Amino acid substitutions in core and NS5A regions of the HCV genome can predict virological decrease with pegylated interferon plus ribavirin therapy

IFN-λ: A New Class of Interferon with Distinct Functions-Implications for Hepatitis C Virus Research

Pegylated interferon-α and ribavirin (PEG-IFN/RBV) is widely used to treat chronic hepatitis C virus infection with notorious adverse reactions since the broad expression of IFN-α receptors on all nucleated cells. Accordingly, a Type III IFN with restricted receptors distribution is much safer as an alternative for HCV therapy. In addition, single nucleotide polymorphisms (SNPs) near the human IFN-λ3 gene, IL-28B, correlate strongly with the ability to achieve a sustained virological response (SVR) to therapy with pegylated IFN-α plus ribavirin in patients infected with chronic hepatitis C. Furthermore, we also discuss the most recent findings: IFN-λ4 predicts treatment outcomes of HCV infection. In consideration of the apparent limitations of current HCV therapy, especially high failure rate and universal side effects, prediction of treatment outcomes prior to the initiation of treatment and developing new alternative drugs are two important goals in HCV research.

Significance of miRNA-122 in chronic hepatitis C patients with serotype 1 on interferon therapy

AIM

Peginterferon (PEG IFN) and ribavirin combination therapy is a curative treatment for chronic hepatitis C virus (HCV) infection, and virological response to IFN therapy has been strongly associated with genetic variation in IL28B single nucleotide polymorphisms (SNP). Recently, miRNA122 (miR-122), which is the most abundant miRNA in the liver, has been reported to be important for the replication of HCV RNA. Therefore, we investigated the correlation of miR-122 expression with virological response to IFN and other clinical data.

METHODS

A total of 51 patients with HCV infection who were treated with IFN therapy at Nagasaki University Hospital from 2006 to 2011 were included in this study. We investigated the correlation of miR-122 expression in liver biopsy specimens with virological response to IFN therapy and other predictors of response, including IL28 SNP.

RESULTS

miR-122 expression did not correlate with IL28 SNP. However, a significant difference was observed in miR-122 expression between patients who showed a sustained virological response (SVR) and those who did not (P < 0.05). Multivariate analysis indicated that miR-122 is an independent predictor of SVR.

CONCLUSION

miR-122 expression could be a marker for predicting the outcome of IFN therapy. Therapies targeting miR-122 may have positive effects not only by directly inhibiting viral propagation but also by ameliorating cholesterol and lipid abnormalities.

Amino acid sequence analysis in patients with chronic HCV genotype 1b infection during pegylated interferon-α2a and ribavirin therapy

BACKGROUND

Amino acid variations in several HCV genomic regions have been reported to be associated with response to interferon (IFN)-α plus ribavirin (RBV) combination therapy. However, the results remain controversial. In this study, we further investigated the amino acid variation of full-length HCV genome and its correlation to the response to pegylated interferon (PEG-IFN)-α2a and RBV combination therapy in patients with HCV genotype 1b (HCV-1b).

METHODS

We retrospectively analysed 18 chronic HCV-1b patients (9 with rapid virological response and 9 non-response to therapy) treated with PEG-IFN-α2a plus RBV for 48 weeks. The nearly full-length HCV genome sequence was amplified by reverse transcription (RT)-PCR followed by cloning and sequencing. Genetic diversity differences between two groups were analysed including the number of amino acid variations in the HCV polyprotein and the mean pair-wise protein distance.

RESULTS

No single amino acid variations were closely associated with treatment outcome. However, the number of amino acid mutations in the NS5B region especially in the thumb domain and in the NS5A-V3 region was associated with the response to PEG-IFN-α/RBV therapy (P=0.002 and P=0.029, respectively). The number of substitutions in the NS5B region was significantly correlated with the numbers of substitutions in the V3 region (r=0.568, P=0.027).

CONCLUSIONS

Amino acid substitutions in the NS5B region especially in the thumb domain and the NS5A-V3 region may play a role in the response to combined PEG-IFN-α2a and RBV therapy in HCV-1b patients.

Utility of controlled attenuation parameter measurement for assessing liver steatosis in Japanese patients with chronic liver diseases

AIM

Steatosis is a common histological feature of chronic liver disease, especially alcoholic and non-alcoholic fatty liver disease, as well as chronic hepatitis C. A recent study showed that evaluating the controlled attenuation parameter (CAP) with transient elastography was an efficient way of non-invasively determining the severity of hepatic steatosis. The objective of this study was to prospectively evaluate the utility of CAP for diagnosing steatosis in patients with chronic liver disease.

