A study by a team of scientists from Boston Children's Hospital and Brigham and Women's Hospital suggests food allergies can be triggered in infants by a lack of certain gut bacteria. As well as identifying which bacteria in human subjects are key to protecting against the onset of food allergies, a subsequent mouse study revealed a specific probiotic cocktail can reverse pre-established allergies.

Over the last few decades rates of food allergies have been rapidly rising in Western industrialized nations. It is unclear exactly why this is happening but one of the more interesting hypotheses is that disruptions to a baby's growing gut microbiome can trigger the onset of food allergies in infancy.

Investigating this hypothesis the new research first set out to examine the gut microbiome composition of a number of infants. The study followed 56 infants with food allergies and 98 infants without. Fecal samples were taken every few months, up to the age of 30 months.

"It's very complicated to look at all of the microbes in the gut and make sense of what they may be doing in food allergy, but by using computational approaches, we were able to narrow in on a specific group of microbes that are associated with a protective effect," explains Georg Gerber, co-first author on the new study.

Homing in on a specific handful of gut bacteria that were in lower abundance in those infants suffering from food allergies, a subsequent mouse study affirmed the allergic association. Mice sensitized to an egg allergen were found to be protected from allergic reactions when administered the specific cocktail of six bacterial species identified by the researchers.

Even more interesting was the finding that these specific bacterial cocktails completely suppressed allergic reactions in mice already sensitized to an allergen. This discovery implies that not only can allergies be prevented from developing in the first place, but a pre-existing allergic response can be reversed after it has already developed.

Talal Chatila, senior author on the study, says his team's research affirms the microbiome is a fundamental mechanism in determining the development of food allergies in a person. Chatila also adds, "in adult mice that had become food-allergic, we could suppress their disease by introducing the good bacteria, which means to us there is the potential to treat somebody with established food allergy and reset their immune system in favor of tolerance."

All of this, of course, needs to be proven in human subjects, but the researchers are already working towards several human clinical trials in both adults and infants. These trials will investigate fecal transplants targeting peanut allergies, as well as specifically generated probiotic mixes for pediatric food allergies.

Chatila ambitiously suggests there could be a product on the market stemming from this research within as little as five years. To achieve this Chatila, along with several other researchers on the project, founded a company called ConsortiaTX with the plan to create novel microbial therapies to treat allergies.

"When you can get down to a mechanistic understanding of what microbes, microbial products, and targets on the patient side are involved, not only are you doing great science, but it also opens up the opportunity for finding a better therapeutic and a better diagnostic approach to disease," says Lynn Bry, co-senior author on the new study, and co-founder of ConsortiaTX. "With food allergies, this has given us a credible therapeutic that we can now take forward for patient care."

The new study was published in Nature Medicine.

Sources: Brigham and Women's Hospital, Boston Children's Hospital