The composition of infants' gut microbiomes may influence their later risk of developing allergies and asthma, a new study says.
Researchers from the University of California, San Francisco, and the Henry Ford Health System analyzed stool samples from nearly 300 infants between the ages of 1 month and 11 months using 16S rRNA sequencing, as they report in Nature Medicine. From this, UCSF's Susan Lynch and her colleagues found that the cohort could be divided into three groups based on their gut microbiome composition.
Each of the three groups also had a different relative risk of developing atopy — a heightened immune response to allergens — by the age of two and asthma by age four. The group with the highest risk, dubbed NGM3, had a lower relative abundance of bacteria like Bifidobacterium, Akkermansia, and Faecalibacterium and higher levels of fungi like Candida and Rhodotorula, the researchers report. In addition, Lynch and her colleagues note that this group has a metabolome that's enriched for pro-inflammatory metabolites.
Additional cell culture experiments of adult T-cells found that the addition of sterile fecal water from NGM3 individuals increased the number of CD4+ cells producing interleukin-4, and this and other findings suggested to the researchers that dysbiosis of the infant gut microbiome might led to CD4+ T cell dysfunction and allergy risk.
"Early-life intervention may be a strategy by which we can offset allergic asthma in perhaps a portion of the population," Lynch tells the Guardian.