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Hepatitis C virus (HCV) has spread worldwide, and it is responsible for potentially severe chronic liver disease and primary liver cancer. Chronic infection remains for life if not spontaneously eliminated and viral persistence profoundly impairs the efficiency of the host's immunity. Attempts have been made to develop an effective vaccine, but efficacy trials have met with failure. The availability of highly efficacious direct-acting antivirals (DAA) has created hope for the progressive elimination of chronic HCV infections; however, this approach requires a monumental global effort. HCV elicits a prompt innate immune response in the host, characterized by a robust production of interferon-α (IFN-α), although interference in IFN-α signaling by HCV proteins may curb this effect. The late appearance of largely ineffective neutralizing antibodies and the progressive exhaustion of T cells, particularly CD8 T cells, result in the inability to eradicate the virus in most infected patients. Moreover, an HCV cure resulting from DAA treatment does not completely restore the normal immunologic homeostasis. Here, we discuss the main immunological features of immune responses to HCV and the epigenetic scars that chronic viral persistence leaves behind. [ABSTRACT FROM AUTHOR]

Background and Aims: Different population genetics studies showed that interactions between killer‐cell immunoglobulin‐like receptors (KIR) and HLA play a role in viral disease outcome, but functional correlates are missing. Building upon our previous work pointing to a regulatory role for KIR3DL1/DS1 in hepatitis C virus (HCV) infection, we analysed whether its expression may affect natural killer (NK) cell function in the presence or absence of its principal ligand HLA‐Bw4 in KIR haplotype A and B carriers, which are characterized by a different representation of activating and inhibitory KIRs. Methods: We performed KIR and HLA class I genotypic analysis in 54 healthy donors (HD) and 50 HCV+ subjects and examined NK cell cytokine secretion and degranulation in the context of KIR3DL1‐HLA‐Bw4 match stratified by KIR haplotype. Results: KIR3DL1‐HLA‐Bw4 match induced functional NK cell modulation, reflected by reduced interferon (IFN)γ production in haplotype B HCV+ patients compared to HD. This functional impairment could be ascribed to the KIR3DS1 negative HCV‐infected patient population, whose NK cells also showed a significantly decreased proportion of KIR3DL1. Haplotype A HCV‐infected patients showed increased NK cell degranulation compared with HD in the absence of KIR‐HLA‐Bw4 match and this activity was associated with increased phosphorylation of signal transducer and activator of transcription (STAT) 1. Conclusions: Our data show that NK cells from HCV+ patients have an unbalanced ability to produce IFNγ and to kill target cells in haplotype A and B carriers, suggesting the existence of complex functional differences governed by KIR‐HLA interaction, particularly on KIR3DL1 expressing NK cells. [ABSTRACT FROM AUTHOR]

Between 80 and 115 million people worldwide are chronically infected with hepatitis C virus, with 60%-90% of these being undiagnosed. Untreated chronic hepatitis C ( CHC) is associated with progressive liver disease, cirrhosis, hepatocellular carcinoma and liver-related mortality. A number of extrahepatic manifestations are also reported in CHC patients, further adding to the burden of the disease. CHC also impacts patients in terms of lower health-related quality of life, higher levels of fatigue and reduced productivity. Furthermore, the later stages of disease are costly for both healthcare systems and society. Pegylated-interferon ( PEG- IFN)+ribavirin ( RBV), for many years the mainstay of treatment, leads to sustained virological response ( SVR) in 40%-70% of patients. However, a substantial number of patients are ineligible for treatment, and many patients fail to achieve SVR with this regimen. Furthermore, PEG- IFN+ RBV leads to impairment of patient-reported outcomes during treatment, and most patients suffer from adverse events, associated with poor adherence, treatment discontinuation and treatment failure. The approval of second-generation direct-acting antivirals ( DAAs) has revolutionized the treatment of CHC patients. All-oral, PEG- IFN and RBV-free regimens have higher efficacy rates, shorter treatment durations, fewer adverse events, higher adherence rates and improvement in PROs from as early as Week 4, compared to PEG- IFN+ RBV regimens. The aim of this article is to review the evidence for HCV infection as a systemic disease, summarizing the impact of hepatitis C and its treatments on clinical, patient and economic outcomes, with a focus on data from Asia and Japan specifically. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are involved in innate immune responses to viral infections either via direct cytotoxicity which destroys virus-infected cells or production of immunoregu-latory cytokines which modulate adaptive immunity and directly inhibit virus replication. These functions are mediated by different NK subpopulations, with cytotoxicity being generally performed by CD56dim NK cells, whereas CD56bright NK cells are mainly involved in cytokine secretion. NK functional defects are usually combined so that impaired degran-ulation is often associated with deficient cytokine production. Innate immunity is thought to be relevant in the control of hepatitis virus infections such as hepatitis B virus (HBV) and hepatitis C virus (HCV), and recent findings reproducibly indicate that NK cells in chronic viral hepatitis are characterized by a functional dichotomy, featuring a conserved or enhanced cytotoxicity and a reduced production of interferon (IFN)-γ and tumor necrosis factor-α. In chronic HCV infection this appears to be caused by altered IFN-α signaling resulting from increased signal transducer and activator of transcription 1 (STAT1) phosphorylation, which polarizes NK cells toward cytotoxicity, and a concomitantly reduced IFN-α induced STAT4 phosphorylation yielding reduced IFN-γ mRNA levels.These previously unappreciated findings are compatible on the one hand with the inability to clear HCV and HBV from the liver and on the other they may contribute to understand why these patients are often resistant to IFN-α-based therapies. [ABSTRACT FROM AUTHOR]

