Type I Hypersensitivity Flashcards
Type I Hypersensitivity is also known as -?
Allergy, or Atopy
What is the mechanism for allergic or atopic reactions?
- First exposure leads to an exaggerated Th2 response
- Overproduction of IL-4
- Excessive production of IgE
- IgE binds to Mast cells
- In the second exposure, the allergen binds to Mast cells
- Activation and degranulation of Mast cells occurs
How does IL-4 lead to the overproduction of IgE?
IL-4 is associated with sotype switching, toward IgE, on B cells
IgE will bind to what receptor along Mast cells?
Fc epsilon RI
If Mast cells secrete substances such as vasoactive amines and lipid mediators, what will occur?
An immediate hypersensitivity reaction, minutes after seconary exposure to an antigen
If Mast cells secrete cytokines, what will occur?
A late phase reaction
The Fc epsilon RI receptor has what characteristics associated with it?
- High affinity
- Nearly irreversible
- Found in 2 forms
- Found on Mast cells, Neutrophils, Eosinophils, Basophils (granulocytes)
IL-33 serves a key role in __________, by promoting Th2 cells responses, and also inducing ______ _______ ____________ in the presence of IgE.
Inflammation
Mast cell degranulation
What cytokines produced by Th2 cells is a potent pruritogenic cytokine, inducing scratching behaviors and atopic dermatitis-like skin lesions?
IL-31
True or False: Food intolerance is not associated with immune-mediated reactions of the digesta.
True
What diagnostic tests can be done to determine for Type I Hypersensitivity?
- Intradermal testing - #1 choice
- PCA, or Passive Cutaneous Anaphylaxis
- ELISA or Western Blot for IgE measurement in blood
