Category:Hypersensitivity - Revision history

Bara at 13:37, 18 August 2010

2010-08-18T13:37:52Z

Bara at 13:34, 18 August 2010

2010-08-18T13:34:00Z

Bara: Replaced content with " Category:Immunological Disorders"

2010-08-18T13:12:03Z

Replaced content with " Category:Immunological Disorders"

Bara: Created page with "==Introduction== Hypersensitivity is a hyperactive immune response to an antigen which leads to cell and tissue damage. It involves normal immune mechanisms directed towards har..."

2010-08-18T13:04:38Z

Created page with "==Introduction== Hypersensitivity is a hyperactive immune response to an antigen which leads to cell and tissue damage. It involves normal immune mechanisms directed towards har..."

New page

==Introduction==

Hypersensitivity is a hyperactive immune response to an antigen which leads to cell and tissue damage. It involves normal immune mechanisms directed towards harmless environmental antigens (ie. [[:Category:Allergic Diseases|allergy]]) or directed at self antigens (ie. [[Autoimmune Diseases - Introduction|autoimmunity]]).

These reactions are antigen specific, occurring only after the immune system has already been sensitised to that antigen. This indicates the [[:Category:Adaptive Immune System|adaptive immune system]] is involved, and such responses can be either humoral or cell mediated. Those initiated by antibodies or antibody-antigen complexes are called ''immediate'' hypersensitivity, as the symptoms are seen within hours of exposure. Conversely, the response for ''delayed-type'' hypersensitivity [[Type IV Hypersensitivity - WikiBlood|(type IV hypersensitivity)]] is not seen for days and is generally cell-mediated.

It is important to note that these responses are part of normal immune defences- in the case of hypersensitivity however the keywords are ''exaggerated'' and ''damaging''.

==Classification==

Hypersensitivity reactions can be classified according to the type of immune mechanism involved, based on a scheme proposed by Gell and Coombs over 40 years ago.
There are four main types, although a fifth has recently been added.

Types I, II and III are antibody-mediated; type IV is cell mediated.

{| border="1" cellpadding="2"
!width="150"|Time of appearance
!width="50"|Type
!width="200"|Immune mechanism
|-
| 2-30 min || I || [[IgE]] mediated
|-
| 5-8 h || II || [[IgG]]: fixed antigen
|-
| 2-8 h || III || [[IgG]] mediated: soluble antigen
|-
| 24-72 h || IV || T cell mediated
|}

==[[Type I Hypersensitivity - WikiBlood|Type I Hypersensitivity]]==
'''[[IgE]]''' mediated disease (for more information see [[Type I Hypersensitivity - WikiBlood|Here]])

==[[Type II Hypersensitivity - WikiBlood|Type II Hypersensitivity]]==
'''[[IgG]]''' mediated disease to '''fixed antigen''' (for more information see [[Type II Hypersensitivity - WikiBlood|Here]])

==[[Type III Hypersensitivity - WikiBlood|Type III Hypersensitivity]]==
'''[[IgG]]''' mediated disease to '''soluble antigen''' (for more information see [[Type III Hypersensitivity - WikiBlood|Here]])

==[[Type IV Hypersensitivity - WikiBlood|Type IV Hypersensitivity]]==
'''T cell''' mediated disease (for more information see [[Type IV Hypersensitivity - WikiBlood|Here]])

==[[Hypersensitivity Flashcards|Hypersensitivity Flashcards]]==

==References==

Books

* Gareth Kitchen '''Immunology and Haematology''' Mosby Elsevier 2007 3rd Edition

* D.C. Blood and V.P. Studdert'''Saunders Comprehensive Veterinary Dictionary''' Elsevier Science 1999 2nd Edition

[[Category:Immunological Disorders]]

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	[[Category:Immunological Disorders]]		[[Category:Immunological Disorders]]

← Older revision		Revision as of 13:12, 18 August 2010
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−	~~==Introduction==~~
−
−	Hypersensitivity is a hyperactive immune response to an antigen which leads to cell and tissue damage. It involves normal immune mechanisms directed towards harmless environmental antigens (ie. [[:Category:Allergic Diseases\|allergy]]) or directed at self antigens (ie. [[Autoimmune Diseases - Introduction\|autoimmunity]]).
−
−
−	These reactions are antigen specific, occurring only after the immune system has already been sensitised to that antigen. This indicates the [[:Category:Adaptive Immune System\|adaptive immune system]] is involved, and such responses can be either humoral or cell mediated. Those initiated by antibodies or antibody-antigen complexes are called ''immediate'' hypersensitivity, as the symptoms are seen within hours of exposure. Conversely, the response for ''delayed-type'' hypersensitivity [[Type IV Hypersensitivity - WikiBlood\|(type IV hypersensitivity)]] is not seen for days and is generally cell-mediated.
−
−	~~It is important to note that these responses are part of normal immune defences- in the case of hypersensitivity however the keywords are ''exaggerated'' and ''damaging''.~~
−
−	~~==Classification==~~
−
−	~~Hypersensitivity reactions can be classified according to the type of immune mechanism involved, based on a scheme proposed by Gell and Coombs over 40 years ago.~~
−	~~There are four main types, although a fifth has recently been added.~~
−
−
−	~~Types I, II and III are antibody-mediated; type IV is cell mediated.~~
−
−
−
−
−	~~{\| border="1" cellpadding="2"~~
−	~~!width="150"\|Time of appearance~~
−	~~!width="50"\|Type~~
−	~~!width="200"\|Immune mechanism~~
−	\|-
−	~~\| 2-30 min \|\| I \|\| [[IgE]] mediated~~
−	\|-
−	~~\| 5-8 h \|\| II \|\| [[IgG]]: fixed antigen~~
−	\|-
−	~~\| 2-8 h \|\| III \|\| [[IgG]] mediated: soluble antigen~~
−	\|-
−	~~\| 24-72 h \|\| IV \|\| T cell mediated~~
−	\|}
−
−	~~==[[Type I Hypersensitivity - WikiBlood\|Type I Hypersensitivity]]==~~
−	~~'''[[IgE]]''' mediated disease (for more information see [[Type I Hypersensitivity - WikiBlood\|Here]])~~
−
−	~~==[[Type II Hypersensitivity - WikiBlood\|Type II Hypersensitivity]]==~~
−	~~'''[[IgG]]''' mediated disease to '''fixed antigen''' (for more information see [[Type II Hypersensitivity - WikiBlood\|Here]])~~
−
−	~~==[[Type III Hypersensitivity - WikiBlood\|Type III Hypersensitivity]]==~~
−	~~'''[[IgG]]''' mediated disease to '''soluble antigen''' (for more information see [[Type III Hypersensitivity - WikiBlood\|Here]])~~
−
−	~~==[[Type IV Hypersensitivity - WikiBlood\|Type IV Hypersensitivity]]==~~
−	~~'''T cell''' mediated disease (for more information see [[Type IV Hypersensitivity - WikiBlood\|Here]])~~
−
−	~~==[[Hypersensitivity Flashcards\|Hypersensitivity Flashcards]]==~~
−
−	~~==References==~~
−
−	~~Books~~
−
−	* Gareth Kitchen '''Immunology and Haematology''' Mosby Elsevier 2007 3rd Edition
−
−	* D.C. Blood and V.P. Studdert'''Saunders Comprehensive Veterinary Dictionary''' Elsevier Science 1999 2nd Edition

	[[Category:Immunological Disorders]]		[[Category:Immunological Disorders]]