More than one and half of current cases of hepatocellular carcinoma in the US, Europe, and Japan are attributable to hepatitis C virus (HCV) infection. HCV is also the primary cause of death in patients with HCV-related cirrhosis, with annual incidences of 0.5%-5% in Europe and 4%-10% in Asia. Screening is based on serum alpha-fetoprotein determination and liver ultrasound scan, but the sensitivity of the former is far less than optimal, and screening intervals are still poorly defined for the latter. Risk factors related to the host or environment, or both, appear to be more relevant than viral factors, such as HCV genotype, in determining disease progression to cirrhosis and cancer, and include age, male gender, severity of liver disease at presentation, coinfection with hepatitis B virus or human immunodeficiency virus, and alcohol abuse. Early liver transplantation in selected cases can be curative, but most patients are not eligible for liver grafting and are treated with locoregional ablative therapies, after which recurrence is common. Recently, orally available inhibitors of the vascular endothelial growth factor receptor have shown a significant, albeit modest, increment of survival in patients with advanced hepatocellular carcinoma, thus paving the way for modern molecular approaches to treatment of this highly malignant tumor. [ABSTRACT FROM AUTHOR]

Hepatitis C virus (HCV) elicits T- and B-cell responses which are believed to play an important role in infection control. B cells have generally been neglected because they do not seem to significantly influence the course of HCV infection. In this review, B lymphocytes are viewed both as classical antibody producing cells, with the hypervariable region 1 being a biologically relevant target protein and as a model of virus–host interaction in lymphoproliferative disorders characteristic of persistent microbial infections. [Copyright &y& Elsevier]

Background/Aims: We developed a single-chain antibody fragment (scFv) to the non-structural 3 protein (NS3) of hepatitis C virus (HCV) and tested its ability to interfere with the HCV replication cycle in infected hepatocytes.Methods: The variable regions of the human monoclonal antibody CM3.B6 that recognizes a conformational epitope within the helicase domain of NS3 were introduced into adenoviral vectors for expression in mammalian hepatocytes. Expression and binding properties of the scFv were analyzed by immunological assays. Effects of intracellular expression of the scFv on HCV replication were assessed in primary hepatocytes isolated from explanted livers of patients with chronic HCV infection by reverse transcription-polymerase chain reaction.Results: Transduction of HepG2 cells by the recombinant adenoviruses resulted in stable, efficient expression of scFv in the cytoplasm that was non-toxic to the cells. The scFv specifically bound to its cognate antigen. Significantly, intracellular expression of scFv resulted in a decrease in HCV genomic RNA in HCV infected hepatocytes.Conclusions: These results indicate that specific binding of a scFv to NS3 may inhibit one or more functions of this essential viral protein thus interfering with the HCV replication cycle. [Copyright &y& Elsevier]

Features a study on the effects of hepatitis C virus (HCV) genotypes on patients with cirrhosis in southern Italy. Details on HCV genotypes; Methods of the study; Results; Discussion.

