Type 4 Hypersensitivity

Question 1

How long do symptoms take to occur in type 4 hypersensitivity reactions?

Answer 1

2-3 days

Question 2

What is the main difference between type 4 hypersensitivity reactions and the others?

Answer 2

It takes much longer

It is NOT antibody mediated, its cell mediated (T cell, monocytes, macrophages)

Question 3

What are examples of Type 4 hypersensitivity reactions?

Answer 3

Dermatitis
Multiple sclerosis
Rheumatoid arthritis

Question 4

Which cells mediate type 4 hypersensitivity?

Answer 4

T cells
macrophages
Monocytes

Question 5

What is the pathophysiology behind type 4 hypersensitivity?

Answer 5

tissue macrophages cells identify an antigen.
they migrate dendritic cells to lymph nodes where they present antigens to T cells. (Dendritic cells load with antigens and present them).
Cytotoxic T cells proliferate, both them and and macrophages secrete tissue necrosis factor that cause an immune response against antigens.