title: Association of HLA class II genes with susceptibility to Crohn's disease.
abstract: BACKGROUND
  Published studies on the association between HLA class II genes and inflammatory bowel disease are contradictory perhaps because of the limited size and ethnic heterogeneity of the populations studied.
  
  
  OBJECTIVE
  To compare the frequencies of HLA class II genes in a large number of French patients with Crohn's disease and in an ethnically matched control group.
  
  
  METHODS
  344 patients (196 F, 148 M, mean age 23.6 years) with Crohn's disease were molecularly genotyped for the HLA-DQB1 and DRB1 alleles. The results were compared with those for an ethnically matched control population of 488 white adults.
  
  
  RESULTS
  There were two significant variations of alleles at the DQB1 locus: an increase in DQB1*0501 allele frequency (chi 2 = 10.6, corrected p value (pc) = 0.01, odds ratio (OR) = 1.61) and a decrease in DQB1*0602/0603 allele frequencies (chi 2 = 8.43, pc = 0.037, OR = 0.66). DRB1 analysis showed associations with three allelic variations: an increase in the frequencies of DRB1*01 (chi 2 = 12.86, pc = 0.003, OR = 1.75) and DRB1*07 alleles (chi 2 = 11.18, pc = 0.008, OR = 1.58) and a very significant decrease in that of the DRB1*03 allele (chi 2 = 19.7, pc = 9.10(-5), OR = 0.46).
  
  
  CONCLUSIONS
  The alleles DRB1*01 and DRB1*07 are associated with susceptibility to Crohn's disease. The strong negative association between the DRB1*03 allele and Crohn's disease suggests that the HLA-DRB1*03 allele mediates 'resistance' to Crohn's disease.
authors.affiliation: Laboratoire de Biochimie, Hôpital B., CH et U Lille, France.
authors.forename: P M
authors.initials: PM
authors.lastname: Danzé
authors.forename: J F
authors.initials: JF
authors.lastname: Colombel
authors.forename: S
authors.initials: S
authors.lastname: Jacquot
authors.forename: M N
authors.initials: MN
authors.lastname: Loste
authors.forename: D
authors.initials: D
authors.lastname: Heresbach
authors.forename: S
authors.initials: S
authors.lastname: Ategbo
authors.forename: S
authors.initials: S
authors.lastname: Khamassi
authors.forename: B
authors.initials: B
authors.lastname: Périchon
authors.forename: G
authors.initials: G
authors.lastname: Semana
authors.forename: D
authors.initials: D
authors.lastname: Charron
authors.forename: J P
authors.initials: JP
authors.lastname: Cézard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003424:Crohn Disease / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D005602:France / Q000453:epidemiology; D005802:Genes, MHC Class II / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011897:Random Allocation