NS5A protein of HCV enhances HBV replication and resistance to interferon response

Hepatitis B Virus Infection: A Mini Review

Hepatitis B and C viruses (HBV and HCV) are the leading causes of end-stage liver disease worldwide. Although there is a potent vaccine against HBV, many new infections are recorded annually, especially in poorly resourced places which have lax vaccination policies. Again, as HBV has no cure and chronic infection is lifelong, vaccines cannot help those already infected. Studies to thoroughly understand the HBV biology and pathogenesis are limited, leaving much yet to be understood about the genomic features and their role in establishing and maintaining infection. The current knowledge of the impact on disease progression and response to treatment, especially in hyperendemic regions, is inadequate. This calls for in-depth studies on viral biology, mainly for the purposes of coming up with better management strategies for infected people and more effective preventative measures for others. This information could also point us in the direction of a cure. Here, we discuss the progress made in understanding the genomic basis of viral activities leading to the complex interplay of the virus and the host, which determines the outcome of HBV infection as well as the impact of coinfections.

In Memory of the Virologist Jianguo Wu, 1957-2022

It is with deep sorrow that we mourn the passing of the virologist Professor Jianguo Wu [...].

A Tribute to Professor Jianguo Wu

It has been a couple of months since Professor Jianguo Wu left us [...].

Pharmacotherapeutic strategies for hepatitis B and hepatitis C coinfection

INTRODUCTION

Hepatitis B (HBV) and Hepatitis C (HCV) infection place a significant burden on the global health system, with chronic carriage leading to cirrhosis and hepatocellular carcinoma. HBV/HCV coinfection can be seen in highly endemic areas and present a heterogenous group given varying virologic profiles. Coinfected patients have a greater risk of advanced liver disease; hence, diagnosis and early antiviral therapy (AVT) should be a priority. Optimal treatment regimens for coinfected patients remain unknown with differing recommendations, particularly relating to the risk of HBV reactivation whilst on AVT for HCV.

AREAS COVERED

This article summarizes the available data on HBV/HCV coinfection with regards to epidemiology, virologic interactions, and risk of HBV reactivation. The authors also provide a framework for the assessment and treatment of coinfected patients.

EXPERT OPINION

There is a moderate risk of HBV reactivation in hepatitis B surface antigen (HBsAg) positive patients undergoing HCV direct-acting antiviral (DAA) treatment; however, clinically significant events are rare. The risk of HBV reactivation in HBsAg negative patients undergoing HCV DAA treatment is negligible. Thus, prophylactic HBV treatment in both groups is not required. The authors recommend close monitoring with HBV treatment if there is evidence of HBV reactivation or elevated alanine aminotransferase levels.

Hepatitis C virus core protein inhibits hepatitis B virus replication by downregulating HBx levels via Siah-1-mediated proteasomal degradation during coinfection

Most clinical and experimental studies have suggested that hepatitis C virus (HCV) is dominant over hepatitis B virus (HBV) during coinfection, although the mechanism remains unclear. Here, we found that HCV core protein inhibits HBV replication by downregulating HBx levels during coinfection in human hepatoma cells. For this effect, HCV core protein increased reactive oxygen species levels in the mitochondria and activated the ataxia telangiectasia mutated-checkpoint kinase two pathway in the nucleus, resulting in an upregulation of p53 levels. Accordingly, HCV core protein induced p53-dependent activation of seven in absentia homolog one expression, an E3 ligase of HBx, resulting in the ubiquitination and proteasomal degradation of HBx. The effect of the HCV core protein on HBx levels was accurately reproduced in both a 1.2-mer HBV replicon and in vitro HBV infection systems, providing evidence for the inhibition of HBV replication by HCV core protein. The present study may provide insights into the mechanism of HCV dominance in HBV- and HCV-coinfected patients.

