Allergic reactions Flashcards
1
Q
What is the mechanism of a type 1 hypersensitivity reaction?
A
This is the antigen reacting with the IgE bound to mast cells
E.g. Anaphylaxis, Atopy
2
Q
What is the mechanism of a type 2 hypersensitivity reaction?
A
Cell bound
IgG or IgM binds to the antigens on the cell surface
E.g. autoimmune haemolytic anaemia, Pernicious anaemia, acute haemolytic transfusion reactions
3
Q
What is the mechanism of a type 3 hypersensitivity reaction?
A
Immune complex
Free antigen and antibody combine
E.g. SLE, post strep GN, extrinsic allergic alveolitis
4
Q
What is the mechanism of a type 4 hypersensitivity reaction?
A
Delayed hypersensitivity
T cell mediated
E.g. MS, GBS, graft vs host disease
