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19 Cards in this Set
- Front
- Back
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Which type of rxns are 'immune complex' mediated?
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Type III
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What is the "immune complex" that leads to tissue damage in Type III rxns?
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circulating soluble Ag-Ab complexes OR can occur at extravascular sites where antigen has been planted (in situ)
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* What is a systemic sickness associated with Type III rxns? Localized?
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Systemic Lupus Erythematosis (SLE)
"Arthus Reaction" |
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What is the prototype systemic immune complex?
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Serum sickness
also: SLE |
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What is usually the "initiation" of an acute Immune complex rxn (Type III)?
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injection of large dose of Ag
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What type of rxn induces vasodilation, complement and can lead to vasculitis?
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Immune complex (Type III)
Deposition of immune complexes in vessel wall leads to localized complement activation and recruitment of polys (as shown). The leukocytes produce injury to the vessel wall, with edema and fibrin deposition. |
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Which disease produces numerous autoantibodies of unknown origin? What type of hyper- rxn is this?
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SLE
Type III (Immune complex - systemic) |
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* How does the glomerulonephritis associated with SLE differ from that of Goodpasture's Syndrome (Anti-GBM) (Type II)?
histologically? |
here it is an "innocent bystander"
SLE = course, granular deposition of complexes Goodpasture's = linear deposition |
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Immune complexes are normally produced in the immune response, why do some cause problems (Type III)?
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produced in excessive amounts
not efficiently cleared |
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* What determines the extent of immune complex deposition?
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Size: smaller complexes are harder for phagocytic system to clear. Larger complexes rapidly removed
Other factors: charge, valence, hemodynamic factors (high pressure and turbulence), affinity to tissue (joints) |
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Which two hypersensitivity Rxns are associated with glomerular nephritis?
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Type II and III
-Goodpasture's Syndrome -SLE |
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Which response is due to sensitized T lymphocytes?
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Type IV: delayed type, cell mediated
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What cytokine drives CD4 cells to become Th1?
*how does this impact Type IV rxns? |
IL-12 --> Th1
Th1 makes the cytokines that induces phagocytic killing by macrophages (IFN-y) (Delayed Type Rxn of Type IV Hypersensitivity) |
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In which rxn might you see a granuloma? what is happening here?
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tuberculin positivity (ppd) --> accumulated macrophages (*persistent TB) become surrounded by lymphs / CD4s
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Does a positive ppd mean you have active TB?
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No. You have been exposed before though (Th1 response)
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What is the purpose of a "two step" ppd?
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To "wake up" or boost hypersensitivity
(common in elderly) |
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* What type of rxn is poison ivy (contact dermatitis)? what is the timeframe?
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Type IV: delayed type
(no rxn on first exposure) not immediate: days |
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what are haptens?
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a small molecule that can elicit an immune response only when attached to a large carrier such as a protein
--> allergens: type IV delayed (poison ivy) |
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What types of hypersensitivity rxns might be generated by transplant?
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all four are possible
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