Establishment of a novel quantitative hepatitis D virus (HDV) RNA assay using the Cobas TaqMan platform to study HDV RNA kinetics

Development of a dual channel detection system for pan-genotypic simultaneous quantification of hepatitis B and delta viruses

Hepatitis B virus (HBV) infection remains a major public health problem and, in associated co-infection with hepatitis delta virus (HDV), causes the most severe viral hepatitis and accelerated liver disease progression. As a defective satellite RNA virus, HDV can only propagate in the presence of HBV infection, which makes HBV DNA and HDV RNA the standard biomarkers for monitoring the virological response upon antiviral therapy, in co-infected patients. Although assays have been described to quantify these viral nucleic acids in circulation independently, a method for monitoring both viruses simultaneously is not available, thus hampering characterization of their complex dynamic interactions. Here, we describe the development of a dual fluorescence channel detection system for pan-genotypic, simultaneous quantification of HBV DNA and HDV RNA through a one-step quantitative PCR. The sensitivity for both HBV and HDV is about 10 copies per microliter without significant interference between these two detection targets. This assay provides reliable detection for HBV and HDV basic research in vitro and in human liver chimeric mice. Preclinical validation of this system on serum samples from patients on or off antiviral therapy also illustrates a promising application that is rapid and cost-effective in monitoring HBV and HDV viral loads simultaneously.

Modelling HDV kinetics under the entry inhibitor bulevirtide suggests the existence of two HDV-infected cell populations

Background & Aims

Bulevirtide (BLV) was approved for the treatment of compensated chronic hepatitis D virus (HDV) infection in Europe in 2020. However, research into the effects of the entry inhibitor BLV on HDV-host dynamics is in its infancy.

Methods

Eighteen patients with HDV under nucleos(t)ide analogue treatment for hepatitis B, with compensated cirrhosis and clinically significant portal hypertension, received BLV 2 mg/day. HDV RNA, alanine aminotransferase (ALT), and hepatitis B surface antigen (HBsAg) were measured at baseline, weeks 4, 8 and every 8 weeks thereafter. A mathematical model was developed to account for HDV, HBsAg and ALT dynamics during BLV treatment.

Results

Median baseline HDV RNA, HBsAg, and ALT were 4.9 log IU/ml [IQR: 4.4-5.8], 3.7 log IU/ml [IQR: 3.4-3.9] and 106 U/L [IQR: 81-142], respectively. During therapy, patients fit into four main HDV kinetic patterns: monophasic (n = 2), biphasic (n = 10), flat-partial response (n = 4), and non-responder (n = 2). ALT normalization was achieved in 14 (78%) patients at a median of 8 weeks (range: 4-16). HBsAg remained at pre-treatment levels. Assuming that BLV completely (∼100%) blocks HDV entry, modeling indicated that two HDV-infected cell populations exist: fast HDV clearing (median t1/2 = 13 days) and slow HDV clearing (median t1/2 = 44 days), where the slow HDV-clearing population consisted of ∼1% of total HDV-infected cells, which could explain why most patients exhibited a non-monophasic pattern of HDV decline. Moreover, modeling explained ALT normalization without a change in HBsAg based on a non-cytolytic loss of HDV from infected cells, resulting in HDV-free HBsAg-producing cells that release ALT upon death at a substantially lower rate compared to HDV-infected cells.

Conclusion

The entry inhibitor BLV provides a unique opportunity to understand HDV, HBsAg, ALT, and host dynamics.

Impact and implications

Mathematical modeling of hepatitis D virus (HDV) treatment with the entry inhibitor bulevirtide (BLV) provides a novel window into the dynamics of HDV RNA and alanine aminotransferase. Kinetic data from patients treated with BLV monotherapy can be explained by hepatocyte populations with different basal HDV clearance rates and non-cytolytic clearance of infected cells. While further studies are needed to test and refine the kinetic characterization described here, this study provides a new perspective on viral dynamics, which could inform evolving treatment strategies for HDV.

Five-year follow-up of 96 weeks peginterferon plus tenofovir disoproxil fumarate in hepatitis D

BACKGROUND & AIMS

Until recently, pegylated interferon-alfa-2a (PEG-IFNa) therapy was the only treatment option for patients infected with hepatitis D virus (HDV). Treatment with PEG-IFNa with or without tenofovir disoproxil fumarate (TDF) for 96 weeks resulted in HDV RNA suppression in 44% of patients at the end of therapy but did not prevent short-term relapses within 24 weeks. The virological and clinical long-term effects after prolonged PEG-IFNa-based treatment of hepatitis D are unknown.

METHODS

In the HIDIT-II study patients (including 40% with liver cirrhosis) received 180 μg PEG-IFNa weekly plus 300 mg TDF once daily (n = 59) or 180 μg PEG-IFNa weekly plus placebo (n = 61) for 96 weeks. Patients were followed until week 356 (5 years after end of therapy).

RESULTS

Until the end of follow-up, 16 (13%) patients developed liver-related complications (PEG-IFNa + TDF, n = 5 vs PEG-IFNa + placebo, n = 11; p = .179). Achieving HDV suppression at week 96 was associated with decreased long-term risk for the development of hepatocellular carcinoma (p = .04) and hepatic decompensation (p = .009). Including complications irrespective of PEG-IFNa retreatment status, the number of patients developing serious complications was similar with (3/18) and without retreatment with PEG-IFNa (16/102, p > .999) but was associated with a higher chance of HDV-RNA suppression (p = .024, odds ratio 3.9 [1.3-12]).

CONCLUSIONS

Liver-related clinical events were infrequent and occurred less frequently in patients with virological responses to PEG-IFNa treatment. PEG-IFNa treatment should be recommended to HDV-infected patients until alternative therapies become available. Retreatment with PEG-IFNa should be considered for patients with inadequate response to the first course of treatment.

CLINICAL TRIAL REGISTRATION

NCT00932971.

Performance of Hepatitis Delta Virus (HDV) RNA Testing for the Diagnosis of Active HDV Infection: Systematic Review and Meta-analysis

Background and Aims

Hepatitis delta virus (HDV) is a defective virus and causes severe liver disease. Several HDV RNA assays have been developed, however the diagnostic efficacy remains unclear.This systematic review and meta-analysis aims to evaluate the diagnostic accuracy of HDV RNA assays to aid in the diagnosis of active hepatitis D.

Methods

The PubMed, Embase, and Cochrane Library databases were systematically searched from the beginning to June 31, 2022. Information on the characteristics of the literature and data on sensitivity, specificity, and area under curve (AUC) of the receiver operating characteristic (ROC) were extracted. Stata 14.0 was used for meta-analysis of the combined sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio.

Results

A total of 10 studies were included in the meta-analysis. The summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of HDV RNA assays for HDV diagnosis were 0.92 (95% CI: 0.87-0.95), 0.90 (95% CI: 0.86-0.93), 7.74 (95% CI: 5.31-11.29), 0.10 (95% CI: 0.06-0.18) and 99.90 (95% CI: 47.08-211.99), respectively. The AUC of the pooled ROC curve was 0.95 (95% CI: 0.92-0.96).

Conclusions

The results show that HDV RNA assays had high diagnostic performance. However, that is limited by the number and quality of studies. Standard protocols for the development of assays by manufacturers and larger studies on the use of the assays are needed.

State of the Art: Test all for Anti-Hepatitis D Virus and Reflex to Hepatitis D Virus RNA Polymerase Chain Reaction Quantification

Diagnosis of HDV exposure is based on clinical assays of anti-hepatitis D antibody and current infection with hepatitis D RNA PCR. The role of hepatitis D antigen testing is not yet defined. RT-qPCR is the gold standard for measuring HDV RNA viral load, which is used to assess response to the treatment of HDV infection. Gaps in testing include poor sensitivity of antigen testing and quantitative HDV RNA accuracy can be affected by the genotypic variability of the virus and variation in laboratory techniques. There is also a limitation in HDV testing due to access, cost, and limited knowledge of testing indications. Droplet digital PCR promises to be a more accurate method to quantify HDV RNA. Also, the recent development of a rapid HDV detection test could prove useful in resource-limited areas.

