Interferon signaling and treatment outcome in chronic hepatitis C. Proc Natl Acad Sci U S A. 2008;105:7034-7039. [PMID: 18467494 DOI: 10.1073/pnas.0707882105]

The impact of fibrosis and steatosis on early viral kinetics in HCV genotype 1-infected patients treated with Peg-IFN-alfa-2a and ribavirin

Hepatitis C viral (HCV) kinetics after initiation of interferon-based therapy provide valuable insights for understanding virus pathogenesis, evaluating treatment antiviral effectiveness and predicting treatment outcome. Adverse effects of liver fibrosis and steatosis on sustained virological response have been frequently reported, yet their impacts on the early viral kinetics remain unclear. In this study, associations between histology status and early viral kinetics were assessed in 149 HCV genotype 1-infected patients treated with pegylated interferon alfa-2a and ribavirin (DITTO trial). In multivariate analyses adjusted for critical factors such as IL28B genotype and baseline viral load, presence of significant fibrosis (Ishak stage > 2) was found to independently reduce the odds of achieving an initial reduction (calculated from day 0 to day 4) in HCV RNA of ≥2 logIU/mL (adjusted OR 0.03, P = 0.004) but was not associated with the second-phase slope of viral decline (calculated from day 8 to day 29). On the contrary, presence of liver steatosis was an independent risk factor for not having a rapid second-phase slope, that is, ≥0.3 logIU/mL/week (adjusted OR 0.22, P = 0.012) but was not associated with the first-phase decline. Viral kinetic modelling theory suggests that significant fibrosis primarily impairs the treatment antiviral effectiveness in blocking viral production by infected cells, whereas the presence of steatosis is associated with a lower net loss of infected cells. Further studies will be necessary to identify the biological mechanisms underlain by these findings.

Apolipoprotein-E and hepatitis C lipoviral particles in genotype 1 infection: evidence for an association with interferon sensitivity

BACKGROUND & AIMS

Hepatitis C virus (HCV) interacts with apolipoproteins B (apoB) and E (apoE) to form infectious lipoviral particles (LVP). Response to peginterferon is influenced by interferon-stimulated genes (ISGs) and IL28B genotype. LDL cholesterol (LDL-C) also predicts interferon response, therefore we hypothesised that LVP may also be associated with interferon sensitivity.

METHODS

LVP (HCV RNA density ≤1.07 g/ml) and 'non-LVP' (d >1.07 g/ml) were measured in 72 fasted HCV-G1 patients by iodixanol density gradient ultracentrifugation and the LVP ratio (LVP/LVP+non-LVP) was calculated. Fasting lipid profiles and apolipoproteins B and E were measured. Interferon-gamma-inducible protein 10 kDa (IP10), a marker of ISGs, was measured by ELISA.

RESULTS

Complete early virological response (EVR) was associated with lower apoE (23.9±7.7 vs. 36.1±15.3 mg/L, p=0.013), higher LDL-C (p=0.039) and lower LVP ratios (p=0.022) compared to null responders. In multivariate linear regression analysis, apoE was independently associated with LVP (R(2) 19.5%, p=0.003) and LVP ratio (p=0.042), and negatively with LDL-C (p<0.001). IP10 was significantly associated with ApoB (p=0.001) and liver stiffness (p=0.032). IL28B rs12979860 CC was associated with complete EVR (p=0.044), low apoE (CC 28±11 vs. CT/TT 35±13 mg/L, p=0.048) and higher non-LVP (p=0.008). Logistic regression analysis indicated that patients with high LVP ratios were less likely to have EVR (odds ratio 0.01, p=0.018).

CONCLUSIONS

In HCV-G1, interferon sensitivity is characterised by low LVP ratios and low apoE levels in addition to higher LDL-C and IL28B rs12979860 CC. Null-response is associated with increased LVP ratio. The association of apoE and LVP with peginterferon treatment response suggests that lipid modulation is a potential target to modify interferon sensitivity.

Neopterin as a marker of response to antiviral therapy in hepatitis C virus patients

Predicting the efficacy of antiviral treatment of hepatitis C virus (HCV) is of importance for both patient well-being and health care expense. The expression of interferon-stimulated genes (IFN-SGs) in the liver was suggested as a marker of response to anti-viral therapy. IFN-SGs encode the guanosine triphosphate cyclohydrolase 1 (GTPCH), a rate-limiting enzyme of pteridines biosynthesis. Neopterin, a stable byproduct of GTPCH-catalyzed reaction, is used as a marker of interferon-induced GTPCH activation. We hypothesized that assessment of neopterin concentrations might predict the response to antiviral therapy. Neopterin concentrations were evaluated in 260 HCV patients treated by pegylated interferon combined with ribavirin. Mean and median pretreatment neopterin concentrations were lower in patients with sustained virological response than in nonresponders. The rate of response was twofold higher among patients with pretreatment neopterin levels <16 nmol/L than in patients with neopterin levels ≥16 nmol/L, even after controlling for HCV genotype status. Our study suggests that the pretreatment level of neopterin might be used in routine clinical practice as rapid and cost-effective marker to predict the response to antiviral therapy in HCV patients.

Attenuation of 40S ribosomal subunit abundance differentially affects host and HCV translation and suppresses HCV replication

For Hepatitis C virus (HCV), initiation of translation is cap-independently mediated by its internal ribosome entry site (IRES). Unlike other IRES-containing viruses that shut off host cap-dependent translation, translation of HCV coexists with that of the host. How HCV IRES-mediated translation is regulated in the infected cells remains unclear. Here, we show that the intracellular level of 40S ribosomal subunit plays a key role in facilitating HCV translation over host translation. In a loss-of-function screen, we identified small subunit ribosomal protein 6 (RPS6) as an indispensable host factor for HCV propagation. Knockdown of RPS6 selectively repressed HCV IRES-mediated translation, but not general translation. Such preferential suppression of HCV translation correlated well with the reduction of the abundance of 40S ribosomal subunit following knockdown of RPS6 or other RPS genes. In contrast, reduction of the amount of ribosomal proteins of the 60S subunit did not produce similar effects. Among the components of general translation machineries, only knockdowns of RPS genes caused inhibitory effects on HCV translation, pointing out the unique role of 40S subunit abundance in HCV translation. This work demonstrates an unconventional notion that the translation initiation of HCV and host possess different susceptibility toward reduction of 40S ribosomal subunit, and provides a model of selective modulation of IRES-mediated translation through manipulating the level of 40S subunit.

Spontaneous clearance of primary acute hepatitis C virus infection correlated with high initial viral RNA level and rapid HVR1 evolution

The aim of this study is to determine whether early viral dynamics and evolution predict outcome of primary acute hepatitis C virus (HCV) infection. HCV- and human immunodeficiency virus-negative injection drug users were enrolled prospectively and followed monthly to identify acute HCV infection using RNA detection. Subjects with more than 1 month between HCV-RNA-negative and -positive visits were excluded to ensure stringent acute infection. Differences in medians of log-transformed viral RNA levels and evolutionary rates in each gene of a 5'-hemigenomic amplicon were assessed using Mann-Whitney's rank-sum test. Correlation coefficient was calculated using Spearman's rank order. Initial viremia level was 50-fold higher in subjects with spontaneous clearance (compared with persistence) of primary acute HCV infection (median, 7.1 versus 5.4 log(10) IU/mL; P = 0.002). Initial viremia level in subjects with interleukin (IL)28B-C allele at rs12979860 and clearance was higher than that in subjects with IL28B-T allele and persistence (P = 0.001). Evolutionary rates in the hypervariable region 1 (HVR1) region of the E2 gene were significantly higher in self-resolvers than those in persistence subjects during early infection, whereas other genes or regions had comparable rates. All major substitutions in HVR1 in persistence subjects were convergent changes, whereas over the same time interval clearance subjects displayed divergent evolution, indicating different immune responses between the two groups.

