Immunology Flashcards
What are the major immune cells in the skin called?
Langerhans cells
Which immune cells are found in the dermis and the epidermis respectively?
Epidermis; CD8+
Dermis; CD4+ and CD8+
(CD8 = cytotoxic killer cells, CD4 = T helper cells)
What is the difference between MHC class I and II?
MHC class I: found on all native cells MHC class II: found on antigen presenting cells
What is the pathological process of psoriasis?
Overreaction of the immune system to small trauma - increased keratin production (no bacteria present on culture)
Which skin surfaces do psoriasis and eczema typically affect?
Psoriasis: extensor surfaces
Eczema: flexor surfaces
What is the disease process in vitiligo?
Melanocytes are attacked by T cells
What is urticaria?
Skin presentation of type 1 hypersensitivity in the form of wheals
What is a type I hypersensitivity reaction?
Immediate allergic reaction that is reproducible upon every contact (after initial exposure to sensitise and produce antibodies) IgE mediated (mast cells/histamine production)
What is the most important thing in diagnosis of an allergy?
History
What is the progression of tests for allergy?
Skin prick test,
IgE (RAST) test - only used to confirm not diagnose),
Challenge test (must be done in a safe clinical environment)
What is the progression of treatment for allergy?
Avoidance,
Anti-histamines,
Corticosteroids (oral prednisolone),
Adrenaline injection (epipen)
What is a type IV hypersensitivity reaction?
T cell mediated delayed reaction (such as preservatives within cosmetics, fragrances, plants, tattoos)
What type of allergic reaction is allergic contact dermatitis and how is this identified?
Type IV
Patch testing
What is the pathology of irritant contact dermatitis?
Non-immunological process where the pattern depends upon the exposure
This doesn’t require prior sensitisation