Chronic hepatitis C virus (HCV) infection affects 71 million people worldwide. The availability of highly efficient direct-acting antivirals has revolutionized the treatment landscape with over 95% cure rates. The WHO has launched a global programme to achieve rather ambitious HCV elimination targets for 2030. This article aims to provide a critical overview of the current HCV elimination programmes in Europe highlighting the elements that should be implemented to achieve elimination and those that are already in place to promote this process. Review of the recently published literature and opinion of experts in the field. Elimination of hepatitis C as a public health threat appears to be a difficult task, which should be subdivided into smaller targets, the so-called micro-elimination goals, to increase chances of success. Macro-elimination strategies based on mass-screening are difficult to implement. Evidence supporting the efficacy of micro-elimination comes from key populations, such as people who inject drugs. HCV elimination is proceeding at different speeds in Europe. Some countries are on target with the WHO's objectives whereas others lack economic support and political advocacy, and have insufficient infrastructures to achieve this. The absence of an effective prophylactic vaccine is hampering the process and should be overcome. Elimination of hepatitis C worldwide appears plausible, but in several countries probably not within the time frame suggested by the WHO. In the absence of vaccination, universal access to HCV treatment would act as a 'therapeutic' option to reduce transmission, especially in high-risk populations. [ABSTRACT FROM AUTHOR]

Background/Aims: Hepatitis C virus (HCV) is a known risk factor for hepatocellular carcinoma (HCC), but whether the risk varies among patients infected with different HCV genotypes is still controversial. We performed a meta-analysis to clarify whether the genotype 1b is associated with a higher risk of HCC than other genotypes. Methods: We identified 57 relevant papers through a literature search to December 2007 but, since age could represent a major confounder, we focused the meta-analysis on the 21 studies presenting age-adjusted risk estimates for HCV genotype 1b vs. other genotypes. We used random-effects models with the DerSimonian–Laird method and assessed heterogeneity between studies and publication bias. Results: Patients infected with HCV genotype 1b have almost double the risk to develop HCC than those infected with other genotypes (Relative Risk (95% Confidence Intervals)=1.78(1.36–2.32)). The pooled risk estimate was somewhat lower when we restricted the analysis to the eight studies conducted in patients with liver cirrhosis (1.60;1.07–2.39) or considering the 36 studies presenting only crude data (1.63;1.30–2.06). In seven studies excluding patients with liver cirrhosis, the RR (95% CI) increased to 2.46(1.69–3.59). Conclusions: This meta-analysis suggests that HCV genotype 1b plays an important role in HCC development, especially in patients with early stage liver disease. [Copyright &y& Elsevier]

Background & Aims Natural killer (NK) cells play an important role in the pathogenesis of hepatitis C virus (HCV) infection. We have previously shown that culture-derived HCV (HCVcc) enhance tumor necrosis-factor-related apoptosis-inducing ligand (TRAIL) expression on healthy NK cells, but not on those from patients infected with HCV, which was likely dependent on accessory cells. Here we sought to elucidate the mechanisms involved in altered TRAIL upregulation in this setting. Methods Peripheral blood mononuclear cells (PBMC) from controls and patients infected with HCV were exposed to HCVcc. Cell depletions were performed to identify cells responsible for NK cell activation. Flow cytometry and ELISA were used to identify the cytokines involved in the NK activation process. Results In patients infected with HCV, soluble factors secreted by control PBMC restored the ability of NK cells to express TRAIL. Of note, CD14+ cell depletion had identical effects upon virus exposure and promoted increased degranulation. Moreover, increased concentrations of interleukin (IL)-18 binding protein a (IL-18BPa) and IL-36 receptor antagonist (IL-36RA) were observed after PBMC exposure to HCVcc in patients with HCV. HCVcc-induced NK cell TRAIL expression was inhibited by IL-18BPa and IL-36RA in control subjects. There were statistically significant correlations between IL-18BPa and indices of liver inflammation and fibrosis, supporting a role for this protein in the pathogenesis of chronic HCV infection. Conclusions During chronic HCV infection, monocytes play a key role in negative regulation of NK cell activation, predominantly via secretion of inhibitors of IL-18 and IL-36. Lay summary Coordination and collaboration between immune cells are essential to fight pathogens. Herein we show that during HCV infection monocytes secrete IL-18 and IL-36 inhibitory proteins, reducing NK cell activation, and consequently inhibiting their ability to express TRAIL and kill target cells. [ABSTRACT FROM AUTHOR]

