HLA GENOTYPES IN CELIAC-DISEASE AND HEALTHY-INDIVIDUALS CARRYING GLIADIN ANTIBODIES

Objective: Coeliac disease is closely associated with the presence of gliadin antibodies and certain HLA class II alleles. The aim of this study was to compare the HLA genotype in gliadin antibody-positive individuals without coeliac disease with that in patients with clinically verified coeliac disease. Design: HLA genotyping was carried out in 65 patients with coeliac disease and the results were compared with those from 19 gliadin antibody-positive and 96 antibody-negative healthy blood donors. Methods: Immunoglobulin G and A gliadin antibodies were measured with a micro-enzyme-linked immunosorbent assay technique. Restriction fragment length polymorphism typing for determination of HLA was carried out by means of Southern blot analysis of restriction digests. Results: Coeliac disease was significantly correlated with the presence of HLA-DR3 and DQ2, whereas DQ1, DQ7, DR1, DR4 and DR5 were all under-represented in coeliac disease patients. Of the extended haplotypes, only DR3-DQ2 was associated with the disease, while DR1-DQ1, DR4-DQ7 and DR5-DQ7 were under-represented. The correlation between DR3-DQ2 and coeliac disease depended on homozygosity; 29% of the patients and 4% of the controls were homozygous for DQ2 compared with 18 and 1%, respectively, for DR3. Only five out of 19 of the gliadin antibody-positive healthy blood donors had HLA genotypes characteristic of coeliac disease, while 15 were DQ1-positive which would be expected to confer protection. Conclusion: These findings suggest that the presence or development of gliadin antibodies is independent of the HLA genotype.