IgE-mediated sensitization to English plantain pollen in seasonal respiratory allergy: identification and partial characterisation of its allergenic components.

Characterisation by SDS-PAGE immunoblotting of plantain pollen extract showed that components of 16,000-20,000 M(r) were frequently reactive with IgE antibody in the sera of subjects with seasonal respiratory allergy. Other, more weakly IgE-binding allergens were seen in the range of 40,000-60,000 M(r). HPLC followed by RAST inhibition demonstrated that components of approximately 17,000 M(r) were also responsible for much of the IgE-binding activity of the extract. These components appeared to have pI values between 4.5 and 5.2. RAST inhibition showed that there were no common IgE-binding epitopes in grass pollen and plantain pollen extracts, indicating that skin test responses should not necessarily be interpreted in terms of cross-reaction. 82 subjects with a clinical history of seasonal, respiratory allergy were screened in a skin prick test survey. 28% were skin test positive to plantain pollen extract. The frequency of positive skin test reactions to plantain pollen extract was greater than that to Betula (23%) and Artemisa (16%), both which are considered to be important allergens. In a larger survey positive RAST scores to plantain pollen were given by 34% of sera from subjects with respiratory allergy. Plantain pollen sensitivity should therefore be considered during diagnosis of seasonal allergy.