Skin Immunology Flashcards
What is hypersensitivity?
Over reaction to antigen
What is autoimmunity?
Reaction to host tissue –> chronic inflammation
What is immunodeficiency?
Infection is not controlled. Tumours may form
What does the keratin layer contain that can directly interact and kill micro-organisms?
antimicrobial peptides (AMP)
What is the function of keratinocytes in the epidermis?
sense pathogens via a cell surface receptor and help mediate an immune response
What can activate keratinocytes in the epidermis?
UV light and sensitisers
What is the main skin resident immune cell?
Langerhans cell
What are Langerhans cells?
Antigen presenting cells characterized by the Birbeck granule
In terms of the layers of the skin, which layer(s) are CD4+ T cells found?
Dermis only
How do dermal DC and Plasmacytoid DC cells differ?
Dermal DC - Ag presenting and secreting cyto/chemokines
Plasmacytoid DC - produce IFNa and secrete cyto/chemokines
What are the clinical signs associated with Allergic Contact Dermatitis?
Inflammatory reaction (dermatitis) with pruritic erythema, oedema and often vesicles at site of chemical contact
What are the two stages of allergic contact dermatitis?
afferent /sensitising stage (repeated sub-threshold exposures that do not produce any signs or symptoms)
efferent/elicitation stage - exposure produces response
What is the standard diagnostic test for allergic contact dermatitis?
Patch test
Give some treatments for allergic contact dermatitis.
avoidance of the chemical
topical or systemic corticosteroids
oral histamine may also help
Give a brief explanation of atopic eczema
Genetic and environmental factors impair the skin barrier function allowing access/sensitisation to allergen and promotes colonisation by micro-organisms.
