Several major childhood allergies may all stem from the gut microbiome gut, according to a new study published in Nature Communications. The research identifies gut microbiome features and early life influences that are associated with children developing any of four common allergies. The study, led by researchers at the University of British Columbia and BC Children’s Hospital, could lead to methods of predicting whether a child will develop allergies, and methods to prevent their development.
“We’re seeing more and more children and families seeking help at the emergency department due to allergies,” said Dr Stuart Turvey, paediatrics professor at UBC and co-senior author on the study, noting that as many as one in three children in Canada have allergies.
The study is one of the first to examine four distinct school-aged paediatric allergies at once: atopic dermatitis, asthma, food allergy and allergic rhinitis. While these allergic diseases each have unique symptoms, the Turvey lab was curious whether they might have a common origin linked to the infant gut microbiota composition.
“These are technically different diagnoses, each with their own list of symptoms, so most researchers tend to study them individually,” says Dr Charisse Petersen, co-senior author on the paper and postdoctoral fellow in the Turvey lab. “But when you look at what is going wrong at a cellular level, they actually have a lot in common.”
For the study, researchers examined clinical assessments from 1115 children who were tracked from birth to age five. Roughly half of the children (523) had no evidence of allergies at any time, while more than half (592) were diagnosed with one or more allergic disorders by an expert physician. The researchers evaluated the children’s microbiomes from stool samples collected at clinical visits at three months and one year of age.
The stool samples revealed a bacterial signature that was associated with the children developing any of the four allergies by five years of age. The bacterial signature is a hallmark of dysbiosis, or an imbalanced gut microbiota, that likely resulted in a compromised intestinal lining and an elevated inflammatory response within the gut.
“Typically, our bodies tolerate the millions of bacteria living in our guts because they do so many good things for our health. Some of the ways we tolerate them are by keeping a strong barrier between them and our immune cells and by limiting inflammatory signals that would call those immune cells into action,” says Courtney Hoskinson, a PhD candidate at UBC and first author on the paper. “We found a common breakdown in these mechanisms in babies prior to the development of allergies.”
Many factors can shape the infant gut microbiota, including diet, place and delivery method of birth and antibiotics exposure. The researchers examined how these types of influences affected the balance of gut microbiota and the development of allergies.
“There are a lot of potential insights from this robust analysis,” says Dr Turvey. “From these data we can see that factors such as antibiotic usage in the first year of life are more likely to result in later allergic disorders, while breastfeeding for the first six months is protective. This was universal to all the allergic disorders we studied.”
Now the researchers hope to leverage the findings to inform treatments that correct an imbalanced gut microbiota and could potentially prevent allergies from developing.
“Developing therapies that change these interactions during infancy may therefore prevent the development of all sorts of allergic diseases in childhood, which often last a lifetime,” says Dr Turvey.
Source: University of British Columbia