METHODS

One hundred and fifty-five consecutive patients with suspected chronic liver disease underwent steatosis diagnosis using CAP, blood sample analyses, computed tomography for assessing the liver/spleen ratio and liver biopsy. Steatosis was graded according to the percentage of fat-containing hepatocytes: S0, less than 5%; S1, 5-33%; S2, 34-66%; and S3: more than 66%.

RESULTS

The CAP was significantly correlated with steatosis grade, and there were significant differences between the CAP value of the S0 patients and those of the patients with other grades of steatosis. S0 and S1-3 hepatic steatosis were considered to represent mild and significant steatosis, respectively. The CAP values of the patients with mild and significant steatosis were significantly different (P < 0.0001). The area under the receiver-operator curve (AUROC) value of the CAP for diagnosing significant steatosis was 0.878 (95% confidence interval, 0.818-0.939), and the optimal CAP cut-off value for detecting significant steatosis was 232.5 db/m. In multivariate analysis, the CAP (P = 0.0002) and the liver to spleen ratio (P = 0.004) were found to be significantly associated with significant steatosis.

CONCLUSION

The CAP is a promising tool for rapidly and non-invasively diagnosing steatosis.

Interleukin-28B single nucleotide polymorphism of donors and recipients can predict viral response to pegylated interferon/ribavirin therapy in patients with recurrent hepatitis C after living donor liver transplantation

BACKGROUND AND AIM

Interleukin-28B (IL28B) single nucleotide polymorphism (SNP) influences viral response (VR) to interferon (IFN) therapy in patients with hepatitis C. We studied the relationship between VR and the IL28B polymorphism (rs8099917) in patients on long-term pegylated IFN plus ribavirin (PEGIFN/RBV) therapy for recurrent hepatitis C after living-donor liver transplantation (LDLT).

METHODS

Thirty-five patients with recurrent hepatitis C after LDLT were treated with PEGIFN/RBV. We evaluated the effect of IL28B SNP on the outcome in 20 patients infected with hepatitis C virus genotype 1 who completed IFN therapy.

RESULTS

The sustained VR (SVR) rate was 54% (19/35) for all patients; 46% (13/28) for genotype 1. The SVR rate of donors' TT group (major genotype) was higher than that of donors' TG+GG group (minor genotype) (73% vs 20%), while that of recipients' TT group was similar to that of recipients' TG+GG group (64% vs 50%). With regard to the combined effect of donors' and recipients' IL28B SNP, the SVR rates of TT:TT (donors':recipients'), TT:TG+GG, TG+GG:any group were 81%, 50%, and 20%, respectively. The VR rate of TT:TT, TT:TG+GG and TG+GG:any group at 12 weeks were 28%, 0%, and 0%; those at 48weeks were 70%, 50%, 20%, and those at the end of treatment were 100%, 50%, 20%, respectively. The multivariate analysis identified IL28B of donors:recipients (TT:TT) as the only independent determinant of SVR (odds ratio 15.0, P=0.035).

CONCLUSION

Measurement of donors' and recipients' IL28B SNP can predict the response to PEGIFN/RBV therapy, and the donors' IL28B SNP might be a more significant predictor than that of the recipients.

Identification of novel HCV deletion mutants in chronic hepatitis C patients

BACKGROUND

The HCV genome consists of a positive 9.6 kb single-strand of RNA. Nucleotide substitutions in the HCV genome are common and a 2 kb deletion has been reported.

METHODS

A total of 117 chronic hepatitis C (CHC) patients who were treated with pegylated interferon plus ribavirin combination therapy were enrolled in this study. Total RNA was extracted from the patients' sera and reverse transcription and PCR were performed. Statistical analysis was performed to evaluate the effects of HCV deletion mutants on treatment with combination therapy.

RESULTS

By amplifying entire HCV genomes using long-distance PCR, novel large deletion mutants were identified. Sequence analysis revealed that these deletions extended approximately 6 kb from the core/E2 region to the NS5A region and that there are three kinds of deletions that are identical at their 3' and 5' extremities. The subgenome virus particles appeared to coexist with full-genome virus particles in the sera of CHC patients despite lacking essential components for HCV viral replication. These short fragments were detected in 26 of 117 patients and were associated with significantly higher HCV RNA levels (P=0.018) and poor response to combination therapy (P=0.043). Moreover, the existence of HCV deletion mutants was significantly associated with virological relapse following combination therapy (P=0.046, OR=3.4).

