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17 Cards in this Set
- Front
- Back
What is type 1 hypersensitivity commonly referred to as?
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Type 1 = allergies w/ IgE mediation
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What immunoglobulin mediates Type I Hypersensitivity reactions?
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IgE
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What immunoglobulin mediates Type II, III hypersensitivity?
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IgG
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What immunoglobulin mediates Type IV hypersensitivity?
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snap! no Ig, this is mediated by T cells
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What three cells are the major player in Type I hypersensitivity?
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Mast cells - mucosal & epithelial tissue
Eosinohpils - connective tissue Basophils - circulation |
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What is hypersensitivity?
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excessive immunological sensitivity to non-damaging allergens
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What is the biggest contributor to allergies?
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dust mite feces!
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How to develop allergy sensitization?
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1. initial exposure
2. allergen is presented via APC to T cell 3. IgE is generated as a result 4. IgE binding to Fc(epsilon)RI on mast cells in preparation for second exposure 5. IgE bound mast cell provides IL-4 and CD40L:CD40 co-stimulation for B cells to produce more IgE |
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What happens after sensitization during any subsequent interaction with the allergen?
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1. allergen exposure takes place
2. allergen binds several IgE on mast cell surface (cross-linking) 3. cascade causes granules to be released containing histamine, TNF-alpha, other inflammatory mediators 4. local inflammation occurs which is perceived as an allergic response |
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What are the physical effects of degranulation?
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1. increased fluid secretion and peristalsis of GI tract
2. decreased diameter, increased mucus secretion of airways 3. increased blood flow and permeability of blood vessels |
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What does atopic mean?
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1. you are predisposed to allergies, possibly genetically.
2. ability to quickly produce immediate hypersensitivity reaction by innocuous antigens mediated by IgE |
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What are the phases of an allergic reaction?
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1. immediate - IgE:mast cell degranulation
2. late-phase - release of inflammatory mediators synthesized by mast cells after activation |
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What two routes of allergen entry can cause anaphylaxis systemic immune responses?
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intravenous
ingestion |
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What is allergic asthma?
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a hypersensitivity response that occurs after initial sensitivity that causes:
1. acute inflammation and mast:IgE degranulate to increase mucus secretion, contract smooth muscle, increase permeability 2. chronic response caused by recruitment and degranulation of eosinophils which eventually causes tissue restructuring |
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What is systemic anaphylaxis?
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intravenous hypersensitivity I response where mast cells degranulate systemically which causes a systemic inflammatory response
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Tx for allergies?
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1. behavioral modification to avoid allergen
2. block inflammation caused by allergen 3. induce tolerance by systematically slowly increasing exposure to cause IgE -> IgG4 and Th2 anergy |
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What is the relationship between parasite (helminth) infection and allergies?
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there is a correlation between increase of parasitic infections and decrease in allergies
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