Immunology

Question 1

What can keratinocytes produce in response to pathogens?

Answer 1

AMPs which directly kill pathogens

Cytokines & chemokines

Question 2

What are Birbeck granules characteristic of?

Answer 2

Langerhans cells

Question 3

Main type of T cell in epidermis

Answer 3

CD8

Question 4

T cell type in dermis

Answer 4

CD4 & CD8

Question 5

CD4 types associated w/ inflammation

Answer 5

Th1 - psoriasis
Th2 - atopic dermatitis
Th17 - psoriasis & atopic dermatitis

Question 6

Purpose of Th1 cells & chemical mediators released

Answer 6

Activate macrophages

IL2, IFNgamma

Question 7

Purpose of Th2 cells & chemical mediators released

Answer 7

Help B cells make Ab

IL4, IL5, IL6

Question 8

Which type of dendritic cell in the dermis is found in diseased skin? Which chemical mediator does it release?

Answer 8

Plasmacytoid dendritic cell (pDC)

IFNalpha

Question 9

What are mast cells in the dermis activated by?

Answer 9

IgE, physical trauma, certain drugs, micro-organisms

Question 10

MHC class I presents (endogenous/ exogenous) antigens?

Answer 10

Endogenous

Class II presents exogenous

Question 11

Which 3 things in the body can psoriasis affect?

Answer 11

Skin, nails, joints

Question 12

What fraction of psoriasis pts have joint disease?

Answer 12

1/3

Question 13

Immunopathogenesis of psoriasis

Answer 13

1. Keratinocytes under stress
2. Chemical signals activate DC, which migrate to the local draining lymph nodes to present to and activate T cells
3. These T cells are drawn back from the circulation and attracted to the dermis by chemokines and secrete IL-17A/17F/22
4. CD8 cells also contribute to the pathogenesis
5. Dermal fibroblasts become involved, which release keratinocyte and epidermal growth factors

Question 14

Which gene mutation is atopic eczema associated with?

Answer 14

Fillagrin - associated w/ severe/early onset disease

Question 15

AMP is reduced/increased in skin in atopic eczema?

Answer 15

Reduced

Question 16

Can atopic eczema be present at birth?

Answer 16

No, but frequently appears in 1st year of life

Question 17

What is Koebner phenomenon?

Answer 17

Skin lesions appearing on lines of trauma

Question 18

What is type I hypersensitivity mediated by?

Answer 18

IgE

Question 19

What are type II & III hypersensivities mediated by?

Answer 19

IgG, IgM

Question 20

What is type IV hypersensitivity mediated by?

Answer 20

Th1 cells (cell-mediated)

Question 21

How can ageing affect skin immune response?

Answer 21

Changes in skin structure (access)
Decreased ability to detect malignant cells – Cancer
Decreased ability to detect Ag – Infection risk
Decreased ability to distinguish “self” from “non-self” (tolerance) – Autoimmunity

Question 22

What is RAST?

Answer 22

A blood test using radioimmunoassay test to detect specific IgE antibodies

Question 23

What dosage of adrenaline is present in an epipen for children & adults?

Answer 23

Children - 150µg

Adults - 300µg