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20 Cards in this Set
- Front
- Back
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What type of hypersensitivity is contact dermatitis? What type of molecule usually causes it?
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Type IV delayed (poison ivy).
Protein w/ hapten |
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Why does type IV take so long?
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B/c the already sensitized Th1 cell has to find its way w/o chemoattractants.
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Mediators of type IV hypersensitivity?
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TH1 and sometimes CD8 CTL
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Mechanism of Type IV
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Allergen w/ hapten taken up by APCs, taken to nodes. TH1 activated. Second exposure, Th1 is circulating and finds allergen, releases pro-inflammatory cytokines.
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How would you involve CD8 cells in type IV?
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Supply a lipid Ag like poison ivy that can get into normal cells and be expressed on MHC1
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Example of type II hypersensitivity?
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X-reactive ab from mycoplasma binding to RBC surface Ag.
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What is the mediator of type II?
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IgM or IgG antibody.
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Example of type III hypersensitivity?
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Serum sickness (administer high dose drug and immune complexes form).
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What is the Arthus reaction?
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It is a type III hypersensitivity reaction to a subQ injection (like allergy test).
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Mediators of type III?
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IgG ab directed at allergen. C3a and C5a anaphylotoxins released.
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Unique thing about type III?
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It causes hemorrhage or petechiae in the skin due to inflammation of bvs.
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Signs of type III hypersensitivity?
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Vasculitis (rash), glomerulonephritis and arthritis.
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Example of type I hypersensitivity?
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Atopic Dermatitis (remember atopy means lots of IgE).
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Mechanism of Atopic Dermatitis?
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Keratinocytes are aggravated by allergen or trauma, release inflammatory cytokines. Th2 attracted to produce IgE.
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Main problem in X-linked agammaglobulinemia? What would you find in this patient's serum?
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The gene coding btk kinase is on X-chromosome. It is required for B cell differentiation.
No IgG, IgA or IgM. Also low B cells. |
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What infections are patient's w/ X-linked agammaglobulinemia susceptible to? What complication results?
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Pyogenic extracellular bacteria
Bronchiectasis from continuous neutrophil infiltration |
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Genetic defect in X-linked SCID? What infections are they predisposed to?
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y chain of IL receptor. Initially thought to be IL-2 problem but really IL-7 problem.
Severe opportunistic infections. |
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Are B cells high or low w/ X-linked SCID?
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Normal but they can't function properly w/o T cell interaction.
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What test is used for assessment of complement MAC system?
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CH50 test (double immunodiffusion).
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What infections are you susceptible to if you have IFN-y deficiency?
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MTB, leishmaniasis, salmonella or anything intracellular. No Th1 response.
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