A novel cell culture model reveals the viral interference during hepatitis B and C virus coinfection

Coinfection of hepatitis B virus (HBV) and hepatitis C virus (HCV) may result in severe liver disease and frequent progression to cirrhosis and hepatocellular carcinoma. Clinical evidence suggests that HBV replication is suppressed by replicating HCV and often rebounds after treatment with drugs against HCV. Thus, a highly efficient cell culture system permissive for HBV/HCV would facilitate investigation on the interaction and pathogenesis after coinfection. Here we reported a robust HBV/HCV coinfection cell culture model by overexpressing human sodium-taurocholate cotransporting polypeptide (NTCP), CD81 and Mir122 into HepG2 cells and investigated interactions between HBV and HCV. In this system, HepG2-NTCP/CD81/Mir122 cells not only supported robust infection and replication of HBV and HCV, but also allowed HBV/HCV coinfection in the single cell level. Our result showed cells with replicating HBV still supported HCV infection. However, HBV replication was suppressed by HCV through the inhibition of HBV core promoter and S promoter II activity, and this inhibition was attenuated by the interferon alpha (IFNα) treatment, suggesting HCV influence on HBV at transcriptional level. Coinfection of HBV/HCV in this system did not block IFN stimulated genes expression. Inhibition of HCV by direct-acting antiviral drugs restored HBV replication and expression of viral genes. Conclusions: HepG2-NTCP/CD81/Mir122 fully supports HBV/HCV coinfection, replication and interaction. This novel cell model offers a platform to advance our understanding of the molecular details of the interaction, pathogenesis and outcomes of HBV/HCV coinfection.

Diminished hepatic IFN response following HCV clearance triggers HBV reactivation in coinfection

In patients with HBV and HCV coinfection, HBV reactivation leading to severe hepatitis has been reported with the use of direct-acting antivirals (DAAs) to treat HCV infection. Here we studied the molecular mechanisms behind this viral interaction. In coinfected cell culture and humanized mice, HBV replication was suppressed by HCV coinfection. In vitro, HBV suppression was attenuated when interferon (IFN) signaling was blocked. In vivo, HBV viremia, after initial suppression by HCV superinfection, rebounded following HCV clearance by DAA treatment that was accompanied by a reduced hepatic IFN response. Using blood samples of coinfected patients, IFN-stimulated gene products including C-X-C motif chemokine 10 (CXCL10), C-C motif chemokine ligand 5 (CCL5), and alanine aminotransferase (ALT) were identified to have predictive value for HBV reactivation after HCV clearance. Taken together, our data suggest that HBV reactivation is a result of diminished hepatic IFN response following HCV clearance and identify serologic markers that can predict HBV reactivation in DAA-treated HBV-HCV-coinfected persons.

Management of hepatitis B and hepatitis C coinfection: an expert review

INTRODUCTION

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections share common routes of transmission. HBV/HCV coinfection can lead to interactions affecting mechanisms of infection and therapy.

AREAS COVERED

In the review, we present epidemiology of HBV/HCV coinfection and current therapeutic options for both viruses. The possibility of drug-drug interactions during the treatment of coinfected patients is discussed. However, the major part of the review is dedicated to interactions between viruses and risk of HBV reactivation during HCV treatment with direct-acting antivirals (DAA). Finally, we analyze available international and national guidelines for the management of HBV reactivations related to DAA administration.

EXPERT OPINION

The most important international societies' guidelines include comments on HBV/HCV coinfection, but due to their inconsistency we present a proposal of management for HBV/HCV coinfected patients focusing mostly on HBV reactivation in patients treated for HCV. We provide some advice that should be considered in future guidelines for the management of HBV/HCV coinfection.

Management Of Patients With Hepatitis B Virus Reactivation Post-DAA Treatment Of Chronic Hepatitis C Virus Infection In HCV-HBV Coinfected Patients With Pretreatment HBeAg Seroconversion And Early Degree Of Hepatic Fibrosis

BACKGROUND AND AIM

Hepatitis C virus (HCV)-HBV coinfection is a significant health problem with rapid progression of liver disease without precise diagnosis and treatment. We aimed in this study to identify if there were any role of HBV antiviral therapy in patients with HBV reactivation after direct-acting antiviral therapy in HCV-HBV coinfected patients.

METHODS

A prospective random study was carried out on 140 patients presenting with chronic HCV and chronic HBV coinfection. All patients had pretreatment HBeAg seroconversion, HBV DNA <2,000 IU/mL, normal liver enzymes, and F0/F1 hepatic fibrosis. They treated with sofosbuvir 400 mg and daklatasvir 60 mg once daily for 3 months. All patients underwent pretreatment hepatic fibrosis assessment using Fibro Scan and laboratory investigations: platelet count, liver-function tests, quantitative HCV PCR, HBsAg, HBc IgG, HBeAg, and HBeAb. All patients were followed up at 1, 3, 6, and 12 months from the start of HCV therapy.

RESULTS

The study enrolled 140 HCV-HBV coinfected patients: 55% were F0 and the rest F1. All our patients had negative HCV PCR at 1 month posttreatment and had achieved sustained virologic response with negative HCV PCR 3 months after treatment end. Four patients showed HBV reactivation with raised HBV DNA PCR and liver enzymes. Their mean age was 23.7±2.7 years, and three were male. Regarding patients with HBV reactivation, at 12 months posttreatment they showed significant decreases in liver enzymes, bilirubin, and INR, with increased platelet count (P=0.001), each with undetectable HBV PCR (P=0.001).

CONCLUSION

HBV-HCV coinfected patients with no/mild hepatic fibrosis, HBeAg seroconversion, and HBV DNA <2,000 IU/mL can complete direct-acting antiviral therapy without HBV antiviral treatment with close monitoring.

Hepatitis B Virus (HBV) Reactivation Following Pharmacological Eradication of Hepatitis C Virus (HCV)

The US Food and Drug Administration issued a black box warning related to the risk of reactivation of overt/occult hepatitis B virus (HBV) infection during direct acting-antivirals (DAA) treatment. This review evaluated the prevalence of HBV reactivation after hepatitis C virus (HCV) pharmacological suppression and hypothesized the management and prevention of this reactivation. During and after DAA-based treatment, reactivation of HBV infection is common in patients with detectable serum HBsAg (from 2% to 57%) and very low (less than 3%) in individuals with isolated anti-HBc antibodies. The severity of hepatic damage may range from HBV reactivation without hepatitis to fulminant hepatic failure requiring liver transplantation. Thus, HBsAg-positive patients should receive nucleo(s)tide analog (NA) treatment or prophylaxis at the same time as DAA therapy. For those patients with occult B infection, there are no sufficient recommendations to start prophylactic treatment. Reactivation of overt or occult HBV infection during or after eradication of HCV infection is an issue to consider, and additional studies would help to determine the best management of this virological and clinical event.

HBV-HCV Coinfection: Viral Interactions, Management, and Viral Reactivation

Hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection is a complex clinical entity that has an estimated worldwide prevalence of 1-15%. Most clinical studies have shown that progression of disease is faster in HBV-HCV coinfected patients compared to those with monoinfection. Hepatocellular carcinoma development appears to have higher rate in coinfections. Viral replication in coinfected cells is characterized by a dominance of HCV over HBV replication. There are no established guidelines for treatment of HBV-HCV coinfection. Studies on interferon-based therapies and direct-acting antivirals have shown varying levels of efficacy. Clinical reports have indicated that treatment of HCV without suppression of HBV increases the risk for HBV reactivation. In this review, we appraise studies on both direct-acting antivirals and interferon-based therapies to evaluate the efficacy and rates of reactivation with each regimen. Screening for and prevention of coinfection are important to prevent serious HBV reactivations.

Hepatitis B virus (HBV) reactivation-The potential role of direct-acting agents for hepatitis C virus (HCV)

Hepatitis C virus (HCV) is known to inhibit hepatitis B virus (HBV) replication in patients with HBV/HCV coinfection. Reactivation of HBV in patients treated for HCV with direct-acting agents (DAAs) has emerged recently as an important clinical consideration. A growing number of case reports and case series support the association between new HCV treatments and HBV reactivation. Yet, very little is known about the specific viral characteristics that facilitate reactivation as functional characterization of the reactivated HBV has been conducted only rarely. This review provides the most recent data on HBV reactivation in the context of DAA initiation and highlights the existing viral genomic data from reactivating viruses. Current functional studies of HBV reactivation are largely limited by the retrospective identification of cases, no standardization of genomic regions that are studied with respect to HBV reactivation, and the lack of inclusion of nonreactivating controls to establish specific viral mutations that are associated with HBV reactivation. Importantly, none of these sequencing studies included cases of HBV reactivation after initiation of DAAs. While new HCV treatments have revolutionized care for HCV infected patients, HBV reactivation will likely increase in frequency, as DAAs are more commonly prescribed. Pretreatment determination of HBV status and thoughtful management of HBV coinfections will be necessary and lead to improved patient safety and yield optimal treatment results.

