Background: Despite the benefits of specific immunotherapy (SIT) being clinically well documented for allergic diseases, new IgE specificities to SIT extract allergens could be induced during the treatment. The authors evaluated these changes in patients allergic to Hymenoptera.
Methods: Six patients allergic to Hymenoptera venom were included in the study. Specific IgE (sIgE) levels determination and IgE immunoblots to Apis mellifera, Vespula spp. and Polistes spp. venom were performed before and after one year of SIT.
Results: All patients had sIgE levels reduction, after the first year of treatment, except one in whom there was an increase in sIgE levels to Apis mellifera venom, and two patients that maintained a similar value for Vespula spp. venom sIgE before and after one year of treatment. The immunoblot analysis revealed that most of the bands detected before beginning SIT, decreased in intensity or disappeared after one year of treatment. 3/6 patients developed new IgE specificities to venom extracts: one patient to the venom allergens in the treatment, other patient to allergens in other venom and another patient to both. After one year of treatment one of these patients tolerated a field sting by the corresponding insect. The newly recognised proteins were all minor allergens.
Conclusion: These results confirm that sIgE levels tend to reduce during SIT, and the bands identifying some allergens in the blot tend to decrease or disappear. Nonetheless venom SIT can be responsible for the induction of new sensitisations to other venom allergens, apparently without clinical relevance.