THE ROLE OF EOSINOPHILS IN THE PATHOGENESIS OF ASTHMA

The characteristic pathological features of asthma include deposition of sub-basement membrane collagen, epithelial desquamation, smooth muscle hypertrophy, mucus gland hyperplasia, the presence of mucus plugs and edema of the submucosa with leukocyte infiltration. Recent investigations using fiberoptic bronchoscopy with lavage (BAL) and endobronchial biopsy have demonstrated inflammation characterized by infiltration of eosinophils and activation of mast cells, lymphocytes and macrophages. Earlier studies have shown that these changes occur in fatal asthma, in mild to moderate asthma and after allergen challenge. In a recent study, Laitinen et al. [1] showed an airway inflammatory process in patients with newly diagnosed asthma who had not received medication, providing further evidence for chronic inflammation in asthmatic airways and its role in the pathogenesis of asthma.