Fecal microbiome transplant in food allergy in humans and mice identifies a role for bile acid metabolites in oral tolerance

Authors

• Rima Rachid, Division of Immunology, Boston Children's Hospital, Boston, MA, USA.
• Monica Martinez-Blanco, Division of Immunology, Boston Children's Hospital, Boston, MA, USA.
• Gavin A. Kuziel, Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
• Emmanuel Stephen-Victor, Division of Immunology, Boston Children's Hospital, Boston, MA, USA.
• Mathieu Groussin, Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany.
• Askarbek Orakov, Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
• George Russell, Barbara Bush Children's Hospital, Maine Medical Center, Portland, ME, USA.

Document Type

Article

Publication Date

8-5-2026

Institution/Department

Pediatrics

Journal Title

Science translational medicine

MeSH Headings

Animals; Humans; Bile Acids and Salts (metabolism); Food Hypersensitivity (immunology, therapy, microbiology); Fecal Microbiota Transplantation; Mice; Adult; T-Lymphocytes, Regulatory (immunology); Administration, Oral; Female; Immune Tolerance; Male

Abstract

The gut microbiome has been implicated in the pathogenesis of food allergy (FA), prompting microbiome-focused interventions. We evaluated, in a phase 1 open-label trial (NCT02960074), the safety and efficacy of oral encapsulated fecal microbiome transplantation (FMT) in 15 adults with peanut allergies. An increase in the peanut reactivity threshold was noted in 3 of 10 participants not pretreated with antibiotics and 3 of 5 participants pretreated with antibiotics, without safety issues. In responders, FMT increased tolerogenic RORγt regulatory T cells (T cells) and decreased T helper 2 cells (T2 cells). Mice transplanted with the microbiomes of post-FMT responders were protected from FA in association with increased RORγt T cell percentages and increased colonization with members of the gut Bacteroides. In both humans and mice, protection by FMT was associated with increased bile acid metabolites. Deletion of a bile salt hydrolase in a candidate protective Bacteroides abrogated FA suppression in mice. These results suggest that FMT is a safe and potentially promising therapeutic modality for treating FA.

First Page

eaee3263

Recommended Citation

Rachid, Rima; Martinez-Blanco, Monica; Kuziel, Gavin A.; Stephen-Victor, Emmanuel; Groussin, Mathieu; Orakov, Askarbek; and Russell, George, "Fecal microbiome transplant in food allergy in humans and mice identifies a role for bile acid metabolites in oral tolerance" (2026). MaineHealth Maine Medical Center. 4610.
https://knowledgeconnection.mainehealth.org/mmc/4610