Ovalbumin in breast milk is associated with a decreased risk of IgE-mediated egg allergy in children

Verhasselt et al., 6 December 2019, The European Journal of Allergy and Clinical Immunology

LETTER TO THE EDITOR

There is an urgent need to delineate early-life factors protecting against food allergy, a rising epidemic affecting up to 10% of children. Prevention strategies now include early introduction of egg and pea-nut into infant diet to induce oral tolerance. However, recent studies demonstrate a significant proportion of infants already have egg sensitisation and clinical reactivity (including anaphylaxis) at 4-6 months of age prior to the first introduction of egg in their solid food diet. This underscores the necessity to identify earlier and safer ways to promote oral tolerance development to food allergens in young infants.

In seminal studies, we demonstrated that the presence of hen's egg-derived allergen ovalbumin (OVA) in breast milk induces oral tolerance and prevents allergic reactions in mice. Here, we addressed whether human data support this observation in a study of 88 breastfed infants at high risk for allergy, who were control participants of a larger double-blind randomized controlled trial (RCT), the Infant Fish Oil Supplementation Study (www.anzctr.org.au; ACTRN12606000281594), where all the mothers are allergic.

Breast milk samples were collected at 3 months (122 samples) and/or at 6 months (102 samples) of lactation, and aliquots  were  stored  at  −80°  prior  to  analysis. OVA levels were determined by ELISA4 (level of detection 50 pg/mL). IgE-mediated egg allergy was defined by a paediatric immunologist on the basis of a questionnaire capturing history of immediate symptoms following ingestion of egg in any  form  and a positive skin prick test (≥3 mm) to egg white. Statistical analyses were performed with SAS 9.4 (The SAS Institute) and GraphPad Prism 6 (GraphPad Software).

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