Hepatitis B virus reactivation among hepatitis C patients treated with direct-acting antiviral therapies in routine clinical practice

BACKGROUND

Hepatitis B (HBV) reactivation in chronic hepatitis C (CHC) patients treated with IFN-free direct acting antiviral (DAA) therapies has recently emerged as a potential risk. Given the potential burden of this issue, further data are needed to establish its actual clinical impact.

OBJECTIVES

The aim of the present study was to analyze the occurrence of HBV reactivation in a cohort of CHC patient treated with DAAs in routine clinical practice.

STUDY DESIGN

Consecutive CHC patients with different genotypes, treated with DAA between January 2015 and January 2016 were included in the study. Subjects had been tested for HBsAg and anti-HBc antibodies before antiviral therapy. HBV-DNA levels were examined in anti-HBc positive patients at baseline and 24 weeks after the end of treatment. Post-treatment HBsAg determination was performed in case of HBV-DNA positivity. Serum anti-HBs kinetics was analysed in anti-HBs and anti-HBc positive subjects.

RESULTS

A cohort of 137 consecutive HCV patients treated with IFN-free regimens in routine clinical practice was evaluated. From this cohort, plasma samples of 44 subjects with positive serology for HBV (anti-HBc positive) were tested for HBV-DNA levels at baseline and 24 weeks after the end of treatment. Two of them were HBsAg-positive, while the others had signs of a past HBV exposure (HBsAg-negative±HBsAb-positive). No reactivation was found in HBcAb-positive and HBsAg-negative subjects. In the two HBsAg-positive, one experienced an increase in HBV-DNA levels of ≥2 log₁₀ IU/mL during treatment. However, the reactivation was without clinical impact and, most important, was followed by HBsAg loss.

CONCLUSIONS

Based on our experience, a past HBV infection seems not to be a condition predisposing to HBV reactivation. On the contrary, in HBsAg-positive subjects not in suppressive treatment with nucleos(t)ide analogs, regular monitoring of HBV-DNA during and after DAA treatment should be considered.

Hepatitis B reactivation during or after direct acting antiviral therapy - implication for susceptible individuals

INTRODUCTION

The FDA issued a warning following 24 cases of HBV reactivation during DAA therapy for HCV, including individuals with inactive, occult and past HBV infection. Clinical presentations ranged from asymptomatic fluctuations in HBV DNA to fulminant hepatic failure, liver transplantation and death. The mechanism is unknown. Areas covered: HCV/HBV coinfection is common, particularly in regions endemic for HBV. HCV and HBV utilize host factors to support replication; both viruses evade/impair host immunity. Clinical presentations of HBV reactivation during DAAs are summarized. Other causes of HBV reactivation are revisited and recent data regarding HBV reactivation are presented. Expert opinion: HBV reactivation during DAAs for HCV occurs, with life-threatening consequences in some individuals. The risk of HBV reactivation is observed in all HBV stages. The rapid removal of HCV likely alters and liberates host-viral ± viral-viral interactions that lead to increased HBV replication. As immune reconstitution occurs with HCV removal, host recognition of HBV DNA likely ensues followed by vigorous host immune responses leading to liver injury (HBV flare). These cases highlight the importance of HBV testing prior to initiating DAA therapy, the need for close monitoring of HBV during therapy and timely administration of anti-HBV therapy to prevent serious sequelae.

HBV/HCV dual infection impacts viral load, antibody response, and cytokine expression differently from HBV or HCV single infection

Hepatitis B virus/hepatitis C virus (HBV/HCV) dual infection is common among high-risk individuals. To characterize the virological and immunological features of patients with HBV/HCV dual infection, we enrolled 1,049 individuals who have been identified as injection drug users. Patients were divided into single and dual infection groups according to the serological markers. We found the average HCV RNA level was significantly lower; however, HBV viral load was significantly higher in HBV/HCV dual-infected patients (n = 42) comparing HCV single infection (n = 340) or HBV single infection (n = 136). The level of anti-HBs in patients who experienced spontaneous HBV clearance was higher than that in HCV single-infected patients with HBV spontaneous clearance. The level of anti-HCV E2 in HBV/HCV dual infection was lower than that detected in HCV single infection. Serum levels of IL-6, IL-8, and TNF-α were significantly lower in HBV/HCV dual-infected patients than in patients infected with HBV or HCV alone. Taken together, two viral replications are imbalanced in dual infected patients. The anti-HBs and anti-HCV E2 antibody production were impaired and proinflammatory IL-6, IL-8, and TNF-α also downregulated due to dual infection. These findings will help further understanding the pathogenesis of HBV/HCV dual infection.