CONCLUSION

Spontaneous clearance of acute HCV infection is predicted by high initial viremia as well as favorable IL28B genotype and is associated with rapid envelope-sequence evolution. This linkage of host genetics, viral dynamics, and evolution provides new directions for mechanistic studies. (HEPATOLOGY 2012;55:1684-1691).

Genetics of IL28B and HCV--response to infection and treatment

The IL28B locus attracted the attention of HCV researchers after a series of genome-wide association studies independently identified a strong association between common IL28B polymorphisms and the outcome of PEG-IFN-α plus ribavirin combination therapy in patients chronically infected with HCV genotype 1. This association was subsequently replicated for other HCV genotypes and has been linked to spontaneous eradication of HCV, development of steatosis and biochemical changes (such as altered levels of γ-glutamyl transpeptidase and LDL). Despite the introduction of direct-acting antiviral drugs, IL28B genetics are likely to play a part in patient selection and treatment decisions-moving towards a personalized approach to therapy. In HCV-infected patients with the so-called favourable IL28B genotype (rs12979860 CC; associated with better treatment response), hepatic expression levels of IL28B and interferon-stimulated genes seem to be reduced at baseline, but are induced more strongly after IFN-α administration, perhaps resulting in more effective elimination of the virus. Clarification of the mechanisms underlying these biological phenomena will lead to improved understanding of the antiviral effects of IFN-λ and, ideally, to the development of better therapies against HCV infection. This Review summarizes current understanding of the role of IL28B in HCV infection and response to therapy.

IL28B genetic variation is associated with spontaneous clearance of hepatitis C virus, treatment response, serum IL-28B levels in Chinese population

BACKGROUND

The interleukin-28B gene (IL28B) locus has been associated with host resistance to hepatitis C virus (HCV) infection and response to PEG-IFN/RBV treatment in western populations. This study was to determine whether this gene variant is also associated with spontaneous clearance of HCV infection, treatment response and IL-28B protein production in Chinese patients.

METHODS

We genotyped IL28B genetic variations (rs12980275, rs8103142, rs8099917 and rs12979860) by pyrosequencing DNA samples from cohorts consisting of 529 subjects with persistent HCV infection, 196 subjects who cleared the infection, 171 healthy individuals and 235 chronic HCV patients underwent IFN/RBV treatment. The expression of IL-28B were measured by ELISA and RT-PCR.

RESULTS

We found that the four IL28B variants were in complete linkage disequilibrium (r2 = 0.97-0.98). The rs12979860 CC genotype was strongly associated with spontaneously HCV clearance and successful IFN/RBV treatment compared to the CT/TT. IL-28B levels in persistent HCV patients were significantly lower than subjects who spontaneously resolved HCV and healthy controls and were also associated with high levels of ALT (alanine aminotransferase) and AST (aspartate aminotransferase). IL-28B levels were also significantly lower in individuals carrying T alleles than CC homozygous.

CONCLUSIONS

Thus, the rs12979860-CC variant upstream of IL28B gene is associated with spontaneous clearance of HCV, susceptible to IFN/RBV treatment and increased IL-28B levels in this Chinese population.

Interleukin 28B polymorphisms are the only common genetic variants associated with low-density lipoprotein cholesterol (LDL-C) in genotype-1 chronic hepatitis C and determine the association between LDL-C and treatment response

Low-density lipoprotein cholesterol (LDL-C) levels and interleukin 28B (IL28B) polymorphism are associated with sustained viral response (SVR) to peginterferon/ribavirin (pegIFN/RBV) for chronic hepatitis C (CHC) infection. IL28B has been linked with LDL-C levels using a candidate gene approach, but it is not known whether other genetic variants are associated with LDL-C, nor how these factors definitively affect SVR. We assessed genetic predictors of serum lipid and triglyceride levels in 1604 patients with genotype 1 (G1) chronic hepatitis C virus (HCV) infection by genome-wide association study and developed multivariable predictive models of SVR. IL28B polymorphisms were the only common genetic variants associated with pretreatment LDL-C level in Caucasians (rs12980275, P = 4.7 × 10(-17), poor response IL28B variants associated with lower LDL-C). The association was dependent on HCV infection, IL28B genotype was no longer associated with LDL-C in SVR patients after treatment, while the association remained significant in non-SVR patients (P < 0.001). LDL-C was significantly associated with SVR for heterozygous IL28B genotype patients (P < 0.001) but not for homozygous genotypes. SVR modelling suggested that IL28B heterozygotes with LDL-C > 130 mg/dL and HCV RNA ≤600 000 IU/mL may anticipate cure rates >80%, while the absence of these two criteria was associated with an SVR rate of <35%. IL28B polymorphisms are the only common genetic variants associated with pretreatment LDL-C in G1-HCV. LDL-C remains significantly associated with SVR for heterozygous IL28B genotype patients, where LDL-C and HCV RNA burden may identify those patients with high or low likelihood of cure with pegIFN/RBV therapy.

Hepatic cell-type specific gene expression better predicts HCV treatment outcome than IL28B genotype

BACKGROUND & AIMS

Cell-type specific expression patterns of hepatic interferon-stimulated genes (ISGs) and single nucleotide polymorphisms (SNPs) near the IL28B gene are associated with response to interferon-based therapy in patients with chronic hepatitis C virus (HCV) infection. It is not known how the IL28B genotype influences the ISG expression pattern and which is a better predictor of treatment response.

METHODS

Patients at the Toronto Western Hospital Liver Centre with known outcome to interferon-based treatment for HCV infection were evaluated. Analysis included hepatic gene expression profile using complementary DNA microarrays, genotype at the IL28B SNP rs12979860, and immunostaining for human myxovirus A protein 1 (MxA) in hepatocytes and macrophages.

RESULTS

The level of ISG immunostaining in hepatic macrophages correlated inversely with that of hepatocytes and was strongly associated with treatment outcome. Gene expression profiles and the IL28B genotype were associated with treatment response, but only absence of MxA staining in macrophages accurately predicted nonresponse to treatment. The positive predictive value (PPV) of the IL28B genotype was 94% and the negative predictive value (NPV) was 51% (n = 209). For messenger RNA expression, the PPV was 94% and the NPV was 54% (n = 65). For detection of MxA in macrophages, the PPV was 60% and the NPV was 98% (n = 110). Of 53 patients with undetectable macrophage MxA staining, only one had a sustained virologic response. IL28B genotype was strongly associated with cell-type specific staining for MxA. There was a stepwise increase in macrophage staining and decrease in hepatocyte staining from the TT (lack of response) to CC SNP (associated with response) in IL28B. By logistic regression, after controlling for the presence of macrophage MxA staining, the IL28B genotype was no longer associated with treatment response.

