CHANGES in gut microbiota were observed at diagnosis in children with food protein-induced enterocolitis syndrome (FPIES), highlighting a potential microbial role in early disease development.
FPIES is a non-IgE-mediated food allergy that primarily affects infants and young children, often presenting with delayed gastrointestinal symptoms such as vomiting and diarrhoea. While its exact cause remains unclear, growing evidence has suggested that early-life gut microbiota may influence immune development and disease onset.
Gut Microbiota Differences at FPIES Diagnosis
In this study, researchers analysed faecal samples from 56 children at the time of FPIES diagnosis and compared them with 43 age-matched healthy controls. Participants were stratified into three age groups, ranging from young infants to children approaching 1 year of age. Gut microbiota composition was assessed using 16S rRNA gene sequencing.
Age emerged as the strongest determinant of gut microbiota composition, reflecting normal microbial development in early life. However, FPIES status was the second most significant factor, with clear differences identified between affected children and controls (p<0.01).
Notably, children with FPIES showed reduced abundance of Bifidobacterium, a genus widely considered beneficial for gut and immune health. In contrast, increased levels of Bacteroides, Haemophilus, and Veillonella were observed. Shifts in major bacterial phyla, including Bacteroidota, Proteobacteria, Actinobacteriota, and Verrucomicrobiota, contributed to these differences.
Importantly, reduced levels of Verrucomicrobiota were linked to specific food triggers associated with FPIES, suggesting that microbial composition may interact with dietary factors in shaping disease expression.
Implications for Early-Life Immune Development
These findings support the concept of gut microbial dysbiosis in FPIES, characterised by a loss of symbiotic bacteria and expansion of potentially pro-inflammatory taxa. Given the critical role of early microbiota in immune system maturation, such imbalances may contribute to abnormal immune responses to dietary proteins.
However, the cross-sectional design of the study limited causal interpretation. It remains unclear whether microbial changes drive disease onset or arise as a consequence of altered diet or inflammation. Additionally, microbiota composition is highly dynamic in infancy, which may influence variability in the findings.
Despite these limitations, the study provides important insight into the microbial landscape at the point of FPIES diagnosis. Future longitudinal studies are needed to determine whether early microbiota-targeted interventions, such as probiotics or dietary modulation, could reduce disease risk or severity.
Reference
Winberg A et al. Loss of symbiotic gut bacteria in children at diagnosis of food protein induced enterocolitis syndrome. J Allergy Clin Immunol. 2026; DOI:10.1016/j.jaci.2026.02.043.
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