Update on occult hepatitis B virus infection

The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

Gene Expression and Antiviral Activity of Interleukin-35 in Response to Influenza A Virus Infection

Interleukin-35 (IL-35) is a newly described member of the IL-12 family. It has been reported to inhibit inflammation and autoimmune inflammatory disease and can increase apoptotic sensitivity. Little is known about the role of IL-35 during viral infection. Herein, high levels of IL-35 were found in peripheral blood mononuclear cells and throat swabs from patients with seasonal influenza A virus (IAV) relative to healthy individuals. IAV infection of human lung epithelial and primary cells increased levels of IL-35 mRNA and protein. Further studies demonstrated that IAV-induced IL-35 transcription is regulated by NF-κB. IL-35 expression was significantly suppressed by selective inhibitors of cyclooxygenase-2 (COX-2) and inducible nitric-oxide synthase, indicating their involvement in IL-35 expression. Interestingly, IL-35 production may have suppressed IAV RNA replication and viral protein synthesis via induction of type I and III interferons (IFN), leading to activation of downstream IFN effectors, including double-stranded RNA-dependent protein kinase, 2',5'-oligoadenylate synthetase, and myxovirus resistance protein. IL-35 exhibited extensive antiviral activity against the hepatitis B virus, enterovirus 71, and vesicular stomatitis virus. Our results demonstrate that IL-35 is a novel IAV-inducible cytokine, and its production elicits antiviral activity.

Direct-acting antiviral treatment in adults infected with hepatitis C virus: Reactivation of hepatitis B virus coinfection as a further challenge

Use of direct-acting antiviral drugs (DAAs) greatly improves management of adults infected with hepatitis C virus (HCV) whether patients are treatment-naive or unsuccessfully pre-treated. Several inhibitors of viral nonstructural proteins (NS3/4A protease, NS5A and NS5B polymerase) allow a rapid HCV clearance and increase rates of sustained virological response. Both the EASL and AASLD guidelines have recently published up-to-date recommendations for their use, addressing each HCV genotype and particular situations. However, management of patients coinfected with hepatitis B virus (HBV) has been developed by these guidelines with reference to cases of HBV reactivation reported during previous anti-HCV regimens containing interferon known active against both HBV and HCV. In the setting of the interferon-free HCV therapies with DAAs only, the possibility of HBV reactivation during treatment of hepatitis C is raised due to viral interferences in HCV/HBV coinfected persons. Herein, we report a case of early HBV reactivation during DAAs-based anti-HCV treatment (ledipasvir/sofosbuvir) in a patient having a resolved HBV infection and chronically infected with HCV genotype 4 and HIV. Moreover, we review similar recent cases of HBV reactivation in patients infected with HBV and HCV genotype 1 during treatment of hepatitis C by regimen incorporating other combination of DAAs (sofosbuvir/simeprevir or daclatasvir/asunaprevir). Due to the potential risk of early HBV reactivation in HCV/HBV-coinfected patients during interferon-free DAAs-based HCV therapies, altogether these cases highlight the necessity to closely monitor HBV coinfection, regardless its stage (chronic, occult, resolved), whatever HCV genotype or class of DAAs used.

