Treatment Algorithm for Managing Chronic Hepatitis B Virus Infection in the United States: 2021 Update.

BACKGROUND & AIMS: Chronic hepatitis B (CHB) infection remains the most frequent etiology of hepatocellular carcinoma globally as well as a major cause of cirrhosis. Despite vaccination, substantial numbers of persons have already been infected with hepatitis B virus and remain at risk of progressive liver disease. METHODS: In 2004, a CHB management algorithm was developed by a panel of North American hepatologists, which was subsequently updated in 2006, 2008, and 2015. Since the most recent version, several developments have altered the management of CHB. Tenofovir alafenamide, with a more favorable safety profile than tenofovir disoproxil fumarate, has been introduced as an initial antiviral choice as well as an alternative for long-term therapy. Quantitation of hepatitis B surface antigen is becoming more widely available in clinical practice, with implications for monitoring response to treatment. Additionally, there has been a shift in how the natural history of CHB is perceived, as newer evidence has challenged the concept that during the immunotolerant phase of infection disease progression is not a concern. Finally, recent analyses indicate that in the United States, the average age of patients with CHB has increased, implying that the presence of comorbidities, including metabolic liver disease, increasing use of biologics associated with aging will increasingly affect disease management. RESULTS: This updated algorithm is intended to serve as a guide to manage CHB while new antiviral strategies are developed. CONCLUSIONS: Recommendations have been based on evidence from the scientific literature, when possible, as well as clinical experience and consensus expert opinion. Points of continued debate and areas of research need are also described.

Multitarget, quantitative nanoplasmonic electrical field-enhanced resonating device (NE2RD) for diagnostics.

Recent advances in biosensing technologies present great potential for medical diagnostics, thus improving clinical decisions. However, creating a label-free general sensing platform capable of detecting multiple biotargets in various clinical specimens over a wide dynamic range, without lengthy sample-processing steps, remains a considerable challenge. In practice, these barriers prevent broad applications in clinics and at patients' homes. Here, we demonstrate the nanoplasmonic electrical field-enhanced resonating device (NE(2)RD), which addresses all these impediments on a single platform. The NE(2)RD employs an immunodetection assay to capture biotargets, and precisely measures spectral color changes by their wavelength and extinction intensity shifts in nanoparticles without prior sample labeling or preprocessing. We present through multiple examples, a label-free, quantitative, portable, multitarget platform by rapidly detecting various protein biomarkers, drugs, protein allergens, bacteria, eukaryotic cells, and distinct viruses. The linear dynamic range of NE(2)RD is five orders of magnitude broader than ELISA, with a sensitivity down to 400 fg/mL This range and sensitivity are achieved by self-assembling gold nanoparticles to generate hot spots on a 3D-oriented substrate for ultrasensitive measurements. We demonstrate that this precise platform handles multiple clinical samples such as whole blood, serum, and saliva without sample preprocessing under diverse conditions of temperature, pH, and ionic strength. The NE(2)RD's broad dynamic range, detection limit, and portability integrated with a disposable fluidic chip have broad applications, potentially enabling the transition toward precision medicine at the point-of-care or primary care settings and at patients' homes.

A Treatment Algorithm for the Management of Chronic Hepatitis B Virus Infection in the United States: 2015 Update.

