Integrated gut metabolome and microbiome fingerprinting reveals that dysbiosis precedes allergic inflammation in IgE‐mediated pediatric cow's milk allergy

• Published in: Allergy (Copenhagen) Vol. 79; no. 4; pp. 949 - 963
• Main Authors: De Paepe, Ellen, Plekhova, Vera, Vangeenderhuysen, Pablo, Baeck, Nele, Bullens, Dominique, Claeys, Tania, De Graeve, Marilyn, Kamoen, Kristien, Notebaert, Anneleen, Van de Wiele, Tom, Van Den Broeck, Wim, Vanlede, Koen, Van Winckel, Myriam, Vereecke, Lars, Elliott, Chris, Cox, Eric, Vanhaecke, Lynn
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01-04-2024
• Subjects: 16S rRNA sequencing; Allergens; Allergies; Animal models; Animals; Casein; Cattle; Child; Child, Preschool; Children; Cholera toxin; Cow's milk; cow's milk allergy; Digestive system; Dysbacteriosis; Dysbiosis; Feces; Female; Fingerprinting; Food allergies; Gastrointestinal tract; Humans; Hypersensitivity; Immunoglobulin E; Immunoglobulin G; Inflammation; Lactoglobulins; Metabolism; Metabolites; Metabolome; Metabolomics; Mice; Microbiomes; Microbiota; Milk Hypersensitivity; multi‐omics; Pediatrics; RNA, Ribosomal, 16S; rRNA 16S; Tryptophan; β-Lactoglobulin; cow's milk allergy; multi‐omics; metabolomics; 16S rRNA sequencing
• ISSN: 0105-4538; 1398-9995; 1398-9995
• DOI: 10.1111/all.16005

Background
IgE‐mediated cow's milk allergy (IgE‐CMA) is one of the first allergies to arise in early childhood and may result from exposure to various milk allergens, of which β‐lactoglobulin (BLG) and casein are the most important. Understanding the underlying mechanisms behind IgE‐CMA is imperative for the discovery of novel biomarkers and the design of innovative treatment and prevention strategies.
Methods
We report a longitudinal in vivo murine model, in which two mice strains (BALB/c and C57Bl/6) were sensitized to BLG using either cholera toxin or an oil emulsion (n = 6 per group). After sensitization, mice were challenged orally, their clinical signs monitored, antibody (IgE and IgG1) and cytokine levels (IL‐4 and IFN‐γ) measured, and fecal samples subjected to metabolomics. The results of the murine models were further extrapolated to fecal microbiome‐metabolome data from our population of IgE‐CMA (n = 22) and healthy (n = 23) children (Trial: NCT04249973), on which polar metabolomics, lipidomics and 16S rRNA metasequencing were performed. In vitro gastrointestinal digestions and multi‐omics corroborated the microbial origin of proposed metabolic changes.
Results
During mice sensitization, we observed multiple microbially derived metabolic alterations, most importantly bile acid, energy and tryptophan metabolites, that preceded allergic inflammation. We confirmed microbial dysbiosis, and its associated effect on metabolic alterations in our patient cohort, through in vitro digestions and multi‐omics, which was accompanied by metabolic signatures of low‐grade inflammation.
Conclusion
Our results indicate that gut dysbiosis precedes allergic inflammation and nurtures a chronic low‐grade inflammation in children on elimination diets, opening important new opportunities for future prevention and treatment strategies.
Early‐stage microbial metabolites, reflective of gut dysbiosis steer the development of the immune system toward food allergies. Allergic inflammation appears at the end of the sensitization through a dysregulation in sphingolipid and energy metabolism. Allergic children on an elimination diet suffer from subacute chronic inflammation, as a consequence of concurrent dysbiosis.Abbreviations: CMA, cow’s milk allergy; rRNA, ribosomal RNA