title: Distinct associations of HLA class II genes with inflammatory bowel disease.
abstract: BACKGROUND
  There are relatively few studies of HLA class II association either with Crohn's disease (CD) or ulcerative colitis (UC). The few available association studies have been carried out by serological techniques, and the results from these studies are inconclusive.
  
  
  METHODS
  The association between HLA class II genes was studied using molecular genotyping in combination with allele-specific oligonucleotide hybridization by polymerase chain reactions.
  
  
  RESULTS
  In UC (n = 74), we observed a positive association with the HLA DR2 allele (P = 0.008) and negative associations with the DR4 (P = 0.018) and DRw6 (P = 0.028) when compared with ethnically matched controls (n = 77). No associations were observed with any DQ alleles. In contrast, in CD (n = 95) we observed a positive association with the combination of DR1 and DQw5 alleles (P = 0.021). Furthermore, stratifying DR1 and DQw5 alleles indicated that neither allele was independently associated with CD, suggesting that the association was with the haplotype rather than either of the alleles individually. A suballele of DQw5, DQB1*0501, contributed this haplotypic association (P = 0.012).
  
  
  CONCLUSIONS
  DR and DQ molecules firmly separate UC and CD on genetic grounds, suggesting that the contribution of the HLA class II genes to the disease susceptibility is quite different for the two disorders.
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: H
authors.initials: H
authors.lastname: Toyoda
authors.forename: S J
authors.initials: SJ
authors.lastname: Wang
authors.forename: H Y
authors.initials: HY
authors.lastname: Yang
authors.forename: A
authors.initials: A
authors.lastname: Redford
authors.forename: D
authors.initials: D
authors.lastname: Magalong
authors.forename: D
authors.initials: D
authors.lastname: Tyan
authors.forename: C K
authors.initials: CK
authors.lastname: McElree
authors.forename: S R
authors.initials: SR
authors.lastname: Pressman
authors.forename: F
authors.initials: F
authors.lastname: Shanahan
authors.forename: S R
authors.initials: SR
authors.lastname: Targan
mesh_terms: D000483:Alleles; D001483:Base Sequence; D003093:Colitis, Ulcerative / Q000235:genetics* / Q000276:immunology; D003424:Crohn Disease / Q000235:genetics* / Q000276:immunology; D005787:Gene Frequency; D005802:Genes, MHC Class II; D006683:HLA-DQ Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data
chemical_list: D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens