HLA-DRB1 GENE POLYMORPHISMS IN PEDIATRIC PATIENTS WITH TYPE 1 AUTOIMMUNE HEPATITIS AND TYPE 1 AUTOIMMUNE HEPATITIS OVERLAP SYNDROME WITH AUTOIMMUNE CHOLANGITIS

Autoimmune hepatitis (AIH) is a rare chronic inflammatory liver disease associated with a loss of immunological tolerance to self-antigens. Susceptibility to AIH is partially determined by the presence of genes related to human leukocyte antigen (HLA), mainly allelic variants of DRB1. The purpose of this study was to investigate the frequencies of the polymorphisms in HLA-DRB1 gene in children and adolescents with type 1 AIH and type 1 AIH overlap syndrome with autoimmune cholangitis (overlap syndrome, OS) in comparison to healthy sex and age-matched individuals (control group). This is a cross-sectional study of 25 pediatric patients diagnosed with type 1 AIH and 18 with OS. Fifty-seven healthy individuals were included as controls. The polymorphisms of the HLA-DRB1 gene were evaluated by PCR and included HLA-DRB1*03, HLA-DRB1*04, HLA-DRB1*07, and HLA-DRB1*13. Our results showed that the presence of the allele HLA-DRB1*13 increased the chance of autoimmune cholangitis (OR=3.96, CI 1.07 to 14.61, P=0.04). The HLA-DRB1*04 and HLA- DRB1*07 have no association with the AIH and autoimmune cholangitis in a young sample. This work demonstrates an association of the main polymorphisms in the HLA-DRB1 gene to AIH with or without cholangitis in a Brazilian sample.