Immunology Flashcards
in what 3 ways does skin contribute to an effective immune system
barrier structure
immune cells in skin secreting cytokines/chemokines
genetics
how do keratinocytes contribute to immunity in the epidermis
sense pathogens by surface receptors
produce cytokines/chemokines
produce antimicrobial proteins
what cell does the birbeck granule characterise
langerhan cell
what lymphocytes are found in the epidermis
CD8+T cells
what lymphocytes are found in the epidermis
CD4 and CD8 T cells
how do TH2 T cells help B cells make antibodies
stimulation via IL4/IL5/IL13
what kind of CD4+T cells are found in atopic dermatitis
TH2 and TH17
what kind of CD4+T cells are found in psoriasis
TH1 and TH17
what immune cells, including lymphocytes, are found in the dermis
CD4 and CD8 lymphocytes mast cells langerhans cells NK cells macrophges neutrophils, if acute immune response active
describe MHC I and its mechanism of action
found on all cells in the body and presents endogenous antigen to T cells
describe MHC II and mechanism of action
found on APC and presents exogenous antigen to T cells for activation of the acquired immune response
describe the immunological events occurring in psoriasis
environmental factor causes KC stress so stimulates DC to produce IFNa, DC activates TH1 and TH17 in skin lymph node which travel to skin and secrete IL17 to cause KC proliferation and attracts neutrophils
fibroblasts in dermis release epidermal growth factors
describe the immunological events occurring in atopic dermatitis
mutations in filaggrin gene lead to dry skin
KC becomes stressed by allergen invading dry skin and causes DC to activate TH2 cells that secrete IL4/IL5/IL13 to proliferate B cells secreting IgE
on second exposure IgE binds mast cells causing histamine and leukotriene release to promote inflammation causing rash on skijn
describe the rapid and late response of type I hypersensitivity
rapid - wheal and flare
delayed - cell infiltration and nodules
in what type of hypersensitivity would you find an arthus reaction and what does it mean
type III
skin reaction slower than type I, but faster than IV
what type of TH cell mediates type IV inflammation, and why is it delayed and how long by
TH1
delayed due to t cell response, usually 24-48 hours
what is hypersensitivity
immune response causing collateral damage to self
what is allergy
hypersensitivity of the immune system
how fast does a type I allergy appear
a minute to 2 hours - fast
common type I allergens
nuts pet dander seafood house dust mite pollen latex bee sting medications
describe pathophysiology of type I hypersensitivity
allergen exposed causes LC to travel to lymph node or dermis to activate TC. TH2 activates B cell to secrete IgE specific against allergen
second exposure - IgE binds and degranulates mast cells to cause proinflammatory mediators and cytokines
what clinical features will you see with type I allergy
urticaria
angioedema
anaphylaxis
investigation of type I allergy?
history, history, history IgE levels Prick test Challenge test - only AFTER prick serum mast tryptase
management of type I allergy?
allergen avoidance antihistamines topical steroid - if antihist not enough adrenaline autoinjector sodium chromoglycate inform/educate medic alert
