The role of microbiota in the formation of allergic diseases

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Relevance. The end of the 20th and the beginning of the 21st century are characterized by the rapid spread of allergic pathology among all population groups in many countries of the world. In developed countries, the frequency of allergic diseases has increased by more than 3.8-10 times, reaching 25% or more. In recent years, the frequency of allergic diseases has increased significantly, most of them have a burdened course, in this regard, allergy is considered a major medical and social problem. According to the research data of the international ISAAC program, the symptoms of bronchial asthma (BA) are 1.0-30.8%. Allergic rhinitis (AR) and hay fever make up 0.2-20%, atopic dermatitis (AD) and eczema - 1.6-4.2%. [1]. Most allergic diseases do not affect life expectancy, do not contribute to the mortality rate of the population, but they significantly reduce the quality of life of patients and lead to significant financial costs. Prevention of allergic diseases is necessary at all stages of a person's life, starting from the prenatal period. For this, a wide variety of methods must be studied and applied. Numerous studies have shown that the microbiota of the human body, in the absence of its changes, is capable of preventing various diseases, including allergic ones. An imbalance in the composition of microorganisms leads to disturbances in the microbial-tissue complex, which predetermines the response of the immune system to foreign agents.
Purpose: to study the influence of a diverse composition of the microbiota on the formation of allergic pathology according to the literature analysis of domestic and foreign authors.
Methods
1. Study design
A retrospective epidemiological analysis of the morbidity of the population of the Voronezh region based on the materials of the statistical reporting form No. 12 (annual) "Information on the number of diseases registered in patients living in the service area of ​​a medical organization") for the period from 2012-2018; questionnaire survey of the population based on the questionnaire developed at the department of epidemiology; search for evidence-based information in the analysis of literature data of domestic and foreign authors. A survey of the population of Voronezh and the Voronezh region, in which 208 respondents participated: students of VSMU named after N.N. Burdenko, students and employees of secondary educational institutions of the Voronezh region, a branch of the SSC PJSC "Rostelecom", LLC "BorMash".
2. Eligibility criteria
Questioning of children aged 13 and 14, adolescents aged 15 to 18, adults of working age from 19 to 59 years.
3. Conditions
FGBOUVO "VSMU named after Burdenko ”, FBUZ“ Center for Hygiene and Epidemiology in the Voronezh Region ”, OTSO PJSC“ Rostelecom ”in Voronezh, LLC“ BorMash ”in the village of Peski, Povorinsky District, Voronezh Region,“ MBOU BGO Borisoglebskaya Secondary School No. 3 ”, Voronezh Region, g. Borisoglebsk, "MKOU Krasnoflotskaya secondary school of Petropavlovsk region", Voronezh region, Petropavlovsk region, Krasnoflotskoe village.
4. Duration of research
Analysis of literature data was started in September 2019. The survey was carried out in 2018-2020.
5. Description of the medical intervention
The respondents were questioned on the presence of allergic diseases confirmed in medical and preventive establishments (MPI), the presence of such in their close relatives, an assessment of possible allergy symptoms, accessibility to healthcare facilities and the use of medicines was carried out. The diversity of the diet of the respondents and the presence of foods to which they had allergic manifestations were also assessed.
6. The main outcome of the study
Coverage of the problem of the influence of the microbial composition of various body systems on the occurrence of allergic pathology according to the literature.
7. Additional study outcomes
Evaluation of the food ration of the respondents and Rosstat data, the possibility of assuming the presence of a variety of microbial flora.
8. Analysis in subgroups
Survey data for children (13-14 years old), adolescents (15-18 years old) and adults (19-59 years old) population of Voronezh and the Voronezh region.
9. Methods of registration of outcomes
The ratio of the part of the population with the revealed signs of the disease to the part of the population that was examined.
10. Statistical analysis
Principles for calculating the sample size: The sample size was not pre-calculated.
Methods of statistical data analysis:
a) Microsoft Office (Excel) program was used.
b) numerical format for presenting quantitative data;
c) data analysis using the Statistica 6.0 and Microsoft Office (Excel) statistical software package.
results
Objects (participants) of the research: the research used the PubMed and Elibrary databases; survey participants (students and working population of Voronezh and the Voronezh region), materials of the statistical reporting form No. 12 (annual) for the period from 2012-2018, Rosstat data.
The main research results: according to numerous studies, the microbial communities of the intestine, respiratory tract, skin in healthy ovom organism have certain ratios between certain microorganisms, while the microbiota of each person is individual.
The human digestive tract is characterized by a wide variety of microbiota. O.S. Medvedev in his lecture "Microbiota and cardiovascular diseases" indicates that 1 g of feces in the small intestine contains 107, and in the large - up to 1012-14 various aerobic and anaerobic microorganisms. Bifidobacteria are an integral component of the human intestinal microflora. Much attention is paid to their immunomodulatory properties. The microbial composition of the respiratory tract is also very diverse due to the migration of bacteria between its departments during inhalation of air [2]. Among the predominant microorganisms in healthy people, there are types such as Firmicutes, Bacteroidetes and Proteobacteria (Prevotell, Streptococcus, Veillonella, etc.). Skin integuments are distinguished by their unique combination of microorganisms, the balance of the number of which provides protection against various inflammatory diseases, including allergic ones.
