title: No simple answers for the Finnish and Russian Karelia allergy contrast: Methylation of CD14 gene.
abstract: Finnish and Russian Karelian children have a highly contrasting occurrence of asthma and allergy. In these two environments, we studied associations between total serum immunoglobulin E (IgE) with methylation levels in cluster of differentiation 14 (CD14).
  
  
  
  Five hundred Finnish and Russian Karelian children were included in four groups: Finnish children with high IgE (n = 126) and low IgE (n = 124) as well as Russian children with high IgE (n = 125) and low IgE (n = 125). DNA was extracted from whole blood cells and pyrosequenced. Three CpG sites were selected in the promoter region of CD14.
  
  
  
  Methylation levels in two of the three CpG sites were higher in the Finnish compared to Russian Karelian children. In the promoter area of CD14, the Finnish compared to Russian children with low IgE had a significant (p < 0.0001) increase in methylation levels at the Amp5Site 2. Likewise, the Finnish compared to Russian children with high IgE had a significant (p = 0.003) increase in methylation levels at the Amp5Site 3. In Russian children with low vs. high IgE, there were significant differences in methylation levels, but this was not the case on the Finnish side. In the regression analysis, adding the methylation variation of CD14 to the model did not explain the higher asthma and allergy risk in the Finnish children.
  
  
  
  The methylation levels in the promoter region of CD14 gene were higher in the Finnish compared to Russian Karelian children. However, the methylation variation of this candidate gene did not explain the asthma and allergy contrast between these two areas.
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, WA, Australia. Kim.Khoo@telethonkids.org.au.
authors.forename: Siew-Kim
authors.initials: SK
authors.lastname: Khoo
authors.affiliation: Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Mäkelä
authors.affiliation: Australian Genome Research Facility Ltd, Perth, WA, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Chandler
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, WA, Australia.
authors.forename: En Nee
authors.initials: EN
authors.lastname: Schultz
authors.affiliation: Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia.
authors.forename: Sarra E
authors.initials: SE
authors.lastname: Jamieson
authors.affiliation: Genetic Services & Familial Cancer Program of Western Australia, King Edward Memorial Hospital for Women, Perth, WA, Australia.
authors.forename: Jack
authors.initials: J
authors.lastname: Goldblatt
authors.affiliation: Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Tari
authors.initials: T
authors.lastname: Haahtela
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, WA, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: LeSouëf
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Perth, WA, Australia. brad.zhang@curtin.edu.au.|Telethon Kids Institute, Centre for Child Health Research, The University of Western Australia, Perth, WA, Australia. brad.zhang@curtin.edu.au.|School of Public Health, Curtin University, Perth, WA, Australia. brad.zhang@curtin.edu.au.|Centre for Genetic Origins of Health and Disease, Curtin University and the University of Western Australia, Perth, WA, Australia. brad.zhang@curtin.edu.au.
authors.forename: Guicheng
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000276:immunology; D001249:Asthma / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D005387:Finland / Q000453:epidemiology; D056726:Genetic Association Studies; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000235:genetics*; D007073:Immunoglobulin E / Q000097:blood; D018950:Lipopolysaccharide Receptors / Q000235:genetics*; D008297:Male; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012306:Risk; D012426:Russia / Q000453:epidemiology; D012959:Socioeconomic Factors
chemical_list: D000485:Allergens; D018950:Lipopolysaccharide Receptors; D007073:Immunoglobulin E
keywords: 
  cluster of differentiation 14
  ; allergy; asthma; immunoglobulin E; methylation