Chronic hepatitis B (CHB) continues to be an important public health problem worldwide, including in the United States. An algorithm for managing CHB was developed by a panel of United States hepatologists in 2004 and subsequently updated in 2006 and 2008. Since 2008, additional data on long-term safety and efficacy of licensed therapies have become available and have better defined therapeutic options for CHB. The evidence indicates that potent antiviral therapy can lead to regression of extensive fibrosis or even cirrhosis, thus potentially altering the natural history of CHB. In addition, appropriate choice of antiviral agent can minimize the risk of resistance. This updated algorithm for managing CHB is based primarily on evidence from the scientific literature. Where data were lacking, the panel relied on clinical experience and consensus expert opinion. The primary aim of antiviral therapy for CHB is durable suppression of serum hepatitis B virus (HBV) DNA to low or undetectable levels. CHB patients who have HBV DNA >2000 IU/mL, elevated alanine aminotransferase level, and any degree of fibrosis should receive antiviral therapy regardless of their hepatitis B e antigen status. CHB patients with HBV DNA >2000 IU/mL and elevated alanine aminotransferase level but no evidence of fibrosis may also be considered for antiviral therapy. Approved antiviral therapies for CHB are interferon alfa-2b, peginterferon alfa-2a, lamivudine, adefovir, entecavir, telbivudine, and tenofovir, although the preferred first-line treatment choices are peginterferon alfa-2a, entecavir, and tenofovir. In determining choice of therapy, considerations include efficacy, safety, rate of resistance, method of administration, duration, and cost.

Characteristics of adults in the hepatitis B research network in North America reflect their country of origin and hepatitis B virus genotype.

BACKGROUND & AIMS: Chronic hepatitis B virus (HBV) infection is an important cause of cirrhosis and hepatocellular carcinoma worldwide; populations that migrate to the United States and Canada might be affected disproportionately. The Hepatitis B Research Network (HBRN) is a cooperative network of investigators from the United States and Canada, created to facilitate clinical, therapeutic, and translational research in adults and children with hepatitis B. We describe the structure of the network and baseline characteristics of adults with hepatitis B enrolled in the network. METHODS: The HBRN collected data on the clinical characteristics of 1625 adults with chronic HBV infection who are not receiving antiviral therapy from 21 clinical centers in North America. RESULTS: Half of the subjects in the HBRN are men, and the median age is 42 years; 72% are Asian, 15% are black, and 11% are white; with 82% born outside of North America. The most common HBV genotype was B (39%); 74% of subjects were negative for the hepatitis B e antigen. The median serum level of HBV DNA when the study began was 3.6 log10 IU/mL; 68% of male subjects and 67% of female subjects had alanine aminotransferase levels higher than the normal range. CONCLUSIONS: The HBRN cohort is used to address important clinical and therapeutic questions for North Americans infected with chronic HBV and to guide health policies on HBV prevention and management in North America.

Next-generation sequencing reveals large connected networks of intra-host HCV variants.

BACKGROUND: Next-generation sequencing (NGS) allows for sampling numerous viral variants from infected patients. This provides a novel opportunity to represent and study the mutational landscape of Hepatitis C Virus (HCV) within a single host. RESULTS: Intra-host variants of the HCV E1/E2 region were extensively sampled from 58 chronically infected patients. After NGS error correction, the average number of reads and variants obtained from each sample were 3202 and 464, respectively. The distance between each pair of variants was calculated and networks were created for each patient, where each node is a variant and two nodes are connected by a link if the nucleotide distance between them is 1. The work focused on large components having > 5% of all reads, which in average account for 93.7% of all reads found in a patient. CONCLUSIONS: Most intra-host variants are organized into distinct single-mutation components that are: well separated from each other, represent genetic distances between viral variants, robust to sampling, reproducible and likely seeded during transmission events. Facilitated by NGS, large components offer a novel evolutionary framework for genetic analysis of intra-host viral populations and understanding transmission, immune escape and drug resistance.

Innate immune tolerance and the role of kupffer cells in differential responses to interferon therapy among patients with HCV genotype 1 infection.

