AIRWAY PROVOCATION TEST WITH RAGWEED POLLEN EXTRACT IN CHINESE ASTHMATICS

As ragweed becomes widespread over China, ragweed pollenosis tends to be more frequent. Incidence of ragweed pollenosis is about 1.04% in Qi ngdao district. To elucidate ragweed as an allergen in the development of bronchial asthma, ragweed pollen extract inhalation airway provoca tion tests (APT) were studied in 55 patients with ragweed pollenosis. A single dosage of 9,000 PNU ragweed pollen extract was applied and po sitive response was defined as more than 35% fall in SGrs at the dose of PT35-Grs. Among 55 patients, positive APTs were found in 27 cases ( 49%), dual late-phase responses in 11 patients, single late-phase resp onses in 2 patients in the complicated asthma group. Late-phase respon ses were related to the increased specific IgE and strong positive ski n test response (wheal>11mm). The results suggested ragweed pollen was one of the important allergens causing bronchial asthma. There was ai rway hyperresponsiveness to ragweed pollen in some patients (20%) with ragweed pollenosis without asthmatic symptoms.