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Dermatology > Skin Immunology > Flashcards

Flashcards in Skin Immunology Deck (32)
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1
Q

How is the keratin layer formed?

A

Terminal differentiation of keratinocytes to corneocytes

2
Q

Name some structural proteins in keratin layer and epidermis

A

Filaggrin, Involucrin, keratin

3
Q

What can activate keratinocytes?

A

UV and sensitizers (e.g. allergic contact dermatitis)

4
Q

What do keratinocytes produce?

A

Antimicrobial peptides (AMPs) that can directly kill pathogens (found at high levels in psoriasis patients). Also cytokines and chemokines

5
Q

What is the main skin resident immune cell?

A

Langerhans cells

6
Q

What type of antigen cells are Langerhans Cells, and what are they characterised by?

A

Antigen presenting cells, Birbeck granule

7
Q

What is the function of Langerhans cells?

A

Act as sentinels in epidermis, process lipid Ag and microbial fragments and present them to effector T cells, help activate T cells

8
Q

Where are T cells sensitised?

A

Thymus

9
Q

What is involved in the interaction in Ag recognition and T cell activation?

A

T cell receptor (TCR) and Major Histocompatibility Complex (MHC)

10
Q

What 2 co-receptors enhance Ag recognition and T-cell activation?

A

CD4/CD8

11
Q

Describe MHC Class II

A

Found on APC (B cells, macrophages), Present to TH cells, Present exogenous Ag

12
Q

Describe MHC Class I

A

Found on almost all cells, Present Ag to cytotoxic T cells, Present endogenous Ag

13
Q

What T lymphocytes are found in the epidermis and dermis?

A

Mainly CD8+T in epidermis, CD4+ and CD8+T in dermis. Also NK cells are found

14
Q

Which CD4+Th cells are associated with inflammation?

A

Th1 (psoriasis), Th2 (atopic dermatitis) and Th17 (psoriasis and atopic dermatitis)

15
Q

What do CD4+ Th1 helper cells do?

A

Activate macrophages to destroy microorganisms aided by IL2 and IFNgamma

16
Q

What do CD4+ Th2 helper cells do?

A

Help B cells to make Ab, with the aid of IL4/5/6

17
Q

What do CD8+ Cytotoxic T cells do?

A

Can kill infected cells directly, important protection against viruses and cancer

18
Q

What is the function of Dermal dendritic cells?

A

Involved in Ag presenting and secreting cyto/chemokines

19
Q

What is the function of Plasmacytoid dendritic cells?

A

Produce IFNalpha, found in diseased skin

20
Q

Name some skin conditions associated with an inappropriate immune response

A

Psoriasis, atopic dermatitis, bullous pemphigoid, contact dermatitis, morphea/systemic sclerosis, urticarial, systemic lupus erythematosus, skin infections and tumours

21
Q

What triggers psoriasis?

A

Environmental factors in genetically susceptible individuals

22
Q

What do keratinocytes do under stress in the T cell mediated immunopathogenesis of psoriasis

A

Release factors that stimulate pDC to produce IFNalpha, release IL-1beta, IL-6 and TNF

23
Q

Describe the DC response in the immunopathogenesis of psoriasis

A

Activated by chemical signals, DC migrate to skin draining lymph node to present to and activate T cells TH1/17

24
Q

Describe what happens to T cells during the immunopathogenesis of psoriasis

A

They are attracted to dermis by chemokines and secrete IL-17A/17F/22. These stimulate KC proliferation, AMP release and neutrophil-attracting chemokines

25
Q

What is a key factor development of atopic eczema?

A

Impairment of skin barrier function. Mutations in fillagrin gene associated with severe/early onset disease, leads to decrease in AMP

26
Q

What cells are found in the lesions of atopic eczema?

A

T cells (Th2), DC, KC, macrophages and mast cells (likely attracted by stressed KC)

27
Q

Name some examples of AI skin conditions

A

Psoriasis, vitiligo, SLE

28
Q

What are the routes of exposure in a type 1 allergy?

A

Skin contact, inhalation, ingestion, injection

29
Q

What is angioedema?

A

Localised swelling of subcutaneous tissue or mucous membranes, non pitting

30
Q

What investigation should be done during anaphylaxis?

A

Serum mast cell tryptase level

31
Q

What dosage of adrenaline is given to adults and children in an autoinjector?

A

300 micro grams adults, 150 children

32
Q

What are some examples of an endogenous dermatitis?

A

Atopic eczema, other skin conditions