immunology Flashcards
what cells are involved in memory
CD4+ T cells, memory B cells, long lived plasma calls
what is acute vaccination
protection provided by the persons OWN immune system
can stimulated by vaccination or naturally acquired infection
what is passive vaccination
protection transferred from another person or animal
what are sources of passive immunity
breast milk
via the placenta
what are the hallmarks of immunodeficiency
SPUR
serious infections
Persistent infections
Unusual infections
Recurrent infection
give examples of secondary immunodeficiencies
extremes of age immunosupressive therapy/steroids anti-cancer treatment cancer malnutrition renal issues diabetes
what is phagocyte deficiency
defect in phagocyte production, mobilisation and recruitment
what is the first step in phagocyte production
mobilisation of phagocytes and precursors from bone marrow or within tissues
what can go wrong in the 1st step of phagocyte production
failure of neutrophil differentiation = failure to produce neutrophils
give examples of neutrophil maturation failure
kostmann syndrome
what is Kostmann syndrome
rare autosomal recessive disorder which results in severe chronic neutropenia
what is the treatment of Kostmann syndrome
stem cell transplant
what is the 2nd step in phagocyte production
up regulation of endothelial adhesion markers which allows neutrophil adhesion and migration into tissues
what can go wrong in the 2nd step of phagocyte production
failure to express leukocyte adhesion markers = leukocyte adhesion deficiency
what is leukocyte adhesion deficiency
rare primary immunodeficiency
what is the 3rd step of phagocyte production
recognition of the organism
what can go wrong in the 3rd step of phagocyte production
antibody or complement deficiency
what is the 4th step of phagocyte production
phagocytosis and organism killing
what can go wrong in the 4th step of phagocyte production
failure of oxidative killing = chronic granulomatous disease
what 5 things can wrong in the adaptive immune system
- failure of lymphocyte precursors
- failure of thymic development
- failure of expression of HLA molecules
- failure of signally, cytokine production and effector functions
- failure of normal apoptosis
give an example of failure of lymphocyte precursor disease
severe combined immunodeficiency
what is severe combined immunodeficiency (SCID)
usually X-linked, mutation in IL-2 receptor which cause low/no T cells
what is the treatment of SCID
stem cell transplant
give an example of thyme development
DiGeorge syndrome
what is DiGeorge syndrome
complex developmental disorder caused by deletion at 22q11 resulting in no/low T cells
what are hypersensitivity diseases
immune response that results in bystander damage to self
how many types of hypersensitivity disease are there
4
what is type I hypersensitivity disease
immediate hypersensitivity
what is type II hypersensitivity disease
direct cell killing
what is type III hypersensitivity disease
immune complex mediated
what is type IV hypersensitivity disease
delayed type hypersensitivity
what Ig type is involved in type I
IgE
examples of type I hypersensitivity disease
asthma
hayfever
anaphylaxis
examples of type II hypersensitivity disease
transfusion reactions
goodpastures
guillan barre
graves disease
examples of type III hypersensitivity disease
farmers lung, bird fanciers lung etc
SLE
examples of type IV hypersensitivity disease
type 1 diabetes
psoriasis
sarcoidosis
TB
features of type I hypersensitivity disease
occurs quickly after exposure to allergen (mins-1/2hrs)
presentation associated by site of contact
what is the gold standard for allergic testing, what other tests are available
skin pick test
ELISA/RAST
tryptase levels = anaphylaxis
features of type II hypersensitivity disease
antibody (IgG or IgM) binds to human cell surface antigen
occurs in 12-18hrs after exposure
management of type II disease
plasmapheresis
immunosuppression
what are the features of type III hypersensitivity diseases
antibody binds forming small immune complexes which are trapped in small vessels, joint, and glomeruli
how are type III hypersensitivity diseases diagnosed
test for presence of specific IgG antibodies
what are the features of type IV hypersensitivity diseases
T cell mediated
delayed
what is the role of mast cells in allergic reactions
mast cells express receptors for Fc region of IgE and on contact with allergen B cells produce specific IgE antibody. with the residual IgE binding to the mast cells. when the allergen is re-encountered the allergen binds to the IgE coated mast cell and disrupts the membrane which causes release of cytokines, IL, and vasoactive mediators (histamine etc.)
