[Airway provocation test with ragweed pollenosis and late-phase reaction]

Ragweed pollen extract inhalation airway provocation test (APT) were studied in 55 patients with ragweed pollenosis. Single dosage of 9000 PNU ragweed extract was applied and positive response was defined as more than 35% fall in SGrs at the dose of PT35-Grs. Among 55 patients, positive APT was found in 27 case (49%), dual late-pase responses in 11 patients, single late-phase response only was found 2 patients in complicated asthma group. Late-phase response were well related to the increased specific IgE, and strong positive skin test response (wheal greater than 11 mm). The results suggested ragweed pollen was one of the important allergen causing bronchial asthma. There was airway hyperresponsiveness to ragweed pollen in some patients (20%) with ragweed pollenosis without asthmatic symptoms.