Clinical analysis of patients suffering from chronic hepatitis B superinfected with other hepadnaviruses

To compare the clinical manifestations, laboratory examinations, and prognoses of patients with chronic hepatitis B (CHB) who were superinfected with hepatitis A virus (HAV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV). Two hundred and eleven patients with confirmed CHB in our hospital, a tertiary teaching hospital in China, between 2005 and 2014 were analyzed retrospectively. Among 211 patients with CHB, 35 were superinfected with HAV, 31 were superinfected with HCV, 22 were superinfected with HDV, and 53 were superinfected with HEV. We analyzed and compared the clinical features of the five groups. The tested biochemical indices and markers of liver function included serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), prothrombin activity (PTA), serum albumin (Alb), and the serum levels of HBV DNA. The peak values of ALT, AST, and TBil were significantly higher in all of the superinfected groups. Lower peak Alb concentration and PTA were also observed in the superinfected patients, with the exception of patients in the CHB + HAV group. The CHB + HCV, and CHB + HEV groups had higher death rates than the CHB monoinfected group, and the difference was statistically significant. Further analysis of the liver failure groups showed that the level of HBV DNA was not correlated with prognosis. The comparison of clinical outcomes revealed that CHB patients superinfected with HCV, HDV, and HEV compared with CHB monoinfection had statistically greater incidences of exacerbation of the condition and poor prognosis, whereas the patients superinfected with HAV generally had better outcomes.

Hepatitis B virus and hepatitis C virus dual infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) share common mode of transmission and both are able to induce a chronic infection. Dual HBV/HCV chronic coinfection is a fairly frequent occurrence, especially in high endemic areas and among individuals at high risk of parenterally transmitted infections. The intracellular interplay between HBV and HCV has not yet been sufficiently clarified, also due to the lack of a proper in vitro cellular model. Longitudinal evaluation of serum HBV DNA and HCV RNA amounts has revealed that complex virological profiles may be present in coinfected patients. Dual HBV/HCV infection has been associated to a severe course of the liver disease and to a high risk of developing hepatocellular carcinoma. Despite the clinical importance, solid evidence and clear guidelines for treatment of this special population are still lacking. This review summarizes the available data on the virological and clinical features as well as the therapeutic options of the dual HBV/HCV infection, and highlights the aspects that need to be better clarified.

Inducible interleukin 32 (IL-32) exerts extensive antiviral function via selective stimulation of interferon λ1 (IFN-λ1)

Interleukin (IL)-32 has been recognized as a proinflammatory cytokine that participates in responses to viral infection. However, little is known about how IL-32 is induced in response to viral infection and the mechanisms of IL-32-mediated antiviral activities. We discovered that IL-32 is elevated by hepatitis B virus (HBV) infection both in vitro and in vivo and that HBV induced IL-32 expression at the level of both transcription and post-transcription. Furthermore, microRNA-29b was found to be a key factor in HBV-regulated IL-32 expression by directly targeting the mRNA 3'-untranslated region of IL-32. Antiviral analysis showed that IL-32 was not sufficient to alter HBV replication in HepG2.2.15 cells. To mimic the viremic phase of viral infection, freshly isolated peripheral blood mononuclear cells were treated with IL-32γ, the secretory isoform, and the supernatants were used for antiviral assays. Surprisingly, these supernatants exhibited extensive antiviral activity against multiplex viruses besides HBV. Thus, we speculated that the IL-32γ-treated peripheral blood mononuclear cells produced and secreted an unknown antiviral factor. Using antibody neutralization assays, we identified the factor as interferon (IFN)-λ1 and not IFN-α. Further studies indicated that IL-32γ effectively inhibited HBV replication in a hydrodynamic injection mouse model. Clinical data showed that elevated levels of IFN-λ1 both in serum and liver tissue of HBV patients were positively correlated to the increased levels of IL-32. Our results demonstrate that elevated IL-32 levels during viral infection mediate antiviral effects by stimulating the expression of IFN-λ1.

The X protein of hepatitis B virus activates hepatoma cell proliferation through repressing melanoma inhibitory activity 2 gene

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer deaths globally. Chronic hepatitis B virus (HBV) infection accounts for over 75% of all HCC cases; however, the molecular pathogenesis of HCC is not well understood. In this study, we found that the expression of the newly identified gene melanoma inhibitory activity 2 (MIA2) was reduced by HBV infection in vitro and in vivo, and that HBV X protein (HBx) plays a major role in this regulation. Recent studies have revealed that MIA2 is a potential tumor suppressor, and that, in most HCCs, MIA2 expression is down-regulated or lost. We found that the knock-down of MIA2 in HepG2 cells activated cell growth and proliferation, suggesting that MIA2 inhibits HCC cell growth and proliferation. In addition, the over-expression of HBx alone induced cell proliferation, whereas MIA2 over-expression impaired the HBx-mediated induction of proliferation. Taken together, our results suggest that HBx activates hepatoma cell growth and proliferation through repression of the potential tumor suppressor MIA2.