Background & Aims The Fc receptor family for immunoglobulin (Ig)G type III (FcγRIII, CD16) is an activating receptor on natural killer (NK) cells and an essential mediator of antibody-dependent cellular cytotoxicity (ADCC). There is only limited information on its role during chronic hepatitis C virus (HCV) infection. We studied CD16 expression in relation to NK cell functional activity in HCV-infected patients and sought mechanistic insights into virus-induced modulation. Methods NK cell CD16 expression and activation status were evaluated ex vivo by flow cytometry in HCV-infected patients and healthy controls (HC) as well as in vitro after co-culture with HCV-infected HuH7.5 cells. Rituximab-mediated ADCC was assessed in HC and HCV-infected patients using Daudi cells as a target. The role of metzincins in CD16 down-modulation was assessed using specific inhibitory molecules and by evaluating intracellular mRNA levels. Results HCV-infected patients exhibited increased frequencies of ex vivo activated NK cells and a concomitantly decreased NK CD16 expression, which resulted in impaired ADCC activity. Moreover, exposure of NK cells to culture-derived HCV recapitulated the ex vivo findings of decreased CD16 expression and increased NK cell activation. Importantly, blockade of metzincin-mediated shedding activity, including selective a disintegrin and metalloproteinase 17 (ADAM-17) inhibition, restored NK CD16 expression. Successful treatment with direct-acting antivirals partially improved NK ADCC function despite delayed CD16 reconstitution. Conclusion Chronic HCV infection induces NK cell activation resulting in ADAM-17-dependent CD16 shedding and consequent impaired ADCC function. Altered ADCC may contribute to failure to eradicate HCV-infected hepatocytes. Lay summary We show here that hepatitis C virus (HCV) activates natural killer (NK) lymphocytes which, as a consequence, loose their Fc receptor for IgG (CD16), an essential molecule for antibody binding. We show that this occurs through the action of enzymes named metzincins, resulting in altered NK-mediated antibody-dependent killing (ADCC) of target cells. This mechanism may contribute to HCV persistence and may represent a general phenomenon whereby some viruses can escape host’s immune responses. [ABSTRACT FROM AUTHOR]

Toll-like receptor 7 (TLR7) is a ssRNA receptor that activates dendritic cells and macrophages upon ssRNA binding; however, little is known of its role in CD4 + T cells. We show here that hepatitis C virus (HCV) induces a dose dependent inhibition of cytokine production and expression of activation markers in CD4 T cells, which were restored by a TLR7-specific antagonist. These findings indicate that HCV induces CD4 T cell impairment via TLR7 which may contribute to failure of virus eradication, casting doubts on the use of TLR7 agonists to boost innate immunity in chronic RNA virus infections. [ABSTRACT FROM AUTHOR]

Background & Aims: A substantial proportion of patients with chronic hepatitis C virus infection treated with pegylated interferon α/ribavirin fail to achieve sustained virological response (SVR). Since growing evidence suggests that innate immunity may influence treatment responses, we examined natural killer (NK) cell phenotypic and functional changes during standard antiviral therapy. Methods: Expression of several NK-cell regulatory molecules was evaluated by flow cytometry in 37 consecutive patients with chronic HCV infection at baseline and at different time points during and after discontinuation of treatment. Cytokine production was evaluated by intracellular staining. Cytolytic potential was assessed as degranulation and as antibody-dependent cytotoxicity. Results: Baseline frequencies of CD56dim NK cells and perforin content were significantly higher, whereas CD16 expression was lower in SVR vs. non-responder subjects. Analysis by linear regression for repeated measures during the first 12weeks showed significantly increased frequencies of activated (CD69+) NK cells in rapid virological responders (RVR) and identified a typical NK cell profile associated with SVR, featuring higher NK perforin content, lower CD16 expression, and higher proportion of CD56dim/CD16− cells. Moreover, SVR patients displayed higher natural and antibody-dependent NK cell cytotoxicity. IL28B rs12979860 CC homozygosis was significantly associated with SVR, independently of NK-cell phenotype and function. Conclusions: Different NK-cell phenotypic and functional features, in patients with chronic hepatitis C treated with standard therapy, were observed between non-responder vs. SVR patients, suggesting a potential role of NK cells in the response to treatment. [Copyright &y& Elsevier]

Abstract: Eradication of hepatitis C virus (HCV) by antiviral therapy is the treatment of choice for mixed cryoglobulinemia secondary to this infection, but many patients fail to achieve sustained viral responses and need second-line treatments. Several studies have demonstrated that the infusion of the anti-CD20 monoclonal antibody rituximab is highly effective for refractory mixed cryoglobulinemia, with a clinical response in approximately 80% of patients, although the relapse rate is high. Virtually all published studies employed a rituximab dosage of 375mg/m2 given four times, a schedule used for treating non-Hodgkin''s lymphomas. Based on a prior pilot study, we designed a phase II single-arm two-stage study (EUDRACT n. 2008-000086-38) to evaluate the efficacy of a lower dosage of rituximab, 250mg/m2 given twice, for refractory mixed cryoglobulinemia. We present here the preliminary results in the first 27 patients enrolled. The overall response rate in 24 evaluable patients was 79%, and the mean time to relapse was 6.5months, similar to the 6.7months reported in studies with high-dose rituximab. Side effects were comparable to those seen in patients treated with high-dose. Increase of HCV viral load, reported in some high-dose studies, was not observed in our patients. Low-dose rituximab may provide a more cost/effective and possibly safer alternative for treating refractory HCV-associated mixed cryoglobulinemia. [Copyright &y& Elsevier]