BACKGROUND & AIMS: In patients with hepatitis C virus (HCV) infection, interferon alfa (IFN-α) alters expression of IFN-stimulated genes (ISGs), but little is understood about factors that determine outcomes of therapy. We used a systems biology approach to evaluate the acute response of patients with chronic hepatitis C to IFN-α therapy. METHODS: We collected liver biopsy samples from 8 treatment-naïve patients with chronic HCV genotype 1 infection at baseline and 24 hours after treatment with IFN-α-2a (10 MU subcutaneously). Blood samples were collected before and up to 48 hours after administration of IFN-α-2a to measure HCV RNA levels and for gene expression analysis. Patients then received pegylated IFN-α-2a and ribavirin on day 5 of the study; therapy continued for up to 48 weeks. RESULTS: Based on the kinetics of HCV RNA during the first 12 weeks of therapy, 2 patients were rapid virologic responders, 4 were early virologic responders, and 2 did not respond to therapy (nonresponders). Nonresponders had high pretreatment levels of ISG expression in the liver but not in peripheral blood mononuclear cells. In responders, after administration of IFN-α, intrahepatic ISG expression increased significantly from baseline and was associated with a rapid phase 1 decrease in HCV. We identified distinct hepatic expression and tissue distribution patterns of ISGs that segregated with treatment outcome. Importantly, Kupffer cells were a local source of IFN that promoted basal expression of ISG in hepatocytes of nonresponders. This finding was validated in cultured THP1 human macrophages that expressed IFN-ß after exposure to viable HCV 2a. When Huh7 K2040 and Huh7 L2198S hepatoma cells were incubated with IFN-α-2a, expression of ISGs peaked by 4 hours and decreased by 72 hours, associated with an increase in level of HCV RNA. This indicates that constitutive exposure to IFN causes hepatoma cells to become tolerant of ISG function. CONCLUSIONS: In patients with chronic HCV infection, IFN production by Kupffer cells might promote innate immune tolerance, characterized by a lack of response to IFN therapy. Strategies to disrupt the virus-host interactions that induce innate immune tolerance should improve therapy.

IFITM1 is a tight junction protein that inhibits hepatitis C virus entry.

UNLABELLED: Type 1 interferon (IFN) continues to be the foundation for the current standard of care combination therapy for chronic hepatitis C virus (HCV) infection, yet the component interferon-stimulated genes (ISGs) that mediate the antiviral actions of IFN are not fully defined. Interferon-induced transmembrane protein 1 (IFITM1) is an ISG product that suppresses early stage infection by a number of viruses through an unknown mechanism of action. Moreover, the actions of IFITM1 on HCV infection are not fully elucidated. Here we identify IFITM1 as a hepatocyte tight junction protein and a potent anti-HCV effector molecule. IFITM1 expression is induced early during IFN treatment of hepatocytes and accumulates at hepatic tight junctions in HCV-infected human patient liver during IFN therapy. Additionally, we found that IFITM1 interacts with HCV coreceptors, including CD81 and occludin, to disrupt the process of viral entry. Thus, IFITM1 is an anti-HCV ISG whose actions impart control of HCV infection through interruption of viral coreceptor function. CONCLUSION: This study defines IFITM1 as an ISG effector with action against HCV entry. Design of therapy regimens to enhance IFITM1 expression should improve the virologic response among HCV patients undergoing treatment with type I IFN.

Case of cryoglobulinaemia associated with chronic hepatitis B.

We present a case of a woman in her 50s with chronic hepatitis B (CHB) who had a longstanding history of arthralgia and swollen joints associated with severe fatigue. Investigations were consistent with a diagnosis of hepatitis B virus (HBV)-related cryoglobulinaemia. Two months after treatment with tenofovir alafenamide, an antiviral therapy for HBV, there was a significant improvement of her symptoms and undetectable serum cryoglobulins. Cryoglobulinaemia is a relatively rare extrahepatic manifestation of HBV infection and only presents in about 2%-4% of the patients with CHB. Its clinical manifestations include purpura, renal dysfunction, arthralgias and neuropathy. Since the presentation of cryoglobulinaemia in CHB can be non-specific, one needs to have a high index of suspicion to avoid delay in diagnosis and treatment.

Highly multiplexed 2-dimensional imaging mass cytometry analysis of HBV-infected liver.

