Hypersensitivity

Hypersensitivity

1. Any immune response against a foreign antigen that is exaggerated beyond the norm

2. type I hypersensitivity or allergy

   • immediate or anaphylactic
   • localized or systemic
   • two part mechanism
     • sensitization upon initial exposure
     • degradation of sensitized cells

3. type II hypersensitivity

   • known as cytotoxic
   • cause by endogenous antigens or haptens
   • 3 syndromes
     • blood transfusion
     • hemolytic disease
     • drug - induced hypersensitivity

4. type III hypersensitivity

   • immune complex
     • localised immune complex disease
     • systematic immune complex disease

5. type IV hypersensitivity

   • known as cell - mediated
   • occured in response to small chemical (hapten) encountered with skin (protein)