Call them to the guardians of the intestinal microbiome: bacteria associated with protection against food allergies. Such bacteria, "good" bacteria, have been identified in the human infant's arm. Other bacteria, "bad" bacteria associated with food allergies in infant patients, have been identified.
These results were reported by researchers based at Boston Children's Hospital (BCH) and Brigham and Women's Hospital (BWH). The researchers also tested whether the good bacteria could be used therapeutically. After delivering the good bacteria to mice, the researchers observed that the mice became more resistant to food allergies and even experienced reversals of established disease.
Details appeared on June 24 in the journal Nature "Microbiotherapy works via a regulatory T-cell MyD88 / RORγt pathway to suppress food allergy." The paper indicates that orally administered microbiological therapy can solve dysbiosis, reset the immune system, and promote tolerance to food allergens.
"Therapy with Clostridials Species Affected by Dysbiose, either as a consortium or as monotherapy with Subdoligranulum Variable suppressed food allergy in mice that made a separate immunomodulatory Bacteroidales consortium," the author's article wrote. "Bacteriotherapy induced expression of regulatory T cells by the transcription factor ROR-γ in a MyD88-dependent manner, which was deficient in fetal allergy children and mice and ineffectively induced by their microbiots."
To confirm this immunomodulatory mechanism, BCH / BWH team was deleted Myd88 or Rorc in T regulatory cells. This makes the scientists aware, lifted the protection of bacterial therapy. "Commensals activate a MyD88 / ROR γt pathway in nascent T regulatory cells to protect against food allergy," they concluded, "while dysbiosis affects this regulatory response to promote disease."
These results point to a new bacterial therapy approach, one that represents a marked contrast to oral immunotherapy, a strategy aimed at increasing the threshold to trigger an allergic reaction by providing an individual small but increasing amount of a food allergy . In contrast to oral immunotherapy, bacteriotherapy attempts to alter the immune system's leads in an allergen-independent manner with the potential to generally treat food allergies rather than desensitize an individual to a particular allergen.
For reasons that remain a mystery, the number of Americans suffering from food allergies has risen sharply over the last decade to as many as 32 million, according to a recent estimate. Almost 8% of the children in the US ̵
One hypothesis is that certain Western lifestyle factors – including an increase in birth after Caesarean section, a decrease in breastfeeding, increased use of antibiotics, and smaller family sizes – interfere with normal microbial balance in the intestine and deprive babies of the good bacteria that Prepares the immune system to recognize food as harmless.
To test this hypothesis, the BCH / BWH team studied intestinal bacteria in babies with and without food allergies. It collected stool samples from 56 food allergic patients and 98 matched controls. As it analyzed the samples for changes in bacterial content, the BCH / BWH team revealed that the bacteria in the feces of babies with food allergies were different from controls. But have these bacterial differences played a role in their food allergies?
To find out, the team transplanted fecal bacteria from the babies to a particular burden of allergically exposed mice. They fed the mouse small doses of chicken-rich protein to sensitize their immune system to this allergen and then challenged the mice with a large dose.
Results: Mice that had gotten faecal bacteria from food allergic babies entered the life-creation reaction called anaphylaxis. "The fecal bacteria from food allergic subjects do not protect against food allergy while bacteria from controls did," said Talal A. Chatila, MD, director of the Food Allergy Program at BCH and one of Nature's senior authors.
"It is very complicated to look at all the microbes in the intestine and sense what they can do in food allergies, but by using calculation methods we could narrow down on a specific group of microbes associated with a protective effect," co noted. -first author Georg Gerber, MD, PhD, MPH, co-director of the Massachusetts Host-Microbiome Center and head of the division of calculation pathology in the pathology department of BWH. "Being able to break down from hundreds of microbial species to only five or six or so has implications for the therapy, and from a basic science perspective, we can begin to figure out how these specific bacteria provide protection."
"This represents a sea shift in our approach to therapy for food allergies," added co-authored Lynn Bry, MD, PhD, director of the Massachusetts Host Microbiome Center at BWH. "We have identified microbes associated with protection and those associated with food allergies in patients. If we administer certain consortia that represent protective microbes as therapeutic, we can not only prevent food allergies from happening, but we can bypass existing food allergies. in preclinical models. "
Chatila, Gerber and Bry are founders and have equity in Consortia Therapeutics, a company that develops a living human biotherapeutic product (CTX-944). (Rima Rachid, MD, Assistant Director of Food Allergy Program at BCH and another co-author of the paper Nature also has equity in the company.) Consortia Therapeutics is preparing for a Phase Ib trial in pediatric food allergy followed by extension for additional allergic diseases.