Presence of functional, autoreactive human milk-specific IgE in infants with cow's milk allergy
Article first published online: 21 SEP 2011
© 2011 Blackwell Publishing Ltd
Clinical & Experimental Allergy
Volume 42, Issue 2, pages 238–247, February 2012
How to Cite
- Issue published online: 30 JAN 2012
- Article first published online: 21 SEP 2011
- Manuscript Accepted: 4 AUG 2011
- Manuscript Revised: 30 JUN 2011
- Manuscript Received: 24 AUG 2010
- AAAAI 2007 Third-Year Fellow-in-Training Award. Grant Number: HD052890-03
- National Institutes of Health/National Institute of Allergy and Infectious Diseases. Grant Numbers: AI44236, AI066738
- National Center for Research Resources. Grant Numbers: AI44236, AI066738, HD052890-03
- NIH K12. Grant Numbers: AI44236, AI066738, RR026134, HD052890-03
- atopic eczema;
- cow's milk allergy;
- endogenous protein;
- human milk;
- IgE antibodies;
- RBL assay;
- SPOT method
Occasionally, exclusively breastfed infants with cow's milk allergy (CMA) remain symptomatic despite strict maternal milk avoidance.
To determine whether or not persistence of symptoms could be due to sensitization against endogenous human milk proteins with a high degree of similarity to bovine allergens.
Ten peptides representing known bovine milk IgE-binding epitopes [α-lactalbumin (ALA), β- and κ-casein] and the corresponding, highly homologous human milk peptides were labelled with sera from 15 breastfed infants with CMA, aged 3 weeks to 12 months, and peptide (epitope)-specific IgE antibodies were assessed. Nine of the 15 breastfed infants became asymptomatic during strict maternal avoidance of milk and other major food allergens; six infants remained symptomatic until weaned. Ten older children, aged 5–15 years, with CMA were also assessed. The functional capacity of specific IgE antibodies was assessed by measuring β-hexosaminidase release from rat basophilic leukaemia cells passively sensitized and stimulated with human and bovine ALA.
A minimum of one human milk peptide was recognized by IgE antibodies from 9 of 15 (60%) milk-allergic infants, and the majority of older children with CMA. Genuine sensitization to human milk peptides in the absence of IgE to bovine milk was occasionally seen. There was a trend towards specific IgE being detected to more human milk peptides in those infants who did not respond to the maternal milk elimination diet than in those who did (P = 0.099). Functional IgE antibody to human ALA was only detected in infants not responding to the maternal diet.
Conclusions and Clinical Relevance
Endogenous human milk epitopes are recognized by specific IgE from the majority of infants and children with CMA. Such autoreactive, human milk-specific IgE antibodies appear to have functional properties in vitro. Their role in provoking allergic symptoms in infants exclusively breastfed by mothers strictly avoiding dietary milk remains unclear.