[An increase of nonspecific airway hyperreactivity after repeated challenge with subthreshold doses of allergen in asthma patients].

The study was performed in 11 patients suffering from stable mild and moderate atopic asthma. Bronchial allergen challenges were performed according to Chai et al method. Airway hyperreactivity-AH (PC20H in mg/ml) was determined in each study day before subthreshold allergen inhalation dose, meaning the dose which did not induce asthmatic responses. Then FEV1 was measured in 2, 5, 15, 30 i 60 min. after allergen provocation throughout 4 to 9 consecutive days. A significant increase of PC20H was observed in 8 patients (xg PC20H in whole group decreased from 0.93 to 0.35 mg/ml after allergen challenges). The authors conclude that allergen inhalation challenge without asthmatic bronchial responses can cause an increase AH.