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12 Cards in this Set
- Front
- Back
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What are type 3 hypersensitivity reactions also known as?
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Immune complex hypersensitivity
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In type 3 reaction, formation of large antigen-antibody immune complexes deposit into tissues and fix complement. How does activation of complement result in tissue damage. How does this differ in type 2?
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Complement activation recruits neutrophils, which release proteolytic enzymes and cause tissue damage.
This differs from type two hypersensitivity in which tissue damage is caused by autoantibody mediated complement activation(not by formation of large immune complexes). |
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One important factor that determines if antigen antibody complexes deposit into tissue is the relative amount of antigen vs antibody. Why do antigen predominant complexes typically form pathogenic deposits?
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Antigen-antibody complexes are cleared when mononuclear phagocytes bind to antibody resulting in endocytosis of the complex. In antigen predominant complexes, fewer antibodies means less clearance and a propensity to form pathogenic deposits.
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What is a pathology term used to describe type 111 inflammation in vessels?
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Fibrinoid necrosis(eosinophilic staining accumulation)
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What are the 2 typical type 111 hypersensitivity reactions?
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Arthus reaction: local deposition of immune complexes
Serum sickness: systemic inflammatory response to immune complexes deposits throughout the body. |
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Describe how anArthus reaction is evoked?
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Antigen is subcutaneously injected into a host with preformed antibodies to this antigen causing localedema and possible ulceration.
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Hypersensitivity pneumonitis(farmer lung) is an Arthus reaction caused by inhalation of what bacteria?
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Thermophilic actinomycetes
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What is the typical clinical presentation of serum sickness?
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Fever, hives, arthralgia, lymphadenopathy, splenomegaly and eosinophilia appear days to weeks after antigen exposure.
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What is the typical clinical presentation of serum sickness?
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Fever, hives, arthralgia, lymphadenopathy, splenomegaly and eosinophilia appear days to weeks after antigen exposure.
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What drug is associated with serum sickness?
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Penicillin. Note that penicillin can cause types, !, 11, and 111 via hapten formation.
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What drug is associated with serum sickness?
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Penicillin. Note that penicillin can cause types, !, 11, and 111 via hapten formation.
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What are well known diseases that result because of type 111 immune complex deposition?
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Poststreptococcal glomerulonephritis, rheumatoid arthritis, and systemic lupus erythematosus.
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