Background/Aims: Liver steatosis is a frequent finding in chronic hepatitis C. An association has been suggested between steatosis and fibrosis progression rate, but the pathogenetic mechanisms linking fatty infiltration and collagen deposition are unknown. Methods: We measured the levels of insulin resistance (as HOMA score) and leptin in 221 non-diabetic chronic hepatitis C patients, to assess their impact on liver steatosis and fibrosis, relative to other factors, using a multivariable logistic regression. Results: When all 221 patients were considered, steatosis was associated with excessive alcohol intake, genotype 3, and serum HCV RNA level, whereas fibrosis was associated with HOMA score and age. In 152 patients infected with genotype non-3, steatosis was associated with alcohol abuse and HCV RNA level, and fibrosis with HOMA score and age. In the 69 patients with genotype 3, steatosis and fibrosis were associated with each other. The association between fibrosis and HOMA score held also when 22 obese patients were excluded from the analysis. Levels of insulin resistance were not correlated with the presence of steatosis. Conclusions: Thus, insulin resistance (but not leptin) may play a role in fibrogenesis in chronic hepatitis C patients infected with genotype non-3. [Copyright &y& Elsevier]

Chronic hepatitis C virus (HCV) infection is the most frequent cause of progressive liver disease and liver cancer in the West. The p53 tumor supressor gene is known to play an important role in carcinogenesis of different tissues being involved in gene transcription, DNA synthesis and repair and somatic mutations of p53 are common in primary liver cancer.The p53 gene displays a common genetic Arg/Pro polymorphism at codon 72 with functional significance, that has been investigated as risk factor in several cancer models. We analyzed p53 codon 72 polymorphism in a group of 340 HCV-infected subjects at different stages of disease, including 84 hepatocellular carcinoma patients.No association between codon 72 genotypes and disease severity or liver cancer was observed. [Copyright &y& Elsevier]

Regulatory T (TR) cells consist of phenotypically and functionally distinct CD4+ and CD8+ T cell subsets engaged both in maintaining self-tolerance and in preventing anti-non-self effector responses (microbial, tumor, transplant, and so on) that may be harmful to the host. Here we propose that the proinflammatory function of virus-specific memory effector CCR7-CD8+ T cells, which are massively recruited in the liver, are inefficient (in terms of IFN-γ production) in patients with chronic hepatitis C virus (HCV) infection because of the concomitant presence of virus-specific CCR7-CDB+ TR cells producing considerable amounts of IL-10. These CDB+ TR cells are antigen specific, as they can be stimulated by HCV epitopes and suppress T cell responses that are in turn restored by the addition of neutralizing anti-IL-10. This study provides for the first time to our knowledge direct evidence of the existence of virus-specific CDB+ TR cells that infiltrate the livers of patients with chronic HCV infection, identifies IL-10 as a soluble inhibitory factor mediating suppression, and suggests that these cells play a pivotal role in controlling hepatic effector CDB+ T cell responses. [ABSTRACT FROM AUTHOR]

Chronic hepatitis C virus (HCV) infection is frequently associated with extrahepatic manifestations, including nonmalignant and malignant B-cell lymphoproliferative disorders. It has been reported that specific changes or recurring motifs in the amino acid sequence of the HCV hypervariable region 1 (HVR1) may be associated with cryoglobulinemia. We searched for specific insertions/deletions and/or amino acid motifs within HVR1 in samples from 80 symptomatic and asymptomatic patients with and 33 patients without detectable cryoglobulins, all with chronic HCV infection. At variance with the results of a previous study which reported a high frequency of insertions at position 385 of HVR1 from cryoglobulinemic patients, we found a 6.2% prevalence of insertions in samples from patients with and a 9.1% prevalence in those without cryoglobulinemia. Moreover, statistical and bioinformatics approaches including Fisher's exact test, k-means clustering, Tree determinant-residue identification, correlation of mutations, principal component analysis, and phylogenetic analysis failed to show statistically significant differences between sequences from cryoglobulin-negative and -positive patients. Our findings suggest that cryoglobulinemia may arise by virtue of as-yet-unidentified host- rather than virus-specific factors. Specific changes in HCV envelope sequence distribution are unlikely to be directly involved in the establishment of pathological B-cell monoclonal proliferation. [ABSTRACT FROM AUTHOR]