Linkage disequilibrium between HLA class II region and autoimmune hepatitis in pediatric patients

Background/Aims: Susceptibility HLA class II alleles associated with autoimmune hepatitis (AIH) were only described in case-control studies. Methods: The transmission/disequilibrium test was used in 50 simplex families with AIH, to determine if affected offspring received the disease-associated allele more frequently than its alternate. HLA-DRB1 and DQB1 allele genotyping and autoimmune regulator (AIRE) polymorphisms located in exons 6, 8 and 10 were investigated by PCR-based methods. Results: HLA-DRB1*03 allele was significantly transmitted from heterozygous parent to affected offspring (81.5%) with type I AIH compared to random expected frequency (50.0%; P = 0.004) or to unaffected offspring (42.8%; P = 0.03). HLA-DRB1*1301 allele showed. an excess transmission to affected children (100%) than expected frequency (P < 0.0001) or unaffected offspring (P = 0.001). The transmission of DQB1*201 or DQB1*0603 alleles showed significant deviation in patients compared to random frequencies: (84.8%; P < 0.0001 for DQB1*0201 or 100%; P < 0.0001 for DQB1*0603). HLA-DQB1*0201 showed a strong association with type 2 AIH in children (100.0%, P = 0.0005). Conclusions: HLA-DRB1 gene is the major genetic determinant in HLA class II region for children with type 1 AIH. Type 2 AIH is associated with the HLA-DQB1gene. Finally, AIRE gene abnormality does not contribute to the development of isolated AIH. (C) 2004 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.