[Effects of latency time on the type of bronchial response in specific provocation tests]

21 asthmatic patients with atopic asthma were studied. Their clinical history, skin tests and bronchial reactivity suggest the responsibility of an allergen (mites). Carbachol induced bronchospasm in all patients after doses varying from 100 to 1000 micrograms. The bronchial response was determined 10-60 min after mite challenge using the following parameters: lung volume, forced expiratory flow, total lung resistance and elastic properties. The measurements were performed using an open whole-body plethysmograph. 14 patients had an early bronchospasm (from 10 to 15 min after the mite challenge), the others had a late reaction (from 20 to 60 min after the mite challenge). The early responses were principally characterized by an increase in pulmonary resistance, suggesting proximal bronchoconstriction. The late reactions were characterized by a decrease in MMEF without a notable increase in pulmonary resistance. These differences between bronchial responses are due to a number of modifications in lung elastic properties. Initial obstruction or intercurrent bronchial infections seem to have no effect on the bronchial reaction in these patients.