Hymenoptera-venom allergy, outcomes of immunotherapy and peripheral blood mast cell biomarkers in a non-European Mediterranean cohort

Abstract

RATIONALE: Insects are increasingly used as nutrient source for people and animals. As they are considered as ''novel food'', several safety aspects need to be evaluated initially, including the risk of allergenicity. METHODS: IgE from patients allergic to crustaceans, house dust mite (HDM) and/or stable flies was evaluated for cross-recognition of proteins in house cricket Acheta domesticus (AD), desert locust Schistocerca gregaria (SG) and Yellow mealworm Tenebrio molitor (TM). For food processing, different extraction methods, enzymatic hydrolysis, and thermal treatment were applied to migratory locust (Locusta migratoria, LM) extract. Then we proceeded with in vivo testing of crustacean allergic subjects. Crude, enzymatically processed and heat-treated extracts of LM were tested in skin prick test (SPT) in patients with clinical crustacean allergy, first as diluted extracts (1:10 v/v in glycerin 50%) followed by SPT with concentrates. Ditto SPT were performed with centrifuged TM (no enzymes). RESULTS: IgE from patients with crustacean-allergy shows crossrecognition of extracts from AD, SG and stable flies; house dust mite allergics' IgE binds to AD and SG proteins; and the flies-allergic patient recognized AD, SG and LM. Food processing such as enzymatic hydrolysis or heat treatment of LM extract not only completely abolished in vitro-binding of cross-reactive IgE, but also its IgE crosslinking capacity in in vivoskin prick tests. However, centrifugation of TM did not reduce SPT reactivity. CONCLUSIONS: This study provides evidence that enzymatic and thermal processing of insects can reduce the risk of these novel foods to elicit cross-reactivity and allergenicity in crustacean-and HDM-allergic patients.