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Eosinophil activation status and corticosteroid responsiveness in severe asthma
M Bossé1, M Audette, G Laflamme
1Unité de Recherche, Centre de Pneumologie de l'Hôpital Laval, Centre Hospitalier Universitaire de Québec, Université Laval, Ste-Foy, Québec, Canada.
International Archives of Allergy and Immunology
|July 19, 2000
Summary
Eosinophils in severe asthma show altered responses to corticosteroids (CS). CS-dependent asthmatics have impaired eosinophil responses, while CS-resistant asthmatics
Area of Science:
- Respiratory Medicine
- Immunology
Background:
- Eosinophils play a role in asthma pathogenesis.
- Investigating eosinophil activation in severe asthma is crucial for understanding disease mechanisms.
Purpose of the Study:
- To investigate eosinophil activation in severe asthma.
- To compare eosinophil activation in patients with different responses to oral corticosteroids (CS).
Main Methods:
- Studied 26 asthmatic patients categorized into CS-sensitive, CS-resistant, and CS-dependent groups.
- Measured calcium ionophore-induced leukotriene C4 (LTC4) release from purified blood eosinophils.
- Assessed the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on LTC4 release and the impact of CS treatment.
Main Results:
- Eosinophils from CS-dependent asthmatics showed impaired response to CS.
- GM-CSF enhanced LTC4 release, with a higher effect in CS-sensitive subjects.
- Serum from CS-resistant subjects inhibited GM-CSF-induced LTC4 release in CS-sensitive asthmatics.
Conclusions:
- Eosinophils in CS-dependent asthma exhibit reduced responsiveness to corticosteroids.
- Serum from CS-resistant asthmatic patients contains an inhibitor affecting eosinophil response to GM-CSF.