Vaginal microbiota is an epigenetic factor for early onset of atopy in children of asthmatic mothers

Abstract

E.A. Boytsova1, T.V. Kosenkova1, N.M. Bogdanova2, V.P. Novikova2,3, M.N. Boldyreva4, O.V. Lavrova3, V.F. Bezhenar’3 1 V.A. Almazov National Medical Research Centre, St. Petersburg, Russian Federation 2 St. Petersburg State Pediatric Medical University, St. Petersburg, Russian Federation 3 Pavlov First St. Petersburg State Medical University, St. Petersburg, Russian Federation 4 NRC Institute of Immunology, Moscow, Russian Federation Background: in recent years, early (i.e., within the first days or weeks of life) onset, severe course, and comorbid nature of allergies are reported in children. The risk of atopic disorder in a child of asthmatic mother is always significantly higher. Sensitization is determined by hereditary load as well as by epigenetic factors. Among them, the course of pregnancy is of crucial importance. Molecular mechanisms of the effect of gestational maternal microbiota (in particular, vaginal microbiocenosis) on the course of pregnancy and delivery as well as their protective role in neonatal health and atopic disorder development are still elusive and require further investigation. Aim: to study vaginal microbiota in pregnant women with asthma, to identify factors affecting vaginal microbiocenosis, and to establish the association between cervical microbiota composition and atopy onset in a child. Patients and Methods: the study included 37 couples, i.e., pregnant w oman with moderate asthma and her child. Pregnant women were enrolled at 36–38 weeks of gestation. Quantitative and qualitative composition of cervical microbiota was studied by polymerase chain reaction. Newborns were observed in maternity hospital and then monthly up to one year; clinical symptoms were assessed. Preeclampsia was diagnosed in 53% and threatened abortion in 47% of pregnant women. Results: in pregnant women with asthma, preeclampsia resulted in reduced levels of Lactobacillus spp. (p=0.29) in cervical mucus while threatened abortion resulted in increased levels of Gardnerella vaginalis (p=0.039). In mothers of children with atopy onset within the first 4 weeks of life, increased levels of Eubacterium spp. (p=0.025) in vaginal microflora were revealed at 38 weeks of gestation. In mothers with hypogalactia, increased levels of Mobiluncus spp. and Corynebacterium spp. (p=0.044) were revealed. Conclusion: threatened abortion and preeclampsia are epigen etic factors which affect cervical microflora composition in pregnant women with asthma and interrupt vertical transfer of microbiota from the mother. The result is the early onset of atopy in the child. Keywords: pregnancy, asthma, vaginal microbiota, children, allergy. For citation: Boytsova E.A., Kosenkova T.V., Bogdanova N.M. et al. Vaginal microbiota is an epigenetic factor for early onset of atopy in children of asthmatic mothers. Russian Journal of Woman and Child Health. 2019;2(3):200–205.