Nonetheless, latter experiences were performed with the first uses of probiotic strains, while today, other microorganisms that can regulate the intestinal environment have been evaluated 
Nonetheless, latter experiences were performed with the first uses of probiotic strains, while today, other microorganisms that can regulate the intestinal environment have been evaluated . Research performed on animals has successfully used various probiotics and prebiotics at different times during childhood, yielding promising results in modifying the microbiota towards a healthy profile and decreasing IgE levels, proinflammatory cytokines, and anaphylaxis symptoms [89C92]. with FA. In this article, we discuss the establishment of the microbiota, the immunological BI-409306 mechanisms that regulate the microbiota of children with food allergies, and the evidence in research focused on its regulation as a means to achieve tolerance to food allergens. 1. Introduction Food allergy (FA) or food allergies are pathologies triggered by exposure to food allergens . The prevalence of immunoglobulin (Ig) E-mediated FA in children has increased in recent years, with figures ranging from 1 to 2 2.53% in the USA  and Canada  to 5.5% in BI-409306 Chile . Higher proportions are observed in self-report studies, reaching up to 25% in some regions . The most common allergens include peanuts, walnuts, eggs, milk, fish, and soy, varying between countries and age groups [3, 6]. Risk factors for the development of FA include vitamin D deficiency, delayed exposure to food allergens, reduced exposure to microorganisms (as suggested by the hygiene hypothesis), and changes in the microbiota . The gut microbiota corresponds to the group of microorganisms that colonize the intestine . The loss of the gut microbiota homeostasis due to changes in their relative abundance and diversity is known as dysbiosis . This condition has been observed in children with FA, whose BI-409306 gut microbiota profiles differ from those without FA . Food allergies developed by mechanisms not mediated by IgE, present in approximately one-third of the population, also present variations in the intestinal microbiota, and a greater relative large quantity of Bacteroides and Alistipes has been observed, in addition to presenting changes associated with probiotic supplementation. Consequently, the alteration of the microbiota would not be associated only with IgE . Currently, the only available treatment for FA consists of the stringent exclusion of the allergen from the diet. Nevertheless, this approach may effect the nutritional state of the patient depending on the type and quantity of allergens involved and the age of the patient at the time of the analysis . Consequently, it is necessary to explore novel therapies to induce food-specific immune tolerance and decrease FA symptoms in these individuals. 2. Differences between the Adult and Infant Defense Systems The immune system of infants is definitely thought to be under active development and training, making it inherently susceptible to react to microbial providers and generate atopic reactions . Throughout neonatal existence, the immune system of the infant relies on the BI-409306 immunity of the mother transferred through the placenta, the exposure during childbirth (the birth canal), and breastfeeding . Although hereditary factors also influence the type of immune response that an infant may develop , several studies possess suggested that nonhereditary factors are the most relevant for shaping the immune system and developing immunity during the 1st year of existence . For example, a recent study on twins characterized 204 immunity-related guidelines and showed that 77% of them were heavily affected by nonhereditary factors . Additionally, it has been reported that immune cells from babies possess high intraindividual heterogeneity, opposed to what has been explained for adults . This observation shows the relevance of environmental exposure during neonatal existence . Most of the components of the immune system Rabbit Polyclonal to TDG of newborns are created but immature in their function . Concerning cell types, neutrophils appear improved in the fetus but fall to levels that may prevail in adulthood a few days after birth, cytotoxic T lymphocytes present low activity compared to adults, and monocytes and macrophages also appear immature . Valiathan et al. measure the concentration of immune cells in different age groups and observed a predominance of lymphocytes, platelets, and B cells that decrease significantly with age, neutrophils and CD8+ T cells increase in adulthood, and natural killer (NK) cells, which are part of the innate immune response, increase.