What else can result when hypersensitivity happens
inflammatory reactions, tissue damage
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what is each type of hypersensitivity mediated by
type I,II,III= antibody mediated. type IV= mediated by T cells and macrophages
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what type of antibody is involved in. Type I hypersensitivity and what does it interact with
IgE. pollen, house dust, certain food etc-innocuous environmental antigens
4 of 20
what happens after IgE responds to antigen
IgE binds to FceRI on mast cells. second encounter with allergen triggers release of inflammatory mediators. produces acute inflammatory Reaction with symptoms such as asthma and rhinitis
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What are the treatments for mild type I hypersensitivity
what are the symptoms of anaphylactic shock and how this be treated with
wheeze, swelling of face. and laryngopharynx, nausea, dizziness, fainting, low blood pressure. can be. treated with adrenaline
8 of 20
what is type II hypersensitivity? when does it occur
antibody-dependent cytotoxic hypersensitivity. occurs in 12-18 hours of exposure to antigen. IgG and IgM bind to a self antigen or a foreign antigen on cells. then phagocytosis, killer cell activity or complement mediated lysis
9 of 20
give some examples of type II reactions
1. blood transfusion reactions when ABO incompatible blood is transferred. 2. Haemolytic disease of the newborn
10 of 20
what results in haemolytic disease of the newborn
incompatibility of Rhesus D blood antigens to RhD-negative mother
11 of 20
what are some symptoms of haemolytic disease of the newborn
Swollen abdomen from enlargement of liver and spleen due to RBC destruction Elevated bilirubin = product of haemoglobin breakdown Facial petechia = haemorrhage due to platelet damage
12 of 20
when does Type III hypersensitivity occur? and what is IC clearance influenced by
18-24 hours.1. Route of Ag exposure eg poor clearance in lung 2. Dose of Ag 3. Size of IC (larger IC fall out of circulation) 4. Binding of Ag directly to tissues
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what are the 3 types of type IV hypersensitivity and when do they occur
contact 48-72 hours tuberculin 48-72 hours .granulomatous 21-28 days
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what is the sensitisation phase of type IV hypersensitivity
Sensitisation : Ag encountered by dendritic cell in skin . Migrates to lymph node. Presents Ag to CD4+ T cell
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what is the elicitation phase of type IV hypersensitivity
Ag subsequently encountered Memory T cells are triggered Inflammation
16 of 20
what dental materials can cause hypersensitivity
Amalgam alloy Gold Mercury Resin-based materials
17 of 20
describe granulomatous
Granuloma formation - aggregation and proliferation of macrophages persisting for weeks
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describe tuberculin
Skin swelling develops after intradermal exposure. Originally seen following injection of tuberculin bacilli
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describe contact
Eczematous reaction at point of contact with Ag.Common with nickel, chromate, pentadecacatechol (in poison ivy)
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Other cards in this set
Card 2
Front
What else can result when hypersensitivity happens
Back
inflammatory reactions, tissue damage
Card 3
Front
what is each type of hypersensitivity mediated by
Back
Card 4
Front
what type of antibody is involved in. Type I hypersensitivity and what does it interact with
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