Probiotics are widely used as a means of dietary correction of the intestinal microbiota in patients not only with alimentary, but also with allergic and inflammatory diseases. They have systemic effects on the human organism. However, the diversity of the composition of probiotic complexes complicates the determination of the beneficial effects of specific microorganisms on the human body. These circumstances call for more research. Investigation of the effect of probiotic intake on the levels of various cytokines may explain the mechanisms of the beneficial effect of probiotic intake on the functioning of the immune system. Objective - to study the effectiveness of the probiotic Bifiform Kids for the prevention of respiratory infections in children with recurrent respiratory infections with gastrointestinal allergy symptoms. Material and methods. The prospective randomized controlled trial included 92 children aged from 4 to 5 years who suffers from more than 5 episodes of respiratory infections per year with gastrointestinal allergy symptoms. Patients from the main group (n=46) were prescribed 2 chewable tablets Bifiform Kids (Lactobacillus rhamnosus GG not less than 1×109 CFU, Bifidobacterium animalis spp. lactis not less than 1×109 CFU, thiamine mononitrate 0.40 mg, pyridoxine hydrochloride 0.50 mg in each) twice per day within 21 days. Patients from the control group (n=46) were prescribed no probiotics during the study period. The study included the measurement of blood serum levels of immunoglobulins A, M, G (by immunoturbodimetry) and E, as well as the concentration of cytokines IL-17, IL-10 (by enzyme immunoassay). Measurements were performed at the 1st day of the study, at the 21st day of the study, and 6 months after the study initiation. The microbiota composition was determined by sequencing the bacterial 16S rRNA genes in DNA preparations isolated from stool samples collected at the start of the study and after 21 days. The Shannon index was calculated for the species of detected bacteria to determine the diversity of the microbiome. The effectiveness of disease prevention was measured by calculating the prevention index and the efficiency coefficient based on the incidence of respiratory infections in both groups during the observation period (6 months). Results. In the main group, the volume of the commensal flora decreased 3 weeks after the study initiation: Enterobacter from 18.3±19.3 to 10.5±18.1%; Enterococcus from 8.7±16.1 to 3.1±10.0%; Clostridium from 3.1±8.1 to 0.5±2.2%. There was a statistically significant increase in the proportion of representatives of the genus Bifidobacterium by 2.2 times (from 16.9±26.4 to 36.5±31.5%, p=0.0017) and a decrease in the Shannon index from 1.1±2.1 up to 0.4±1.1 (p<0.05). In the control group, there were no statistically significant changes in the microbiota content. In the main group, after 21 days, the blood IL-10 level increased from 11.3±15.4 to 15.7±13.4 pg/ml, and the IL-17 concentration decreased from 8.9±7.7 to 6.5±7.1 pg/ml (p=<0.05) while maintaining this trend by the 6th month of observation. There were no changes in these indicators in children from the control group. The main group demonstrated a significant (р=<0.05) decrease in the level of IgE from 184±121 to 104±67 and 114±54 kU/l, and a significant increase in IgA from 0.73±0.45 to 1.33±0.65 and 1.21±0.57 g/l after 3 weeks and at the end of the probiotic intake, respectively. The level of IgA in the main group remained higher during the study compared to the control group. The main group demonstrated a 3-fold decrease in the incidence of respiratory infections in comparison with the control group. The efficiency index was 3.21, the therapeutic response was 69%. Conclusion. The results of the study show the effectiveness of the complex probiotic for the respiratory infections prevention in children with gastrointestinal allergy symptoms.
Keywords: BB-12; IL-10; IL-17; IgA; IgE; LGG; frequently ill children; probiotics; recurrent respiratory infections; respiratory infections.
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