title: Allergic disease in 8-year-old children is preceded by delayed B cell maturation.
abstract: BACKGROUND
  We previously reported that exposure to a farming environment is allergy-protective, while high proportions of neonatal immature/naïve CD5+B cells and putative regulatory T cells (Tregs) are risk factors for development of allergic disease and sensitization up to 3 years of age.
  
  
  OBJECTIVE
  To examine if B and T cell maturation are associated with allergic disease and farming environment over the first 8 years in life.
  
  
  METHODS
  In the prospective FARMFLORA study, including both farming and non-farming families, 48 of 65 children took part in the 8-year follow-up study. Various B and T cell maturation variables were examined in blood samples obtained at several occasions from birth to 8 years of age and related to doctors' diagnosed allergic disease and sensitization, and to farming environment.
  
  
  RESULTS
  We found that the incidence of allergic disease was lower among farmers' compared to non-farmers' children during the 8-year follow-up period, and that farmers' children had higher proportions of memory B cells at 8 years of age. Moreover, a high proportion of neonatal CD5+B cells was a risk factor for and may predict development of allergic disease at 8 years of age. A high proportion of Tregs was not protective against development of these conditions.
  
  
  CONCLUSIONS
  High proportions of neonatal naïve B cells remained as a risk factor for allergic disease in school-aged children. Thus, the accelerated B cell maturation observed among farmers' children may be crucial for the allergy-protective effect of a farming environment.
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Strömbeck
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Nordström
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Andersson
authors.affiliation: Pediatric Clinic, Skaraborg Hospital, Lidköping, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Andersson
authors.affiliation: Pediatric Clinic, Skaraborg Hospital, Lidköping, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Johansen
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Maglio
authors.affiliation: Department of Infectious Diseases, University of Gothenburg, Gothenburg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Rabe
authors.affiliation: Department of Infectious Diseases, University of Gothenburg, Gothenburg, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Adlerberth
authors.affiliation: Department of Infectious Diseases, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A E
authors.initials: AE
authors.lastname: Wold
authors.affiliation: Department of Pediatrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Hesselmar
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Rudin
authors.affiliation: Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A-C
authors.identifier: http://orcid.org/0000-0002-4303-8266
authors.initials: AC
authors.lastname: Lundell
mesh_terms: D000368:Aged; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D002648:Child; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis* / Q000276:immunology* / Q000401:mortality; D007114:Immunization; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007156:Immunologic Memory; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012882:Skin Tests; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000378:metabolism
chemical_list: D007073:Immunoglobulin E
keywords: B cells; T cells; allergic disease; basic immunology; basic mechanisms; clinical immunology; environment and hygiene hypothesis; farm; pediatrics