[Ultrastructure of bronchial biopsies obtained by fibroscopy during a remission between crises in asthmatic adults]

This study describes the ultrastructure of bronchial biopsies from ten patients with bronchial asthma in remission. The superficial submucosa was the seat of a cellular infiltration: the plasma-cells are the most numerous. Light microscopy shows thickening of bronchial basement membrane. By electron microscopy, the basement membrane appears intact and the thickness consists of collagen fibrils in plexiform arrangement. The epithelium shows goblet cells and basal cells hyperplasia and lesions of the ciliated cells. The defects in the ciliary ultrastructure are: compound cilia, abnormal cilia and internalized cilia. They can be regarded as non specific lesions. Two types of cells infrequent in the bronchial mucosa are found: one characterized by apparition of a dictyosome with mucous secretion; the second by defects of the cellular membrane and little electron dense cytoplasm. These two types of cells show a "mitochondrial barrier" like the ciliated cells. This study reveals that numerous lesions are seen in the bronchial mucosal of patients with severe asthma even in remission.