Quantitative HBeAg is a strong predictor of HBeAg loss among patients receiving pegylated interferon.

BACKGROUND: HBeAg loss is an important endpoint for antiviral therapy in chronic hepatitis B (CHB), however there are no reliable biomarkers to identify patients who will respond to the addition of pegylated interferon to nucleos(t)ide analogue (NA) therapy. AIM: To evaluate the use of serum biomarkers to predict HBeAg loss. METHODS: HBeAg positive CHB participants on NAs who switched-to or added-on 48 weeks pegylated interferon alpha2b (clinicaltrial.gov NCT01928511) were evaluated at week 72 for HBeAg loss. The predictive ability of qHBeAg, qHBsAg, HBV RNA and clinical variables for HBeAg loss were investigated. RESULTS: HBeAg loss occurred in 15/55 (27.3%) participants who completed 48 weeks of pegylated interferon. There was a lower baseline qHBeAg (1.18 IU/mL [2.27] versus 10.04 IU/mL [24.87], P = 0.007) among participants who lost HBeAg. Baseline qHBeAg (OR = 0.15, 95% CI 0.03-0.66, P = 0.01) and detectable HBV DNA at baseline (OR = 25.00, 95% CI 1.67-374.70, P = 0.02) were independent predictors of HBeAg loss. In addition, on-treatment qHBeAg was also a strong predictor of HBeAg loss (OR = 0.39, 95% CI 0.18-0.81, P = 0.012). The models combining detectable baseline HBV DNA with baseline (C-statistic 0.82) and on-treatment (C-statistic 0.83) had good accuracy for predicting HBeAg loss. A rise in qHBeAg ≥ 10 IU/ml was a predictor of flare (ALT ≥ 120 U/ml) on univariable analysis but not after adjustment for treatment arm. CONCLUSIONS: Baseline and on-treatment qHBeAg is a useful biomarker that can identify participants on NA therapy who may benefit from adding or switching to pegylated interferon.

Characterization of HBV surface antigen isoforms in the natural history and treatment of HBV infection.

BACKGROUND: The loss of HBV HBsAg or functional cure is a desirable goal of hepatitis B management. The relative abundances of HBsAg isoforms may offer additional diagnostic and predicting values. To evaluate the clinical utility of HBsAg isoforms, we developed novel prototype assays on the ARCHITECT automated serology platform that specifically detects total-HBsAg (T-HBsAg), large (L-HBsAg), and middle (M-HBsAg) products of the S gene to determine the isoform composition of human specimens from acute and chronic HBV infection and during long-term nucleos(t)ide analog therapy. RESULTS: In the early phase of acute HBV infection, L-HBsAg and M-HBsAg emerged within days and were in parallel to T-HBsAg during the entire course of infection. M-HBsAg levels were consistently higher than L-HBsAg levels. Patients with HBeAg(+) chronic hepatitis B had higher T-HBsAg, M-HBsAg, and L-HBsAg levels compared with HBeAg(-) patients. Correlations of M-HBsAg and L-HBsAg to T-HBsAg were similar in both. In contrast, there was no strong correlation between L-HBsAg or M-HBsAg with HBV DNA levels. During long-term nucleos(t)ide analog treatment, changes in HBsAg isoform abundance were proportional to T-HBsAg regardless of treatment responses for both HBeAg(+) and HBeAg(-) chronic hepatitis B. A larger sample size may be necessary to detect a significant difference. CONCLUSION: HBsAg isoform compositions parallel T-HBsAg levels in both acute and chronic hepatitis B infection. L-HBsAg and M-HBsAg individual biomarkers do not appear to provide an additional diagnostic benefit for staging chronic disease or monitoring response to treatment with current therapies.

More DNA and RNA of HBV SP1 splice variants are detected in genotypes B and C at low viral replication.

HBV produces unspliced and spliced RNAs during replication. Encapsidated spliced RNA is converted into DNA generating defective virions that are detected in plasma and associated with HCC development. Herein we describe a quantitative real-time PCR detection of splice variant SP1 DNA/RNA in HBV plasma. Three PCR primers/probe sets were designed detecting the SP1 variants, unspliced core, or X gene. Plasmids carrying the three regions were constructed for the nine HBV genotypes to evaluate the three sets, which were also tested on DNA/RNA extracted from 193 HBV plasma with unknown HCC status. The assay had an LOD of 80 copies/ml and was equally efficient for detecting all nine genotypes and three targets. In testing 84 specimens for both SP1 DNA (77.4%) and RNA (82.1%), higher viral loads resulted in increased SP1 levels. Most samples yielded < 1% of SP1 DNA, while the average SP1 RNA was 3.29%. At viral load of ≤ 5 log copies/ml, the detectable SP1 DNA varied by genotype, with 70% for B, 33.3% for C, 10.5% for E, 4% for D and 0% for A, suggesting higher levels of splicing in B and C during low replication. At > 5 log, all samples regardless of genotype had detectable SP1 DNA.

