Maternal antibodies to allergens protect offspring from allergy

Published online: January 24, 2019

Immunoglobulin E (IgE)-associated allergy affects almost 30% of the population world-wide. The symptoms of allergy which include hay fever, allergic asthma, skin inflammation, food allergies and life-threatening anaphylactic shock, are due to IgE recognition of per se innocuous environmental antigens, so-called “allergens”. From observational studies conducted on birth cohorts which are representative for the populations of the respective regions, it became apparent that allergic sensitizations occur very early in life. However, it is still unknown which factors may protect children against developing IgE sensitization and allergic symptoms.

In the study by Hochwallner et al. in The Journal of Allergy and Clinical Immunology (JACI) the authors investigated if the passive transfer of allergen-specific antibodies of the IgG type from mother to child via the placenta during pregnancy can convey protection from allergic sensitization to the offspring. The concept that allergen-specific IgG can protect against allergic symptoms is supported by the fact that allergy can be successfully treated by allergen-specific immunotherapy which induces production of allergen-specific, blocking IgG antibodies. Similarly, it was demonstrated that administration of blocking IgG can prevent allergy symptoms upon exposure to the respective allergens. However, it was unknown if maternal IgG may prevent allergic sensitization in children.

In a Swedish birth cohort, blood samples from 99 mother-child pairs were collected during pregnancy and, after delivery, at the age of 6, 12 and 60 months, respectively. Employing microarray technology which allows for detection of antibodies to a large panel of allergens in a single step while consuming only one drop of serum sample, the authors measured allergen specific IgG in mothers’ sera and IgE in sera of the offspring. The association of maternal IgG measured at birth with IgE-sensitization of their children at 5 years of age was assessed.
In their trial, Hochwallner et al. succeeded in demonstrating that if levels of allergen-specific IgG in mothers’ serum samples exceeded a defined threshold level, their offspring did not develop allergic sensitization to the same respective allergen within the complete observation period, i.e., during their first 5 years of life. Hence, these observations suggest that the transfer of maternal IgG antibodies from mother to child in utero actually can confer protection from allergies to the children. Based on these results, a novel strategy for prophylaxis of allergies can be envisioned which is based on the induction of allergen-specific IgG by vaccination or on passive administration of allergen-specific IgG to pregnant women.

The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

Graphical Abstract