IgE crossreactivity between mugwort pollen (Artemisia vulgaris) and hazelnut (Abellana nux) in sera from patients with sensitivity to both extracts

Background An association between sensitization to Compositae pollens and hypersensitivity to hazelnut has been previously described. There is no previous in vitro study about crossreactivity between mugwort pollen and hazelnut. Objectives To study mugwort pollen and hazelnut allergens and to assess if there is IgE crossreactivity between mugwort pollen and hazelnut. Methods A serum pool formed by 28 individual sera with specific IgE to mugwort pollen and hazelnut was used to investigate IgE crossreactivity. RAST-inhibition, SDS-PAGE/IEF immunoblotting inhibition assays were performed by preineubation of the sera with mugwort pollen and hazelnut. Results RAST to hazelnut was inhibited up to 63% by mugwort pollen, but the mugwort pollen RAST was only inhibited up to 36% by hazelnut. In SDS-PAGE immunoblotting mugwort pollen showed nine allergens ranging from < 16 to 65kDa and hazelnut had four main allergens: 42kDa, 17kDa and < 16kDa (two bands). In the SDS-PAGE immunoblotting inhibition hazelnut partially inhibited all the mugwort pollen bands, except that with 19kDa, whereas mugwort pollen produced a nearly total inhibition of all the hazelnut allergens. In isoeleetrofocusing immunoblotting mugwort pollen had two groups of allergens: pI 7.5–8.5 and pi 3.5–5.2 and hazelnut one group of allergens: pI 5.2–5.8. In the isoeleetrofocusing immunoblotting inhibition hazelnut produced a partial inhibition of all the bands of mugwort pollen and mugwort pollen partially inhibited all the allergenic bands of hazelnut. Conclusions The RAST and SDS-PAGE/IEF immunoblotting inhibition results provide evidence of IgE cross reactivity between mugwort pollen and hazelnut allergens. The inhibition of hazelnut by mugwort pollen is higher than the inhibition of mugwort pollen by hazelnut in both RAST inhibition and SDS-PAGE immunoblotting inhibition. These results suggest that mugwort pollen allergens would behave as primary immunogens in the association between sensitivity to mugwort pollen and hazelnut.