HDV RNA assays: Performance characteristics, clinical utility, and challenges

Coinfection with HBV and HDV results in hepatitis D, the most severe form of chronic viral hepatitis, frequently leading to liver decompensation and HCC. Pegylated interferon alpha, the only treatment option for chronic hepatitis D for many years, has limited efficacy. New treatments are in advanced clinical development, with one recent approval. Diagnosis and antiviral treatment response monitoring are based on detection and quantification of HDV RNA. However, the development of reliable HDV RNA assays is challenged by viral heterogeneity (at least 8 different genotypes and several subgenotypes), intrahost viral diversity, rapid viral evolution, and distinct secondary structure features of HDV RNA. Different RNA extraction methodologies, primer/probe design for nucleic acid tests, lack of automation, and overall dearth of standardization across testing laboratories contribute to substantial variability in performance characteristics of research-based and commercial HDV RNA assays. A World Health Organization (WHO) standard for HDV RNA, available for about 10 years, has been used by many laboratories to determine the limit of detection of their assays and facilitates comparisons of RNA levels across study centers. Here we review challenges for robust pan genotype HDV RNA quantification, discuss particular clinical needs and the importance of reliable HDV RNA quantification in the context of drug development and patient monitoring. We summarize distinct technical features and performance characteristics of available HDV RNA assays. Finally, we provide considerations for the use of HDV RNA assays in the context of drug development and patient monitoring.

Diagnosis of HDV: From virology to non-invasive markers of fibrosis

Hepatitis D viral infection in humans is a disease that requires the establishment of hepatitis B, relying on hepatitis B surface Ag and host cellular machinery to replicate and propagate the infection. Since its discovery in 1977, substantial progress has been made to better understand the hepatitis D viral life cycle, pathogenesis and modes of transmission along with expanding on clinical knowledge related to prevention, diagnosis, monitoring and treatment. The availability of serologic diagnostic assays for hepatitis D infection has evolved over time with current widespread availability, improved detection and standardized reporting. With human migration, the epidemiology of hepatitis D infection has changed over time. Thus, the ability to use diagnostic assays remains essential to monitor the global impact of hepatitis D infection. Separately, while liver biopsy remains the gold standard for the staging of this rapidly progressive and severe form of chronic viral hepatitis, there is an unmet need for clinical monitoring of chronic hepatitis D infection for management of progressive disease. Thus, exploration of the utility of non-invasive fibrosis markers in hepatitis D is ongoing. In this review, we discuss the virology, the evolution of diagnostics and the development of non-invasive markers for the detection and monitoring of fibrosis in patients with hepatitis D infection.

Development of quantitative multiplex RT-qPCR one step assay for detection of hepatitis delta virus

Hepatitis Delta is a disease caused by exposure to hepatitis B (HBV) and hepatitis D (HDV) viruses, usually with a more severe clinical outcome when compared to an HBV monoinfection. To date, the real prevalence of HDV infection is underestimated and detection methods are poorly available, especially in more endemic regions. Therefore, a one-step RT-qPCR method for quantification of HDV-RNA was developed. Biological samples were selected between 2017 and 2023 from patients at the Ambulatório Especializado em Hepatites Virais of the Centro de Pesquisa em Medicina Tropical de Rondônia and Serviço de Assistência Especializada and underwent the test developed by this study and a second quantitative RT-qPCR assay. The slope of the initial quantitative assay was - 3.321 with an efficiency of 100.04% and amplification factor equal to 2. Analysis of the repeatability data revealed a Limit of Quantification of 5 copies/reaction and Limit of Detection (95%) of 2.83 copies per reaction. In the diagnostic sensitivity tests, there was an accuracy of 97.37% when compared to the reference test. This assay proved to be highly efficient and reproducible, making it a valuable tool to monitor hepatitis Delta patients and assess the risk of disease progression, as well as the effectiveness of treatment.

Week 96 Results of Switching from Tenofovir Disoproxil Fumarate-Based Antiretroviral Therapy to Coformulated Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide among HIV/Hepatitis B Virus-Coinfected Patients

Data regarding the durability of tenofovir alafenamide (TAF)-containing antiretroviral therapy (ART) in maintaining hepatitis B virus (HBV) viral suppression among HIV/HBV-coinfected patients are limited. Between February and October 2018, 274 HIV/HBV-coinfected participants who had achieved HIV RNA of <50 copies/mL with tenofovir disoproxil fumarate (TDF)-containing ART and switched to elvitegravir/cobicistat/emtricitabine/TAF were prospectively enrolled. Serial plasma HIV and HBV viral loads, HBV and hepatitis D virus (HDV) serology, renal parameters, metabolic profiles, and bone mineral density (BMD) were assessed through 96 weeks. At baseline and weeks 48, 72, and 96, 5.8%, 5.1%, 5.8%, and 5.1% of the participants had plasma HBV DNA of ≥20 IU/mL, and 0%, 0.7%, 1.5%, and 2.2% had HIV RNA of ≥50 copies/mL, respectively. Hepatitis B surface antigen (HBsAg) loss occurred in 1.5% of 274 participants, and hepatitis B e-antigen (HBeAg) loss or seroconversion occurred in 14.3% of 35 HBeAg-positive participants. Compared with baseline, the median urine protein-to-creatinine ratio (79 versus 63 mg/g, P < 0.001) and β2-microglobulin-to-creatinine ratio (165 versus 83 μg/g, P < 0.001) continued to decrease at week 96. BMD of the spine and hip slightly increased (mean change, +0.9% and +0.5%, respectively). The median triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol and high-density lipoprotein (HDL)-cholesterol increased from baseline to week 96 (116 versus 141, 166 versus 190, 99 versus 117, and 42 versus 47 mg/dL, respectively; all P < 0.001), and most of the increases occurred in the first 48 weeks of the switch. Our study showed that switching from TDF-containing ART to elvitegravir/cobicistat/emtricitabine/TAF maintained HBV and HIV viral suppression through 96 weeks among HIV/HBV-coinfected patients. Proteinuria continued to improve, while fasting lipids increased and BMD stabilized at 96 weeks after the switch. IMPORTANCE Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide as a maintenance therapy showed durable and high rates of viral suppression for HIV/HBV-coinfected patients, with only 5.1% and 2.2% of patients having HBV DNA of ≥20 IU/mL and HIV RNA of ≥50 copies/mL, respectively, at 96 weeks. Our study fills the data gap on the long-term clinical effectiveness of tenofovir alafenamide-containing antiretroviral therapy in people living with HIV who have HBV coinfection.

Sequence diversity of hepatitis D virus in Mongolia

Introduction

The Hepatitis Delta Virus (HDV) is a defective, single-stranded RNA virusoid encoding for a single protein, the Hepatitis Delta Antigen (HDAg), which requires the hepatitis B virus (HBV) envelope protein (HBsAg) for its transmission. Currently, hepatitis D is the most aggressive form of viral hepatitis and treatment options are limited. Worldwide 12 million people are chronically infected with HDV being at high risk for progression to cirrhosis and development of liver cancer.

Objectives

Although it is well established that Mongolia is the country with the highest prevalence of HDV infections, the information on the molecular epidemiology and factors contributing to HDV sequence diversity are largely unclear. The aim of the study was to characterize the sequence diversity of HDV in rural areas from Mongolia and to determine the extent of HLA class I-associated selection pressure.

Patients and methods

From the HepMongolia cohort from rural areas in Mongolia, 451 HBsAg-positive individuals were selected and anti-HDV, HDV-RNA and the sequence of the large HDAg was determined. For all individuals the HLA class I locus was genotyped. Residues under selection pressure in the presence of individual HLA class I types were identified with the recently published analysis tool HAMdetector.

Results

Of 431 HBsAg positive patients, 281 were anti-HDV positive (65%), and HDV-RNA could be detected in 207 of 281 (74%) of patients. The complete large HDAg was successfully sequenced from 131 samples. Phylogenetic analysis revealed that all Mongolian HDV isolates belong to genotype 1, however, they separate into several different clusters without clear regional association. In turn, from phylogeny there is strong evidence for recent local transmission events. Importantly, we found multiple residues with strong support for HLA class I-associated selection pressure consistent with a functional CD8⁺ T cell response directed against HDV.

Conclusion

HDV isolates from Mongolia are highly diverse. The molecular epidemiology suggests circulation of multiple subtypes and provides evidence for ongoing recent transmissions.

