title: Gut microbiota and allergy: the importance of the pregnancy period.
abstract: Limited microbial exposure is suggested to underlie the increase of allergic diseases in affluent countries, and bacterial diversity seems to be more important than specific bacteria taxa. Prospective studies indicate that the gut microbiota composition during the first months of life influences allergy development, and support the theory that factors influencing the early maturation of the immune system might be important for subsequent allergic disease. However, recent research indicates that microbial exposure during pregnancy may be even more important for the preventative effects against allergic disease. This review gives a background of the epidemiology, immunology, and microbiology literature in this field. It focuses on possible underlying mechanisms such as immune-regulated epigenetic imprinting and bacterial translocation during pregnancy, potentially providing the offspring with a pioneer microbiome. We suggest that a possible reason for the initial exposure of bacterial molecular patterns to the fetus in utero is to prime the immune system and/or the epithelium to respond appropriately to pathogens and commensals after birth.
authors.affiliation: 1] Department of Clinical and Experimental Medicine, Division of Pediatrics, Linköping University, Sweden [2] Research Institute, Hospital for Sick Children, University of Toronto, Ontario, Canada.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Abrahamsson
authors.affiliation: Research Institute, Hospital for Sick Children, University of Toronto, Ontario, Canada.
authors.forename: Richard You
authors.initials: RY
authors.lastname: Wu
authors.affiliation: 1] Department of Clinical and Experimental Medicine, Division of Pediatrics, Linköping University, Sweden [2] Department of Clinical and Experimental Medicine, Unit of Autoimmunity and Immune Regulation, Division of Clinical Immunology, Linköping University, Sweden.
authors.forename: Maria C
authors.identifier: 0000000221175366
authors.initials: MC
authors.lastname: Jenmalm
mesh_terms: D044127:Epigenesis, Genetic / Q000276:immunology*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000276:immunology* / Q000382:microbiology*; D064307:Microbiota; D008954:Models, Biological; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000382:microbiology*