[The eosinophil and bronchial asthma].

Eosinophils have been observed in and around the wall of bronchi in bronchial biopsies and in bronchoalveolar lavage fluid from asthmatics. Early studies of eosinophils suggested that they might combat inflammation induced by type I hypersensitivity reaction. However, in the past two decades new information regarding the biology of the eosinophils has been obtained. There is now increasing evidence to suggest that eosinophils may play a key role in asthma by damaging respiratory epithelium, by generating LTC4 and PAF, and by releasing cytokines. This hypothesis is supported by the recent observations of a significant correlation between airway hyperresponsiveness and the magnitude of bronchial eosinophilia, and by the several observations of a coincident occurrence of late asthmatic response and bronchial eosinophilia.