Term
| Type 1 Hypersensitivity (cause, examples) |
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Definition
CAUSE : preformed IgE binds free antigen triggers histamine release from mast cells
EXAMPLE: anaphylaxis, test via scratch test |
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Term
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Definition
CAUSE: IgM and IgG - bind antigen and lead to lysis or phagocytosis.
EXAMPLE: hyperacute organ rejection, direct and indirect COOMBs test (test for antibodies to RBCs) |
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Term
| Type III Hypersensitivity (remember type 3 has 3 types of reactions) |
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Definition
CAUSE: immune complexes... - involve antigen + antibody (IgG) and complement fixation.
1) Immune complex (antigen + IgG antibody + complement) - attract neutrophils which release lysosomal enzymes
2) Serum Sickness: antibodies to foreign proteins are produced - takes about 5 days. Most is caused by drugs.
3) Arthus reaction: local subacute reaction where complexes form in the skin --> edema, necrosis, and complement activation |
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Term
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Definition
T cell mediated (all other types 1-3 are antibody mediated)
Tcells encounter the antigen and activate macrophages,
4T's"
1) Tcell mediated
2) Transplant rejection (chronic and irreversible)
3) TB skin tests
4) Touching (cause of contact dermatitis) |
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Term
| Pneumonic for 4 types of Hypersensitivty |
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Definition
ACID
A (type 1) = Anaphylactic and Atopic
C (type 2) = Cytotoxic (antibody mediated)
I (type 3) = immune complex mediated
D (type 4) = Delayed (T cell mediated) |
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