Basic Skin Immunology

Question 1

How are T cells activated?

Answer 1

The T cell receptor and MHC are both bound for activation

Subsequent binding from co-receptors (CD4 or CD8) enhance this activation and aid differentiation

Question 2

What effect does the compromised skin barrier in eczema have?

Answer 2

Allows access and increased sensitisation to antigens

Promotes colonisation by microorganisms

Question 3

Which MHC complex(es) is/are most problematic in terms of skin graft rejection?

Answer 3

MHC class 1

(presents self antigens, hence all will be foreign)

Question 4

Which type of antigen does MHC class 1 present to cytotoxic T cells?

Answer 4

Endogenous antigen

Question 5

Which type of hypersensitivity is related to mast cell degranulation?

Answer 5

Type 1

Question 6

Describe the immunopathogenesis of psoriasis

Answer 6

Keratinocytes become under stress

Plasmacytoid dendritic cells secrete IFN alpha

Keratinocytes secrete IL-1 beta, IL-6 and TNF

Dermal dendritic cells activate and present to TH1 and TH17 cells

T cells enter the dermis and secrete IL-17A, IL-17F and IL-22

This induces keratinocyte prolifeation, antimicrobial protein release and neutrophil recruitment

Question 7

Which type of cell comprises the keratin layer?

Answer 7

Corneocytes

Question 8

Which immune cells are most associated with atopic dermatitis?

Answer 8

TH2 CD4+

TH17 CD4+

Question 9

Which immune cells are associated with psoriasis?

Answer 9

TH1 CD4+

TH17 CD4+

Question 10

Which type of T cell is most prominent in the epidermis?

Answer 10

CD4+

(CD4 and CD8 both found in dermis)

Question 11

What is released by cells of the body when they become infected?

Answer 11

Interferon alpha

Question 12

Type IV hypersensitivity is mediated by which immune cell?

Answer 12

TH1

Question 13

Which dendritic cell is associated with diseased skin?

Answer 13

Plasmacytoid

Question 14

What is the main immune cell in the epidermis?

Answer 14

Langerhans cell

Question 15

Which immune cell is most useful against worms and parasites?

Answer 15

Mast cells

Question 16

Within the dermis, which dendritic cell is responsible for antigen presentation primarily?

Answer 16

Dermal dendritic cells

Question 17

How do the roles of plasmacytoid dendritic cells and dermal dendritic cells differ?

Answer 17

Plasmacytoid - associated with disease skin and secrete INFa

Dermal - associated with antigen presentation in the dermis

Question 18

Which type of T cell activates macrophages and how do they achieve this?

Answer 18

TH1

Release IL2 and IFN gamma

Question 19

What is the name given to the characterstic tennis racket-shaped component of Langerhans cells?

Answer 19

Birbeck granules