METHODS: Patients (n=109) presenting to the University of North Carolina allergy clinic with possible alpha-gal allergy were interviewed regarding reactions to stinging insects. Sera were later assayed for sIgE to alpha-gal and mammalian allergens as well as venoms (honey bee, white-faced hornet, common wasp, paper wasp and fire ant) using Phadia ImmunoCAP platform. Control subjects (n=26) were also enrolled for comparison.
RESULTS: Subjects with alpha-gal allergy reported a higher rate non-local reactions following insect sting and were 5 times more likely to be sensitized (>0.35) to any of five venom allergens compared to controls (Chi-square prob=0.0244). Among alpha-gal allergic subjects sensitization to common wasp was most frequent (30.3%), whereas among controls it was fire ant (15.4%). Notably, having alpha-gal allergy was associated with a 3.6-fold increased risk of sensitization to multiple venom sIgE (95% CI 1.02-12.78) compared to controls. Total IgE was not different between the groups.
CONCLUSIONS: Development of IgE following ecto-parasitic tick bites and stinging insect envenomations may have a shared immunologic determinant or predisposition, other than just atopy. Given that both conditions are influenced by environmental exposures, ongoing climate change is likely to make these allergic conditions more common.