HBcrAg Levels Are Associated With Virological Response to Treatment With Interferon in Patients With Hepatitis Delta

Standard treatment of hepatitis delta virus (HDV) infection remains pegylated-interferon alfa (peg-IFNα) in most centers, which is not only associated with rather low efficacy but several adverse events. Hepatitis B core-related antigen (HBcrAg) is linked to intrahepatic covalently closed circular DNA levels and has previously been suggested as response predictor in IFN-based treatment of hepatitis B virus (HBV) mono-infection. This study aimed to investigate the value of HBcrAg in the management of patients with HBV/HDV co-infection undergoing peg-IFNα treatment. The Hep-Net-International-Delta-Hepatitis-Intervention Trial-2 study included 120 patients co-infected with HBV/HDV. Patients were treated for 96 weeks with peg-IFNα and either tenofovir or placebo. Ninety-nine patients with HDV-RNA results 24 weeks after end of treatment (FU24) were included in this analysis, of whom 32 patients (32.3%) had undetectable HDV RNA at FU24. HBcrAg was measured at baseline, week 12, 24, 48, 96, and FU24. HBcrAg levels showed no significant correlation with HDV RNA but were significantly linked to treatment outcome. HBcrAg levels < 4.5 log IU/mL at baseline, week 24, and week 48 had high negative predictive value (NPV) for achieving undetectable HDV RNA at FU24 (81.8%, 87.1% and 95.0%, respectively). Similarly, HBcrAg levels at week 96 were significantly higher in patients with viral relapse until FU24 (3.0 vs. 3.63 log IU/mL; P = 0.0089). Baseline, week 24, and week 48 HBcrAg levels were also associated with the likelihood of achieving HBsAg level < 100 IU/mL at FU24 (HBcrAg < 3.0 log IU/mL: NPV 91.7%, 90.4% and 92.3%, respectively). Test statistics improved when combining HBcrAg with additional viral and clinical parameters. Conclusion: HBcrAg is linked to treatment response to peg-IFNα in patients with HBV/HDV co-infection and could be a promising marker to determine treatment futility.

Hepatitis D: challenges in the estimation of true prevalence and laboratory diagnosis

Hepatitis delta virus (HDV) is a defective single negative chain RNA virus, as its envelope protein synthesis is dependent on hepatitis B virus (HBV). Studies have consistently shown that coinfection of HBV and HDV is the most serious form of viral hepatitis, with accelerated progression to liver cirrhosis and hepatocellular carcinoma. About 74 million of HBV surface antigen (HBsAg) positive patients worldwide are also co-infected with HDV. Besides, patients with intravenous drug use and high-risk sexual behavior are at higher risk of HDV infection. Therapeutic schedules for HDV are limited, and relapse of HDV has been observed after treatment with pegylated interferon alpha. To reduce the transmission of HDV, all people infected with HBV should be screened for HDV. At present, several serological and molecular detection methods are widely used in the diagnosis of HDV. However, due to the lack of international standards diagnostic results from different laboratories are often not comparable. Therefore, the true prevalence of HDV is still unclear. In this manuscript, we have analyzed various factors influencing the estimation of HDV prevalence. We have also discussed about the advantages and disadvantages of currently available HDV laboratory diagnostic methods, in order to provide some ideas for improving the detection of HDV.

Strong Replication Interference Between Hepatitis Delta Viruses in Human Liver Chimeric Mice

Background

Hepatitis D Virus (HDV) is classified into eight genotypes with distinct clinical outcomes. Despite the maintenance of highly conserved functional motifs, it is unknown whether sequence divergence between genotypes, such as HDV-1 and HDV-3, or viral interference mechanisms may affect co-infection in the same host and cell, thus hindering the development of HDV inter-genotypic recombinants. We aimed to investigate virological differences of HDV-1 and HDV-3 and assessed their capacity to infect and replicate within the same liver and human hepatocyte in vivo.

Methods

Human liver chimeric mice were infected with hepatitis B virus (HBV) and with one of the two HDV genotypes or with HDV-1 and HDV-3 simultaneously. In a second set of experiments, HBV-infected mice were first infected with HDV-1 and after 9 weeks with HDV-3, or vice versa. Also two distinct HDV-1 strains were used to infect mice simultaneously and sequentially. Virological parameters were determined by strain-specific qRT-PCR, RNA in situ hybridization and immunofluorescence staining.

Results

HBV/HDV co-infection studies indicated faster spreading kinetics and higher intrahepatic levels of HDV-3 compared to HDV-1. In mice that simultaneously received both HDV strains, HDV-3 became the dominant genotype. Interestingly, antigenomic HDV-1 and HDV-3 RNA were detected within the same liver but hardly within the same cell. Surprisingly, sequential super-infection experiments revealed a clear dominance of the HDV strain that was inoculated first, indicating that HDV-infected cells may acquire resistance to super-infection.

Conclusion

Infection with two largely divergent HDV genotypes could be established in the same liver, but rarely within the same hepatocyte. Sequential super-infection with distinct HDV genotypes and even with two HDV-1 isolates was strongly impaired, suggesting that virus interference mechanisms hamper productive replication in the same cell and hence recombination events even in a system lacking adaptive immune responses.

Recommendations of the AGG (Task Force for Obstetrics, Section Maternal Diseases) on the Management of Maternal Hepatitis B, C and D Infection in Pregnancy

These statements and recommendations should provide appropriate information about maternal and fetal routes of infection, screening, detection of risk factors, diagnostic procedures, treatment, birth planning and peripartum and postpartum management of maternal hepatitis infection and offer pointers for prenatal counselling and routine clinical care on delivery wards.

Residual low HDV viraemia is associated HDV RNA relapse after PEG-IFNa-based antiviral treatment of hepatitis delta: Results from the HIDIT-II study

The role of low levels of HDV-RNA during and after interferon therapy of hepatitis D is unknown. We re-analysed HDV RNA in 372 samples collected in the HIDIT-2 trial (Wedemeyer et al, Lancet Infectious Diseases 2019) with the Robogene assay (RA; Jena Analytics). Data were compared with the previously reported in-house assay (IA). We detected HDV-RNA in one-third of samples previously classified as undetectable using the highly sensitive RA. Low HDV viraemia detectable at week 48 or week 96 was associated with a high risk for post-treatment relapse, defined as HDV RNA positivity in both assays at week 120. HDV RNA relapses occurred in 10/15 (67%) patients with detectable low HDV RNA at week 48 and in 10/13 (77%) patients with low viraemia samples at week 96. In contrast, the post-treatment relapse rate was lower in patients with undetectable HDV RNA in both assays during treatment.

A transient early HBV-DNA increase during PEG-IFNα therapy of hepatitis D indicates loss of infected cells and is associated with HDV-RNA and HBsAg reduction

HBV-DNA levels are low or even undetectable in the majority HDV-infected patients. The impact of PEG-IFNα on HBV-DNA kinetics in HDV-infected patients has not been studied in detail. We analysed data of a prospective treatment trial where 120 HDV-RNA-positive patients were randomized to receive PEG-IFNα-2a plus tenofovir-disoproxil-fumarate (PEG-IFNα/TDF, n = 59) or placebo (PEG-IFNα/PBO; n = 61) for 96 weeks. At week 96, HBV-DNA was still quantifiable in 71% of PEG-IFNα/PBO-treated patients but also in 76% of PEG-IFNα/TDF-treated patients, despite low HBV-DNA baseline values. Surprisingly, a transient HBV-DNA increase between weeks 12 and 36 was observed in 12 in PEG-IFNα/TDF-treated and 12 PEG-IFNα/PBO-treated patients. This increase was positively associated with HBsAg loss [(P = 0.049, odds ratio (OR) 5.1] and HDV-RNA suppression (P = 0.007, OR 4.1) at week 96. Biochemical markers of cell death (M30 and ALT) were higher during the HBV-DNA peak but no distinct systemic immune pattern could be observed by screening 91 soluble inflammatory markers. In conclusion, an early increase in HBV-DNA during PEG-IFNα-2a therapy occurred in more than 20% of patients, even in TDF-treated patients. This transient HBV-DNA rise may indicate PEG-IFNα-induced cell death and lead to long-term HDV-RNA suppression and HBsAg loss.