CONCLUSIONS

HCV deletion mutants may affect the HCV life cycle and reduce the antiviral effects of interferon therapy for CHC.

IL28B polymorphism is associated with fatty change in the liver of chronic hepatitis C patients

BACKGROUND

Several single nucleotide polymorphisms (SNPs) within the interleukin 28B (IL28B) locus are associated with sustained viral response in chronic hepatitis C (HCV) patients who were treated with pegylated interferon (PEG-IFN) plus ribavirin (RBV) combination therapy. Recently, an association between γ-GTP level and IL28B genotype was identified. In this study, the relationship between IL28B genotype and liver steatosis was analyzed.

METHODS

One hundred fifty-three patients who underwent liver biopsy before PEG-IFN plus RBV combination therapy were enrolled. The level of liver steatosis was measured using a BIOREVO BZ-9000 microscope, and the proportion of fatty change and clear cell change were calculated using Dynamic cell count BZ-H1C software. IL28B SNP genotype (rs8099917) was determined using the Invader Assay.

RESULTS

Vesicular change was significantly associated with body mass index (BMI), HCV RNA titer, serum aspartate aminotransferase, γ-GTP, IL28B genotype and liver fibrosis level (P < 0.05). Clear cell change was significantly associated with serum aspartate aminotransferase, γ-GTP and IL28B genotype by univariate logistic regression analysis (P < 0.05). Under multiple logistic regression, IL28B genotype (OR(adj) = 8.158; 95% CI 2.412-27.589), liver fibrosis (OR(adj) = 2.541; 95% CI 1.040-6.207) and BMI (OR(adj) = 1.147; 95% CI 1.011-1.301) were significant independent factors for vesicular change and IL28B genotype (OR(adj) = 3.000; 95% CI 1.282-7.019) for clear cell change.

CONCLUSION

In this study, a new quantitative method to objectively evaluate hepatic steatosis was described. IL28B genotypes were significantly associated with both vesicular and clear cell changes of livers in chronic hepatitis C patients.

The yin and yang of viruses and interferons

Interferons (IFNs)-α/β are critical effectors of the innate immune response to virus infections. Through activation of the IFN-α/β receptor (IFNAR), they induce expression of IFN-stimulated genes (ISGs) that encode antiviral proteins capable of suppressing viral replication and promoting viral clearance. Many highly pathogenic viruses have evolved mechanisms to evade an IFN response and the balance between the robustness of the host immune response and viral antagonistic mechanisms determines whether or not the virus is cleared. Here, we discuss IFNs as broad-spectrum antivirals for treatment of acute virus infections. In particular, they are useful for treatment of re-emerging virus infections, where direct-acting antivirals (DAAs) have limited utility due to DAA-resistant mutations, and for newly emerging virus strains in which the time to vaccine availability precludes vaccination at the onset of an outbreak.

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

The present study was designed to determine the predictive factors for the viral response to pegylated interferon-alpha plus ribavirin combination therapy (PEGIFN/RBV) administered after curative treatment for hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC). The study group was 78 patients treated between January 2005 and January 2009. The sustained viral response (SVR) rate was 25.8% (15/58) in patients infected with HCV-genotype 1 and 55.0% (11/20) in those with genotype 2. Among the 78 patients, 32 (41.0%) could not complete the treatment protocol, and this was because of HCC recurrence in 17 (53%) of them. Multivariate analysis identified partial early viral response (pEVR) as the only independent determinant of SVR [odds ratio (OR) 14.73, P = 0.013] for patients with genotype 1. Multivariate analysis identified male gender (OR 8.72, P = 0.001) and interleukin-28B (IL-28B) genotype (rs8099917) TT (OR 7.93, P = 0.007) as independent predictors of pEVR. Multivariate analysis also identified IL-28B genotype GG+TG (OR 14.1, P = 0.021) and α-fetoprotein >30 (OR 5.4, P = 0.031) as independent predictors of null response. Patients with SVR showed a better survival rate than those without SVR (P = 0.034). The second HCC recurrence rate tended to be lower in patients with SVR than in those without SVR (P = 0.054). With regard to the prognosis of patients with SVR, it is desirable to achieve SVR with interferon therapy even when administered after HCC treatment. IL-28B genotype is a potentially useful marker for the response to PEGIFN/RBV therapy administered after curative treatment of HCV-related HCC.

