Hypersensitivity

Question 1

Type 1 hypersensitivity

Answer 1

IgE response.
Allergies and anaphylaxis
Antigen binds to IgE, causes mast cells to be sensitized and release histamine.

Food allergies, ragweed etc

Question 2

Type 2 hypersensitivity

Answer 2

Antibody mediated
Antibodies bind to antigen on a cell surface
IgG or IgM attacks our own antigens and will opsonise cell or cause complement cascade.

Myasthenia Gravis, Graves’ disease, blood transfusions and haemolytic disease of the newborn

Question 3

Type 3 hypersensitivity

Answer 3

Immune complex of antibody and antigen.
Stimulates complement, causing neutrophils to be released and localised destruction of cells.

Serum sickness

Question 4

Type 4 hypersensitivity

Answer 4

Cell mediated
Occurs 1-3 days after exposure to antigen
Large amount of antigen required

Metals, venom

Question 5

How many types of hypersensitivity reactions are there?

Answer 5

4