Ten-year follow-up of a randomized controlled clinical trial in chronic hepatitis delta

Hepatitis delta virus (HDV) infection causes the most severe form of viral hepatitis. PEG-interferon alpha-2a (PEG-IFNα-2a) is the only effective treatment but its long-term clinical impact is unclear. The aim of this study was to investigate the long-term outcome after 48 weeks of pegylated interferon alpha-2a therapy. We performed a retrospective follow-up study of the Hep-Net-International-Delta-Hepatitis-Intervention-Study 1 (HIDIT-I trial). Patients had received 48 weeks of treatment with either PEG-IFNα-2a plus adefovir dipivoxil (ADV) (Group I), PEG-IFNα-2a alone (Group II) or adefovir dipivoxil alone (Group III). Liver-related complications were defined as liver-related death, liver transplantation, liver cancer and hepatic decompensation defined as development of Child-Pugh scores B or C or an increase in Model for End-stage Liver Disease (MELD) scores of five or more points in relation to baseline values. Patients were considered for further analysis when they were retreated with PEG-IFNα-2a. Follow-up data (at least 1 visit beyond post-treatment week 24) were available for 60 patients [Group I, (n = 19), Group II (n = 20), Group III (n = 21)]. Mean time of follow-up was 8.9 (1.6 - 13.4) years. 19 patients were retreated with IFN-based therapy: 42% (n = 8) in PEG-IFNα-2a arms and 58% (n = 11) in the adefovir only arm. Clinical complications on long-term follow-up occurred in 17 patients and were associated with nonresponse to therapy and baseline cirrhosis. The annual event-free survival rate in patients with cirrhosis vs noncirrhotic patients at year 5 and 10 was 70% vs 91% and 35% vs 76%. Long-term follow-up of a large randomized clinical trial suggests that off-treatment HDV RNA response to PEG-IFNα-2a treatment leads to improved clinical long-term outcome.

Peginterferon alfa-2a plus tenofovir disoproxil fumarate for hepatitis D (HIDIT-II): a randomised, placebo controlled, phase 2 trial

BACKGROUND

Hepatitis D is the most severe form of chronic viral hepatitis. Treatment guidelines recommend 1 year of peginterferon alfa, which is effective in 25-30% of patients only. Whether prolonged therapy with peginterferon alfa-2a for 96 weeks and combination therapy with tenofovir disoproxil fumarate (TDF) would increase hepatitis D virus (HDV) RNA suppression is unknown. We aimed to explore whether prolonged treatment of HDV with 96 weeks of peginterferon would increase HDV RNA response rates and reduces post-treatment relapses.

METHODS

We did two parallel, investigator-initiated, multicentre, double-blind randomised, controlled trials at 14 study sites in Germany, Greece, Romania, and Turkey. Patients with chronic HDV infection and compensated liver disease who were aged 18 years or older were eligible for inclusion. All patients were HBsAg positive for at least 7 months, anti-HDV positive for at least 3 months, and HDV-RNA positive at the local laboratory at the screening visit. Patients were ineligible if alanine aminotransferase levels were higher than ten times above the upper limit of normal and if platelet counts were lower than 90 000 per μL, or if they had received interferon therapy or treatment with a nucleoside and nucleotide analogue within the preceding 6 months. Patients were randomly assigned by blinded stratified block randomisation (1:1) to receive 180 μg of peginterferon alfa-2a weekly plus either TDF (300 mg once daily) or placebo for 96 weeks. The primary endpoint was the percentage of patients with undetectable HDV RNA at the end of treatment assessed by intention to treat. The trials are registered as NCT00932971 and NCT01088659.

FINDINGS

Between June 24, 2009, and Feb 28, 2011, we randomly assigned 59 HDV RNA-positive patients to receive peginterferon alfa-2a plus TDF and 61 to receive peginterferon alfa-2a plus placebo, including 48 (40%) patients with cirrhosis to the two treatment groups (23 in the peginterferon alfa-2a plus TDF group and 25 in the peginterferon alfa-2a plus placebo group). The primary endpoint was achieved in 28 (48%) of 59 patients in the peginterferon alfa-2a plus TDF group and in 20 (33%) of 61 patients in the peginterferon alfa-2a plus placebo group (odds ratio 1·84, 95% CI 0·86-3·91, p=0·12). We recorded 944 adverse events (459 in the peginterferon alfa-2a plus TDF group and 485 in the peginterferon alfa-2a plus placebo group). The most common adverse events were haematological, behavioural (eg, fatigue), musculoskeletal, influenza-like syndromes, and psychiatric complaints.

INTERPRETATION

Addition of TDF resulted in no significant improvement in HDV RNA response rates at the end of treatment. These findings highlight that alternative treatment options are needed for hepatitis D.

FUNDING

The HepNet Study-House (a project of the German Liver Foundation founded by the German Liver Foundation, the German Ministry for Education and Research, and the German Center for Infectious Disease Research), Hoffmann-La Roche, and Gilead Sciences.

Laboratory Diagnosis and Monitoring of Viral Hepatitis

Many microbes, toxins, autoimmune diseases, and neoplastic diseases may cause liver inflammation; however, 5 viruses whose main pathogenesis is liver disease are referred to as hepatitis A, B, C, D, and E viruses. These viruses cause a significant burden of global illness. With the exception of hepatitis A virus, all may cause chronic infection potentially leading to cirrhosis and hepatocellular carcinoma. Excellent serologic and nucleic acid detection methods are available for determining the precise cause and, in some cases, the duration of infection. Diagnostics are critical for identifying individuals needing treatment and for monitoring the treatment success.

Characterization of hepatitis B and delta coinfection in Israel

BACKGROUND

Characteristics of hepatitis B (HBV) and delta (HDV) coinfection in various geographical regions, including Israel, remain unclear. Here we studied HDV seroprevalence in Israel, assessed HDV/HBV viral loads, circulating genotypes and hepatitis delta antigen (HDAg) conservation.

METHODS

Serological anti HDV IgG results from 8969 HBsAg positive individuals tested in 2010-2015 were retrospectively analyzed to determine HDV seroprevalence. In a cohort of HBV/HDV coinfected (n=58) and HBV monoinfected (n=27) patients, quantitative real-time PCR (qRT-PCR) and sequencing were performed to determine viral loads, genotypes and hepatitis delta antigen (HDAg) protein sequence.

RESULTS

6.5% (587/8969) of the HBsAg positive patients were positive for anti HDV antibodies. HDV viral load was >2 log copies/ml higher than HBV viral load in most of the coinfected patients with detectable HDV RNA (86%, 50/58). HDV genotype 1 was identified in all patients, most of whom did not express HBV. While 66.6% (4/6) of the HBV/HDV co-expressing patients carried HBV-D2 only 18.5% (5/27) of the HBV monoinfections had HBV-D2 (p=0.03). Higher genetic variability in the HDAg protein sequence was associated with higher HDV viral load.

CONCLUSIONS

The overall significant prevalence of HDV (6.5%) mandates HDV RNA testing for all coinfected patients. Patients positive for HDV RNA (characterized by low HBV DNA blood levels) carried HDV genotype 1. Taken together, the significant HDV seroprevalence and the lack of effective anti-HDV therapy, necessitates strict clinical surveillance especially in patients with higher HDV viral loads and increased viral evolution.

Development and performance of prototype serologic and molecular tests for hepatitis delta infection

Worldwide, an estimated 5% of hepatitis B virus (HBV) infected people are coinfected with hepatitis delta virus (HDV). HDV infection leads to increased mortality over HBV mono-infection, yet HDV diagnostics are not widely available. Prototype molecular (RNA) and serologic (IgG) assays were developed for high-throughput testing on the Abbott m2000 and ARCHITECT systems, respectively. RNA detection was achieved through amplification of a ribozyme region target, with a limit of detection of 5 IU/ml. The prototype serology assay (IgG) was developed using peptides derived from HDV large antigen (HDAg), and linear epitopes were further identified by peptide scan. Specificity of an HBV negative population was 100% for both assays. A panel of 145 HBsAg positive samples from Cameroon with unknown HDV status was tested using both assays: 16 (11.0%) had detectable HDV RNA, and 23 (15.7%) were sero-positive including the 16 HDV RNA positive samples. Additionally, an archival serial bleed panel from an HDV superinfected chimpanzee was tested with both prototypes; data was consistent with historic testing data using a commercial total anti-Delta test. Overall, the two prototype assays provide sensitive and specific methods for HDV detection using high throughput automated platforms, allowing opportunity for improved diagnosis of HDV infected patients.

