Difference between revisions of "Type III Hypersensitivity"

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(New page: right|thumb|150px|Type III hypersensitivity antibody excess-Brian Catchpole RVC 2008 [[Image:Type III hypersensitivity antigen exce...)
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==Introduction==
 
 
[[Image:Type III hypersensitivity antibody excess.jpg|right|thumb|150px|Type III hypersensitivity antibody excess-Brian Catchpole RVC 2008]]
 
[[Image:Type III hypersensitivity antibody excess.jpg|right|thumb|150px|Type III hypersensitivity antibody excess-Brian Catchpole RVC 2008]]
  
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In the normal animal, immune complexes (lattice of soluble antigen and antibodies) are formed and removed all the time. They are broken up by complement, transported to the spleen by RBC's and phagocytosed. When the amount of immune complexes formed (due to rapid influx of antigen) does not equal the amount that are being cleared it causes type III hypersensitivity (an excess of immune complexes).
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In the normal animal immune complexes (lattice of soluble antigen and antibodies) are formed and removed all the time. They are broken up by complement, transported to the spleen by RBC's and phagocytosed. When the amount of immune complexes formed (due to rapid influx of antigen) does not equal the amount that are being cleared it causes type III hypersensitivity (an excess of immune complexes).
  
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==Location of the immune complexes:==
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The effects depend upon where the immune complexes are deposited:
  
 
'''Locally:'''
 
'''Locally:'''
  
 
1. Inhaled antigen leads to hypersensitivity pneumonitis
 
1. Inhaled antigen leads to hypersensitivity pneumonitis
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* Farmers lung (humans) - inhalation of fungal spores
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* Farmers lung (humans)-inhalation of fungal spores
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* Pigeon fancier's disease - repeated inhalation of dried pigeon faeces
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* Pigeon fancier's disease-repeated inhalation of dried pigeon faeces
 
* Mouldy hay containing ''Micropolyspora felis''  
 
* Mouldy hay containing ''Micropolyspora felis''  
  
 
2. Intradermal and subcutaneous injection of antigen (with high levels of circulating antibody) leads to localised immune complexes which cause acute inflammation.
 
2. Intradermal and subcutaneous injection of antigen (with high levels of circulating antibody) leads to localised immune complexes which cause acute inflammation.
  
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3. Vasculitis - due to antigen deposition in blood vessels.
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3. Vasculitis
  
 
4. Arthritis
 
4. Arthritis
  
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5. [[Glomerulonephritis]]
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5. Glomerulonephritis
 
* Can occur as an adverse effect of antibody response to infection if there is significant levels of antigen in the circulation. Examples of diseases that can cause this are:
 
* Can occur as an adverse effect of antibody response to infection if there is significant levels of antigen in the circulation. Examples of diseases that can cause this are:
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** [[Leishmania|Leishmaniasis]]
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** Leishmaniasis
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** [[Lyme Disease|Lyme disease]]
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** Lymes disease
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** [[African Swine Fever|African swine fever]]
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** African swine fever
  
  
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1. Drug reactions (eg. penicillins and sulphonamides)
 
1. Drug reactions (eg. penicillins and sulphonamides)
  
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2. [[Systemic Lupus Erythematosus|Systemic lupus erythematous (SLE)]]- antigen is a self antigen (autoimmune disease of dogs and cats)
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2. Systemic lupus erythematous (SLE)- antigen is a self antigen (autoimmune disease of dogs and cats)
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==From Pathology==
 
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*[[Complement#Complement Fixation Pathways|Complement fixing]] immune complexes
 
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*[[IgG]] or [[IgM]]
 
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*Complexes deposit in tissue -> fix complement -> cytokines and othe factors attrack neutrophils -> release lysosomal enzymes, activation of complement and coagulation, platelet aggregation -> tissue damage
 
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*Immune complex vasculitis -> [[Haemorrhage#Purpura haemorrhagica|purpura haemorrhagica]]
 
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*Includes:
 
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**[[Systemic Lupus Erythematosus|Systemic lupus erythematosus]]
 
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**[[Canine Dermatomyositis|Canine dermatomyositis]]
 
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<br><br>
 
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{{Jim Bee 2007}}
 
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[[Category:Hypersensitivity]]
 

Revision as of 13:53, 26 August 2008

Type III hypersensitivity antibody excess-Brian Catchpole RVC 2008
Type III hypersensitivity antigen excess-Brian Catchpole RVC 2008


In the normal animal immune complexes (lattice of soluble antigen and antibodies) are formed and removed all the time. They are broken up by complement, transported to the spleen by RBC's and phagocytosed. When the amount of immune complexes formed (due to rapid influx of antigen) does not equal the amount that are being cleared it causes type III hypersensitivity (an excess of immune complexes).

The effects depend upon where the immune complexes are deposited:

Locally:

1. Inhaled antigen leads to hypersensitivity pneumonitis

  • Farmers lung (humans)-inhalation of fungal spores
  • Pigeon fancier's disease-repeated inhalation of dried pigeon faeces
  • Mouldy hay containing Micropolyspora felis

2. Intradermal and subcutaneous injection of antigen (with high levels of circulating antibody) leads to localised immune complexes which cause acute inflammation.

3. Vasculitis

4. Arthritis

5. Glomerulonephritis

  • Can occur as an adverse effect of antibody response to infection if there is significant levels of antigen in the circulation. Examples of diseases that can cause this are:
    • Leishmaniasis
    • Lymes disease
    • African swine fever


Systemically:

Due to increased quantities of antigen systemically.


Generalised effects:

  • Vasculitis
  • Erythema
  • Oedema
  • Neutropaenia
  • Proteinuria (caused by of kidney damage)


1. Drug reactions (eg. penicillins and sulphonamides)

2. Systemic lupus erythematous (SLE)- antigen is a self antigen (autoimmune disease of dogs and cats)

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