RESUMO
<p><b>OBJECTIVE</b>Autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) are two autoimmune diseases of unknown etiology. Genetic factors appear to be involved in the pathogenesis of both diseases. Tumor necrosis factor (TNF)-alpha is one of the proinflammatory cytokines and immunomodulators, and is implicated in the pathogenesis of AIH and PBC. In this study, we studied the association between Chinese patients with AIH, PBC and the polymorphisms in promoter-region polymorphisms of the TNF-alpha gene at position -308 and -238.</p><p><b>METHODS</b>We have investigated four candidate gene loci in 49 patients with AIH, 58 patients with PBC, and 160 healthy controls. The polymorphisms were assessed by the PCR specifically for the single-nucleotide polymorphisms.</p><p><b>RESULTS</b>We found the difference in the TNF-alpha gene at position -308 genotype distributions between Chinese health controls and Caucasian health controls. Although the percent of TNF-alpha*2 was decrease on PBC patient group (10.34% vs. 16.88%), there was no significant difference between PBC patients and health control in the Chinese. There were also no significant differences between AIH and health control on the TNF-alpha gene at position -308 and -238.</p><p><b>CONCLUSION</b>Our findings suggest that the TNF-alpha promoter-region polymorphisms distribution is different between differe of ethnic groups; there are no genetic links of the TNF-alpha promoter-region polymorphisms to AIH and PBC in Chinese.</p>