Type 4 Hypersensitivity

Question 1

What is type 4 hypersensitivity?

Answer 1

Cell mediated

Question 2

What cells are involved?

Answer 2

Lymphocytes

Macrophafes

Question 3

What is the pathogenesis of type 4 hypersensitivity?

Answer 3

Sensitisation phase

• antigen presentation
• activate TH1

Effector phase

• macrophages reactivated
• release oxygen radicals
• tissue damage + local inflammation

Question 4

What diseases are caused by type 4 hypersensitivity due to exogenous antigens?

Answer 4

Contact hypersensitivity

Granulomatous hypersensitivity

Question 5

What diseases are caused by type 4 hypersensitivity due to endogenous antigens?

Answer 5

Diabetes mellitus

Hasimoto’s thyroiditis

Question 6

What is contact hypersensitivity?

Answer 6

Epidermal reaction to endogenous protein

Question 7

How long after exposure does contact hypersensitivity occur?

Answer 7

48-72 hr

Question 8

What can trigger contact hypersensitivity?

Answer 8

Nickel
Poison ivy
Organic chemicals

Question 9

How long after exposure does granulomatous hypersensitivity occur?

Answer 9

21-48 days

Question 10

What are some examples of granulomatous hypersensitivity?

Answer 10

TB
Leprosy
Sarcoidosis

Question 11

How can type 4 hypersensitivity be managed?

Answer 11

Anti-inflammatory drugs

Monoclonal antibodies