Autoimmune hepatitis in Brazilian patients is not linked to tumor necrosisfactor alpha polymorphisms at position-308

Background/Aims: Susceptibility to autoimmune hepatitis (AIH) has been link ed to different HLA-DR antigens, Recently, AIH type 1 was associated with p olymorphisms in the tumor necrosis factor alpha gene promotes (TNFA) at pos ition -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 wh ere 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 contr ols 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 positiv e 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 diseq uilibrium with MLA-DRB1*0301, (C) 2001 European Association for the Study o f the Liver. Published by Elsevier Science B.V. All rights reserved.