title: Genetic impact of a butyrophilin-like 2 (BTNL2) gene variation on specific IgE responsiveness to Dermatophagoides farinae (Der f) in Japanese.
abstract: BACKGROUND
  Dermatophagoides farinae (Der f) is one of the most frequently implicated allergens in several allergic diseases. Several genome-wide screens have identified a linkage between chromosome 6p21 and mite-specific IgE responsiveness. Butyrophilin-like 2 (BTNL2) is a member of the immunoglobulin superfamily and, on the basis of its homology to B7-1, has been implicated as a costimulatory molecule involved in T-cell activation. BTNL2 resides in the HLA region on chromosome 6p21, and significant associations between BTNL2 gene polymorphisms and several inflammatory diseases have been reported.
  
  
  OBJECTIVE
  The aim of this study was to examine whether BTNL2 gene polymorphisms are associated with specific IgE responses to Der f.
  
  
  METHODS
  Three single nucleotide polymorphisms (SNPs), including 2 coding SNPs and 1 intron SNP, were studied. One of the coding SNPs was the rs2076530 A > G, which has a functional consequence. A total of 863 unrelated Japanese subjects (447 positive and 416 negative for IgE to Der f) were recruited for a case-control study.
  
  
  RESULTS
  Controlling for gender, age, smoking, and the presence of asthma, multiple logistic regression analyses showed that homozygosity of the rs2076530 A allele, which has been reported to be a risk allele for sarcoidosis, was associated with a risk of sensitization towards Der f (Odds ratio; 1.55, p = 0.0060).
  
  
  CONCLUSIONS
  Although an association which may be due to the linkage disequilibrium with other genes in 6p21 needs to be ruled out, the present findings suggest that the BTNL2 gene might be one of the candidate genes that is responsible for the pathogenesis of Der f-specific IgE responsiveness.
authors.affiliation: First Department of Medicine, Hokkaido University School of Medicine, Hokkaido, Japan. satkonno@med.hokudai.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Konno
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takahashi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hizawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hattori
authors.forename: Ayumu
authors.initials: A
authors.lastname: Takahashi
authors.forename: Akira
authors.initials: A
authors.lastname: Isada
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Maeda
authors.forename: Shau-Ku
authors.initials: SK
authors.lastname: Huang
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000071797:Butyrophilins; D040001:Dermatophagoides farinae / Q000276:immunology*; D005260:Female; D005802:Genes, MHC Class II; D006239:Haplotypes; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide
chemical_list: C408263:BTNL2 protein, human; D000071797:Butyrophilins; D008562:Membrane Glycoproteins; D007073:Immunoglobulin E