IL28B polymorphism may guide pegylated interferon plus ribavirin therapy even after curative treatment for hepatitis C virus-related hepatocellular carcinoma

Host APOBEC3G protein inhibits HCV replication through direct binding at NS3

Human APOBEC3G (hA3G) is a cytidine deaminase that restricts replication of certain viruses. We have previously reported that hA3G was a host restriction factor against hepatitis C virus (HCV) replication, and hA3G stabilizers showed a significant inhibitory activity against HCV. However, the molecular mechanism of hA3G against HCV remains unknown. We show in this study that hA3G’s C-terminal directly binds HCV non-structural protein NS3 at its C-terminus, which is responsible for NS3’s helicase and NTPase activity. Binding of hA3G to the C-terminus of NS3 reduced helicase activity, and therefore inhibited HCV replication. The anti-HCV mechanism of hA3G appeared to be independent of its deamination activity. Although early stage HCV infection resulted in an increase in host hA3G as an intracellular response against HCV replication, hA3G was gradually diminished after a long-term incubation, suggesting an unknown mechanism(s) that protects HCV NS3 from inactivation by hA3G. The process represents, at least partially, a cellular defensive mechanism against HCV and the action is mediated through a direct interaction between host hA3G and HCV NS3. We believe that understanding of the antiviral mechanism of hA3G against HCV might open an interesting avenue to explore hA3G stabilizers as a new class of anti-HCV agents.

Hepatic interferon-gamma-induced protein-10 expression is more strongly associated with liver fibrosis than interleukin-28B single nucleotide polymorphisms in hepatocellular carcinoma resected patients with chronic hepatitis C

AIM

Single nucleotide polymorphisms (SNP) around IL-28B and interferon (IFN)-stimulated gene (ISG) expression are predictors of response to standard therapy involving IFN for chronic hepatitis C virus (HCV) infection. We analyzed the association between these predictors to improve the prediction of the response to IFN therapy after liver resection for hepatocellular carcinoma (HCC).

METHODS

Data were collected from 74 patients with HCV-induced HCC. The IL-28B genotype and hepatic ISG mRNA levels were analyzed to clarify their association, focusing on the progression of liver fibrosis.

RESULTS

Fifty patients were identified as having major alleles (rs8099917 TT) and the remaining 24 patients had minor alleles (rs8099917 TG or GG). Hepatic ISG15 expression was lower in the IL-28B major group than that in the IL-28B minor group (P < 0.005). IP-10 expression was similar between the IL-28B major and minor groups (P = 0.44). IP-10 expression was elevated with advancing stages of liver fibrosis in HCV infected patients (P = 0.005). In patients with mild or no fibrosis, the IL-28B major group had lower IP-10 expression than the IL-28B minor group (P = 0.02). However, in patients with advanced fibrosis, IP-10 expression was not different between the IL-28B major and minor groups (P = 0.66).

CONCLUSION

Hepatic ISG15 expression is associated with IL-28B polymorphisms, while IP-10 is strongly affected by liver fibrosis.

Insulin resistance undermines the advantages of IL28B polymorphism in the pegylated interferon alpha-2b and ribavirin treatment of chronic hepatitis C patients with genotype 1

BACKGROUND & AIMS

Recent studies have suggested that insulin resistance exerts a strong influence on chronic hepatitis C virus (HCV) infection. We analyzed pretreatment factors useful for predicting sustained virological response (SVR), especially interleukin (IL) 28B polymorphism and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR).

METHODS

This cohort study consisted of 328 chronic hepatitis C patients with HCV genotype 1 who were treated for 48 weeks with pegylated interferon (PegIFN) α-2b and ribavirin (RBV). Genotyping of the polymorphisms in the IL28B gene region (rs8099917) on chromosome 19 was performed on DNA collected from each patient.

RESULTS

No significant difference in IL28B genotype distribution was found according to HOMA-IR. Multivariate analysis identified the IL28B TT genotype (OR=5.97, 95% CI 2.15-16.55, p=0.0006) and the baseline HOMA-IR (OR=0.65, 95% CI 0.48-0.87, p=0.0044) as significant, independent pretreatment predictors of SVR. Receiver operating characteristic analyses to determine the optimal threshold values of HOMA-IR for predicting SVR showed that the areas under the curve (AUC) were high for both IL28B TT (AUC=0.774, HOMA-IR cut-off value: 2.45) and IL28B TG/GG genotypes (AUC=0.772, HOMA-IR cut-off value: 1.55).

CONCLUSIONS

For HCV genotype 1, both IL28B and baseline HOMA-IR are independent pretreatment predictors of SVR in patients treated with PegIFNα-2b and RBV. Insulin resistance undermines the advantages of IL28B polymorphism to obtain SVR.

Meta-analysis: IL28B polymorphisms predict sustained viral response in HCV patients treated with pegylated interferon-α and ribavirin

BACKGROUND

Interleukin (IL) 28B single nucleotide polymorphisms can predict sustained virological response (SVR) in hepatitis C virus (HCV) patients following pegylated interferon-alpha (PEG IFN-α) and ribavirin treatment.

AIM

To design a meta-analysis to determine IL28B genotypes', rs12979860 CC and rs8099917 TT, correlation with SVR in PEG IFN-α/ribavirin-treated HCV patients.

METHODS

Meta-analysis was performed in 17 studies of rs12979860 CC vs. CT/TT and 17 of rs8099917 TT vs. TG/GG. Odds ratios (OR) and confidence intervals (95% CI) were calculated by fixed- or random-effects models. Heterogeneity, sensitivity analysis and publication bias were also assessed.

RESULTS

Of 4252 Asian, Caucasian and African HCV patients analysed for rs12979860, SVR was more frequent in CC (vs. CT/TT; OR = 4.76, 95% CI: 3.15-7.20). Moreover, CC was associated with SVR for HCV genotype-1 or -4 infections (OR(genotype 1) = 5.52, 95% CI: 3.74-8.15; OR(genotype 4) = 8.11, 95% CI: 4.13-15.93), regardless of ethnicity. Of 4549 Caucasian and Asian HCV patients analysed for rs8099917, SVR was more frequent in TT (vs. TG/GG; OR = 3.31, 95% CI: 2.39-4.59). Moreover, TT was associated with SVR for HCV-1 (OR(genotype 1) = 4.28, 95% CI: 2.87-6.38). Rs8099917 TT predictive value was stronger in Asians (OR(Asians) = 8.09, 95% CI: 5.63-11.61; OR(Caucasians) = 3.00, 95% CI: 2.03-4.45). Ethnicity stratification revealed that rs8099917 TT had slight predictive value in Asian HCV-2/3 patients (OR = 1.99, 95% CI: 1.09-3.62).

CONCLUSIONS

IL28B rs12979860 CC and rs8099917 TT are strong SVR predictors for PEG IFN-α/ribavirin-treated HCV-1 patients, regardless of ethnicity. In HCV-2/3, rs12979860 CC has no SVR predictive value, but rs8099917 TT was slightly associated with SVR in Asians.

Prediction of response to pegylated-interferon-α and ribavirin therapy in Chinese patients infected with different hepatitis C virus genotype

BACKGROUND

The standard treatment for patients with chronic hepatitis C (CHC), pegylated interferon-α (PEG-IFN) plus ribavirin (RBV) does not provide a sustained virological response (SVR) in all patients. Genetic variations at the interleukin 28B (IL-28B) locus are important in predicting outcome following therapy in CHC patients.

RESULTS

We investigated the role of IL28B variations (rs8099917) in response to PEG-IFN-α/RBV treatment and evaluated its association with the risk of the null virological response (NVR) and relapse (REL) in different viral genotypes. We found that the overall distributions of the genotype among the SVR, NVR, and REL groups were significantly different (P < 0.001). Patients with the TG genotype had an increased risk of NVR and REL (OR = 6.45 95% CI = 2.88-14.47, P < 0.001 for NVR; OR = 2.51, 95% CI = 1.29-4.86, P = 0.006 for REL, respectively), and patients with the GG genotype had a further increased risk of NVR and REL (OR = 12.04, 95% CI = 3.21-45.13, P < 0.001 for NVR; ,OR = 4.30, 95% CI = 1.21-15.13, P = 0.017 for REL, respectively). G variant genotypes (TG+GG) also had an increased risk of NVR and REL, and there was a significant trend for a dose-effect of G allele on the risk of NVR and REL (P < 0.05). The SVR rate in TT higher than in TG+GG was more pronounced in those patients infected with non-G1 compared to the patients infected with G1. The treatment response did differ based on the rs8099917 genotype in patients with different viral genotypes, compared with patients infected with the non-G1, the G1 infected patients had an increased risk of NVR and REL (OR = 2.03 95% CI = 1.03-4.01, P = 0.04 for NVR and OR = 2.58, 95% CI = 1.35-4.94, P = 0.004 for REL, respectively). Moreover, multivariate regression analysis show that the rs8099917 G allele was the only independent factor significantly associated with a NVR and REL.

CONCLUSION

This study suggests that host genetic polymorphisms rs8099917 in the vicinity of IL-28B is the most important predictor of treatment response of PEG-IFN-α/RBV for HCV patients in China.