Association of human leucocyte-DR and DQ antigens in coeliac disease: a family study

Background and Aims: No family studies regarding the association of coeliac disease with the human leucocyte antigen (HLA)-DQ locus are available. Moreover, no HLA studies have been carried out in coeliac disease patients from India. The aim of this study was to study the HLA class II (DR and DQ) antigens in children with coeliac disease and in their first-degree relatives. Methods: Fifteen children with coeliac disease and their first-degree relatives (birth parents of all the coeliac disease patients and fifteen siblings) were studied. A group of 123 healthy unrelated and ethnically matched subjects were used as controls. The HLA-DR and -DQ typing was carried out by a complement-dependent microlymphocytotoxicity assay. The transmission disequilibrium test was used for analysis of results. Results: There was no association of coeliac disease with DR phenotypes. Ninety-three per cent of patients (14/15) carried the DQ2 allele. DQ2 was transmitted in 15 of 19 informative cases (transmission probability of 79%, χ2 6.368 with 1 df, nominal P = 0.012 and P value corrected for multiple test = 0.035). The haplotype relative risk associated with DQ2 was 5.71 (95% confidence interval 1.71- 16.28). Conclusion: Coeliac disease in Indian children is predominantly associated with HLA-DQ2