Chapter 20 - Allergy Flashcards
what do allergic responses result from?
what are immune responses driven by? how are they carried? what activity do they contain?
harmful immune responses
non-infections Ags carried in particles, have protease activity
what kind of groups comprise allergens?
proteins and glycoproteins
what 2 ways do allergens activate the innate immune response?
intrinsic enzymatic activity
activation of PRRs
indoor allergens are associated with?
outdoor allergens?
asthma
allergic rhinitis
what are the sources of airborne proteins or glycoproteins?
tree and grass pollen
mold spores
animal dander
dust mite or cockroach secretions
what are 2 forms of dominant source allergens?
timothy grass pollen (UK)
birch pollen (Sweden)
what influences the development of atopy?
genetic factors (polymorphisms)
environmental factors (sensitization, # siblings, hygiene, vacc)
what effects Th2-mediated allergic inflammation?
Defects in target organs (skin, gut, bronchi)
Triggers (viral infections, allergen exposure, smoke, pollutants)
what are some factors favoring Th1 protective immunity?
TB, older siblings, day care exposure, farm life
What are some factors favoring Th2 phenotype leading to allergic diseases?
antibiotic use, diet, sensitization to dust mites, urban (thug) life
what is the risk of passing on atopic trait if both parents are atopic?
1 parent?
0 parents
75%
50
15
polymorphisms in what genes are known to cause atopy?
Beta chain of FcERIBeta
IL-4 gene
HLA-DR alleles
CD14
what is CD14, what does a polymorphism in it promote?
part of receptor for LPS
hypersensitivity
patients with ragweed pollen allergy have IgE and IgG hypersensitivity due to what allelic association?
HLA-DR2
what does high levels of IgE in the cord blood of infants predict?
future development of atopy
what is the main postulate of the hygiene hypothesis?
the increased incidence of allergy is associated with the decrease in exposure to common infections during early life
how can atopic (Th2) phenotype be prevented?
Th1 type response
what can limit the development of unrelated allergen-mediated disease?
increased # of Tregs
Anaphylaxis is what type of hypersensitivity?
what Ags and what effectors does it display?
what kind of damage is it associated with?
Type I, Ag: insect venoms, drugs, food
Effectors: IgE on basophils and mast cells
oedema, bronchoconstriction, vascular collapse, death