The serological markers of acute infection with hepatitis A, B, C, D, E and G viruses revisited

Viral hepatitis is a liver infection caused by one of the six hepatitis viruses: hepatitis A, B, C, D, E, and G virus (HAV to HEV and HGV). These agents differ in their biological, immunological, pathological and epidemiological characteristics. They cause infections that, when symptomatic, lead to clinical manifestations and laboratory findings that are not specific to a particular virus, often making differential diagnosis difficult, especially when no knowledge is available regarding the patient's medical history or the epidemiological background. A number of acute-phase serological markers, such as anti-HAV, anti-HBc, anti-HDV and anti-HEV IgM antibodies, are able to provide a clear indication of an infection caused by HAV, HBV, HDV or HEV. Anti-HCV antibodies and HGV/RNA are used for the diagnosis of HCV and HGV infections. The importance of each of these markers will be reviewed, and different factors that can interfere with the diagnosis of acute infections caused by these viruses will be described.

Emerging concepts for the treatment of hepatitis delta

Hepatitis delta virus (HDV) causes the most severe form of human viral hepatitis and is associated with a higher risk of cirrhosis, liver decompensation and liver cancer. Interferon alpha is the only agent that has demonstrated efficacy to date, although response rates are low and it is associated with significant side effects. A better understanding of the relevant molecular virology has resulted in the identification of new candidate targets. Future therapeutic options are rapidly evolving as several new agents have entered clinical development, including the entry inhibitor myrcludex-B, the nucleic acid polymer REP2139-Ca inhibiting HBV surface antigen secretion, the farnesyltransferase inhibitor lonafarnib that targets virus assembly, and a better tolerated interferon-interferon lambda.

Non-invasive fibrosis score for hepatitis delta

BACKGROUND & AIMS

Identifying advanced fibrosis in chronic hepatitis delta patients and thus in need of urgent treatment is crucial. To avoid liver biopsy, non-invasive fibrosis scores may be helpful but have not been evaluated for chronic hepatitis delta yet.

METHODS

We evaluated eight non-invasive fibrosis scores in 100 HDV RNA-positive patients with available central histological reading. New cut-off values were calculated by using Receiver Operating Characteristics and Youden indexes. Predictors for the presence of ISHAK F3-6 were revealed by t-tests or Mann-Whitney tests.

RESULTS

None of the tested scores had an area under the curve (AUROC) > 0.8 and performed according to our predefined requirements of a sensitivity of >80% and a positive predictive value (PPV) >90% - even after adaption. However, the ELF score was able to identify advanced fibrosis with a high sensitivity (93%) and PPV (81%), but relies on expensive extracellular matrix markers with bad availability in many endemic regions of HDV. Thus, we developed a novel non-invasive approach and identified low cholinesterase (P=.002), low albumin (P=.041), higher gamma glutamyl transferase, as well as older age (P<.001) as predictors of fibrosis resulting in the Delta Fibrosis Score (DFS). The DFS performed with a sensitivity of 85% and PPV of 93% with an AUROC of 0.87.

CONCLUSIONS

Existing non-invasive fibrosis scores are either impracticable or do not perform well in chronic hepatitis delta patients. However, the new Delta Fibrosis Score is the first non-invasive fibrosis score specifically developed for chronic hepatitis delta and requires only standard parameters.

Antiviral treatment and liver-related complications in hepatitis delta

Hepatitis delta virus (HDV) is the most severe form of viral hepatitis. Pegylated interferon alfa (PEG-IFNα) is effective in only 25%-30% of patients and is associated with frequent side effects. The aim of this study was to analyze the clinical long-term outcome of hepatitis delta in relation to different antiviral treatment strategies. We studied 136 anti-HDV-positive patients who were followed for at least 6 months in a retrospective single-center cohort (mean time of follow-up, 5.2 years; range, 0.6-18.8). Liver cirrhosis was already present in 62 patients at first presentation. Twenty-nine percent of patients did not receive any antiviral treatment, 38% were treated with interferon alfa (IFNα)-based therapies, and 33% received nucleos(t)ide analogues (NAs) only. Clinical endpoints defined as hepatic decompensation (ascites, encephalopathy, and variceal bleeding), hepatocellular carcinoma, liver transplantation, and liver-related death developed in 55 patients (40%). Patients who received IFNα-based therapies developed clinical endpoints less frequently than those treated with NA (P = 0.02; HR, 4.0) or untreated patients (P = 0.05; HR, 2.2; 17%, 64%, and 44%), respectively, which was significant in both chi-square and Kaplan-Meier analysis. In addition, considering various clinical and virological parameters, IFNα therapy was independently associated with a more benign clinical long-term outcome in multivariate logistic regression analysis (P = 0.04; odds ratio, 0.25; 95% confidence interval, 0.07-0.9). Loss of HDV RNA during follow-up was more frequent in IFNα-treated patients and strongly linked with a lower likelihood to experience liver-related complications.

CONCLUSION

IFNα-based antiviral therapy of hepatitis delta was independently associated with a lower likelihood for clinical disease progression. Durable undetectability of HDV RNA is a valid surrogate endpoint in the treatment of hepatitis delta. (Hepatology 2017;65:414-425).

First international external quality assessment for hepatitis delta virus RNA quantification in plasma

Infection by the hepatitis delta virus (HDV), a satellite of the hepatitis B virus (HBV), increases viral liver disease severity. Its diagnosis is thus vital for HBV-infected patients. HDV-RNA load (HDVL) should be assessed and monitored in plasma using real-time reverse-transcriptase polymerase chain reaction assays. Taking advantage of the recently-developed World Health Organization (WHO) HDV international standard (WHO-HDV-IS), the first international external quality control for HDVL quantification was performed. Two panels of samples were sent to 28 laboratories in 17 countries worldwide. Panel A comprised 20 clinical samples of various genotypes (1, 2, and 5-8) and viral loads, including two negative controls. Panel B, composed of dilutions of the WHO-HDV-IS, allowed the conversion of results from copies/mL into IU/mL for HDVL standardization and interlaboratory comparisons. Comprehensive analysis revealed a very high heterogeneity of assay characteristics, including their technical steps and technologies. Thirteen labs (46.3%) properly quantified all 18 positive samples; 16 (57.1%) failed to detect one to up to 10 samples, and several others underestimated (>3 log IU/mL) HDVL of African genotype strains (1 and 5-8). Discrepancies were mainly attributed to either primers or probe mismatches related to the high genetic variability of HDV and, possibly, to the complex secondary structure of the target genomic RNA. The labs were grouped in four clusters by the statistical analysis of their performances. The best clusters comprised the 17 labs that obtained the expected HDVL values, including five that otherwise failed to quantify one or two samples.

CONCLUSION

The results of this international quality-control study underline the urgent need to improve methods used to monitor HDV viremia and will be instrumental in achieving that goal. (Hepatology 2016;64:1483-1494).

Treatment of chronic hepatitis D with the entry inhibitor myrcludex B: First results of a phase Ib/IIa study

BACKGROUND & AIMS

The therapeutic option for patients with chronic hepatitis delta virus infection (CHD) is limited to interferon alpha with rare curative outcome. Myrcludex B is a first-in-class entry inhibitor inactivating the hepatitis B virus (HBV) and hepatitis D virus (HDV) receptor sodium taurocholate co-transporting polypeptide. We report the interim results of a pilot trial on chronically infected HDV patients treated with myrcludex B, or pegylated interferon alpha (PegIFNα-2a) or their combination.

METHODS

Twenty-four patients with CHD infection were equally randomized (1:1:1) to receive myrcludex B, or PegIFNα-2a or their combination. Patients were evaluated for virological and biochemical response and tolerability of the study drugs at weeks 12 and 24.

RESULTS

Myrcludex B was well tolerated and no serious adverse event occurred. Although hepatitis B surface antigen levels remained unchanged, HDV RNA significantly declined at week 24 in all cohorts. HDV RNA became negative in two patients each in the Myrcludex B and PegIFNα-2a cohorts, and in five patients of the Myrcludex B+PegIFNα-2a cohort. ALT decreased significantly in the Myrcludex B cohort (six of eight patients), and HBV DNA was significantly reduced at week 24 in the Myrcludex B+PegIFNα-2a cohort. Virus kinetic modeling suggested a strong synergistic effect of myrcludex B and PegIFNα-2a on both HDV and HBV.

CONCLUSIONS

Myrcludex B showed a strong effect on HDV RNA serum levels and induced ALT normalization under monotherapy. Synergistic antiviral effects on HDV RNA and HBV DNA in the Myr-IFN cohort indicated a benefit of the combination of entry inhibition with PegIFNα-2a to treat CHD patients.

