Identification of early life risk factors for food allergy is mandatory to halt the rising of this public health issue. We recently showed the presence of house dust mite allergen, Der p 1, in maternal milk. This observation suggests that Der p allergen in neonate gut may affect gut mucosal immunity ontogeny and long term food allergy susceptibility.

We addressed this hypothesis in mice by exposing lactating mother to Der p and analyzing gut mucosal immunity in 16 days old offspring. We found that pups exposed to Der p through breast milk have a significantly increased gut permeability, secretion of IL-5 and IL-13 by innate lymphoid cells and frequency of GATA3 expressing CD4 T lymphocyte in their lamina propria. If mothers are concomitantly exposed to a dietary allergen, Ovalbumin, the presence of Der p hinders the induction of OVA specific FoxP3 regulatory T cells. We tested offspring susceptibility to food allergy in adulthood and found that mice breastfed by mothers exposed to both OVA and Der p show increased diarrhea, mMMCP1 and OVA specific IgE levels in serum compared to mice exposed to OVA only. The effects of Der p on mucosal immunity and food allergy susceptibility were found to depend on Der p protease activity. We further assessed whether this observation could be translated to the Human. We found in a birth cohort that risk of allergic sensitization to food allergen at 1 year was significantly increased by the presence of Der p 1 in maternal milk.

The evidence that house dust mite, an ubiquitous source of respiratory allergen,  could profoundly affect gut immune ontogeny and the risk for food allergy may promote the research for new strategies to prevent food allergy in early life.