12 terms

hypersensitivity

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List examples of hypersensitivity type 2
Myasthenia Gravis (Abs bind the receptors on the postsynaptic membrane, so NTs can't bind and muscle can't contract)
Grave's disease (upregulation of thyroid->increased thyroglobulin levels-> thyrotoxicosis)
Goodpasture's disease (antibasement membrane antibodies)
Immune hemolytic anemias
What are type 3 hypersensitivity reactions?
Immune complexes formed from antibody/antigen complexes circulating in the blood
Which type of hypersensitivity is responsible for many forms of vasculitis?
Type 3

Immune complexes activate complement and damage the vessel walls, causing hemorrhage and thrombosis.
What type of hypersensitivity is responsible for serum sickness?
Type 3
List some examples of type 3 hypersensitivity reactions
glomerulonephritis (some types)
vasculitis (many types)
serum sickness
SLE
arthus reaction
How is type 4 different from the other 3?
Antibodies play little to no part
Reaction is mediated by macrophages (APCs) and T cells
tissue hallmark is the granuloma
What type of hypersensitivity is anaphylaxis?
Type 1

important components: antigens binding to mast cells via IgE immunoglobulin receptors -> release of granules containing chemical mediators (eg leukotrienes, prostaglandins, etc.)

causes bronchospasm, edema, platelet activation, chemotaxis
List examples of type 1 hypersensitivity
Anaphylaxis
Asthma
Allergies
Hay Fever
Eczema
Where do antibodies bind in type 2 hypersensitivity?
Basement membrane
How do neutrophils play a role in type 2?
PMNs bind to the antigen-antibody-complement complexes and damage the BM, allowing protein and RBCs to leak into urine
How does a MAC play a role in type 2?
Antigen-Antibody interaction activates complement, then forms a membrane attack complex that punches holes in the membrane rupturing the cell (lysis)
List examples of MAC-induced cell lysis in type 2 hypersensitivity
hemolytic anemias
incompatible blood transfusion reactions