Since colonization and an increase in the diversity of the human intestinal flora begins even during the period of intrauterine development, it is necessary to carefully monitor possible factors that contribute to violations of the microbial composition. Conditionally pathogenic microflora is endowed with the ability to colonize the digestive tract much faster than beneficial bifidobacteria and lactobacilli, which causes immune disorders and subsequent sensitization. The development of food allergies can contribute to the occurrence of respiratory (asthma, rhinitis) and skin (dermatitis) allergic manifestations, since many food allergens cross with pollen, medicinal and other allergens. The nature of the diet, the variety of the diet, the presence of a sufficient amount of dietary fiber, contributes to the formation of the species diversity of the intestinal microbiome, and, as a consequence, the increased resistance of the human body to various environmental factors, including allergic genesis. Elimination of an allergen is not only an effective treatment, but also an opportunity to confirm the presence of a disease. In the Russian Federation, elimination dietary diagnostics is recognized as the most gentle method in comparison with provocative tests [3]. A non-specific hypoallergenic diet will also help to alleviate the symptoms of an allergic disease.
The literature describes studies of the positive effect of microbiota correction on the severity of allergic manifestations. Parakhonsky A.P. used Lactobacillus casei to correct dysbiosis in patients with BA, AR and AD. The treatment provided improved asthma control and reduced the amount of basic drugs. In the case of AR, there was a decrease in the frequency of symptoms, no need for therapy. Such treatment of dysbiosis in AD promoted lengthening of the remission period, restoration of the immune balance [4].
Additional results of the study: analysis of the nature of nutrition of the population of the Voronezh region revealed an imbalance in the diet [5], while the assessment of the diet of respondents by the main groups of products: bread products, vegetables, fruits and berries, meat and dairy products, eggs, fish, sugar and confectionery, vegetable oil and other fats, soft drinks, has determined its sufficient variety. The absence of two or more food groups in the diet was observed in 20% of women and 24% of men. Cases of allergic manifestations to food were isolated. For women, such products were: root crops, fresh fruits and berries, citrus fruits, nuts and seeds, fruit and vegetable juices, seafood and fish caviar, chocolate and sweets, honey, fruit drinks, some spices. Men were allergic to mushrooms, fresh fruits and berries, citrus fruits, canned fish, chocolate and sweets and honey. About 70% of the surveyed women and 90% of men did not have a confirmed diagnosis of an allergic disease in a healthcare facility, while experiencing symptoms typical of allergic pathology - 73% of respondents.
Adverse events: none.
Discussion
Summary of the main result of the study: Analyzing the literature, we can note the emergence of increasing evidence that the microbiota can influence many vital homeostatic processes that support a healthy immune system. Despite the high achievements in the field of laboratory diagnostics, the isolation and decoding of the microbial composition of a particular person presents certain difficulties. The availability of methods for correcting the microbial composition of a macroorganism opens up new possibilities for the prevention and treatment of various allergic diseases.
Discussion of the main result of the study: according to the literature, one of the causes of allergic diseases should be considered microflora dysbiosis, and it is an increase in the amount of anaerobic flora that leads to pathological changes. The detection of anaerobes is technically a sore. The most informative methods are gas chromatography, mass spectrometry, sequencing, but due to their high cost, their use in the Voronezh region is limited. It is known that a varied diet is one of the factors that have a positive effect on the composition of the microbial flora of the body. The questionnaire survey shows that the majority of respondents consume all food products from the proposed groups, the cases of sensitization to food products are minimal. This suggests a sufficient variety of microflora, which prevents the sensitization of the body.
Research limitations: sample size, estimation methods used.
Conclusion
The microbiota of the human body plays an important role in the stable functioning of all its systems. Strengthening the diagnostic base for detecting the composition of the microbial flora will contribute to the development of targeted methods for correcting dysbiosis. The data obtained by the questionnaire method make it possible to subjectively assess the diversity of the intestinal microbiota in terms of the diet. The questions in the questionnaire regarding the presence of allergic symptoms revealed that most of the respondents experienced them, but did not go to the doctor for one reason or another. Among the reasons: lack of time, lack of a specialist at the patient's place of residence, self-medication. The lack of referrals indicates that diagnoses are not registered in health care facilities. This indicates a discrepancy between the indicators of official statistics and true cases of allergic diseases.

About the authors

Alina Alekseevna Pchelinceva

Воронежский государственный медицинский университет им. Н.Н. Бурденко, кафедра эпидемиологии

Author for correspondence.
Email: a_mivi@mail.ru
ORCID iD: 0000-0003-4988-2035

Студентка 6 курса Воронежского государственного медицинского университета им. Н.Н. Бурденко

Russian Federation

References