Hepatitis C virus infection suppresses the interferon response in the liver of the human hepatocyte chimeric mouse

BACKGROUND AND AIMS

Recent studies indicate that hepatitis C virus (HCV) can modulate the expression of various genes including those involved in interferon signaling, and up-regulation of interferon-stimulated genes by HCV was reported to be strongly associated with treatment outcome. To expand our understanding of the molecular mechanism underlying treatment resistance, we analyzed the direct effects of interferon and/or HCV infection under immunodeficient conditions using cDNA microarray analysis of human hepatocyte chimeric mice.

METHODS

Human serum containing HCV genotype 1b was injected into human hepatocyte chimeric mice. IFN-α was administered 8 weeks after inoculation, and 6 hours later human hepatocytes in the mouse livers were collected for microarray analysis.

RESULTS

HCV infection induced a more than 3-fold change in the expression of 181 genes, especially genes related to Organismal Injury and Abnormalities, such as fibrosis or injury of the liver (P = 5.90E-16∼3.66E-03). IFN administration induced more than 3-fold up-regulation in the expression of 152 genes. Marked induction was observed in the anti-fibrotic chemokines such as CXCL9, suggesting that IFN treatment might lead not only to HCV eradication but also prevention and repair of liver fibrosis. HCV infection appeared to suppress interferon signaling via significant reduction in interferon-induced gene expression in several genes of the IFN signaling pathway, including Mx1, STAT1, and several members of the CXCL and IFI families (P = 6.0E-12). Genes associated with Antimicrobial Response and Inflammatory Response were also significantly repressed (P = 5.22×10(-10)∼1.95×10(-2)).

CONCLUSIONS

These results provide molecular insights into possible mechanisms used by HCV to evade innate immune responses, as well as novel therapeutic targets and a potential new indication for interferon therapy.

Redefining baseline demographics: the role of genetic testing in hepatitis C virus infection

The current standard of care for hepatitis C virus (HCV) infection is pegylated interferon and ribavirin. Unfortunately, treatment cures at best only 40% to 50% of patients infected with genotype 1 HCV, the most common HCV genotype in Western countries. Treatment is also expensive and is often poorly tolerated. Therefore, the identification of patients most likely to benefit from treatment is clinically important. Genome-wide association studies have recently identified genetic variants, most notably IL28B and ITPA, which will enhance the ability of clinicians to personalize antiviral therapy for HCV infection.

Impact of ribavirin dose reduction on the efficacy of pegylated interferon plus ribavirin combination therapy for elderly patients infected with genotype 1b and high viral loads

AIM

  To examine the impact of ribavirin dose reduction on the efficacy of pegylated interferon (PEG IFN) plus ribavirin combination therapy for elderly patients infected with genotype 1b and high viral loads.

METHODS

  A total of 72 patients, over 65 years old, were recruited for this study. Patients were divided into groups receiving either 600-800 mg of ribavirin according to bodyweight (Group 1, n = 36) or 400 mg of ribavirin (Group 2, n = 36) plus 1.5 µg/kg (range: 1.3-2.0 µg/kg) of PEG IFN-α-2b for 48 weeks.

RESULTS

  Total ribavirin doses were administrated at 9.80 ± 2.39 mg/kg per day (3.29 ± 0.80 g/kg) for Group 1 and 5.87 ± 1.82 mg/kg per day (1.97 ± 0.61 g/kg) for Group 2 (P < 0.001). According to the total clearance (CL/F) of ribavirin, 34 of 36 patients in Group 1 received over-doses of ribavirin. In contrast, numbers of those receiving equivalent doses of ribavirin were two of 36 patients in Group 1 and 36 of 36 patients in Group 2, respectively (P < 0.001). End-of-treatment response (ETR) rates were observed in 23 of 36 patients (63.9%) in the standard ribavirin dose protocol and in 23 of 36 patients (63.9%) in the reduction ribavirin dose protocol (NS). Sustained virological response (SVR) rates were observed in 11 of 36 patients (30.6%) in the standard ribavirin dose protocol, and in 13 of 36 patients (36.1%) in the reduced ribavirin dose protocol (NS).

CONCLUSION

  Reduction of ribavirin doses for elderly patients did not affect the outcome for the 48-week combination therapy.