Intestinal Microbiota Composition in Children Under Two Years of Age with Food Allergies: Cross Sectional Study

Background. Study of the intestinal microbiota in children with allergic diseases during the first 1000 days of life is necessary for pathogenetic correction validation of intestinal dysbiosis during the “window of opportunity” period. Several studies on intestinal microbiota in children during the first 1000 days of life have been conducted in Russia, but not among children with allergies.

Objective. The aim of the study is to examine the intestinal microbiota composition in children under two years of age with food allergies.

Methods. The study included full-term children aged 6–24 months with food allergy who were followed up on outpatient basis. The taxonomic composition of intestinal microbiota was analyzed via 16S rRNA sequencing. Biological material was collected at home. The taxonomic profile of intestinal microbiota is presented as the relative abundance of taxa, calculated as the proportion (in %) of reads assigned to each taxon out of the total number of reads.

Results. The taxonomic composition of intestinal microbiota was studied in 60 children: 37 of them were of the first year of life (6–12 months) and 23 were of the second year of life (13–24 months). Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria were revealed in both age groups, while children aged 13–24 months additionally had Verrucomicrobia. Ruminococcaceae family (p = 0.006), unclassified type of Lachnospiraceae family (p < 0.001), and Gemmiger (p = 0.007) were revealed more frequently in children aged 13–24 months, whereas Veillonella (p = 0.007) was revealed less frequently. Opportunistic microorganisms of Veillonella parvula (p = 0.017), Erysipelatoclostridium ramosum, and Intestinibacter bartlettii were revealed in children aged 6–12 months, while the proportion of Faecalibacterium prausnitzii was higher (p = 0.049) in children of the second year of life. Children of the second year of life showed lower degree of sensitization to cow’s milk proteins, while sensitization level to chicken egg proteins remained unchanged.

Conclusion. Children of the second year of life with food allergy have higher abundance of commensal microbes was observed in the absence of pathobionts. This result suggests the compensatory tolerance development in children with food allergy early in childhood.

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