Immunology/Biochem

Question 1

How do keratinocytes help in immunological response?

Answer 1

Produce antimicrobrial peptides (AMPs) that can directly kill pathogens

Produce cytokines and chemokines

Question 2

Give a factfile on Langerhans cells

Answer 2

Type of dendritic cell

APC cells

Characterised by Birbeck granule

• act as sentinels (guardians) in epidermis
• process Ag and present to effector T cells -> activate T cells

Question 3

Where do you primarily find CD8+ T cells?

Where do you primarily find CD4+ T cells?

Answer 3

CD8+ T cells - epidermis

CD4+ and CD8+ T cells - dermis

Only the big CD8 make it to surface

Question 4

Match:

Helper T cells
Cytotoxic T cells

CD4+
CD8+

Help B cells to make Ab
Activate macrophages
Can kill infected cells directly
Important protection against viruses and cancer

Answer 4

Helper T cells

• CD4
• Help B cells to make Ab
• Activate macrophages

Cytoxic T cells

• CD8
• can kill infected cells directly
• important protection against viruses and cancer

Question 5

Why does immunodeficiency occur?

Answer 5

Inadequate immune response

Question 6

Match the following cells to where they can be found in epidermis/dermis:

Keratinocytes
CD4
CD8
Langerhans cells
Dendritic cells
Macrophages
NK cells
Melanocytes
Fibroblasts

Answer 6

Epidermis

• CD8
• Keratinocytes
• Langerhans
• Melanocytes

Dermis

• CD4
• CD8
• Dendritic cells
• Macrophages
• Fibroblasts
• NK cells

Question 7

3 examples of autoimmune skin condiitons

Answer 7

Psoriasis
Vitiligo
Systemic lupus erythematosus

Question 8

What is a key factor in the pathophysiolgy of atopic eczema?

Answer 8

Impairment in skin barrier function

Early onset/ severe disease - associated with mutations in fillagrin gene -> less AMP in skin

Question 9

Brief overview of pathophysiology of psoriasis?

Answer 9

Keratinocytes (KC) under stress -> stimulate DC -> migrate to lymph and stimulate T cells -> stimulate KC proliferation and AMP (antimicrobrial peptides) release

Question 10

Name and describe the role of two dendritic cells found in the dermis

Answer 10

Dermal DC - involved in Ag presenting

Plasmacytoid DC (pDC) - produce INFa (found in diseased skin)

Question 11

What 3 local effects does mast cell degranulation cause in the dermis of the skin?

Answer 11

• vasodilation
• increased permeability of vessels
• smooth muscle contraction

Question 12

Which 2 types of immune response are most typically seen in the skin?

How would you test for both types?

Answer 12

I and IV

I - Skin prick/ specific IgE antibody tests (RAST)
IV - skin patch

Question 13

Split the following diseases into type I or IV reactions:

• Urticaria (hives)
• Contact dermatitis
• Angio-odema (swelling)
• Photo-allergy
• Anaphylaxis
• Skin response to bacteria/fungi/viruses
• Abnormal delayed response in atopic eczema

Answer 13

Type I

• Urticaria
• Angio-oedema
• Anaphylaxis

Type IV

• contact dermatitis
• delayed response in atopic eczema
• skin reaction to bacteria/fungi/viruses
• photo-allergy

Question 14

Explain what is meant by sensitisation to an allergen?

Answer 14

Exposed once to allow allergen to form - IgE to form

Get allergic reaction 2nd time try