Studies of human hepatitis B virus (HBV) immune pathogenesis are hampered by limited access to liver tissues and technologies for detailed analyses. Here, utilizing imaging mass cytometry (IMC) to simultaneously detect 30 immune, viral, and structural markers in liver biopsies from patients with hepatitis B e antigen+ (HBeAg+) chronic hepatitis B, we provide potentially novel comprehensive visualization, quantitation, and phenotypic characterizations of hepatic adaptive and innate immune subsets that correlated with hepatocellular injury, histological fibrosis, and age. We further show marked correlations between adaptive and innate immune cell frequencies and phenotype, highlighting complex immune interactions within the hepatic microenvironment with relevance to HBV pathogenesis.

Liver Cancer-Specific Serine Protease Inhibitor Kazal Is a Potentially Novel Biomarker for the Early Detection of Hepatocellular Carcinoma.

INTRODUCTION: Liver cancer-secreted serine protease inhibitor Kazal (LC-SPIK) is a protein that is specifically elevated in cases of hepatocellular carcinoma (HCC). We assessed the performance of LC-SPIK in detecting HCC, including its early stages, in patients with cirrhosis, hepatitis B virus (HBV), and hepatitis C virus (HCV). METHODS: We enrolled 488 patients, including 164 HCC patients (81 early HCC) and 324 controls in a blinded, prospective, case-control study. Serum LC-SPIK levels were determined by an enzyme-linked immunosorbent assay-based assay. The performance of serum LC-SPIK and α-fetoprotein (AFP), including area under the curve (AUC), sensitivity, and specificity, are compared. The performance of LC-SPIK was evaluated in an independent validation cohort with 102 patients. RESULTS: In distinguishing all HCC patients from those with cirrhosis and chronic HBV/HCV, LC-SPIK had an AUC of 0.87, with 80% sensitivity and 90% specificity using a cutoff of 21.5 ng/mL. This is significantly higher than AFP, which had an AUC of 0.70 and 52% sensitivity and 86% specificity using a standard cutoff value of 20.0 ng/mL. For early-stage HCC (Barcelona Clinic Liver Cancer stage 0 and A), LC-SPIK had an AUC of 0.85, with 72% sensitivity and 90% specificity, compared with AFP, which had an AUC of 0.61, with 42% sensitivity and 86% specificity. In addition, LC-SPIK accurately detected the presence of HCC in more than 70% of HCC patients with false-negative AFP results. DISCUSSION: The study provided strong evidence that LC-SPIK detects HCC, including early-stage HCC, with high sensitivity and specificity, and might be useful for surveillance in cirrhotic and chronic HBV/HCV patients, who are at an elevated risk of developing HCC.

Interferon regulatory factor-3 activation, hepatic interferon-stimulated gene expression, and immune cell infiltration in hepatitis C virus patients.

UNLABELLED: Interferon regulatory factor-3 (IRF-3) activation directs alpha/beta interferon production and interferon-stimulated gene (ISG) expression, which limits virus infection. Here, we examined the distribution of hepatitis C virus (HCV) nonstructural 3 protein, the status of IRF-3 activation, and expression of IRF-3 target genes and ISGs during asynchronous HCV infection in vitro and in liver biopsies from patients with chronic HCV infection, using confocal microscopy and functional genomics approaches. In general, asynchronous infection with HCV stimulated a low-frequency and transient IRF-3 activation within responsive cells in vitro that was associated with cell-to-cell virus spread. Similarly, a subset of HCV patients exhibited the nuclear, active form of IRF-3 in hepatocytes and an associated increase in IRF-3 target gene expression in hepatic tissue. Moreover, ISG expression profiles formed disease-specific clusters for HCV and control nonalcoholic fatty liver disease patients, with increased ISG expression among the HCV patients. We identified the presence of T cell and plasmacytoid dendritic cell infiltrates within all biopsy specimens, suggesting they could be a source of hepatic interferon in the setting of hepatitis C and chronic inflammatory condition. CONCLUSION: These results indicate that HCV can transiently trigger IRF-3 activation during virus spread and that in chronic HCV, IRF-3 activation within infected hepatocytes occurs but is limited.

Hepatic IFN-Induced Protein with Tetratricopeptide Repeats Regulation of HCV Infection.

