Microbiome in Inner‐City Asthma

Abstract

Prevalence of childhood asthma has increased dramatically over the past several decades in Western nations, and particularly in inner city populations. Evidence has emerged for both local environmental exposure in infancy and early life gut microbiome disturbances as associated with childhood allergic asthma development. This has led to the hypothesis that the house dust microbial environment of infants may influence their developing gut microbiome in a manner that alters the risk for childhood allergic disease and asthma development. We have recently demonstrated that house dust microbiome composition varies across inner‐city homes and that this variability is significantly related to allergic disease development in children raised in these environments. Children who develop atopy and recurrent wheezing at age three lack environmental microbial exposures in their house dust that are encountered by children who do not develop these disease phenotypes. The majority of these organisms enriched in allergy‐protective households have been previously described in the human gut microbiome. Moreover, murine studies have demonstrated that exposure of mice to dust from allergy protective households, alters the composition of the gut microbiome in a manner that protects against airway allergen challenge. A specific species, Lactobacillus sakei, found to be significantly enriched in the gut microbiome of these protected animals, was capable of conferring airway protection against both allergen and respiratory viral infection in animals supplemented orally with this species. Hence the growing evidence supports a strong role for household microbial exposures as playing a role in shaping gut microbiome composition in early infancy, in a manner that influences mucosal adaptive responses to a variety of airway insults.