title: HLA-DR and -DQ phenotypes in inflammatory bowel disease: a meta-analysis.
abstract: BACKGROUND
  Susceptibility to inflammatory bowel disease (IBD) is partially genetically determined and the HLA class II genes are candidates for a role in genetic susceptibility to IBD, because their products play a central role in the immune response. Multiple studies have reported associations between HLA-DR or -DQ phenotypes and either ulcerative colitis or Crohn's disease, but much of the data are still controversial.
  
  
  OBJECTIVE
  To estimate overall associations between HLA class II phenotypes and IBD, and to establish the relative risk conferred by HLA-DR and -DQ phenotypes by meta-analysis.
  
  
  METHODS
  Medline was searched for publications reporting on the relation between IBD and HLA class II phenotypes. Raw data were extracted by recalculating the number of phenotypes or the number of alleles of the main antigens. Odds ratios and confidence intervals were calculated according to the Mantel-Haenszel method.
  
  
  RESULTS
  DR2, DR9, and DRB1*0103 were positively associated with ulcerative colitis, and a negative association was found for DR4 and ulcerative colitis. For Crohn's disease a positive association was found with DR7, DRB3*0301, and DQ4 and a negative association with DR2 and DR3.
  
  
  CONCLUSIONS
  Both ulcerative colitis and Crohn's disease are associated with specific HLA class II phenotypes. Further analysis of these phenotypes and subgroup analysis may elucidate how these alleles contribute to susceptibility to IBD.
authors.affiliation: Laboratory for Experimental Internal Medicine, Academic Medical Centre, G2-105, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: P C
authors.initials: PC
authors.lastname: Stokkers
authors.forename: P H
authors.initials: PH
authors.lastname: Reitsma
authors.forename: G N
authors.initials: GN
authors.lastname: Tytgat
authors.forename: S J
authors.initials: SJ
authors.lastname: van Deventer
mesh_terms: D015415:Biomarkers / Q000032:analysis; D003093:Colitis, Ulcerative / Q000235:genetics*; D003424:Crohn Disease / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006683:HLA-DQ Antigens / Q000032:analysis*; D006684:HLA-DR Antigens / Q000032:analysis*; D006801:Humans; D010641:Phenotype
chemical_list: D015415:Biomarkers; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens