Type 2 Hypersensitivity Flashcards
What type of reaction is type 2 hypersensitivity?
Cell bound reaction
What is type 2 hypersensitivity mediated by?
Antibodies
Which antibodies is type 2 hypersensitivity mediated by?
IgG
IgM
What are the antibodies directed against in type 2 hypersensitivity?
Antigens found on the surface of cells or fixed within certain tissues
What does type 2 hypersensitivity lead to?
Cell or tissue damage
What happens with the antibody binds to the relevant antigen?
Damage occurs
How does damage occur in type 2 hypersensitivity?
complement activation
Fc binding and stimulation of phagocytes
antibody dependent cellular cytotoxicity (ADCC)
effects on target cell function
What does the bound antibody react with?
The Fc receptor on the macrophage
What are some examples of type 2 hypersensitivity reactions?
Blood transfusion reaction
Haemolytic disease of the new born
How is a blood transfusion reaction a type 2 hypersensitivity reaction
Anti-A and Anti-B are IgM antibodies
How is a Haemolytic disease of the new born a type 2 hypersensitivity reaction?
If a rhesus negative mother has a rhesus positive baby, exposure to the babies blood during birth will cause the mother to produce IgG to rhesus
What are the possible effects on target cell function?
Inhibition of function
Stimulation
What other diseases can be classed as type 2 hypersensitivity reactions?
Some organ specific autoimmune diseases
What organ specific autoimmune diseases can be classed as type 2 hypersensitivity reactions?
- Grave’s disease (TSH receptor)
- myasthenia gravis (acetylcholine receptor)
- Goodpasture’s syndrome (Type IV collagen)
- pemphigus (desmosomes)
What are the 2 forms of management of type 2 hypersensitivity reactions?
Prevention
Immunosuppression
