Hypersensitivity (Type 1,2,3,4) | Immunology Notes | Budding Forensic Expert

Hypersensitivity | Type I , Type II, Type III, Type IV | Immunology | Milik Ahmed

Type I:

• IgE antibodies mediated

• Inflammation occurs

• Cause Smooth muscle spasm

• Immediate action (Within 1 Hour)

• The IgE releases antibodies against the soluble antigens which results in mast cell degranulation and release of histamine and other inflammatory mediators.

  
  
  
  

• Examples:

1. Allergic Bronchial Asthma,

2. Allergies (nuts, eggs, milk, penicillin, pollen etc)

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Type II:

• IgG or IgM antibodies mediated

• Cytotoxic: kill cells by complement,

• Phagocytosis

• Interfere with cell functions

• Immediate action (Hours to Days)

  
  
  
  

• Examples:

1. Autoimmune diseases(immune thrombocytopenia,autoimmune neutropenia, myasthenia gravis, Goodpasture syndrome.)

2. Hemolytic disease of the newborn

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Type III:

• IgG/IgM antibodies

• immune complex mediated

• Inflammation occurs 

• Immediate Action (1-3 Weeks)

  
  
  
  

• Examples:

1. Serum sickness(induced by drugs,antivenom, antitoxin)

2. Arthus reaction

Type IV:

• T-Cell Mediated

• Inflammation occurs 

• Cytotoxic

• Delayed Response (Days to Weeks)

  
  
  
  

• Examples:

1. Contact dermatitis (poison ivy, cosmetics...)

2. Tuberculosis skin test

   
   

   Hypersensitivity Difference Table: