Epigenetic signature links early life microbiota to childhood allergic disease

Published: July 18, 2020

Allergic rhinitis is one of the most common inflammatory diseases of the nasal mucosa, which is a physical and immune barrier to inhaled allergens and microbes. These exposures can alter epigenetic patterns and immune responses and contribute to risk for allergic and airway diseases.

In a recent study published in The Journal of Allergy and Clinical Immunology (JACI), Morin et al. evaluated the relationship between nasal microbiota composition measured at one week, one month and three months and the onset of allergic rhinitis by age 6, considering DNA methylation and gene expression patterns in nasal epithelial cell of the same children at age 6 as potential mediators of these effects. The study focused on children participants in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) birth cohort. The authors hypothesized that the early life microbial exposure could leave a lasting signature in DNA methylation impacting risk for the development of allergic rhinitis.

Morin et al. reported 956 differentially methylated CpG sites between allergic rhinitis cases and controls, which formed three modules of co-methylated CpGs. One of these allergic rhinitis-associated modules was correlated with both microbiota diversity at one week and the expression of genes involved in lysosome and bacterial invasion of epithelial cell processes. The association between microbial diversity at one week and AR at age 6 was significantly reduced by inclusion of the correlated module as a covariate in the model, indicating that a large proportion of the effect of microbial exposure in infancy on AR in childhood is mediated through DNA methylation changes in nasal mucosal cells.

This study is the first to show a longitudinal connection between microbial composition in early life with epigenetic patterns and development of disease in the upper airways in childhood. The authors suggest that nasal microbiota composition in infancy contributes to the development of allergic rhinitis in childhood by shaping the DNA methylation landscape and altering gene expression in the upper airways. Early intervention to modulate microbial composition could have a significant impact on allergic disease development.

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

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