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16 Cards in this Set
- Front
- Back
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hypersensitivity triggered by IgE bound to mast cells
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Type 1
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hypersensitivity mediated by Ab against fixed cellular or tissue antigens
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Type 2
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hypersensitivity mediated by deposition of immune complexes [Ab and its antigen[ on tissue leading to compliment fixation and inflammation
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type 3
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hypersensitivity mediated by cellular immune response without involvement of Ab
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Type 4
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when does Desensitization occur
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allergen now produces IgG which replaces IgE on mast cells and prevents Type 1 reactions
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How does a mast cell activate during Type I?
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allergen cross links IgE on surface of mast cell
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How does Sensitization occur in Type I?
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allergen presented by Macrophage to CD4Th2 cell
Tcell produces IL4 and IL5 IL4=plasma cell switch from IgM to IgE synthesis IL5=increases production of eosionophils |
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What type of Hypersensitivity?
Atopy = hay fever, eczema, hives, asthma, bee sting ANaphylaxis = generalized ultiorgan dysfunction (bronchospasm and hypotension) drug hypersensitivity |
Type I
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4 Types of Complement dependent reactions in Type II hypersensitivity
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cell lysis by IgM antibody
tissue damage by IgG Ab - calls in C5a Phagocytosis - IgG and C3b COmplement independent reactions -Anti-cell receptor IgG Ab --may inhibit or stimulate receptor sites (myasthenia gravis or hyperthyroidism) |
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Type III hypersensitivity Mechanisms
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exposure to antigen leads to Ab and continued ere-exposure elevates antigen-Ab complexes
1. cause vascular permeability from MAC 2. produces C5a to attract Neutrophils which damage tissue in area of deposition |
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Type IV hypersensitivity
what are the 2 different types? |
CD4 lymphocytes or Th1 cells
CD8 lymphocytes - cell-mediated cytoxicity |
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Type IV hypersensitivity - CD4 lymp/Th1 cells
--delayed hypersensitivity reaction --Direct damage |
CD4 lympho interact with Macrophag to cause
-caseous necrosis of TB -demyelination of MS Activated CD4 lympho produce cytokines which generate inflammation / fibrosis ex: Scleroderma |
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Type IV hypersensitivity - CD8 lympho/cell-mediated cytoxicity
-CD8 T cells -Contact dermatitis |
CD8 T-cells interact with altered MHC I antigens on normal own cells or neoplastic, viral, or donor cells causing cell injury
(ex: POLYMYOSITIS) CD8 T cells attack Antigens (or altered neoantigens from chemical damage) in skin (ex: POISON IVY and NICKEL EXPOSURE) |
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Anti-DNA complexes in systemic Lupus Erythematosis damage kidney, skin, joints
this is an example of what type of hypersensitivity? |
Type III
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Glomerular damage in glomerulonephritis after streptococcal infection
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Type III hypersensitivity
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SLE causes Anemia, neutropenia and thrombocytopenia from what hypersensitivity reaction?
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Type II
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