A STAT4 variant increases liver fibrosis risk in Caucasian patients with chronic hepatitis B

BACKGROUND

Host genetic modifiers of the natural history of chronic hepatitis B (CHB) remain poorly understood. Recently, a genome-wide association study (GWAS)-identified polymorphism in the STAT4 gene that contributes to the risk for hepatocellular carcinoma (HCC) was shown to be associated with the full spectrum of hepatitis B virus (HBV) outcomes in Asian patients. However, the functional mechanisms for this effect are unknown and the role of the variant in modulating HBV disease in Caucasians has not been investigated.

AIMS

To determine whether STAT4 genetic variation is associated with liver injury in Caucasian patients with CHB and to investigate potential mechanisms mediating this effect.

METHODS

STAT4 rs7574865 was genotyped in 1085 subjects (830 with CHB and 255 healthy controls). STAT4 expression in liver, PBMCs and NK cells, STAT4 phosphorylation and secretion of interferon-gamma (IFN-γ) according to STAT4 genetic variation was examined.

RESULTS

STAT4 rs7574865 genotype was independently associated with hepatic inflammation (OR: 1.42, 95% CI: 1.07-2.06, P = 0.02) and advanced fibrosis (OR: 1.83, 95% CI: 1.19-2.83, P = 0.006). The minor allele frequency of rs7574865 was significantly lower than that in healthy controls. rs7574865 GG risk carriers expressed lower levels of STAT4 in liver, PBMCs and in NK cells, while NK cells from patients with the risk genotype had impaired STAT4 phosphorylation following stimulation with IL-12/IL-18 and a reduction in secretion of IFN-γ.

CONCLUSION

Genetic susceptibility to HBV persistence, hepatic inflammation and fibrosis in Caucasians associates with STAT4 rs7574865 variant. Downstream effects on NK cell function through STAT4 phosphorylation-dependent IFN-γ production likely contribute to these effects.

Clinical features and outcomes of hepatocellular carcinoma in Caucasian cirrhotic patients on long-term analogue therapy for hepatitis B

BACKGROUND

Long-term oral nucleos(t)ide analogue (NUC) therapy in hepatitis B virus (HBV)-related compensated cirrhotics prevents clinical decompensation but not hepatocellular carcinoma (HCC) development.

AIMS

To define the clinical features and outcomes of HCC in long-term NUC-treated HBV patients.

METHODS

All HCCs developing between 2005 and 2016 in NUC-treated HBV patients under surveillance were studied, excluding those that occurred within the first 6 months of therapy. Clinical features of HCC, alpha faetoprotein (AFP) patterns and patients' outcome were studied.

RESULTS

Seventy-six HCC patients were included. Median age was 67 (40-83) years, 84% males, 96% Caucasian, 95% HBeAg-negative, 96% with undetectable HBV DNA, 83% with normal ALT levels, and 92% with compensated cirrhosis. Median serum AFP levels were 4 (1-3615) ng/mL (>7 ng/mL in 36%). HCC was monofocal in 78%, had a median diameter of 20 (6-57) mm and was in its early stage in 92% which allowed potentially curative treatments in 78% (39% ablation, 28% surgical resection, 11% liver transplantation). Overall, a complete response was obtained in 61 (80%) patients: in 40 after a first-line treatment, in 3 after the second-line treatment, in 2 after the third-line treatment, while 16 underwent liver transplantation (8 as second line). During 45 (7-144) months after HCC diagnosis, 19 patients died, 84% from HCC progression. The median time to recurrence was 20.2 (3-53) months, and the cumulative 5-year liver-related survival was 74%.

CONCLUSIONS

HCCs developing in patients under long-term NUC treatment were single, small tumours, amenable to curative therapies able to confer excellent 5-year survival rates.