Cross-allergenicity of pollens from the Compositae family: Artemisia vulgaris, Dendranthema grandiflorum, and Taraxacum officinale.

Background: Chrysanthemum, dandelion, and mugwort belong to the Compositae (Asteraceae) family. Their cross-allergenicity has not yet been completely evaluated.

Objective: To investigate the sensitization and cross-allergenicity of these 3 plants.

Methods: We reviewed 6,497 respiratory allergic patients who underwent skin prick tests (SPTs) during the last 10 years (1995-2005) and analyzed the sensitization rates of the 3 pollens. We sorted this population by wheal size and selected the monosensitized or cosensitized patients. Their serum samples were used to evaluate specific IgE (sIgE) and cross-allergenicity of the 3 pollens by CAP, immunoblotting, and inhibition enzyme-linked immunosorbent assay (ELISA).

Results: On SPTs, mugwort, chrysanthemum, and dandelion sensitized 13.4%, 10.0%, and 8.5% of the enrolled population, respectively, and 5.2% of the population was cosensitized to all 3 pollens. Some patients were monosensitized to 1 species (1.5% to chrysanthemum, 1.4% to dandelion, and 4.5% to mugwort). In inhibition ELISA that used a pooled serum sample cosensitized to all 3 pollens, mugwort inhibited sIgE bindings to chrysanthemum, dandelion, and mugwort up to 95%, 86%, and 96%, respectively. The 50% inhibitory allergen concentrations for sIgE to each of the 3 species were not different between solid-phase antigen and mugwort. The mugwort sIgE of this pooled serum was suppressed up to 74% and 27% by chrysanthemum and dandelion, respectively. The 50% inhibitory allergen concentrations of chrysanthemum and dandelion for mugwort sIgE were 0.3 and 57.0 microg/mL, respectively, whereas that of mugwort was 0.05 microg/mL. We found a patient who was truly monosensitized to dandelion.

Conclusion: Chrysanthemum and dandelion were frequently cosensitized with mugwort in the general population with respiratory allergic diseases. These 2 species also showed extensive cross-allergenicity with mugwort. True monosensitization to these 2 species was possible.