Serological and molecular expression of Hepatitis B infection in patients with chronic Hepatitis C from Tunisia, North Africa

BACKGROUND

This study reports the prevalence and the viral aspects of HBV infection in HCV-positive patients from Tunisia, a country with intermediate and low endemicity for hepatitis B and C, respectively.

RESULTS

HBV infection was assessed in the serum samples of 361 HCV-positive patients and compared to a group of HCV negative individuals. Serological markers were determined by ELISA tests and HBV DNA by real-time PCR. HBV serological markers were found in 43% and 44% of patients and controls, respectively. However, the serological and molecular expression of HBV infection differed in the two groups: The group of patients included more individuals with ongoing HBV infection, as defined by the presence of detectable HBsAg and or HBV DNA (17% and 12%, respectively). Furthermore, while most of the controls with ongoing HBV infection expressed HBsAg, the majority of HCV and HBV positive patients were HBsAg negative and HBV DNA positive. Genotyping of HCV isolates showed large predominance of subtype 1b as previously reported in Tunisia. Comparison of the replicative status of the two viruses found low HBV viral load in all co-infected patients as compared to patients with single HBV infection. In contrast, high levels of HCV viremia levels were observed in most of cases with no difference between the group of co-infected patients and the group with single HCV infection.

CONCLUSIONS

This study adds to the knowledge on the prevalence and the virological presentation of HCV/HBV dual infection, providing data from the North African region. It shows that, given the local epidemiology of the two viruses, co-infected patients are likely to have low replication levels of HBV suggesting a suppressive effect of HCV on HBV. In contrast, high replication levels for HCV were fond in most cases which indicate that the presence of circulating HBV-DNA does not necessarily influence HCV replication.

Dual chronic hepatitis B virus and hepatitis C virus infection

Dual hepatitis B virus (HBV) and hepatitis C virus (HCV) infection are common in HBV or HCV endemic areas. However, several clinical and pathogenetic issues remain unresolved. First, clinical and in vitro studies suggest the interactions between two viruses. The dynamics of the interaction in untreated setting versus treated setting and its influence on the long-term outcomes await further studies. A key issue regarding viral interactions is whether modulation of infection occurs in the same dually infected individual hepatocyte of the liver. Clarifying this issue may help to understand the reciprocal interference between HCV and HBV and provide clues for future immunopathogenetic studies. Second, the prevalence and clinical significance of coexisting occult HBV infection in patients with chronic HCV infection need further investigations. Third, combination therapy of peginterferon alfa-2a and ribavirin appears to be just as effective and safe for the treatment of hepatitis B surface antigen (HBsAg)-positive patients chronically infected with active chronic hepatitis C as it is in patients with HCV monoinfection. Nevertheless, one-third of dually infected patients with nondetectable serum HBV DNA-level pretreatment developed HBV reactivation posttreatment. How to prevent and treat this reactivation should be clarified. Furthermore, about 10% of the dually infected patients lost HBsAg. Underlying mechanisms await further investigations. Finally, the optimal treatment strategies for dually infected patients with hepatitis B e antigen-positive chronic hepatitis B should be identified in future clinical trials.

Hepatitis B and C virus coinfection: a novel model system reveals the absence of direct viral interference

Coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV) has been associated with severe liver disease and frequent progression to cirrhosis and hepatocellular carcinoma. Clinical evidence suggests reciprocal replicative suppression of the two viruses, or viral interference. However, interactions between HBV and HCV have been difficult to study due to the lack of appropriate model systems. We have established a novel model system to investigate interactions between HBV and HCV. Stable Huh-7 cell lines inducibly replicating HBV were transfected with selectable HCV replicons or infected with cell culture-derived HCV. In this system, both viruses were found to replicate in the same cell without overt interference. Specific inhibition of one virus did not affect the replication and gene expression of the other. Furthermore, cells harboring replicating HBV could be infected with cell culture-derived HCV, arguing against superinfection exclusion. Finally, cells harboring replicating HBV supported efficient production of infectious HCV.

