Prevalence of sensitization to weed pollens of Humulus scandens, Artemisia vulgaris , and Ambrosia artemisiifolia in northern China

Objective Weed pollens are common sources of allergens worldwide. The prevalence of weed pollen sensitization is not yet fully known in China. The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia, Ambrosia , and Humulus in northern China. Methods A total of 1 144 subjects (aged from 5 to 68 years) visiting our clinic from June to October 2011 underwent intradermal testing using a panel of 25 allergen sources. Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris, Ambrosia artemisiifolia , and Humulus scandens , and against the purified allergens, Art v 1 and Amb a 1. Results Of 1 144 subjects, 170 had positive intradermal reactions to pollen and 144 donated serum for IgE testing. The prevalence of positive intradermal responses to pollens of Artemisia sieversiana, Artemisia annua, A. artemisiifolia , and H. scandens was 11.0%, 10.2%, 3.7%, and 6.6%, respectively. Among the intradermal positive subjects, the prevalence of specific IgE antigens to A. vulgaris was 58.3%, to A. artemisiifolia 14.7%, and to H. scandens 41.0%. The prevalence of specific IgE antigens to the allergen Art v 1 was 46.9%, and to Amb a 1 was 11.2%. The correlation between the presence of IgE antibodies specific to A. vulgaris and to the Art v 1 antigen was very high. Subjects with A. artemisiifolia specific IgE also had A. vulgaris specific IgE, but with relatively high levels of A. vulgaris IgE antibodies. There were no correlations between the presence of IgE antibodies to H. scandens and A. vulgaris or to H. scandens and A. artemisiifolia . Conclusions The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about 13.5%. Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization.