Tumor necrosis factor gene polymorphisms and clearance or progression of hepatitis B virus infection


Grazia Anna Niro, MD, Division of Gastroenterology, Casa Sollievo della Sofferenza Hospital, Viale Cappuccini, 71013 San Giovanni Rotondo (FG), Italy.
Tel: +39 0882 410263
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e-mail: nirograzia@tiscalinet.it


Abstract: Objectives: We evaluated the influence of tumor necrosis factor-α (TNF-α) promoter gene polymorphisms on clearance of hepatitis B virus (HBV) and outcome of HBV chronic hepatitis.

Methods: Four TNF-α promoter polymorphisms (T-1031C, C-863A, G-308A, and G-238A) were evaluated by direct sequencing in 184 chronic HBV carriers hepatitis B surface antigen (HBsAg) positive and 96 controls with documented sero-clearance (HBsAg negativity, positivity for anti-HBs and anti-HBc IgG). Frequencies of single-nucleotide polymorphisms (SNPs) and haplotypes in the control group were compared with those of the chronic carrier group and with clinically defined subgroups of the latter: asymptomatic carriers, patients with compensated hepatitis, decompensated cirrhotics, and patients with hepatocellular carcinoma. Furthermore, subgroups of chronic carriers were compared among them.

Results: In the chronic carrier group, the −308G allele was more frequent in those with a family history of HBV infection (96% vs 88% of those with non-familial transmission). The G/G genotype at position −308 was found in all chronic carriers with decompensated cirrhosis but in only 78% of controls (P=0.01) and was more frequent in decompensated cirrhotics than in the other subgroups. The distribution of TNF-α gene polymorphisms in the carrier group was not significantly different from that in the sero-clearance control group. TNF-α SNPs at positions −1031/−863 and −863/−238 were in linkage disequilibrium. The TCGG haplotype (−T1031, −C863, −G308, −G238) was significantly associated with end-stage liver disease.

Conclusion: The TNF-α promoter polymorphisms do not appear to be determinant of HBV sero-clearance in southern Italians. The genotype −308G/G and haplotype TCGG are associated with an unfavorable prognosis in patients with chronic HBV infection.