Hypersensitivites

Question 1

What is type I mediated by ?

Answer 1

IGE, mast cells and basophils

Question 2

What is type II mediated by ?

Answer 2

IGG/IGM and effects cell surfaces

Question 3

What is type 3 mediated by ?

Answer 3

Immune complexes of the IGG/IGM and antigens

Question 4

What is type IV mediated by ?

Answer 4

Cell mediated T cells

Question 5

What is the onset of type I?

Answer 5

Immediate

Question 6

What is the onset of type II &III?

Answer 6

Subacute occurring within hours-days

Question 7

What is the onset of type IV?

Answer 7

Delayed 48-72 hours

Question 8

What is the mechanism of type I?

Answer 8

When an invidiual is first exposed to allergens, B cells produce IGE which binds to mast cells.

Question 9

What happens during re-exposure ?

Answer 9

The same allergen cross-links IGE on the surface of these cells leading to release of histamine

Question 10

What is the mechanism of type 11?

Answer 10

iGG/IGM antibodies bind to antigens on the surface of cells which can result in cell destruction through complement or phagocytosis

Question 11

Mechanism for type 111?

Answer 11

Antigen-antibody complexes are formed and deposited in tissues leading to inflammatory responses. These complexes activated the complement system leading to tissue damage

Question 12

Mechanism for type IV?

Answer 12

Exposure to antigens been T cells become sensitised, re-exposure they release cytokines that recruit and activate macrophages lead to inflammation and tissue damage