CONCLUSIONS

The cell-type-specific expression pattern of ISGs varies among patients with different IL28B genotypes and is a strong predictor of response to interferon-based treatment.

Modulation of hepatitis C virus release by the interferon-induced protein BST-2/tetherin

Hepatitis C virus is a leading cause of chronic hepatitis and liver cancer. Little information exists on the interplay between innate defense mechanisms and viral antagonists that promote viral egress. Herein, the effects of Tetherin/BST-2 on HCV release were investigated. In Huh-7.5 hepatocytes, low expression levels of BST-2 were detected. Treatment of Huh-7.5 cells with IFNα, elevated BST-2 expression levels. However, HCV could not alter the expression of IFNα-induced BST-2, nor of stably over-expressed BST-2. Significantly, over expressed BST-2 moderately blocked HCV production and release from Huh-7.5 cells. Functional analysis of BST-2, confirmed its ability to inhibit the release of HIV delta-Vpu from Huh-7.5-BST-2 cells. HIV-Vpu antagonized BST-2 activity and rescued HIV delta-Vpu release from Huh-7.5-BST-2 cells. However, vpu slightly rescued HCV release and production from Huh-7.5-BST-2. We conclude that BST-2 moderately restricts HCV production and release from Huh-7.5 hepatocytes, while the virus lacks mechanisms to counteract this restriction.

Genetic variation in IL28B and treatment outcome in HBeAg-positive and -negative chronic hepatitis B patients treated with Peg interferon alfa-2a and adefovir

In a cohort of 95 chronic hepatitis B patients, who were treated with peg-interferon and adefovir for 1 year, and who had 15% HBsAg loss (overall), no association was found between IL28B polymorphisms and HBeAg seroconversion or HBsAg clearance. These findings suggest that any association with outcome, if present, is less than that seen in chronic hepatitis C. Additional studies are needed to enlarge sample size and to refine our understanding of IL28B biology in the context of chronic hepatitis B response to immunomodulatory and direct antiviral therapy.

Interferon-stimulated gene pathways in the treatment of viral hepatitis

Viral hepatitis has been treated empirically for more than 30 years with interferon (IFN)-based therapies, although in the early days of the IFN era, very little was known regarding the mechanisms of action through which IFN acts and the strategies that viruses deploy to escape the antiviral state induced by the activation of the IFN system. Over the years, we have learned how key effector molecules in this system are expressed and interact. On the verge of novel, IFN-free regimens for viral hepatitis, we can take advantage of this huge bulk of research data in order to gain better understanding of how resistance to IFN develops in our patients, to use IFN more effectively in conjunction with other drugs and to devise new treatments.

HCV infection induces a unique hepatic innate immune response associated with robust production of type III interferons

BACKGROUND & AIMS

Polymorphisms in the IL28B gene have been associated with clearance of hepatitis C virus (HCV), indicating a role for type III interferons (IFNs) in HCV infection. Little is known about the function of type III IFNs in intrinsic antiviral innate immunity.

METHODS

We used in vivo and in vitro models to characterize the role of the type III IFNs in HCV infection and analyzed gene expression in liver biopsy samples from HCV-infected chimpanzees and patients. Messenger RNA and protein expression were studied in HCV-infected hepatoma cell lines and primary human hepatocytes.

RESULTS

HCV infection of primary human hepatocytes induced production of chemokines and type III IFNs, including interleukin (IL)-28, and led to expression of IFN-stimulated genes (ISGs). Chimpanzees infected with HCV showed rapid induction of hepatic type III IFN, associated with up-regulation of ISGs and minimal induction of type I IFNs. In liver biopsy specimens from HCV-infected patients, hepatic expression of IL-28 correlated with levels of ISGs but not of type I IFNs. HCV infection produced extensive changes with gene expression in addition to ISGs in primary human hepatocytes. The induction of type III IFNs is regulated by IFN regulatory factor 3 and nuclear factor κB. Type III IFNs up-regulate ISGs with a different kinetic profile than type 1 IFNs and induce a distinct set of genes, which might account for their functional differences.

CONCLUSIONS

HCV infection results predominantly in induction of type III IFNs in livers of humans and chimpanzees; the level of induction correlates with hepatic levels of ISGs. These findings might account for the association among IL-28, level of ISGs, and recovery from HCV infection and provide a therapeutic strategy for patients who do not respond to IFN therapy.

Pharmacology and therapeutic potential of interferons

Interferon (IFN) is widely recognised to be an integral part of the innate immune response to viral infection. Since its initial discovery in 1957 by Isaacs and Lindenmann, various IFN sub-types have been identified and there are now three distinct classes recognised-Type I (IFN-α and IFN-β), Type II (IFN-γ) and Type III (IFN-λ), distinguished by their differing receptors. As well as displaying profound antiviral activity in vivo, IFN has anti-proliferative, cytotoxic and anti-tumoural roles. In an attempt to harness their immunomodulatory potential, investigators and clinicians have investigated the use of IFNs for the treatment of human diseases with considerable success. For example, IFN-α preparations are now a critical component in the treatment of chronic Hepatitis C infection and IFN-β therapy is now the first line treatment for relapsing remitting multiple sclerosis. However, IFN therapy is also associated with significant morbidity and in some patients is poorly tolerated. In this review, we explore the scientific basis for IFN therapy and outline its therapeutic scope. We describe the commonly encountered side effects and attempt to explain the less well recognised pulmonary complications including emerging evidence of life threatening and irreversible pulmonary vascular pathology. Finally, we look to the future of interferon drug treatment, examining the potential for emerging therapies.

Human Interferon Regulatory Factor 2 Gene Expression is Induced in Chronic Hepatitis C Virus Infection-A Possible Mode of Viral Persistence

BACKGROUND

The interferon regulatory factors (IRFs) are a family of transcription factors known to be involved in the modulation of cellular responses to interferons (IFNs) and viral infection. While IRF-1 acts as a positive regulator, IRF-2 is known to repress IFN-mediated gene expression. The increase in the IRF-1/IRF-2 ratio is considered as an important event in the transcriptional activation of IFN-α gene toward development of the cellular antiviral response.

OBJECTIVE

This study was performed to assess the expression of IRF mRNAs along with the expression level of IFN-α, its receptor (IFNAR-1), and the signal transduction factor (STAT-1) in treatment naive hepatitis C virus (HCV)-infected subjects.

MATERIALS

Thirty-five chronically infected (CHC) patients and 39 voluntary blood donors as controls were included in the study. Quantification of HCV-RNA (ribonucleic acid) and genotyping were done by real-time polymerase chain reaction (PCR) and hybridization assays, respectively, using patient's serum/plasma. In both controls and patients, the serum level of IFN-α and IFN-α was measured by flow cytometry. Target gene expressions were studied by retro-transcription of respective mRNAs extracted from peripheral blood mononuclear cells (PBMCs) followed by PCR amplification and densitometry. Minus-strand HCV-RNA as a marker of viral replication in PBMCs was detected by an inhouse PCR assay.

