Allergic Flashcards
What are the 4 clinical features of bronchial asthma
1) Acute attacks of SOB- acute airway obstruction due to contraction of smooth muscle
2) Mucus hypersecretion
3) Airway inflammation
4) Bronchial hyper-responsiveness
Name some of the common triggers for asthma
- Allergens
- Chemical irritants
- Dust/ smoke
- Post exercise
- Post coughing
- Post hyperinflation
- Viral colds
Name the 2 phases of asthma
1- Bronchospasm/ early phase
2- Inflammation- late phase
What bronchial hyper-responsivness
A state characterised by easy bronchospasm
How is bronchial hyper-responsivess monitored?
- Assessed with bronchial challenge test
- Uses spaspogens such as histamine and metacholine to assess bronchospasm
3 histological changes seen in asthma
- Goblet cell hyperplasia
- Thick sub basement membrane
- Cellular infiltrate
What signals the B cells to switch to produce IgE
First signal: IL-4, IL-13
Second signal: when CD14 on B cells bind to its ligand on T cells
What does IgE bind to when it circulates in the blood?
- High affinity IgE receptors on mast cells (Fc-epsilon-RI)
- Low affinity receptors on lymphocytes, eosinophils, platelets and macrophages
What does the mast cell release once activated
Histamine
Leukotriene
Cytokines
What causes acute obstruction in asthma?
Inhaled allergen
Via histamine and leukotriene
Constrics smooth muscle
Where do eosinophils originate
Bone marrow
What interleukins regulate eosinophils
IL-3, IL-5
What mediates terminal differentiation of eosinophils?
GM-CSF
IL-5
Eosiophils are a rich source of…
Leukotrienes
Which cell contains proteins that damage airway epithelium and increase bronchial hyper responsiveness
Eosinophils
