Autoimmune hepatitis in Brazilian patients is not linked to tumor necrosis factor α polymorphisms at position-308

Background/Aims: Susceptibility to autoimmune hepatitis (AIH) has been linked to different HLA-DR antigens, Recently, AIH type 1 was associated with polymorphisms in the tumor necrosis factor alpha gene promotes (TNFA) at position -308. In this respect, the frequency of the TNFA*2 allele, in linkage disequilibrium with HLA-DRB1*0301, was shown to be significantly increased in whites with AIH type 1. The aim of this study was to assess the role of TNFA alleles in conferring susceptibility to AIH, studying a population where the disease is not primarily associated with HLA-DRB1*03. Methods: The determination of HLA-DRB1 and TNFA alleles was performed in 92 patients with ALH type 1, 29 subjects with AIH type 2 and 53 healthy controls by polymerase chain reaction-based techniques. Results: The distribution of TNFA alleles was similar in patients with AIH types 1 and 2, when compared with controls. In addition, the TNFA*2 allele was identified in patients carrying HLA-DR antigens other than HLA-DRB1*03. Interestingly, higher gammaglobulin levels were observed in TNFA*2 positive patients. Conclusions: Our data indicate that susceptibility to AIH remains primarily linked to the HLA-DRB1 locus, and suggest that the association of AIH with TNFA*2 previously observed in whites might be secondary to a linkage disequilibrium with MLA-DRB1*0301, (C) 2001 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.