The gut microbiota significantly influences the development and functioning of a child's immune system. From the first days of life, it actively participates in the development of innate and acquired immunity, promoting the development of immune tolerance and protecting the body from infectious agents. Alterations in the composition of intestinal microflora, or dysbiosis, lead to a weakening of the mucosal barrier and can cause immune imbalances. This paper examines the fundamental mechanisms of interaction between the microbiota and the immune system, as well as the relationship between dysbiotic changes and the development of allergic (e.g., atopic dermatitis, bronchial asthma) and autoimmune diseases (such as type 1 diabetes mellitus and celiac disease). Particular attention is paid to modern methods for the prevention and correction of dysbiosis in children, including breastfeeding, the use of probiotics, and the rational use of antibacterial agents.

intestinal microbiota, children, immunity, dysbiosis, allergy, autoimmune diseases, probiotics.

Marchesi, J. R., Ravel, J. (2015). Glossary of terms for microbiome research: an authors' proposal. Microbiome; 3:31.

Kostic, A. D., Xavier, R. J., & Gevers, D. (2014). The microbiome in inflammatory bowel diseases: current status and prospects. Gastroenterology; 146(6), 1489–1499.

Pittayanon, R., Lau, J. T., Leontiadis, G. I., et al. Differences in the gut microbiota in patients with irritable bowel syndrome: a systematic review. Gastroenterology; 157; 1:97–108.

Turnbaugh, P. J., Ley, R. E., Mahold, M. A. et al. An obesity-associated gut microbiome with enhanced energy harvesting capacity // Nature. 2006. Vol. 444. pp. 1027–1031.

Tamburini S, et al. The early-life microbiome: implications for health // Nat Med. 2016.

Shao Y, et al. (2019). Delayed microbiota development and cesarean section. Nature, 574, 117–121.

Backhed F, et al. Gut microbiota dynamics in human infants // Cell Host Microbe. 2015. Vol. 17. pp. 690–703.

Vatanen T, et al. (2016). Variations in microbial lipopolysaccharide immunogenicity and their contribution to autoimmunity. Cell, 165(4), 842–853.

Kostic, A. D., et al. Dynamics of the human gut microbiota during the progression of type 1 diabetes. Cell Host Microbe; 2015; vol. 17; no. 2; pp. 260–273.

Sher, J. W., Szczesnak, A., & Longman, R. S. (2013). Expansion of Prevotella copri and increased susceptibility to arthritis. eLife; 2; e01202.

Gevers, D., et al. Microbiota in patients with onset Crohn's disease before therapy. Cell Host Microbe; 2014; vol. 15; pp. 382–392.

Berer, K., et al. (2017). Gut microbiota of patients with multiple sclerosis as a factor in disease development in animal models. Nature, 552(7684), 1–5.

Martin R., et al. Breast milk as a source of lactic acid bacteria for the infant gut // J Pediatr Gastroenterol Nutr. 2003. Vol. 37. pp. 1–6.

Tan, J., et al. (2014). The role of short-chain fatty acids in health and disease. Advances in Immunology, 121, 91–119.

Fiocchi A., et al. World Allergy Organization recommendations for the prevention of allergic diseases: probiotics // World Allergy Organ J. 2015. Vol. 8. pp. 1–16.

Korpela, K., et al. (2016). Association of the gut microbiome with lifelong antibiotic use in Finnish preschool children. Nature Communications, 7, 10410.