Type I, II, III Hypersensitivity Flashcards
Some inflammatory molecules released by mast cells:
Cytokines: IL-4, IL-13 (stimulate Th2); IL-3, IL-5, GM-CSF (promote eosinophils)
Chemokines: CCL3 (chemotactic for monocytes, macrophages, neutrophils)
Treatment for hay fever?
H1 antagonists (inhibit histamine to H1 receptors)
- Benadryl crosses BBB
- Claritin doesn’t
Where are H1 receptors?
- endothelial cells
- smooth muscle cells
- nerve cells (CNS)
- hematopoietic cells
What does histamine do?
- toxic to parasites
- increase vascular permeability
- smooth muscle contraction
What do leukotrienes do?
- smooth muscle contraction
- increase vascular permeability
- mucus secretion
Aspirin blocks…
Cyclooxygenase pathway (convert Arachidonic acid to prostaglandin)
Montelukast (Singulair) blocks…
Leukotriene binding to receptor (LTC4 is important mediator for allergies)
Basophils secrete:
IL-4 and IL-13, and therefore have a role in Th2 differentiation and response
Eosinophil production in the bone marrow is stimulated by:
IL-5
Degranulation of eosinophils induced by…
eotaxin, C5a, antigens (via IgE)
Toxic to cells and parasites
Eosinophils secrete:
- Eosinophil cationic protein (a neurotoxin; preformed granule)
- IL-3, IL-5, GM-CSF (amplify eosinophil production and activation)
- CXCL8 (promote influx of leukocytes)
- Leukotrienes C4, D4, E4
What is atopy?
Genetic predisposition to allergies
Allergic reaction sensitization:
Allergic reaction Effector phase:
- produce Th2, IgE
- binding to mast cells and basophils
- Acute: mast cell/basophil degranulation
- Late phase: eosinophils, Th2 cells
Treatment of anaphylactic shock?
Epinephrine: increase HR/BP, bronchodilation
Drugs to treat allergic reactions:
- Inhibit inflammation [corticosteroids, anti-LTC4-R/Montelukast, Chromolyn sodium (prevent mast cell degranulation)]
- Bronchodilators
- Antihistamines
- Anti-IgE (omalizumab or Xolair) - decrease effects of antibody
