Association of TBX21 T-1993C polymorphism with viral persistence but not disease progression in hepatitis B virus carriers

Aim: Transcription factor T-bet is responsible for the differentiation of naive T lymphocytes, and its expression level is linked with different responses to some viral infections, including hepatitis B virus (HBV) infection. In this report we examine whether promoter polymorphisms of the TBX21 gene (encoding T-bet) are associated with susceptibility to HBV persistence or disease progression in chronic HBV carriers.

Methods: Three previously reported promoter polymorphisms, T-1993C, T-1514C and G-1499A, were analyzed by polymerase chain reaction restriction fragment length polymorphism analysis. Two common polymorphisms, T-1993C and T-1514C, were selected for genotyping in 1074 chronic HBV carriers, 310 spontaneously recovered controls and 374 HBV naive controls. Of 1074 HBV carriers, 234 were considered to be asymptomatic carriers and 840 were found to have chronic progressive liver disease including cirrhosis and hepatocellular carcinoma. Haplotypes were constructed for each subject and associations with the susceptibility to persistent HBV infection were estimated by logistic regression.

Results: The –1993C allele in the TBX21 promoter was significantly more common among chronic HBV carriers compared with recovered controls (χ² = 6.65, P = 0.01). In contrast, the frequency of TT haplotype at positions –1993/–1514, was significantly higher in recovered controls than chronic HBV carriers (P = 0.0027, odds ratio = 1.57; 95% confidence interval, 1.16–2.12). In HBV carriers, the TBX21 promoter polymorphisms were not linked to disease progression.

Conclusion: The TBX21 promoter polymorphisms do not appear to be determinant of disease progression in Chinese HBV carriers. The T-1993C polymorphism in the TBX21 promoter influences susceptibility to persistent HBV infection.