RESULTS

Both IRF-1 and IRF-2 genes were significantly enhanced in CHC than in control subjects (P < 0.001). A significant positive correlation (r (2) = 0.386, P <0.01) was obtained between higher IRF-2 gene expression and increasing level of HCV-RNA. Chronically infected subjects (13%) harboring replicating HCV in PBMCs showed no significant differences in gene expressions than the subjects without HCV in PBMCs.

CONCLUSION

Our findings indicate that HCV modulates host immunity by inducing IRF-2 gene to counteract IRF-1-mediated IFN-α gene expression. Since the IRF-2 gene is known to encode oncogenic protein, the role of IRF-2 in CHC patients developing hepatocellular carcinoma warrants further studies.

Circulating sCD14 is associated with virological response to pegylated-interferon-alpha/ribavirin treatment in HIV/HCV co-infected patients

Objectives

Microbial translocation (MT) through the gut accounts for immune activation and CD4+ loss in HIV and may influence HCV disease progression in HIV/HCV co-infection. We asked whether increased MT and immune activation may hamper anti-HCV response in HIV/HCV patients.

Methods

98 HIV/HCV patients who received pegylated-alpha-interferon (peg-INF-alpha)/ribavirin were retrospectively analyzed. Baseline MT (lipopolysaccharide, LPS), host response to MT (sCD14), CD38+HLA-DR+CD4+/CD8+, HCV genotype, severity of liver disease were assessed according to Early Virological Response (EVR: HCV-RNA <50 IU/mL at week 12 of therapy or ≥2 log₁₀ reduction from baseline after 12 weeks of therapy) and Sustained Virological Response (SVR: HCV-RNA <50 IU/mL 24 weeks after end of therapy). Mann-Whitney/Chi-square test and Pearson's correlation were used. Multivariable regression was performed to determine factors associated with EVR/SVR.

Results

71 patients displayed EVR; 41 SVR. Patients with HCV genotypes 1–4 and cirrhosis presented a trend to higher sCD14, compared to patients with genotypes 2–3 (p = 0.053) and no cirrhosis (p = 0.052). EVR and SVR patients showed lower levels of circulating sCD14 (p = 0.0001, p = 0.026, respectively), but similar T-cell activation compared to Non-EVR (Null Responders, NR) and Non-SVR (N-SVR) subjects. sCD14 resulted the main predictive factor of EVR (0.145 for each sCD14 unit more, 95%CI 0.031–0.688, p = 0.015). SVR was associated only with HCV genotypes 2–3 (AOR 0.022 for genotypes 1–4 vs 2–3, 95%CI 0.001–0.469, p = 0.014).

Conclusions

In HIV/HCV patients sCD14 correlates with the severity of liver disease and predicts early response to peg-INF-alpha/ribavirin, suggesting MT-driven immune activation as pathway of HIV/HCV co-infection and response to therapy.

An orally available, small-molecule interferon inhibits viral replication

Most acute hepatitis C virus (HCV) infections become chronic and some progress to liver cirrhosis or hepatocellular carcinoma. Standard therapy involves an interferon (IFN)-α-based regimen, and efficacy of therapy has been significantly improved by the development of protease inhibitors. However, several issues remain concerning the injectable form and the side effects of IFN. Here, we report an orally available, small-molecule type I IFN receptor agonist that directly transduces the IFN signal cascade and stimulates antiviral gene expression. Like type I IFN, the small-molecule compound induces IFN-stimulated gene (ISG) expression for antiviral activity in vitro and in vivo in mice, and the ISG induction mechanism is attributed to a direct interaction between the compound and IFN-α receptor 2, a key molecule of IFN-signaling on the cell surface. Our study highlights the importance of an orally active IFN-like agent, both as a therapy for antiviral infections and as a potential IFN substitute.

The treatment response of chronically hepatitis C virus-infected patients depends on interferon concentration but not on interferon gene expression in peripheral blood mononuclear cells

The current treatment of chronic hepatitis C is based on pegylated alpha interferon (PEG-IFN-α) and ribavirin. The aim of this study was to identify biological and clinical variables related to IFN therapy that could predict patient outcome. The study enrolled 47 patients treated with PEG-IFN and ribavirin combined therapy. The interferon concentration was measured in serum by a bioassay. The expression of 93 interferon-regulated genes in peripheral blood mononuclear cells was quantified by real-time quantitative reverse transcription-PCR (RT-PCR) before and after 1 month of treatment. The interferon concentration in the serum was significantly lower in nonresponders than in sustained virological responders. Moreover, a significant correlation was identified between interferon concentration and interferon exposition as well as body weight. The analysis of interferon-inducible genes in peripheral blood mononuclear cells among the genes tested did not permit the prediction of treatment outcome. In conclusion, the better option seems to be to treat patients with weight-adjusted PEG-IFN doses, particularly for patients with high weight who are treated with PEG-IFN-α2a. Although the peripheral blood mononuclear cell samples are the easiest to obtain, the measurement of interferon-inducible genes seems not be the best strategy to predict treatment outcome.

Dynamics of regulatory T cells and plasmacytoid dendritic cells as immune markers for virological response in pegylated interferon-α and ribavirin therapy for chronic hepatitis C patients

BACKGROUND

For the treatment of chronic hepatitis C, a combination of pegylated interferon-α (PEG-IFNα) and ribavirin has been widely used as a standard of care. Enhancement of immune response against hepatitis C virus (HCV) is known to be involved in the efficacy of the combination therapy. Our aim was to elucidate whether or not the frequency or function of blood cells is related to the outcome of the therapy.

METHODS

Sixty-seven chronic hepatitis C patients with high viral load of HCV genotype 1 infection who underwent 48 weeks of PEG-IFNα2b and ribavirin therapy were examined. During the treatment, frequencies of myeloid or plasmacytoid dendritic cells, Th1, Th2 cells, NK cells, and regulatory T cells were phenotypically determined.

RESULTS

Among the patients enrolled, 29 showed a sustained virological response (SVR), 18 a transient response (TR) and 17 no response (NR). The clinical and immunological markers were compared between the SVR and non-SVR patients, including TR and NR. Based on clinical, histological, immunological parameters, and cumulative dosage of PEG-IFNα2b and ribavirin, multivariate analyses revealed that higher platelet counts and higher regulatory T cell frequency at week 12 are indicative of SVR. Even in patients who attained complete early virological response at week 12, multivariate analyses disclosed that higher platelet counts and higher plasmacytoid dendritic cell frequency are indicative of SVR.

CONCLUSIONS

In PEG-IFNα and ribavirin combination therapy for chronic hepatitis C patients, the increments of regulatory T cells and plasmacytoid dendritic cell frequency are independently related to favorable virological response to the therapy.

Triple therapy with telaprevir: results in hepatitis C virus-genotype 1 infected relapsers and non-responders

Treatment for chronic hepatitis C virus (HCV) infection has evolved considerably in the last few years. Combination therapy with pegylated interferon (PEG-IFN)-α plus ribavirin (RBV) has been the standard of care (SoC) treatment in the past few years. Several viral and host factors have been associated with treatment failure, including age, male gender, ethnicity, genotype, IL28B genotype, steatosis, obesity and insulin resistance. Several studies have also shown that in patients who fail treatment, several interferon-stimulated genes are upregulated before treatment. Recently, the NS3/4A protease inhibitors telaprevir and boceprevir have been approved and are considered the new SoC therapy in combination with PEG-IFN-α/RBV in HCV genotype 1 treatment-naïve patients, as well as in previously treated patients, with significant improvements in SVR rates. The REALIZE phase III trial with telaprevir in previously treated patients showed SVR rates of 83-88% in prior relapsers, 54-58% in prior partial responders and, 29-33% in prior non-responders.

