Hypersensitivity and Allergy Flashcards
What is Type 1 Hypersensitivity?
Allergy (environmental non-infectious antigens)
What is the time period for the immediate reaction in Type 1 hypersensitivity?
Less than 30 minutes
What is the Sensitisation in Type 1 Hypersensitivity?
First encounter with the antigen resulting in activation of APC and Memory effector cells
What is are the overlying mechanism involved in Type 1 Hypersensitivity?
- Adaptive response
- Mast cell activation
What is involved in the adaptive response of Type 1 Hypersensitivity?
- Abnormal TH2 Cell Response
- IgE production
Where are Mast Cell found?
- Mucosal tissue
- Epithelial tissue
- Connective Tissue surrounding blood vessels
What happens in the second exposure to the allergen?
Allergen-IgE cross linking occurs.
This leads to Mast Cell Degranulation
What happens in the first exposure response?
TH2 response leading to
- Activation of APC
- Memory Effector Cells
What are the mediators release as a result of Mast Cell activation?
- Histamine
- Leukotriene C4, D4, E4
- Tryptase
- Platelet Activating Factor
What causes Uriticaria?
Mast cell activation in Epidermis
Release of
- Histamine
- Leukotrienes
What can Urticaria lead to if there is prolonged and chronic exposure to allergen?
- Atopic Dermatitis
- Eczema
What causes Angioedema?
Mast Cell Activation in Deep Dermis
Release of
- Histamine
- Bradykinin
Where does Angioedema affect?
- Lip
- Eyes
- Tongue
- Upper Respiratory Airways
What is used to give symptomatic relief of Allergy?
Anti-histamines
Corticosteroids
Leukotriene Receptor Antagonists
How is Desensitization therapy administered to patients?
- Anti-IgE monoclonal antibody
- Oral immunotherapy targeting: Shift from TH2 to TH1, Inhibitory anti-inflammatory cytokines, CD4+CD25 Regulatory T cells, Allergen specific blocking IgG
