Mugwort (Artemisia vulgaris) represents an important source of weed pollen allergens. The objectives of the present study were (i) to analyze the IgE binding profiles in a group of mugwort-allergic patients, (ii) to identify individual marker allergens crucial for the diagnosis of mugwort allergy and (iii) to identify potential crossreactive allergens present in ragweed (Ambrosia artemisiifolia) pollen extract.
Sera from 100 pediatric mugwort-allergic patients were analyzed for their IgE binding pattern to natural mugwort and ragweed pollen proteins, purified natural and recombinant Art v 1, recombinant Art v 4 and recombinant Amb a 1 using immunoblots and ELISA.
91% of the patients' sera tested displayed IgE binding to one or more mugwort pollen allergens in ELISA and 88% were positive in immunoblot. Purified natural Art v 1 was recognized by 79%, the recombinant protein by 39% of the patients tested and purified recombinant Art v 4 by 34% of the patients' sera. 67% of the sera displayed crossreactive IgE to one or more ragweed pollen allergens. Recombinant Amb a 1 was noted in only 14% of the mugwort-allergic sera.
Allergen-specific in vitro diagnosis was performed in 100 pediatric mugwort-allergic serum samples. Using two allergens (Art v 1 and Art v 4), 91% of the patients could be identified as mugwort pollen-sensitized patients by IgE in vitro tests. Crossreactivity to ragweed pollen allergens was demonstrated by in vitro experiments, suggesting a new important and potent allergen source expanding across Europe.