19. Hypersensitivity Reactions - Type I

Question 1

What is a synonym for type I hypersensitivity?

Answer 1

Anaphylactic hypersensitivitiy

Question 2

How soon after exposure to an allergen do the symptoms of type I hypersensitivity occur?

Answer 2

Immediate. Occurs within minutes after exposure to Ag

Question 3

What class of antibody is involved in the pathology of allergic urticaria and systemic anaphylaxis?

Answer 3

IgE

Question 4

What cells of the immune system is IgE antibody capable of binding to?

Answer 4

Mast cells and Basophils

Question 5

What are the clinical effects of histamine, leukotrienes, and cytokines released during type I hypersensitivity?

Answer 5

Chemical mediators cause:

1. smooth muscle contractions
2. Increased Vasodialation and vasopermeability
3. Increased mucous secretion

Question 6

How are desensitization shots thought to reduce the symptoms of allergies?

Answer 6

Increasing doses of allergen are administered to the patient as allergy shots or as a sublingual immunotherapy. Thought to stimulate production of blocking Abs (IgG Abs directed against allergen compete with IgE for binding of allergen).

Question 7

What test is used to measure total serum IgE?

Answer 7

RIST - radioimmunosorbent test

Question 8

What test is used to measure allergen-specific IgE?

Answer 8

RAST - radioallergosorbent test