LAY SUMMARY

Myrcludex B is a new drug to treat hepatitis B and D infection. After 24weeks of treatment with myrcludex B and/or pegylated interferon α-2a, HDV R NA, a relevant marker for hepatitis D infection, decreased in all patients with chronic hepatitis B and D. Two of eight patients which received either myrcludex B or pegylated interferon α-2a, became negative for HDV RNA, and five of seven patients who received both drugs at the same time became negative. The drug was well tolerated.

Hepatitis Delta co-infection in humanized mice leads to pronounced induction of innate immune responses in comparison to HBV mono-infection

BACKGROUND & AIMS

The limited availability of hepatitis Delta virus (HDV) infection models has hindered studies of interactions between HDV and infected hepatocytes. The aim was to investigate the antiviral state of HDV infected human hepatocytes in the setting of co-infection with hepatitis B virus (HBV) compared to HBV mono-infection using human liver chimeric mice.

METHODS

Viral loads, human interferon stimulated genes (hISGs) and cytokines were determined in humanized uPA/SCID/beige (USB) mice by qRT-PCR, ELISA and immunofluorescence.

RESULTS

Upon HBV/HDV inoculation, all mice developed viremia, which was accompanied by a significant induction of hISGs (i.e. hISG15, hSTATs, hHLA-E) compared to uninfected mice, while HBV mono-infection led to weaker hISG elevations. In the setting of chronic infection enhancement of innate defense mechanisms was significantly more prominent in HBV/HDV infected mice. Also the induction of human-specific cytokines (hIP10, hTGF-ß, hIFN-ß and hIFN-λ) was detected in HBV/HDV co-infected animals, while levels remained lower or below detection in uninfected and HBV mono-infected mice. Moreover, despite the average increase of hSTAT levels determined in HBV/HDV infected livers, we observed a weaker hSTAT accumulation in nuclei of hepatocytes displaying very high HDAg levels, suggesting that HDAg may in part limit hSTAT signaling.

CONCLUSIONS

Establishment of HDV infection provoked a clear enhancement of the antiviral state of the human hepatocytes in chimeric mice. Elevated pre-treatment ISG and interferon levels may directly contribute to inflammation and liver damage, providing a rationale for the more severe course of HDV-associated liver disease. Such antiviral state induction might also contribute to the lower levels of HBV activity frequently found in co-infected hepatocytes.

Prevalence of hepatitis D virus infection among hepatitis B virus-infected individuals in India

BACKGROUND

The prevalence of hepatitis D virus (HDV) infection among persons with hepatitis B virus (HBV) infection shows geographic variation and has declined in recent times in several regions. In India, studies during the 1990s showed highly variable anti-HDV prevalence rates among HBV-infected persons; however, data using molecular testing and recent data are not available. We therefore studied the prevalence of HDV infection in HBV-infected patients using tests for anti-HDV and HDV ribonucleic acid (RNA).

METHODS

Two cohorts of patients with HBV infection were enrolled (cohort A, n = 150, January to December 2012; cohort B, n = 168, October 2013 to April 2014). Sera from cohort A were tested for IgG anti-HDV using three enzyme immunoassays and those from cohort B for IgG anti-HDV using an enzyme immunoassay and for HDV RNA using a real-time amplification assay.

RESULTS

Of the 318 subjects (259 male; mean age 36.9 years), 161 (50.6 %) had chronic hepatitis B, 101 (31.8 %) had cirrhosis, 52 (16.3 %) had acute viral hepatitis, and 4 (1.3 %) had acute liver failure. In cohort A, all specimens tested negative for anti-HDV antibodies using all the three assays. In cohort B, all specimens tested negative for anti-HDV IgG as well as HDV RNA.

CONCLUSION

Our data indicate that HDV infection is uncommon in northern India.

Primary biliary acids inhibit hepatitis D virus (HDV) entry into human hepatoma cells expressing the sodium-taurocholate cotransporting polypeptide (NTCP)

BACKGROUND

The sodium-taurocholate cotransporting polypeptide (NTCP) is both a key bile acid (BA) transporter mediating uptake of BA into hepatocytes and an essential receptor for hepatitis B virus (HBV) and hepatitis D virus (HDV). In this study we aimed to characterize to what extent and through what mechanism BA affect HDV cell entry.

METHODS

HuH-7 cells stably expressing NTCP (HuH-7/NTCP) and primary human hepatocytes (PHH) were infected with in vitro generated HDV particles. Infectivity in the absence or presence of compounds was assessed using immunofluorescence staining for HDV antigen, standard 50% tissue culture infectious dose (TCID50) assays and quantitative PCR.

RESULTS

Addition of primary conjugated and unconjugated BA resulted in a dose dependent reduction in the number of infected cells while secondary, tertiary and synthetic BA had a lesser effect. This effect was observed both in HuH-7/NTCP and in PHH. Other replication cycle steps such as replication and particle assembly and release were unaffected. Moreover, inhibitory BA competed with a fragment from the large HBV envelope protein for binding to NTCP-expressing cells. Conversely, the sodium/BA-cotransporter function of NTCP seemed not to be required for HDV infection since infection was similar in the presence or absence of a sodium gradient across the plasma membrane. When chenodeoxycolic acid (15 mg per kg body weight) was administered to three chronically HDV infected individuals over a period of up to 16 days there was no change in serum HDV RNA.

CONCLUSIONS

Primary BA inhibit NTCP-mediated HDV entry into hepatocytes suggesting that modulation of the BA pool may affect HDV infection of hepatocytes.

Identification of a natural intergenotypic recombinant hepatitis delta virus genotype 1 and 2 in Vietnamese HBsAg-positive patients

Hepatitis D virus (HDV) infection is acquired as a co- /superinfection of Hepatitis B virus (HBV) and can modulate the pathophysiology of chronic hepatitis B and related liver diseases including hepatocellular carcinoma. Among the eight distinct HDV genotypes reported, relatively few studies have attempted to investigate the prevalence of HDV mixed genotypes and RNA recombination of HDV. With a recorded prevalence of 10-20% HBV infection in Vietnam, this study investigated the HDV variability, HDV genotypes and HDV recombination among twenty-one HDV isolates in Vietnamese HBsAg-positive patients. HDV subgenomic and full-length genome sequences were obtained using newly established HDV-specific RT-PCR techniques. The nucleotide homology was observed from 74.6% to 99.4% among the investigated full-length genome of the HDV isolates. We observed HDV genotype 1 and HDV genotype 2 in the investigated Vietnamese patients. Although no HDV genotype mixtures were observed, we report here a newly identified recombinant of HDV genotypes (HDV 1 and HDV 2). The identified recombinant HDV isolate C03 revealed sequence homology to both HDV genotype 1 (nt1 to nt907) and HDV genotype 2 (nt908 to nt1675; HDAg coding region) with a breakpoint at nt908. Our findings demonstrate the prevalence of intergenotypic recombination between HDV genotypes 1 and 2 in a Vietnamese HBsAg-positive patient. Extended investigation on the distribution and prevalence of HDV, HDV mixed genotypes and recombinant HDV genotypes in a larger Vietnamese population offers vital insights into understanding of the micro-epidemiology of HDV and subsequent pathophysiology in chronic HBV- /HDV-related liver diseases.

Understanding early serum hepatitis D virus and hepatitis B surface antigen kinetics during pegylated interferon-alpha therapy via mathematical modeling

There is little information on the early kinetics of hepatitis delta virus (HDV) and hepatitis B surface antigen (HBsAg) during interferon-α therapy. Here a mathematical model was developed and fitted to frequent HDV and HBsAg kinetic data from 10 patients during the first 28 weeks of pegylated-interferon-α2a (peg-IFN) therapy. Three patients achieved a complete virological response (CVR), defined as undetectable HDV 6 months after treatment stopped with loss of HBsAg and anti-HBsAg seroconversion. After initiation of therapy, a median delay of 9 days (interquartile range [IQR]: 5-15) was observed with no significant changes in HDV level. Thereafter, HDV declined in a biphasic manner, where a rapid first phase lasting for 25 days (IQR: 23-58) was followed by a slower or plateau second phase. The model predicts that the main effect of peg-IFN is to reduce HDV production/release with a median effectiveness of 96% (IQR: 93-99.8). Median serum HDV half-life (t1/2 ) was estimated as 2.9 days (IQR: 1.5-5.3) corresponding to a pretreatment production and clearance of about 10(10) (IQR: 10(9.7) -10(10.7) ) virions/day. None of the patients with flat second phase in HDV achieved CVR. HBsAg kinetics of decline paralleled the second phase of HDV decline consistent with HBsAg-productive-infected cells being the main source of production of HDV, with a median t1/2 of 135 days (IQR: 20-460). The interferon lambda-3 polymorphism (rs12979860) was not associated with kinetic parameters.