CONCLUSION

HBV and HCV can replicate in the same cell without evidence for direct interference in vitro. Therefore, the viral interference observed in coinfected patients is probably due to indirect mechanisms mediated by innate and/or adaptive host immune responses. These findings provide new insights into the pathogenesis of HBV-HCV coinfection and may contribute to its clinical management in the future.

Advance in molecular mechanism of interferon to treat chronic hepatitis B

The antiviral efficacy of interferon-α (IFN-α) therapy for chronic hepatitis B (CHB) is not only related to DNA load and genetype of HBV before treatment, gene mutation of HBV and polymorphism of type II HLA in the host, but also depends on the immunity of CHB patients. Researchers pay more and more attention to the mutant strain of virus and phenotypes of genes. However, the mechanism of interferon to resist HBV and the escape mechanism of HBV against the IFN therapy have not been clarified yet. This paper reviews the mechanism of IFN therapy and the influencing factors at molecular and genetic levels.

Effects of silymarin on hepatitis C virus and haem oxygenase-1 gene expression in human hepatoma cells

BACKGROUND/AIMS

Hepatitis C virus (HCV) infection is a global medical problem. The current standard treatment of chronic hepatitis C (CHC), pegylated interferon plus ribavirin, is prolonged, expensive, has serious side effects and, at best, is only 50% effective. Silymarin (SI) is a natural antioxidant often used by patients with CHC, although its efficacy for decreasing HCV levels or ameliorating CHC remains uncertain. HCV infection is associated with increased hepatic oxidative stress, and one of the antioxidant enzymes that protect cells against this stress is haem oxygenase-1 (HO-1).

METHODS

We investigated effects of SI on HCV and HO-1 gene expression in Huh-7 cells, CNS3 and 9-13 cells (the latter two stably expressing HCV-proteins).

RESULTS

Silymarin significantly downregulated HCV core mRNA (by 20%-36%) and protein (by 30%-60%) in CNS3 cells. In contrast, SI did not decrease HCV NS5A mRNA or protein expression in 9-13 cells. HO-1 mRNA was upregulated (60%-400%) by SI in Huh-7, CNS3 and 9-13 cells, whereas BTB and CNC homology 1 and nuclear factor erythroid related factor 2 mRNA levels were not affected. The effect of SI to downregulate HCV core was not related to changes in the Janus-activated tyrosine kinases-signal transducer and activators of transcription signalling pathway.

CONCLUSIONS

Silymarin may be of benefit in CHC, although prospective, randomized, controlled trials are needed to be certain.

Characterization of a peptide domain within the GB virus C NS5A phosphoprotein that inhibits HIV replication

Background

GBV-C infection is associated with prolonged survival in HIV-infected people and GBV-C inhibits HIV replication in co-infection models. Expression of the GBV-C nonstructural phosphoprotein 5A (NS5A) decreases surface levels of the HIV co-receptor CXCR4, induces the release of SDF-1 and inhibits HIV replication in Jurkat CD4+ T cell lines.

Methodology/Principal Findings

Jurkat cell lines stably expressing NS5A protein and peptides were generated and HIV replication in these cell lines assessed. HIV replication was significantly inhibited in all cell lines expressing NS5A amino acids 152–165. Substitution of an either alanine or glycine for the serine at position 158 (S158A or S158G) resulted in a significant decrease in the HIV inhibitory effect. In contrast, substituting a phosphomimetic amino acid (glutamic acid; S158E) inhibited HIV as well as the parent peptide. HIV inhibition was associated with lower levels of surface expression of the HIV co-receptor CXCR4 and increased release of the CXCR4 ligand, SDF-1 compared to control cells. Incubation of CD4+ T cell lines with synthetic peptides containing amino acids 152–167 or the S158E mutant peptide prior to HIV infection resulted in HIV replication inhibition compared to control peptides.

Conclusions/Significance

Expression of GBV-C NS5A amino acids 152–165 are sufficient to inhibit HIV replication in vitro, and the serine at position 158 appears important for this effect through either phosphorylation or structural changes in this peptide. The addition of synthetic peptides containing 152–167 or the S158E substitution to Jurkat cells resulted in HIV replication inhibition in vitro. These data suggest that GBV-C peptides or a peptide mimetic may offer a novel, cellular-based approach to antiretroviral therapy.