Hepatic expression of MxA and OAS1 in an ex vivo liver slice assay independently predicts treatment outcomes in chronic hepatitis C

Antiviral effect of interferon is mediated by the expression of interferon-stimulated genes (ISGs). However, because of the difficulty in obtaining paired liver biopsies before and after interferon treatment, the key ISGs expressed in human hepatocytes and responsible for interferon-based antiviral activities in chronic hepatitis C remain illusive. Prior to a standard course of peginterferon plus ribavirin therapy, 104 patients underwent a liver biopsy. A small piece of the liver biopsy sample from each patient was submitted for ex vivo tissue culture in the presence or absence of interferon. Hepatic expression of 8 ISGs was detected by RT-PCR. The ISG expression patterns and clinicopathological variables were correlated with subsequent treatment outcomes. Multivariate logistic regression analysis showed that hepatic MxA expression (P = 0.008) and leucocyte count (P = 0.040) independently predicted the end of therapeutic virological response, while hepatic OAS1 expression (P = 0.003), genotype 1 (P = 0.002), HCV-RNA level (P = 0.007), AST/ALT ratio (P = 0.004) and leucocyte count (P = 0.034) independently predicted the sustained virological response. Immunohistochemistry analysis showed that interferon-induced OAS1 expression localized to the hepatocytes. In conclusion, hepatic MxA and OAS1 expression predicted, respectively, the end of therapeutic and sustained virological responses in interferon-based treatment of chronic hepatitis C.

Treatment of non-genotype 1 hepatitis C virus patients

The HCV genotype will remain an important, independent pre-treatment predictor of virological response. While direct acting antivirals (DAA) will improve in the coming months the rates of virological response in patients with HCV-1, the development of DAAs effective against other HCV genotypes is at an earlier stage. Therefore, Peg-Interferon and Ribavirin will continue to be used in the near future as standard treatment in these patients. In this manuscript, we will discuss highly debated aspects related to non-1 HCV genotypes. First of all, the predictive role of IL28B genetic variation, secondarily specific aspects related to HCV-4. In the final part, we will highlight potential differences between HCV-2 and HCV-3. Indeed, despite the fact that HCV-2 and HCV-3 have been evaluated together in the majority of studies, HCV-3 patients achieve lower rates of virological response as compared to HCV-2. Whether a genotype individualized treatment may increase virologic response is the object of current investigations.

Plasma IL-6 and IL-9 predict the failure of interferon-α plus ribavirin therapy in HIV/HCV-coinfected patients

BACKGROUND

The cytokine profile plays an important role in treatment outcome of hepatitis C virus (HCV) infection, and probably modulates the immune response against HCV. The aim of this study was to evaluate which cytokines affect the response to interferon-α (IFN-α) and ribavirin therapy and how these cytokines change 72 weeks after starting anti-HCV therapy in HIV/HCV-coinfected patients.

METHODS

We carried out a retrospective follow-up study of 65 patients on anti-HCV therapy. A sustained virological response (SVR) was defined as an undetectable HCV viral load up to 24 weeks after the end of treatment. Cytokines were measured using a multiplex immunoassay kit.

RESULTS

On starting anti-HCV therapy, non-responder (NR) patients had higher levels of interleukin (IL)-6, IL-9, IL-10 and tumour necrosis factor (TNF)-α (P < 0.05), while IL-17A levels were increased in SVR patients (P = 0.058). However, only patients with high levels of IL-6 and IL-9 had decreased odds to achieve SVR (P < 0.05). Plasma levels of IL-6 and IL-9 had a high predictive value for SVR failure [area under the ROC curve (AUC) 0.839 (95% CI 0.733-0.945) and AUC 0.769 (95% CI 0.653-0.884)]. In addition, during anti-HCV therapy, IL-1β showed an increase in NR patients (P = 0.015) and IL-10 decreased in SVR patients (P = 0.049). After clearing HCV infection, low levels of TNF-α, IL-6, IL-9, IL-10, IL-13 and IL-22 were found in SVR patients (P < 0.05), as well as IL-1β, but only near statistical significance (P = 0.073).

CONCLUSIONS

High plasma levels of IL-6 and IL-9 had a high predictive value for SVR failure. Furthermore, clearing of HCV infection was associated with low inflammatory and T helper (Th)2/Th9/Th22 cytokine levels.

Genomics and proteomics in liver fibrosis and cirrhosis

Genomics and proteomics have become increasingly important in biomedical science in the past decade, as they provide an opportunity for hypothesis-free experiments that can yield major insights not previously foreseen when scientific and clinical questions are based only on hypothesis-driven approaches. Use of these tools, therefore, opens new avenues for uncovering physiological and pathological pathways. Liver fibrosis is a complex disease provoked by a range of chronic injuries to the liver, among which are viral hepatitis, (non-) alcoholic steatohepatitis and autoimmune disorders. Some chronic liver patients will never develop fibrosis or cirrhosis, whereas others rapidly progress towards cirrhosis in a few years. This variety can be caused by disease-related factors (for example, viral genotype) or host-factors (genetic/epigenetic). It is vital to establish accurate tools to identify those patients at highest risk for disease severity or progression in order to determine who are in need of immediate therapies. Moreover, there is an urgent imperative to identify non-invasive markers that can accurately distinguish mild and intermediate stages of fibrosis. Ideally, biomarkers can be used to predict disease progression and treatment response, but these studies will take many years due to the requirement for lengthy follow-up periods to assess outcomes. Current genomic and proteomic research provides many candidate biomarkers, but independent validation of these biomarkers is lacking, and reproducibility is still a key concern. Thus, great opportunities and challenges lie ahead in the field of genomics and proteomics, which, if successful, could transform the diagnosis and treatment of chronic fibrosing liver diseases.

Innate immunity: a new chapter for hepatitis C

The immune response to hepatitis C virus (HCV) and the mechanisms leading to successful resolution are complex. Much work has been done on understanding the adaptive immune response to HCV due to the imperative of trying to find a vaccine. However the importance of the innate immune system is being increasingly recognized. This has culminated in the discovery of IL-28B as a key genetic element in recovery from HCV in diverse populations. This association is one of the strongest in anti-viral immunity and represents a paradigm shift in how we view the immune response to HCV infection.

Very low viral load (VLVL) relapse following treatment of naïve patients with chronic hepatitis C

BACKGROUND

Sustained virologic response (SVR) to treatment of naïve patients with chronic hepatitis C (HCV) with pegylated interferon and ribavirin is 50-60%. Patients who relapse have a poor response to re-treatment. We report a group of relapse patients with SVR to low-dose re-treatment after 6 months.

AIM

Characterization of HCV relapse patients with very low viral load (VLVL) (HCV RNA <5,000 IU/ml) 6 months after stopping full-dose initial treatment.

