Expression of the high-affinity receptor for IgE on bronchial epithelial cells of asthmatics.

Bronchial epithelial cells are the first cells to come into contact with inhaled pneumoallergens. It has been suggested that these cells may play an important role in the allergic response, and indeed bronchial epithelial cells of some atopic asthmatic subjects have been shown to express the low-affinity receptor for IgE on their surface. In this report we demonstrate, using bronchial biopsies, that bronchial epithelial cells of some asthmatic subjects express both the alpha and gamma chains of the high-affinity receptor for IgE (Fc epsilon RI) on their surface and that they are capable of fixing IgE. Second, using reverse transcription-polymerase chain reaction, we show that both control and asthmatic subjects have messenger RNA for Fc epsilon RI. Finally, we demonstrate that this receptor may be functional since stimulation of the cells with the antibody to the alpha chain of Fc epsilon RI results in the liberation of 15-hydroxyeicosatetraenoic acid from epithelial cells of asthmatic, but not control, subjects or subjects suffering from chronic bronchitis. These data suggest that bronchial epithelial cells from at least some asthmatic subjects express a functional high-affinity receptor for IgE and it is therefore possible that these cells may be able to interact directly with inhaled allergens.