Interferons (IFNs) suppress viral infection through the induction of >400 interferon-stimulated genes (ISGs). Among ISGs, IFN-induced protein with tetratricopeptide repeats (IFITs) is one of the most potent and well-characterized ISGs. IFIT family consists of 4 cluster genes. It has been suggested that the antiviral action of each IFIT employs distinct mechanisms. In addition, it has been shown that each IFIT exhibits its antiviral properties partially in a pathogen-specific manner. To date, the expression profile of IFITs in the liver, as well as the antiviral potency of the individual IFITs in the regulation of hepatitis C virus (HCV) infection, is not yet fully defined. Our previous study found that the expression of hepatic IFITs is well correlated with the outcome of IFN-based antiviral therapy. This study explored the significance of each IFIT in the suppression of HCV. Our in vitro and in vivo studies with humanized liver chimeric mouse system revealed that IFIT1, 2, and 3/4 play an important role in the suppression of HCV. In addition, our in vitro experiment found that all IFITs possess a comparable anti-HCV potency. Follow-up studies collectively indicated that IFITs suppress HCV likely through 2 distinct mechanisms: (1) inhibition of internal ribosome entry site-dependent viral protein translation initiation complex according to experiments with bicistronic reporter assay as well as confocal microscopic analyses and (2) sequestration of viral genome based on an experiment using replication defective viral genome. In conclusion, our study defined the importance of IFITs in the regulation of HCV and also suggested the multifaceted antiviral actions.

Correction: Application of the Doylestown algorithm for the early detection of hepatocellular carcinoma.

[This corrects the article DOI: 10.1371/journal.pone.0203149.].

Application of the Doylestown algorithm for the early detection of hepatocellular carcinoma.

BACKGROUND: We previously developed a logistic regression algorithm that uses AFP, age, gender, ALK and ALT levels to improve the detection of hepatocellular carcinoma (HCC). In 3,158 patients from 5 independent sites, this algorithm, referred to as the "Doylestown" algorithm, increased the AUROC of AFP 4% to 12% and had equal benefit regardless of tumor size or the etiology of liver disease. AIMS: Analysis of the Doylestown algorithm using samples from individuals taken before their diagnosis of HCC. METHODS: Here, the algorithm was tested using samples at multiple time points from (a) patients with established chronic liver disease, without HCC (120 patients) and (b) 116 patients with HCC diagnosis (85 patients with early stage HCC and 31 patients with recurrent HCC), taken at the time of, and up to 12 months prior to cancer diagnosis. RESULTS: Among patients who developed HCC, comparing the Doylestown algorithm at a fixed cut-off to AFP at 20 ng/mL, the Doylestown algorithm increased the True Positive Rate (TPR) in identification of HCC from 36 to 50%, at a time point of 12 months prior to the conventional HCC detection. Similar results were obtained in those patients with recurrent HCC, where the Doylestown algorithm increased TPR in detection of HCC from 18% to 59%, at 12 months prior to detection of recurrence. CONCLUSIONS: This algorithm significantly improves the prediction of HCC by AFP alone and may have value in the early detection of HCC.

The APRI may be enhanced by the use of the FIBROSpect II in the estimation of fibrosis in chronic hepatitis C.