METHODS

We identified 120 consecutive naïve patients over 4 years treated with pegylated interferon alpha-2a and ribavirin with full-dose therapy for 24 weeks (non-genotype 1) or 48 weeks (genotype 1) with baseline liver biopsy and at least 6 months of follow-up after treatment. HCV RNA by PCR and hepatic blood tests were obtained monthly during treatment and at least 1, 3, and 6 months post treatment.

RESULTS

Of the initially treated patients, 54.2% had SVR, 25% non-response and 20.8% relapsed. Four of 25 who relapsed (16%) and one similar patient referred to our program had HCV RNA <5,000 IU/ml 6 months after stopping treatment (VLVL relapse). Significant differences (P < 0.05) compared with the 21 other relapse patients included all five patients who were genotype 1; 4/5 had cirrhosis, baseline HCV RNA was lower, and all had SVR to less intensive re-treatment for 6 months.

CONCLUSION

VLVL relapse patients should be sought, because SVR to re-treatment is common despite genotype 1 cirrhosis.

Targeted impairment of innate antiviral responses in the liver of chronic hepatitis C patients

BACKGROUND & AIMS

Innate sensing of viral infection activates a global defense response including type I interferon (IFN) and IFN-stimulated genes (ISGs) expression. We previously reported that HCV NS3/4A protease, an essential protein in viral polyprotein processing, can abrogate antiviral signaling pathways and effectors' response when ectopically expressed in human hepatocytes by cleaving antiviral adaptor CARDIF. However, whether HCV mediates evasion of innate immunity in patients with chronic infection remains unclear.

METHODS

In this study, paired liver biopsies and corresponding purified hepatocytes of chronic hepatitis C patients and controls were subjected to transcriptional analysis of selected innate immune genes and to CARDIF protein detection.

RESULTS

We report that an antiviral response is largely supported by infected hepatocytes as demonstrated by upregulation of the representative antiviral genes ISG15, ISG56, and OASL as well as chemokines genes CXCL9, CXCL10, and CXCL11 measured in both HCV-derived liver biopsies and hepatocytes; that the mRNA levels of these indicator ISGs correlate inversely with HCV RNA level; and more importantly that expression of the early responsive IRF3-dependent genes type I IFNβ, type III IL28A/IL29, and chemokine CCL5 are severely compromised and associated to a global decrease of CARDIF adaptor in infected hepatocytes.

CONCLUSIONS

Altogether the data argue for a strong viral strategy that counteracts the host's early antiviral response of hepatocytes from chronic patients without impairing ISGs induced via classical IFN pathway.

Steatosis and insulin resistance in response to treatment of chronic hepatitis C

This review will focus on the impact of steatosis and insulin resistance on the response to antiviral therapy for chronic hepatitis C. Hepatitis C virus (HCV) infection is known to have direct and/or indirect effects on lipid and glucose metabolism, leading to, among other disturbances, steatosis and insulin resistance, respectively. Some of these disturbances have a marked HCV genotype distribution. For example, on average, patients with HCV genotype 3 have the highest prevalence and severity of viral fatty liver. On the other hand, the current global spread of the metabolic syndrome represents a formidable cofactor of morbidity in HCV-related chronic liver disease. Thus, the pathogenesis of steatosis and insulin resistance in patients with chronic hepatitis C may often be dual, i.e. viral and metabolic. This distinction is relevant because the effect (if any) of steatosis or insulin resistance on the response to antiviral agents seems to depend on their pathogenesis. Accumulating data suggest that viral fatty liver may not impact on response to therapy, while metabolic steatosis does. Similarly, viral insulin resistance may not reduce the rate of response to therapy to the same extent that metabolic insulin resistance does. Some implications for patient management are discussed.

Hepatic STAT1-nuclear translocation and interleukin 28B polymorphisms predict treatment outcomes in hepatitis C virus genotype 1-infected patients

BACKGROUND

We investigated associations between signal transducer and activator of transcription (STAT) 1 in pretreated liver tissues, interleukin (IL) 28B polymorphism and treatment response in hepatitis C virus (HCV)-infected patients treated with peginterferon and ribavirin.

METHODS AND FINDINGS

We performed immunostaining analysis of STAT1 in liver tissues and determined IL28B polymorphism at rs8099917. We then compared the results with treatment outcomes in HCV genotype 1 patients with high viral load who were receiving peginterferon plus ribavirin. In univariate analysis, younger age, white blood cell counts, virological responder, early virological responder (EVR), mild activity (A1) of liver inflammation grading, and lower STAT1 nuclear-stain of hepatocytes in zone 1, zone 2 and total zones of liver were associated with sustained virological responder (SVR). Multivariate analysis showed that EVR, age and hepatic STAT1 nuclear-stain in zone 2 of liver were independent predictors of SVR. It was also revealed that IL28B and STAT1-nuclear translocation in hepatocytes are independent predictors of response to treatment with peginterferon and ribavirin in chronic hepatitis C patients.

CONCLUSIONS

Concomitant assessment of lower STAT1 nuclear-stain of hepatocytes and IL28B polymorphism is useful for prediction of SVR in HCV genotype 1 patients.

Liver protein profiling in chronic hepatitis C: identification of potential predictive markers for interferon therapy outcome

The current anti-hepatitis C virus (HCV) therapy, based on pegylated-interferon alpha and ribavirin, has limited success rate and is accompanied by several side effects. The aim of this study was to identify protein profiles in pretreatment liver biopsies of HCV patients correlating with the outcome of antiviral therapy. Cytosolic or membrane/organelle-enriched protein extracts from liver biopsies of eight HCV patients were analyzed by two-dimensional fluorescence difference gel electrophoresis and mass spectrometry. Overall, this analysis identified 21 proteins whose expression levels correlate with therapy response. These factors are involved in interferon-mediated antiviral activity, stress response, and energy metabolism. Moreover, we found that post-translational modifications of dihydroxyacetone kinase were also associated with therapy outcome. Differential expression of the five best performing markers (STAT1, Mx1, DD4, DAK, and PD-ECGF) was confirmed by immunoblotting assays in an independent group of HCV patients. Finally, we showed that a prediction model based on the expression levels of these markers classifies responder and nonresponder patients with an accuracy of 85.7%. These results provide evidence that the analysis of pretreatment liver protein profiles is valuable for discriminating between responder and nonresponder HCV patients, and may contribute to reduce the number of nonresponder patients exposed to therapy-associated risks.

Activating NK cell receptor expression/function (NKp30, NKp46, DNAM-1) during chronic viraemic HCV infection is associated with the outcome of combined treatment

Specific NK cell killer inhibitory receptor (KIR):HLA haplotype combinations have been associated with successful clearance of acute and chronic HCV infection. Whether an imbalance of activating NK cell receptors also contributes to the outcome of treatment of chronic HCV infection, however, is not known. We studied peripheral NK cell phenotype and function in 28 chronically viraemic HCV genotype I treatment-naïve patients who underwent treatment with pegylated IFN-α and ribavirin. At baseline, chronically infected patients with sustained virological response (SVR) had reduced CD56(bright) CD16(+/-) cell populations, increased CD56(dull) CD16(+) NK cell proportions, and lower expression of NKp30, DNAM-1, and CD85j. Similarly, reduced NK cell IFN-γ production but increased degranulation was observed among nonresponding (NR) patients. After treatment, CD56(bright) CD16(+/-) NK cell numbers increased in both SVR and NR patients, with a parallel significant increase in activating NKp30 molecule densities in SVR patients only. In vitro experiments using purified NK cells in the presence of rIL-2 and IFN-α confirmed upregulation of NKp30 and also of NKp46 and DNAM-1 in patients with subsequent SVR. Thus, differences in patient NK cell receptor expression and modulation during chronic HCV-1 infection are associated with subsequent outcome of standard treatment. Individual activating receptor expression/function integrates with KIR:HLA genotype carriage to determine the clearance of HCV infection upon treatment.