CONCLUSION

Modeling results provide insights into HDV-host dynamics, the relationship between serum HBsAg levels and HBsAg-infected cells, IFN's mode of action, and its effectiveness. The observation that a flat second phase in HDV and HBsAg kinetics was associated with failure to achieve CVR provides the basis to develop early stopping rules during peg-IFN treatment in HDV-infected patients.

Hepatitis D virus coinfection and superinfection

HDV is a defective RNA pathogen requiring the simultaneous presence of HBV to complete its life cycle. Two major specific patterns of infection have been described: the coinfection with HDV and HBV of a susceptible, anti-HBs-negative individual, or the HDV superinfection of a chronic HBV carrier. Coinfection mostly leads to the eradication of both agents, whereas the majority of patients with HDV superinfection evolve to chronic HDV infection and hepatitis. Chronic HDV infection worsens the preexisting HBV-related liver damage. HDV-associated chronic liver disease (chronic hepatitis D) is characterized by necroinflammation and the relentless deposition of collagen culminating, within a few decades, into the development of cirrhosis and hepatocellular carcinoma.

Development and evaluation of a baseline-event-anticipation score for hepatitis delta

Hepatitis delta is considered the most severe form of viral hepatitis, but variables associated with disease progression are poorly defined. This study aimed to identify risk factors associated with worse clinical outcome in patients with hepatitis delta and to develop a clinical score to determine their risk of experiencing liver-related morbidity or mortality. We followed 75 HBsAg-anti-HDV-positive patients with hepatitis delta for up to 16 years (median 5 years). The baseline-event-anticipation score (BEA score) was developed based on variables associated with the development of liver-related clinical complications. Age, region of origin, presence of cirrhosis, albumin, INR, hyperbilirubinemia and thrombocytopenia were all associated with the development of an event in the training cohort. The BEA score included age, sex, region of origin, bilirubin, platelets and INR. Points were allocated according to hazard ratios, and three risk groups were defined: BEA-A mild risk, BEA-B moderate risk and BEA-C high risk. Hazard ratios of BEA-B and BEA-C patients for liver-related clinical endpoints were 9.01 and 25.27 vs BEA-A with an area under curve of the receiving operating characteristic curve of 0.88. The accuracy of the BEA score was confirmed in two independent validation cohorts followed in Barcelona (n = 77) and Düsseldorf (n = 62). Delta hepatitis is associated with a very severe long-term outcome. The BEA score is easy to apply and predicts with a very high accuracy the development of liver-related complications in patients with hepatitis delta.

Relevance of a full-length genomic RNA standard and a thermal-shock step for optimal hepatitis delta virus quantification

Hepatitis D virus (HDV) is a defective RNA virus that requires the surface antigens of hepatitis B virus (HBV) (HBsAg) for viral assembly and replication. Several commercial and in-house techniques have been described for HDV RNA quantification, but the methodologies differ widely, making a comparison of the results between studies difficult. In this study, a full-length genomic RNA standard was developed and used for HDV quantification by two different real-time PCR approaches (fluorescence resonance energy transfer [FRET] and TaqMan probes). Three experiments were performed. First, the stability of the standard was determined by analyzing the effect of thawing and freezing. Second, because of the strong internal base pairing of the HDV genome, which leads to a rod-like structure, the effect of intense thermal shock (95°C for 10 min and immediate cooling to -80°C) was tested to confirm the importance of this treatment in the reverse transcription step. Lastly, to investigate the differences between the DNA and RNA standards, the two types were quantified in parallel with the following results: the full-length genomic RNA standard was stable and reliably mimicked the behavior of HDV-RNA-positive samples, thermal shock enhanced the sensitivity of HDV RNA quantification, and the DNA standard underquantified the HDV RNA standard. These findings indicate the importance of using complete full-length genomic RNA and a strong thermal-shock step for optimal HDV RNA quantification.

Anti-HDV IgM as a marker of disease activity in hepatitis delta

Background

Hepatitis delta frequently leads to liver cirrhosis and hepatic decompensation. As treatment options are limited, there is a need for biomarkers to determine disease activity and to predict the risk of disease progression. We hypothesized that anti-HDV IgM could represent such a marker.

Methods

Samples of 120 HDV-infected patients recruited in an international multicenter treatment trial (HIDIT-2) were studied. Anti-HDV IgM testing was performed using ETI-DELTA-IGMK-2-assay (DiaSorin). In addition, fifty cytokines, chemokines and angiogenetic factors were measured using multiplex technology (Bio-Plex System). A second independent cohort of 78 patients was studied for the development of liver-related clinical endpoints (decompensation, HCC, liver transplantation or death; median follow up of 3.0 years, range 0.6–12).

Results

Anti-HDV IgM serum levels were negative in 18 (15%), low (OD<0.5) in 76 (63%), and high in 26 (22%) patients of the HIDIT-2 cohort. Anti-HDV IgM were significantly associated with histological inflammatory (p<0.01) and biochemical disease activity (ALT, AST p<0.01). HDV replication was independent from anti-HDV IgM, however, low HBV-DNA levels were observed in groups with higher anti-HDV IgM levels (p<0.01). While high IP-10 (CXCL10) levels were seen in greater groups of anti-HDV IgM levels, various other antiviral cytokines were negatively associated with anti-HDV IgM. Associations between anti-HDV IgM and ALT, AST, HBV-DNA were confirmed in the independent cohort. Clinical endpoints occurred in 26 anti-HDV IgM positive patients (39%) but in only one anti-HDV IgM negative individual (9%; p = 0.05).

Conclusions

Serum anti-HDV IgM is a robust, easy-to-apply and relatively cheap marker to determine disease activity in hepatitis delta which has prognostic implications. High anti-HDV IgM levels may indicate an activated interferon system but exhausted antiviral immunity.

Late HDV RNA relapse after peginterferon alpha-based therapy of chronic hepatitis delta

Interferon alpha is the only treatment option for hepatitis delta virus (HDV). Trials investigating the efficacy of pegylated interferon alpha (PEG-IFNa) showed HDV RNA negativity rates of 25-30% 24 weeks after therapy. However, the clinical and virological long-term outcome of HDV-infected patients treated with PEG-IFNa is unknown. We performed a retrospective-prospective follow-up of 77 patients treated for 48 weeks with either PEG-alfa-2a and adefovir (ADV) or either drug alone in the Hep-Net-International-Delta-Hepatitis-Intervention-Study 1 (HIDIT-1) trial. Long-term follow-up data were available for 58 out of 77 patients (75%) with a median time of follow-up of 4.5 (0.5-5.5) years and a median 3 visits per patient. Patients treated with ADV alone received retreatment with PEG-IFNa (48% versus 19%; P = 0.02) more often. Hepatitis B virus surface antigen (HBsAg) became negative in six PEG-IFNa-treated patients until the end of long-term follow-up (10%). Sixteen patients tested HDV RNA-negative 6 months after PEG-IFNa treatment who were entered in the long-term follow-up study. Out of these, nine individuals tested HDV RNA-positive at least once during further long-term follow-up, with seven patients being HDV RNA-positive at the most recent visit. Clinical endpoints (liver-related death, liver transplantation, hepatic decompensation, hepatocellular carcinoma) were observed in three PEG-IFNa-treated (8%) and three ADV-treated (14%) patients during posttreatment long-term follow-up with an overall annual event rate of 2.5% (4.9% in cirrhosis). Sequencing confirmed the reappearance of pretreatment virus strains in all cases.

CONCLUSION

Late HDV RNA relapses may occur after PEG-IFNa therapy of hepatitis delta and thus the term sustained virological response should be avoided in HDV infection. The annual posttreatment rate of clinical events in hepatitis delta patients eligible for PEG-IFNa therapy is about 2.5% and 4.9% in patients with cirrhosis.