BACKGROUND: Multiple serum markers to estimate hepatic fibrosis in chronic liver disease have been proposed. The AST/Platelet Ratio Index (APRI) is a simple biochemical index that has been shown to be useful and accurate in about 50% of patients with chronic hepatitis C. We determined if the combination of the APRI and the FIBROSpect II, a commercially available hepatic fibrosis marker that measures 3 components of the extracellular hepatic matrix, would further help distinguish mild from significant fibrosis in a group of patients with chronic hepatitis C. METHODS: In an outpatient setting, 93 consecutive patients were studied who were undergoing staging liver biopsy for chronic hepatitis C who had a liver biopsy length>or=1.5 cm. All had blood drawn at the time of the biopsy. Liver biopsies were staged for fibrosis by the Batts Ludwig criteria (F0-F4). Patients with previous anti-viral therapy, hepatocellular carcinoma, an organ transplant, or co-infection with HIV or hepatitis B were excluded. The APRI was calculated and FIBROSpect II determined. RESULTS: The AUC of the ROC curve for the APRI and FIBROSpect II were 0.887 and 0.879 respectively. Using cutoffs of or=1.2 for significant fibrosis, the APRI correctly estimated 19 of 20 patients with mild fibrosis for an NPV of 95.0%, and 31 of 33 patients with significant fibrosis for a PPV of 93.6%. The FIBROSpect II also works best utilizing 2 cutoffs, and using cutoffs of or=85 it correctly identified 18 of 18 patients with mild fibrosis and all 26 patients with significant fibrosis for an NPV and PPV of 100% for both. Among the 40 patients who could not be classified by the APRI, an additional 16 could be correctly classified using the FIBROSpect II with cutoffs of or=85. This lowered the indeterminate zone from 43.0 to 25.8%. By combining the APRI and the FIBROSpect II, the AUC for the ROC curve improved significantly to 0.931 (p=0.013). CONCLUSIONS: The APRI and the FIBROSpect II are both accurate tests for separating mild from significant fibrosis. By using the APRI as the initial screen, >50% of patients with mild or significant fibrosis can be correctly identified. If the patient falls in the indeterminate zone, then the more expensive FIBROSpect II could be obtained. This strategy could decrease the number of liver biopsies.

A framework for management of hepatitis C in prisons.

The prevalence of chronic hepatitis C virus (HCV) infection in prisons ranges from 12% to 31%. There are generally accepted--albeit still evolving--guidelines for identification and treatment of hepatitis C in the community. However, there is less agreement among health professionals caring for prisoners about best practices for identification, medical management, and treatment of hepatitis C. Inmates often lack health care before incarceration. In prisons, infected persons could be identified and the management of infection initiated; however, the high prevalence of HCV infection among prisoners would impose a disproportionate cost for hepatitis C care on the correctional system. The optimal solution is for prison and public health systems in the United States to jointly provide targeted HCV testing and standard-of-care hepatitis C medical management, treatment, and prevention programs to prison inmate populations. The authors report on a January 2003 meeting of experts in prison health, public health, hepatology, and infectious diseases and explore the clinical care, prevention, and collaboration needed to provide hepatitis C management in prisoners.

Screening for hepatitis A and B antibodies in patients with chronic liver disease.

Chronic liver disease (CLD) is highly prevalent, and hepatitis C is one of the leading causes. Acute hepatitis A or B in patients with chronic hepatitis C can lead to more severe hepatic injury and a higher fatality rate than in patients without hepatitis C. Thus, the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention and the World Health Organization recommend that persons with CLD be vaccinated against hepatitis A virus (HAV), and the ACIP and the National Institutes of Health recommend vaccination against both HAV and hepatitis B virus (HBV) in patients with chronic hepatitis C. Because coinfection with HAV or HBV in patients with chronic hepatitis C or CLD is common, antibody screening prior to hepatitis A or B vaccination can identify patients who are already immune to these viruses and thus do not need to be vaccinated. Selective hepatitis A vaccination (i.e., vaccination of patients who test negative for either HAV antibody immunoglobulin G or total antibodies to HAV) is most cost-effective in areas where the local prevalence of hepatitis A is higher than the national prevalence and in populations with higher background rates of HAV exposure compared with the general population, such as older adults, foreign-born patients, African Americans, and persons with CLD or hepatitis C. Although not usually recommended for healthy adults or those with compensated CLD because of virtually 100% postvaccination seroconversion, serologic testing after hepatitis A vaccination is recommended in patients with decompensated or advanced end-stage liver disease because of the much lower seroconversion rates in these patients. Selective vaccination against HBV in patients with CLD or hepatitis C is also recommended. Testing for hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) is considered the most efficient and reasonably cost-effective method to screen for hepatitis B serologic markers because HBsAg identifies individuals with both acute and chronic HBV infection, and anti-HBs identify those who are immune secondary to vaccination or past infection. Testing for antibodies to hepatitis B core antigen is needed to further distinguish between immunity due to vaccination and immunity due to past infection, but it is not recommended as the only screening test for HBV immunity. Postvaccination testing for hepatitis B seroconversion is recommended in all patients with CLD, especially in those with more advanced disease, because the rate of seroconversion is generally lower than in healthy adults. If patients with CLD are not adequately protected after a standard course of hepatitis B vaccination, a repeat course of vaccination using the standard schedule or an accelerated schedule (days 0, 7, and 21) should be considered.

