Pathophysiology of Asthma Flashcards
Which T helper cells are involved with the immune mechanism of asthma?
Th2 - pro-atopic; pro-asthmatic
Which inflammatory cells are most significantly implicated in asthma?
Eosinophils - number of eosinophils correlates with severity of asthma and magnitude of airway hyper-responsiveness
What do the following released by eosinophils do?
Eosinophil cationic protein
Major basic protein
Leukotrienes
Eosinophil cationic protein - epithelial shedding
Major basic protein - epithelial damage, loss of tight junctions, ciliostasis, epithelial Cl- and water secretion
Leukotrienes - Smooth muscle contraction
How are mast cells involved in the pathophysiology of asthma?
Histamine → bronchoconstriction, microvascular leakage, mucus secretion
PDG2, leukotrienes → bronchoconstriction
IL-5 → eosinophilic differentiation
Name a clinical treatment for atopic patients.
Omalizumab - antibody against IgE
What happens in the pathophysiology of early phase allergic asthmatic response?
Wheeze, cough, SOB
IgE cross linking on mast cells
Degranulation
Bronchoconstriction in minutes
What happens in the pathophysiology of the late phase of an allergic asthmatic response?
Bronchodilators do not fully reverse airway obstruction.
Influx of eosinophils, basophils, lymphocytes, macrophages, T cells, dendritic cells
→ mucus production
How does the airway remodel in asthma? (4 marks)
There is a loss of ciliated epithelial cells
Thickening of the basement membrane
Fibroblast/myofibroblast activation → hypertrophy of muscles
Smooth muscle hyper-responsiveness (histamine challenge test, metacholine challenge test)
Name a mast cell stabiliser
Sodium cromoglycate
What does mepolizumab do?
Binds IL-5, main cytokine released by mast cells (act against eosinophil differentiation)
What are leukotriene receptor antagonists specifically helpful for? (ACE)
Aspirin induced asthma
Cold-air induced asthma
Exercise inducsed asthma
Defines asthma COPD syndrome.
Asthma → airway remodelling → asthma COPD syndrome
FEV1/FVC = <0.7
