Dw. Lu et al., AIRWAY PROVOCATION TEST WITH RAGWEED POLLEN EXTRACT IN CHINESE ASTHMATICS, Asian Pacific Journal of Allergy and Immunology, 12(2), 1994, pp. 125-129
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.