Recent advances in micro/nanotechnologies for global control of hepatitis B infection.

The control of hepatitis B virus (HBV) infection is a challenging task, specifically in developing countries there is limited access to diagnostics and antiviral treatment mainly due to high costs and insufficient healthcare infrastructure. Although the current diagnostic technologies can reliably detect HBV, they are relatively laborious, impractical and require expensive resources that are not suitable for resource-limited settings. Advances in micro/nanotechnology are pioneering the development of new generation methodologies in diagnosis and screening of HBV. Owing to combination of nanomaterials (metal/inorganic nanoparticles, carbon nanotubes, etc.) with microfabrication technologies, utilization of miniaturized sensors detecting HBV and other viruses from ultra-low volume of blood, serum and plasma is realized. The state-of-the-art microfluidic devices with integrated nanotechnologies potentially allow for inexpensive HBV screening at low cost. This review aims to highlight recent advances in nanotechnology and microfabrication processes that are employed for developing point-of-care (POC) HBV assays.

Current Concepts of HBV/HCV Coinfection: Coexistence, but Not Necessarily in Harmony.

Hepatitis B and hepatitis C are important causes of chronic liver disease globally. Although HBV/HCV coinfection is not uncommon, its epidemiology is poorly defined. Numerous studies provided evidence that coinfection accelerates liver disease progression and increases the risk of hepatocellular carcinoma. By applying new cell culture models to examine the interaction of both viruses, investigators concluded that HBV and HCV replicate in the same hepatocyte without interference. The roles of innate and adaptive immunity in determining the viral replication and disease outcomes still need rigorous investigation. To date, no standard-of-care recommendation exists for HBV/HCV coinfection. Pegylated interferon and ribavirin combination therapy demonstrated similar efficacy in suppressing HCV RNA in coinfection and HCV monoinfection. However, HBV reactivation during therapy can be a challenge. Future clinical trials evaluating the addition of a nucleoside/nucleotide analog for selective patients with HBV/HCV coinfection are essential for successful management of HBV/HCV coinfection.

Current status of antiviral therapy for hepatitis B.

Chronic hepatitis B (CHB) is a major public health problem affecting up to 400 million people globally. Complications of CHB including liver failure and hepatocellular carcinoma result in 1.2 million deaths per year, making CHB the 10th leading cause of mortality worldwide. The natural history of CHB is variable and complex. The past decade witnessed important developments for the therapy of hepatitis B and marked the new era of oral therapy. The ultimate goal of CHB therapy is to arrest the progression of liver injury and to prevent the development of liver failure and hepatocellular carcinoma. Currently, six agents are approved for the treatment of CHB. Each of these agents, given as monotherapy, has been shown to produce virological, biochemical, and histological benefits for both HBeAg positive and negative CHB. There are, however, limitations in spite of their efficacy. The significant side-effect profile of interferon, for example, limits its long-term use. The approved oral agents are tolerable with prolonged use but drug resistance could limit long-term monotherapy. To date, combination therapy with nucleoside analogue and pegylated interferon or two nucleos(t)ide analogues given for one year does not show superiority in durability of response compared to monotherapy. Ongoing research effort is critical to identify the ideal hepatitis B therapy that is safe, effective, and produces durable response with a finite course of therapy. It is equally important to conduct a well designed, prospective natural history study to identify predictors of disease progression. This will accurately guide treatment strategy for this important disease.