title: HLA-DR, DQ genotypes of celiac disease patients and healthy subjects from the West of Ireland.
abstract: Celiac disease (CD) has one of the strongest class II HLA associations of any human illness. We used DNA-RFLP typing to study the class II HLA genotypes of celiac disease patients from the West of Ireland, the geographic area with the highest rate of celiac disease in the world. We confirmed the high frequency of HLA-DR3 in this population, and we were also able to demonstrate the additional risk of developing celiac disease imparted by HLA-DR7. This was done by clearly distinguishing DR7,DQ2 haplotypes from DR7,DQ9 haplotypes, and by "subtraction analysis" of haplotype frequencies. As reported in other populations, most of the patients without DR3 were heterozygous for DR7 and DR11 or 12 (DR5), or had DR4. We used PCR-RFLP and direct sequencing of amplified DNA to examine HLA-DR4 subtypes. The frequency of HLA-DR4 was markedly decreased in patients compared with controls (p = 0.000001) and there was a significant alteration of DR4 subtypes of the patients compared with controls (p = 0.0227). Moreover, all of the CD patients (5 of 5) with DR4 had a haplotype associated with the DQB1*0302 allele compared with only 11 of 23 control subjects with DR4. Our results in this population with exceptionally high risk of CD strongly support the DQ heterodimer hypothesis and suggest that the recently described sequence difference between the DQB1*02 alleles of DR3 and DR7 may contribute to a synergistic increased risk when these haplotypes are inherited together. In addition, our findings suggest a role for HLA-DQ in DR4-associated CD.
authors.affiliation: Department of Internal Medicine, University of South Alabama, Mobile, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Michalski
authors.forename: C C
authors.initials: CC
authors.lastname: McCombs
authors.forename: T
authors.initials: T
authors.lastname: Arai
authors.forename: R C
authors.initials: RC
authors.lastname: Elston
authors.forename: T
authors.initials: T
authors.lastname: Cao
authors.forename: C F
authors.initials: CF
authors.lastname: McCarthy
authors.forename: F M
authors.initials: FM
authors.lastname: Stevens
mesh_terms: D002446:Celiac Disease / Q000235:genetics* / Q000276:immunology; D005500:Follow-Up Studies; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D015803:HLA-DR3 Antigen / Q000235:genetics; D015804:HLA-DR4 Antigen / Q000235:genetics; D015809:HLA-DR7 Antigen / Q000235:genetics; D006239:Haplotypes; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D006801:Humans; D007494:Ireland
chemical_list: D006683:HLA-DQ Antigens; C053186:HLA-DQ2 antigen; D006684:HLA-DR Antigens; D015803:HLA-DR3 Antigen; D015804:HLA-DR4 Antigen; D015809:HLA-DR7 Antigen; D000949:Histocompatibility Antigens Class II