[Histopathological changes and hyperresponsiveness in asthmatic airways: relationship to peak expiratory flow]

The application of bronchial biopsies in asthma has shown that even in daily asthma there is evidence of airway inflammation. These include inflammatory cells, mainly eosinophil, infiltration, epithelium damage, thickening of basement membrane and bronchial smooth muscle hypertrophy. Furthermore, there is increasing evidence that these inflammatory changes are associated with airway hyperresponsiveness, airflow limitation and respiratory symptoms. Our biopsy data also showed that the degree of eosinophil infiltration in the bronchial mucosa and the thickness of basement membrane significantly correlated with non-specific airway responsiveness. In addition, changes in PEF value over a period of 10 weeks in a patient with asthma, coincided well with those in sputum eosinophil count and sputum eosinophil cationic protein (ECP) level determined during the same period. These findings suggest that non-specific airway responsiveness and PEF may reflect the inflammatory status of the bronchi in asthmatics.