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18 Cards in this Set
- Front
- Back
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Hypersensitivity Reaction
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= a pathologic process that results from specific interactions between antigens (exogenous or endogenous) and either humoral antibodies or sensitized lymphocytes.
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Another definition of
Hypersensitivity Reaction |
a condition in which the body’s defenses react with
exaggerated or inappropriate immune response to what is or is erroneously perceived to be a foreign substance, often causing severe inflammation. |
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Gell and Combs Classification
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4 types of hypersensitivity reactions (below).
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TYPE 1 HYPERSENSITIVITY REACTIONS
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(aka IgE–Mediated Reactions, or, Allergy and Anaphylaxis )
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Mast cell degranulation & histamine release
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MAST CELL STABILIZERS
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Actions of histamine
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ANTIHISTAMINES
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Bronchospasm
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BRONCHODILATORS
Beta2 Agonists Anticholinergics |
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Production of Arachidonic acid by Phospholipase A2
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Nasal Steroid
Inhaled Steroid PO steroid |
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Production of Prostaglandins by Cyclooxygenase
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PO NSAIDs
Advil (ibprofen) |
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Actions of Leukotrienes
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Leukotriene Receptor Blockers
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Late Phase Release of cytokines IL-1 ,4, 5, 6 & TNF
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STEROIDS, nasal, inhaled or po
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Anaphylaxis
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Antihistamine (to stop early phase rxn)
Steroid (to block late phase response) Epinephrine (vasoconstriction, heart stimulation, bronchodilation) |
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TYPE 2 HYPERSENSITIVITY REACTIONS
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(ADCC- Ab-dependent T cell-mediated cytotoxicity)
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TYPE 2 HYPERSENSITIVITY REACTIONS
3 types |
1) Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)
2) Complement-Dependent Reactions 3) Antibody-Mediated Cellular Dysfunction |
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TYPE 3 HYPERSENSITIVITY REACTIONS
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aka Immune-Complex-Mediated
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Type 3 musts:
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1) ICs cause activation of complement.
2) Neutrophils and other granulocytes are attracted by both ICs and activated complement… and then the granulocytes themselves become activated / angry. |
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TYPE 4 HYPERSENSITIVITY REACTIONS
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1)Delayed-type Hypersensitivity ( mediated by CD4+ T-lymphocytes)
2)Direct Cell Cytotoxicity ( mediated by CD8+ T-lymphocytes ) |
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Two Examples of Type 4:
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Poison Ivy
Tuberculin Reaction |
