Fecal microbiome and metabolome differ in healthy and food-allergic twins

BACKGROUNDThere has been a striking generational increase in the prevalence of food allergies. We have proposed that this increase can be explained, in part, by alterations in the commensal microbiome.METHODSTo identify bacterial signatures and metabolic pathways that may influence the expression of this disease, we collected fecal samples from a unique, well-controlled cohort of twins concordant or discordant for food allergy. Samples were analyzed by integrating 16S rRNA gene amplicon sequencing and liquid chromatography-tandem mass spectrometry metabolite profiling.RESULTSA bacterial signature of 64 operational taxonomic units (OTUs) distinguished healthy from allergic twins; the OTUs enriched in the healthy twins were largely taxa from the Clostridia class. We detected significant enrichment in distinct metabolite pathways in each group. The enrichment of diacylglycerol in healthy twins is of particular interest for its potential as a readily measurable fecal biomarker of health. In addition, an integrated microbial-metabolomic analysis identified a significant association between healthy twins and Phascolarctobacterium faecium and Ruminococcus bromii, suggesting new possibilities for the development of live microbiome-modulating biotherapeutics.CONCLUSIONTwin pairs exhibited significant differences in their fecal microbiomes and metabolomes through adulthood, suggesting that the gut microbiota may play a protective role in patients with food allergies beyond the infant stage.TRIAL REGISTRATIONParticipants in this study were recruited as part of an observational study (ClinicalTrials.gov NCT01613885) at multiple sites from 2014 to 2018.FUNDINGThis work was supported by the Sunshine Charitable Foundation; the Moss Family Foundation; the National Institute of Allergy and Infectious Diseases (NIAID) (R56AI134923 and R01AI 140134); the Sean N. Parker Center for Allergy and Asthma Research; the National Heart, Lung, and Blood Institute (R01 HL 118612); the Orsak family; the Kepner family; and the Stanford Institute for Immunity, Transplant and Infection.