Interferon-gamma - Inducible Inflammation: Contribution to Aging and Aging-Associated Psychiatric Disorders

Aging is associated with the chronic, low grade, Th-1 type inflammation. The key Th-1 type, pro-inflammatory cytokine, interferon-gamma (IFNG), transcriptionally induces the rate-limiting enzyme of tryptophan (TRY) - kynurenine (KYN) pathway, indoleamine 2,3- dioxygenase (IDO). Activation of IDO shunts TRY metabolism from production of serotonin (substrate of antidepressant effect) and its derivatives: N-acetylserotonin (an agonist to the receptors of brain derived neurotropic factor), and melatonin (regulator of sleep and other circadian rhythms), towards production of KYN and its derivatives (anxiogenic, neurotoxic and pro-oxidant factors). Some of kynurenines up-regulate nitric oxide synthase (NOS). Concurrently with activation of IDO, IFNG induces guanosine triphosphate cyclohydrolase I (GTPCH), the rate limiting enzyme of GTP conversion into BH2 (and increases formation of a stable derivative of BH2, neopterin, at the expense of production of BH4, the mandatory co-factor of NOS). Combination of increased NOS activity (by kynurenines) with decreased formation of BH4 leads to the uncoupling of NOS with consequent shift of arginine metabolism from biosynthesis of NO to formation of superoxide anion and other free radicals, and exacerbation of depression, anxiety and cognitive impairment caused by kynurenines. Polymorphism of IFNG (+874) T/A gene, that encodes production of IFNG protein, impacts the IDO and GTPCH activity that might be assessed in humans by KYN/TRY ratio and neopterin concentrations in biological fluids (e.g., blood, urine and spinal fluid). The hypothesis of IFNG inducible IDO/GTPCH inflammation cascade helps to understand the increased association between aging, inflammation and aging-associated psychiatric and medical (insulin resistance, obesity) disorders. Evaluation of markers of IFNG-inducible inflammation cascade might be used to assess the severity of corresponding behavioral and cognitive changes and the efficacy of pharmacological interventions (e.g., IDO inhibitors).

Association between IL28B polymorphisms and first-phase viral load decrease in chronic hepatitis C virus-infected patients treated with peginterferon alfa-2b/ribavirin

Host polymorphisms in the IL28B region have recently been associated with outcome of treatment for hepatitis C virus (HCV) infection. This study clearly shows an association between first-phase viral load decrease and the IL28B rs12979860 polymorphism in chronic HCV-infected patients. Furthermore, a higher treatment efficiency factor (ɛ) was found in those HCV-infected patients with a CC genotype compared with those with a CT and TT genotype. This study highlights the importance of host response mechanisms in relation to favourable clearance of HCV.

ISG56 and IFITM1 proteins inhibit hepatitis C virus replication

Hepatitis C virus (HCV) often leads to persistent infection. Interferon (IFN) and IFN-stimulated genes (ISGs) are amplified during HCV infection but fail to eliminate virus from the liver in a large number of infected patients. We have observed previously that HCV infection induces IFN-β production in immortalized human hepatocytes (IHH) as early as 24 h after infection, although virus replication is not inhibited. To gain insights on possible countermeasures of virus for the suppression of host antiviral response, the cellular transcriptional profiles of ISGs were examined after various treatments of IHH. The majority of ISGs were upregulated in IFN-treated IHH from the level for mock-treated cells. However, the comparison of ISG expression in IFN-treated IHH and IFN-pretreated, HCV genotype 2a-infected IHH indicated that virus infection suppresses the upregulation of a subset of effector molecules, including ISG56 and IFITM1. Similar results were observed for HCV-infected Huh7 cells. Subsequent study suggested that the exogenous expression of ISG56 or IFITM1 inhibits HCV replication in IHH or Huh7 cells, and the knockdown of these genes enhanced HCV replication. Further characterization revealed that the overexpression of these ISGs does not block HCV pseudotype entry into Huh7 cells. Taken together, our results demonstrated that ISG56 and IFITM1 serve as important molecules to restrict HCV infection, and they may have implications in the development of therapeutic modalities.

Hepatitis C virus induces interferon-λ and interferon-stimulated genes in primary liver cultures

Hepatitis C virus (HCV) replication in primary liver cells is less robust than that in hepatoma cell lines, suggesting that innate antiviral mechanisms in primary cells may limit HCV replication or spread. Here we analyzed the expression of 47 genes associated with interferon (IFN) induction and signaling following HCV infection of primary human fetal liver cell (HFLC) cultures from 18 different donors. We report that cell culture-produced HCV (HCVcc) induced expression of Type III (λ) IFNs and of IFN-stimulated genes (ISGs). Little expression of Type I IFNs was detected. Levels of IFNλ and ISG induction varied among donors and, often, between adapted and nonadapted HCV chimeric constructs. Higher levels of viral replication were associated with greater induction of ISGs and of λ IFNs. Gene induction was dependent on HCV replication, as ultraviolet light-inactivated virus was not stimulatory and an antiviral drug, 2'-C-methyladenosine, reduced induction of λ IFNs and ISGs. The level of IFNλ protein induced was sufficient to inhibit HCVcc infection of naïve cultures.

CONCLUSION

Together, these results indicate that despite its reported abilities to blunt the induction of an IFN response, HCV infection is capable of inducing antiviral cytokines and pathways in primary liver cell cultures. Induction of ISGs and λ IFNs may limit the growth and spread of HCV in primary cell cultures and in the infected liver. HCV infection of HFLC may provide a useful model for the study of gene induction by HCV in vivo.

Hepatitis C virus fails to activate NF-κB signaling in plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) respond to viral infection by production of alpha interferon (IFN-α), proinflammatory cytokines, and cell differentiation. The elimination of hepatitis C virus (HCV) in more than 50% of chronically infected patients by treatment with IFN-α suggests that pDCs can play an important role in the control of HCV infection. pDCs exposed to HCV-infected hepatoma cells, in contrast to cell-free HCV virions, produce large amounts of IFN-α. To further investigate the molecular mechanism of HCV sensing, we studied whether exposure of pDCs to HCV-infected hepatoma cells activates, in parallel to interferon regulatory factor 7 (IRF7)-mediated production of IFN-α, nuclear factor kappa B (NF-κB)-dependent pDC responses, such as expression of the differentiation markers CD40, CCR7, CD86, and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and secretion of the proinflammatory cytokines TNF-α and interleukin 6 (IL-6). We demonstrate that exposure of pDCs to HCV-infected hepatoma cells surprisingly did not induce phosphorylation of NF-κB or cell surface expression of CD40, CCR7, CD86, or TRAIL or secretion of TNF-α and IL-6. In contrast, CpG-A and CpG-B induced production of TNF-α and IL-6 in pDCs exposed to the HCV-infected hepatoma cells, showing that cell-associated virus did not actively inhibit Toll-like receptor (TLR)-mediated NF-κB phosphorylation. Our results suggest that cell-associated HCV signals in pDCs via an endocytosis-dependent mechanism and IRF7 but not via the NF-κB pathway. In spite of IFN-α induction, cell-associated HCV does not induce a full functional response of pDCs. These findings contribute to the understanding of evasion of immune responses by HCV.

