Early oral exposure to house dust mite allergen through breast milk: A potential risk factor for allergic sensitization and respiratory allergies in children

In recent years, the concept has emerged that early oral exposure to food antigens may be necessary for immune tolerance induction and long-term prevention of inappropriate immune reactions to food and this concept has been tested in recent interventional trials with some promising results.3,4 Clinical trials have recently showed that introducing solid food while continuing to breast-feed may enhance chances of tolerance induction and prevent food allergy.5 We further proposed that oral exposure to aeroallergens through breast milk may affect the risk to develop respiratory allergies.6 Recently, we demonstrated the presence of respiratory allergens from Der p and Blomia tropicalis HDM in human breast milk.7,8 This surprising observation may be explained by the fact that Der p particules are ingested after lung mucociliary clearance of inhaled Der p particules and from food contaminated with dust2; Der p particules would then follow the same route as dietary antigens to maternal milk.7Der p 1 in maternal milk was found in similar quantities as dietary egg antigen ovalbumin and to be immunoreactive.7 In a mouse model, we found that Der p in breast milk promoted subsequent allergic sensitization in the progeny.7 In the present study, our main objective was to assess whether early exposure to Der p 1 transferred from the mother to the newborn through breast milk would affect child's subsequent development of allergic sensitization, asthma, and allergic rhinitis in the first 5 years of life, using prospective population-based data from the French Etude des Déterminants pré et post-natal du development et de la santé de l'Enfant birth cohort (http://eden.vjf.inserm.fr) (for mother-children pairs characteristics, see Tables E1-E3 in this article's Online Repository at www.jacionline.org).