ref> (DTH), [[(Cell-mediated_immunity)|Cell-mediated immune memory response]], antibody-independent|| *[[Contact dermatitis]] *[[Tuberculin skin test]] *[[Chronic transplant rejection]] || *[[T-cells]] |} ==Type 5 and 6 == This is an additional type that is sometimes (often in Britain) used as a distinction from Type 2.<ref>Rajan TV. The Gell-Coombs classification of hypersensitivity reactions: a re-interpretation. ''Trends Immunol''. 2003 Jul;24(7):376-9. PMID 12860528</ref> Instead of binding to cell surface components, the antibodies recognize and bind to the cell surface [[receptor (biochemistry)|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: *[[Graves disease]] *[[Myasthenia gravis]] (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.) == See also == * [[Allergy]] ==References== <references/> ==External links== * {{GPnotebook|-529858552}} * {{FPnotebook|ENT46}} {{Consequences of external causes}} {{Immune disorders}} [[Category:Immune system]] [[Category:Immune system disorders]] [[Category:Allergology]] [[de:Überempfindlichkeitsreaktion]] [[no:Hypersensitivitet]] [[pl:Nadwrażliwość]] [[vec:Clasificaxion de Gell e Coombs]] [[fi:Yliherkkyys]]