Maternal transfer of the most potent peanut allergen Ara h 2 into human breast milk in a German cohort

摘要

BackgroundPeanut allergy is known to be one of the most severe foodallergies. The aim of our breast milk study was to investigatethe transfer of the most potent peanut allergen Ara h2 into human breast milk in a German cohort. Therefore,the time courses of appearance after ingestion, the potentialrisk of sensitization to peanuts via breast milk inGermany and, if possible, the way Ara h 2 will be processedin vivo after secretion into breast milk was studied.MethodsOf 32 lacating, non-peanut allergic women, breast milksamples were collected at different time points afteringestion of 100 g dry roasted peanuts (approved by thelocal ethics committee). Breast milk samples were analysedfor peanut protein in SDS-PAGE, Western blotand ELISA (Neogen Veratox ELISA? and an ELISAagainst digestion resistant Ara h 2 (DRP-Ara h 2)).Natural Ara h 2 was digested by Enzynorm f? andKreon? to mimic the effect of the combined gastric andduodenal digestion in vivo and, subsequently, analysedby N-terminal sequencing and MALDI TOF MS.ResultsAra h 2 was undetectable using Western blot. Performingthe Neogen Veratox ELISA? against crude peanutextract peanut proteins still remained undetectable.However, Ara h 2 was identified by an ELISA againstDRP-Ara h 2 in 8/32 women (25 %) at different concentrationsand time points of appearance. To assess theway Ara h 2 is processed in vivo, natural Ara h 2 wasdigested into several digestion resistant immunoreactivepeptides <15 kDa after treatment with Enzynorm f?and Kreon?, and a 12 kDa fragment was identified byN-terminal sequencing and mass spectrometry correspondingto the middle part of Ara h 2.ConclusionsAfter maternal ingestion Ara h 2 is secreted into breastmilk in our German cohort in 25 % of the volunteers,individually either rapidly (after 1h, 2h or 4 h) or delayed(after 8h or 12h) and in different concentrations. Tostudy Ara h 2 or Ara h 2 peptides that survive digestionand pass into human breast milk antibodies against the12 kDa fragment are now raised for enrichment strategiesto characterize these sensitizing or tolerogenic peanutstructures in our breast milk samples.