Therapeutic implications of hepatitis C virus resistance to antiviral drugs

Treatment of chronic hepatitis C is currently based on a combination of pegylated interferon-o! and ribavirin. Neither drug exerts direct selective pressure on viral functions, meaning that interferon-a/ribavirin treatment failure is not due to selection of interferon-a- or ribavirin-resistant viral variants. Several novel antiviral approaches are currently in preclinical or clinical development, and most target viral enzymes and functions, such as hepatitis C virus protease and polymerase. These new drugs all potentially select resistant viral variants both in vitro and in vivo, and resistance is therefore likely to become an important issue in clinical practice.

IL28B polymorphisms predict reduction of HCV RNA from the first day of therapy in chronic hepatitis C

BACKGROUND & AIMS

Single nucleotide polymorphisms (SNPs) associated with IL28B influence the outcome of peginterferon-α/ribavirin therapy of chronic hepatitis C virus (HCV) infection. We analyzed the kinetics of HCV RNA during therapy as a function of IL28B SNPs.

METHODS

IL28B SNPs rs8099917, rs12979860, and rs12980275 were genotyped in 242 HCV treatment-naïve Caucasian patients (67% genotype 1, 28% genotype 2 or 3) receiving peginterferon-α2a (180 μg weekly) and ribavirin (1000-1200 mg daily) with serial HCV-RNA quantifications. Associations between IL28B polymorphisms and early viral kinetics were assessed, accounting for relevant covariates.

RESULTS

In the multivariate analyses for genotype 1 patients, the T allele of rs12979860 (T(rs12979860)) was an independent risk factor for a less pronounced first phase HCV RNA decline (log(10) 0.89IU/ml among T carriers vs. 2.06 among others, adjusted p < 0.001) and lower rapid (15% vs. 38%, adjusted p = 0.007) and sustained viral response rates (48% vs. 66%, adjusted p < 0.001). In univariate analyses, T(rs12979860) was also associated with a reduced second phase decline (p = 0.002), but this association was no longer significant after adjustment for the first phase decline (adjusted p = 0.8). In genotype 2/3 patients, T(rs12979860) was associated with a reduced first phase decline (adjusted p = 0.04), but not with a second phase decline.

CONCLUSIONS

Polymorphisms in IL28B are strongly associated with the first phase viral decline during peginterferon-α/ribavirin therapy of chronic HCV infection, irrespective of HCV genotype.

Genetic variants of interferon-stimulated genes and IL-28B as host prognostic factors of response to combination treatment for chronic hepatitis C

Chronic hepatitis C (CHC) is a worldwide health problem that is highly related to liver fibrosis, cirrhosis, and hepatocellular carcinoma. The achievement of response to the current standard of care-pegylated interferon plus ribavirin-has recently been described to be associated with single-nucleotide polymorphisms (SNPs) near the IL-28B gene. Additionally, baseline expression levels of genes involved in interferon (IFN)-stimulated genes (ISGs) have been found to be related to treatment outcome. In the present study, 285 patients were genotyped for 63 SNPs within genes of the IFN signaling pathway (IPGs) and ISGs. Two ISG polymorphisms-OASL rs12819210 (odds ratio (OR)=2.1, P=0.03) and IFIT1 rs304478 (OR=2.5, P=0.01)-were found to be independent predictive factors of sustained virological response (SVR) after adjusting for other clinical covariates. Furthermore, the predictive value of IL-28B SNP was notably improved by simultaneous genotyping of rs12819210 and rs304478, particularly in patients with the worst prognosis (viral genotype 1, area under the curve (AUC)=0.74). In conclusion, ISG SNPs could constitute a valuable tool for individualizing CHC therapy.

Early activation of interferon-stimulated genes in human liver allografts: relationship with acute rejection and histological outcome

BACKGROUND

Innate immunity mechanisms have been shown to play a paramount role in organ transplantation. Our aim was to investigate the hypothesis that activation of the interferon system may affect clinically relevant outcomes, such as acute rejection and/or early fibrosis progression, after liver transplantation.

METHODS

We studied 71 consecutive recipients (57 males; 25 with hepatitis C) who underwent two per protocol graft biopsies: the first, within 60 days after the transplant operation (median 24) and the second, after 1 year. The mRNA expression for five interferon-stimulated genes (Mx1, OAS2, PKR, IRF7A, IFI16) was measured on the first biopsy specimens. The main outcome measures were acute rejection during the first post-transplant year and fibrosis progression at the second biopsy.

RESULTS

On multivariate analysis, the independent predictors of gene expression were hepatitis C (Mx1, OAS2, PKR and IFI16), donor age (IFI16) and recipient gender (IRF7A) (P < .05 for all). During the first post-transplant year, 19/71 patients (27%) had acute cellular rejection. At multivariate analysis, acute cellular rejection was independently predicted by high IRF7A mRNA expression. At the end of follow-up, 25 patients had some degree of fibrosis (F2 or higher in seven cases). On multivariate analysis, hepatitis C etiology, recipient age, and OAS2 overexpression were independent predictors of early fibrosis progression.

CONCLUSIONS

In the early postoperative period of liver transplantation, interferon-stimulated gene activation is dependent on hepatitis C recurrence (the main factor responsible for early fibrosis progression) and donor age, and is related to the risk of acute cellular rejection.

Toll like receptor 3 expression as a novel predictor of response to treatment in chronic hepatitis C virus patients

PURPOSE

This work was carried out to study the level of pretreatment hepatic expression of Toll like receptor 3 (TLR3) among chronic HCV patients, aiming to determine if there are consistent differences in gene expression, between those who show complete early virological response (cEVR) at week-12 of Pegylated-Interferon α-2a plus ribavirin treatment and others who are not responding to this combination, also if this could be used to predict treatment outcomes.

METHOD

A total of 61 chronic hepatitis C patients were enrolled in the study. For all of them, baseline hepatitis C virus (HCV) viral load was determined and TLR3 gene expression was examined in their hepatic percutaneous needle biopsy specimens using a real time-polymerase chain reaction technique. Hepatic TLR3 was also traced using immunohistochemistry. All patients followed a 12-week regimen of Pegylated-Interferon α-2a plus ribavirin then post-treatment viral load was assayed.

RESULTS

Hepatic expression of TLR3 was significantly increased in the non-responder group as compared to those who showed complete early virological response to the used treatment regimen. Using receiver operator characteristic (ROC) curve analysis, a cutoff level of 1.5 was set for TLR3 expression to distinguish responders from non-responders to the 12-week treatment regimen used.

CONCLUSION

In conclusion, measuring the hepatic expression of the interferon stimulated gene, TLR3 could provide a new molecular marker for pre-treatment prediction of complete early viral clearance, thus helping in patients' selection and optimizing treatment outcomes.