Persistent hepatitis D virus mono-infection in humanized mice is efficiently converted by hepatitis B virus to a productive co-infection

BACKGROUND & AIMS

Clinical studies have shown that hepatitis delta virus (HDV) infection can persist for years and intrahepatic latency of the large delta antigen (HDAg) has been detected following liver transplantation. However, large HDAg arising via RNA-editing is associated with increasing amounts of non-infectious HDV quasi-species. This study investigated whether HDV could persist intrahepatically in the absence of HBV in vivo and whether infectious HDV could subsequently be released following HBV super-infection.

METHODS

Humanized mice were infected with HDV particles lacking HBV. To test for rescue of latent HDV infection 3 and 6 weeks HDV mono-infected mice were super-infected with HBV. Viral loads and cell toxicity were determined by qRT-PCR and immunohistochemistry.

RESULTS

The presence of HDAg-positive human hepatocytes determined after 2, 3, and 6 weeks of HDV inoculation demonstrated establishment and maintenance of intrahepatic HDV mono-infection. Although intrahepatic amounts of large HDAg and edited HDV RNA forms increased over time in HDV mono-infected livers, HBV super-infection led to prompt viremia development (up to 10(8) HDV RNA and 10(7) HBV-DNA copies/ml) even after 6 weeks of latent mono-infection. Concurrently, the number of HDAg-positive human hepatocytes increased, demonstrating intrahepatic HDV spreading. The infectivity of the rescued HDV virions was verified by serial passage in naive chimeric mice.

CONCLUSIONS

HDV mono-infection can persist intrahepatically for at least 6 weeks before being rescued by HBV. Conversion of a latent HDV infection to a productive HBV/HDV co-infection may contribute to HDV persistence even in patients with low HBV replication and in the setting of liver transplantation.

Serological and molecular diagnosis of hepatitis delta virus infection: results of a French national quality control study

A French national quality control study for the serological and molecular diagnosis of hepatitis delta virus (HDV) was organized. Total HDV antibodies were properly detected by all laboratories; 8/14 laboratories failed to detect low titers of IgM, and 6/11 failed to quantify and/or underestimated the RNA viral load in several samples. These discrepancies are likely related to the molecular diversity of HDV.

Development of a reverse transcription quantitative real-time PCR-based system for rapid detection and quantitation of hepatitis delta virus in the western Amazon region of Brazil

The hepatitis delta virus (HDV) is a pathogen that causes a severe and rapidly progressive disease of hepatocytes. The measurement of viral load in the peripheral blood of patients with HDV infections is important for diagnosis, treatment monitoring, and support for follow-up studies of viral replication during the course of the disease. This study reports the development of an assay capable of detecting and quantifying the abundance of HDV particles in serum samples, based on reverse-transcription quantitative PCR (RT-qPCR). Two standards for calibration were produced for determining the viral load of HDV: a cDNA cloned into a linear plasmid and a transcribed RNA. For validating this assay, 140 clinical samples of sera were used, comprising 100 samples from patients who tested positive for anti-HDV and hepatitis B virus surface antigen (HBsAg) by ELISA; 30 samples from blood donors; 5 samples monoinfected with hepatitis B virus (HBV); and 5 samples monoinfected with hepatitis C virus (HCV). The HDV RT-qPCR assay performed better when calibrated using the standard based on HDV cDNA cloned into a linear plasmid, yielding an efficiency of 99.8% and a specificity of 100% in the in vitro assays. This study represents the first HDV RT-qPCR assay developed with clinical samples from Brazil and offers great potential for new clinical efficacy studies of antiviral therapeutics for use in patients with hepatitis delta in the western Amazon region.

High prevalence and significance of hepatitis D virus infection among treatment-naïve HBsAg-positive patients in Northern Vietnam

Background

Hepatitis D virus (HDV) infection is considered to cause more severe hepatitis than hepatitis B virus (HBV) monoinfection. With more than 9.5 million HBV-infected people, Vietnam will face an enormous health burden. The prevalence of HDV in Vietnamese HBsAg-positive patients is speculative. Therefore, we assessed the prevalence of HDV in Vietnamese patients, determined the HDV-genotype distribution and compared the findings with the clinical outcome.

Methods

266 sera of well-characterized HBsAg-positive patients in Northern Vietnam were analysed for the presence of HDV using newly developed HDV-specific RT-PCRs. Sequencing and phylogenetic analysis were performed for HDV-genotyping.

Results

The HDV-genome prevalence observed in the Vietnamese HBsAg-positive patients was high with 15.4% while patients with acute hepatitis showed 43.3%. Phylogenetic analysis demonstrated a predominance of HDV-genotype 1 clustering in an Asian clade while HDV-genotype 2 could be also detected. The serum aminotransferase levels (AST, ALT) as well as total and direct bilirubin were significantly elevated in HDV-positive individuals (p<0.05). HDV loads were mainly low (<300 to 4.108 HDV-copies/ml). Of note, higher HDV loads were mainly found in HBV-genotype mix samples in contrast to single HBV-infections. In HBV/HDV-coinfections, HBV loads were significantly higher in HBV-genotype C in comparison to HBV-genotype A samples (p<0.05).

Conclusion

HDV prevalence is high in Vietnamese individuals, especially in patients with acute hepatitis B. HDV replication activity showed a HBV-genotype dependency and could be associated with elevated liver parameters. Besides serological assays molecular tests are recommended for diagnosis of HDV. Finally, the high prevalence of HBV and HDV prompts the urgent need for HBV-vaccination coverage.

One-step real-time PCR assay for detection and quantitation of hepatitis D virus RNA

Hepatitis D virus (HDV) is a defective virus which requires hepatitis B virus (HBV) surface antigen (HBsAg) for its assembly. Hepatitis B infected individuals co-infected or superinfected with HDV often present with more severe hepatitis, progress faster to liver disease, and have a higher mortality rate than individuals infected with HBV alone. Currently, there are no commercially available clinical tests for the detection and quantitation of HDV RNA in the United States. A one-step TaqMan quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for detection of HDV RNA, designing primers located in the region just downstream from the HDV antigen gene. The assay has the potential to detect all eight HDV genotypes. A quantifiable synthetic RNA control was also developed for use in the determination of HDV RNA titers in clinical samples. The limit of detection of this assay is 7.5×10(2) HDV RNA copies/ml with a dynamic range of six logs. Most clinical specimens tested (40/41) fell within the linear range of the assay. The median HDV RNA titer of the tested specimens was 6.24×10(6) copies/ml, with a range of 8.52×10(3)-1.79×10(9) copies/ml. Out of 132 anti-HDV-positive specimens 41 (31.1%) were positive for HDV RNA.

Commercial real-time reverse transcriptase PCR assays can underestimate or fail to quantify hepatitis delta virus viremia

BACKGROUND & AIMS

Hepatitis delta virus (HDV) infection causes fulminant hepatitis and increases the severity of chronic hepatitis B virus infection, leading to cirrhosis, liver failure, or hepatocellular carcinoma. There are 8 HDV genotypes (genotypes 1-8). We previously developed a TaqMan real-time reverse transcriptase (RT)-PCR method that is able to quantify viral load of all HDV genotypes (linear from 2 to 8 log(10) copies/mL). We compared its results with those from 3 commercial real-time RT-PCR assays: the Lightmix HDV kit (designed to quantify HDV genotype 1 [HDV-1]), and the RoboGene and the DiaPro HDV RNA quantification kits (designed to quantify all genotypes).

METHODS

We selected RNA from 128 clinical samples of all HDV genotypes except HDV-4, with various HDV viral load values. We also analyzed 5 samples, collected over time, from each of 6 patients infected with strains of different genotypes.

RESULTS

Quantification results from the commercial kits for HDV-1 from European or Asian samples were consistent with those from our method, however, they underestimated (0.5-1 log(10) with Lightmix and DiaPro) and did not detect (1 and 4 samples with Lightmix and DiaPro, respectively) HDV-1 African samples. Moreover, the commercial kits greatly underestimated HDV viral load of almost all non-genotype-1 strains (about 2-3 log(10)), and even did not detect HDV-7 or HDV-8 RNA in several samples with high concentrations of virus.

CONCLUSIONS

Commercial kits accurately quantify HDV-1 in samples from European and Asian patients. However, they can dramatically underestimate or fail to quantify HDV viral load from samples from African patients infected with strains of genotypes 1 and 5 to 8.