title: Association of the single-nucleotide polymorphism and haplotype of the interleukin 18 gene with atopic dermatitis in Koreans.
abstract: BACKGROUND
  IL-18 is a proinflammatory cytokine that plays an important role for T-helper type 1 (Th1) and Th2 cytokine in the presence/absence of IL-12. It has been recently shown that human IL-18 plays a role in atopic dermatitis (AD) by enhancing IL-4 and IL-13 production and by stimulating the synthesis of IgE.
  
  
  OBJECTIVE
  We wanted to evaluate the associations of single-nucleotide polymorphism (SNP) and the haplotype in the IL-18 gene, hence we performed genotyping for the SNPs in the IL-18 gene in AD patients and normal controls.
  
  
  METHODS
  We genotyped three SNPs from the IL-18 gene for the 1120 case-control samples (646 AD patients and 474 normal controls). We measured the serum IL-18, IL-4 and IL-13 concentrations in 74 individuals (25 ADe, 25 ADi and 24 controls) by performing ELISA.
  
  
  RESULTS
  The rs795467 SNP and haplotype T-T-C were significantly associated with AD, and especially between the ADe and normal control groups (P=0.03 and 0.01). The serum IL-18 concentration was higher in the AD group than in the normal controls without any correlation with the rs795467 polymorphism. We did not find any correlations between the serum IL-18 levels and the SCORing atopic dermatitis index, the blood eosinophil counts and the ECP, and there was no correlation between the serum IL-18 levels and the serum IL-4 and IL-13 levels.
  
  
  CONCLUSIONS
  We found that the one SNP and the haplotype T-T-C were strongly associated with the allergic type of AD, but not with the non-allergic intrinsic type. These data support the hypothesis that IL-18 up-regulates IgE production, yet more experiments will be needed to prove the in vivo involvement of Th2 cytokine.
authors.affiliation: Department of Dermatology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea.
authors.forename: E
authors.initials: E
authors.lastname: Kim
authors.forename: J-E
authors.initials: JE
authors.lastname: Lee
authors.forename: J-H
authors.initials: JH
authors.lastname: Namkung
authors.forename: J-H
authors.initials: JH
authors.lastname: Park
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.forename: E-S
authors.initials: ES
authors.lastname: Shin
authors.forename: E-Y
authors.initials: EY
authors.lastname: Cho
authors.forename: J-M
authors.initials: JM
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000097:blood / Q000235:genetics* / Q000276:immunology; D005260:Female; D006239:Haplotypes / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D018664:Interleukin-12 / Q000097:blood / Q000276:immunology; D018793:Interleukin-13 / Q000097:blood / Q000276:immunology; D020382:Interleukin-18 / Q000097:blood / Q000235:genetics* / Q000276:immunology; D015847:Interleukin-4 / Q000097:blood / Q000276:immunology; D007723:Korea; D008297:Male; D020641:Polymorphism, Single Nucleotide; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
chemical_list: C508598:IL4 protein, human; D018793:Interleukin-13; D020382:Interleukin-18; D018664:Interleukin-12; D015847:Interleukin-4; D007073:Immunoglobulin E