Hypersensitivity Flashcards
Atopic Allergies are a what to what?
Heritable Predisposition to Environmental Antigens
Name the two phases of hypersensitivity
Sensitisation Phase
Elicitation Phase
What happens in the sensitization phase?
First exposure to antigen = IgE production
Proliferation of T/B cells / memory
IgE sensitize MC
What happens in the elicitation phase?
Memory T/B produce IgE
MC degranulate
Type 1 Hypersensitivity is stimulated by what?
What receptor does IgE bind to on MC after Il-4 stimulation to cause MC degranulation
Haptens / Proteins / Asthma molecules
FCeR1
What else (3) is released from MC? What do these do?
Chymase - Inflammation
Tryptase- Mucous Secretion
N-CFA = chemoattractant (neutrophils)
The skin prick test is used for what hypersensitivity ?
What does it produce within 20 minutes?
Hypersens 1
Zone of Erythema + Localized Wheal
What test is used to detect circulating IgE to known antigen?
RAST
Immunotherapy of type 1 involves an injection of what and how is it done?
What shift is seen?
Intradermal dilute injection of antigen
IgA/IgG production = competition
Th2 –> Th1
What drug is given to decrease circulating IgE + decrease FCeR1 density on MC for type 1
Omalizumab
What is a MC stabalizer>
Cromolyn Sodium
What bacteria causes a releases of IFN-Y which does what which is beneficial for type 1?
Mycobacterium TB
Releases IFN-Y from T cells = Inhibits Class Switching
In type 3 hypersens, what deposits?
What does this activate
Soluble antigen-AB complexes
Classical Complement
What is found on RBC that removes these complexes found in type 3?
CR1
What is attracted to these complexes and what causes it (complement)?
Polymorfs
C5a
Why does nephritus occur in type 3?
Why does arthritus occur in type 3?
Glom cells have CR1
Synovial cells have CR1
Name a systemic hypersensitivity
What happens in it
SLE
dsDNA not removed properly = auto AB
Name a localized hypersensitivity
What happens in it
Farmers Lung
IgG against mould spores = Immune complexes in alveoli