Role of serum HBV RNA and hepatitis B surface antigen levels in identifying Asian patients with chronic hepatitis B suitable for entecavir cessation.

BACKGROUND: Treatment cessation in chronic HBV infection may be durable in certain patient subgroups before hepatitis B surface antigen (HBsAg) seroclearance. The role of serum HBV RNA in determining treatment cessation suitability has not been well-investigated. METHODS: Nucleos(t)ide analogue (NUC) treatment was discontinued in non-cirrhotic patients with chronic HBV with serum HBsAg <200 IU/mL and fulfilling internationally recommended criteria for treatment cessation. Patients were monitored till 48 weeks with baseline and serial measurements of serum HBsAg, HBV RNA and hepatitis B core-related antigen. NUCs were resumed when HBV DNA reaches >2000 IU/mL regardless of alanine aminotransferase (ALT) levels. RESULTS: 114 entecavir-treated patients (median age 58.4 years, median serum HBsAg 54.4 IU/mL) with median treatment duration of 6.7 years were recruited. The 48-week cumulative rate of HBV DNA >2000 IU/mL was 58.1%. End-of-treatment serum HBV RNA and off-treatment serial HBV RNA were both independently associated with HBV DNA >2000 IU/mL (HR 2.959, 95% CI 1.776 to 4.926, p<0.001; HR 2.278, 95% CI 1.151 to 4.525, p=0.018, respectively). Patients with HBV RNA ≥44.6 U/mL had a cumulative 48-week rate of 93.2%, while combining HBV RNA undetectability and HBsAg <10 IU/mL had a cumulative 48-week rate of 9.1%. 24 patients (38.7%) developed off-treatment ALT elevation, highest peak ALT was 1515 U/L. 8 patients (median serum HBsAg 2.6 IU/mL) developed HBsAg seroclearance. CONCLUSION: Serum HBV RNA measurement is essential for deciding on entecavir cessation in patients with chronic HBV, especially with low HBsAg levels. Patients can be stratified on their risk of off-treatment relapse based on both viral determinants. TRIAL REGISTRATION NUMBER: NCT02738554.

Comparative biomarkers for HBsAg loss with antiviral therapy shows dominant influence of quantitative HBsAg (qHBsAg).

BACKGROUND: Biomarkers such as quantitative HBsAg (qHBsAg), quantitative hepatitis B virus (HBV) core-related antigen (qHBcrAg) and HBV RNA may be useful in predicting HBsAg loss in patients with chronic hepatitis B (CHB) undergoing antiviral therapy. AIM(S): Our study evaluated qHBsAg, HBV RNA and qHBcrAg as a posthoc analysis of a randomized clinical trial of peginterferon±NA to determine their utility in predicting HBsAg loss. METHODS: CHB patients who completed therapy with 48weeks peginterferon alpha2b ± nucleoside analogue therapy (clinicaltrial.gov NCT01928511) were evaluated at week 72 for HBsAg loss. The predictive ability of qHBsAg, qHBcrAg, HBV RNA and other variables were investigated by univariate and multivariate logistic models for HBeAg-negative patients by odds ratios, area under the curve (AUC), sensitivity, specificity, and positive and negative likelihood ratios (LR). RESULTS: HBsAg loss occurred in 15/114(13%) HBeAg-negative CHB patients who completed 48 weeks of peginterferon. At baseline, qHBsAg was superior to HBcrAg and HBV RNA with AUC 0.916, 0.649 and 0.542, respectively. Using multivariate analysis, the model comprising treatmentarm, age, gender, baseline qHBsAg, HBcrAg and HBV RNA, weeks 4 & 8 qHBsAg had the highest AUC(0.98), but the univariate model with week 8 qHBsAg <70 IU/mL had AUC 0.96. Hence, the contributions of variables other than qHBsAg were marginal. HBV RNA and qHBcrAg were weak predictors of HBsAg loss. Kinetics of the novel markers showed only qHBsAg had a good relationship with HBsAg loss while HBV RNA had a marginal relationship and HBcrAg did not change at all, and none had a good relationship with viral rebound. CONCLUSIONS: On-treatment biomarker predictors were better than baseline ones, and the best predictor of HBsAg loss at 72 weeks was week 8 qHBsAg <70 IU/mL.

HBV RNA Profiles in Patients With Chronic Hepatitis B Under Different Disease Phases and Antiviral Therapy.

BACKGROUND AND AIMS: Large-scale comprehensive studies on HBV RNA in chronic hepatitis B are lacking. We aimed to study the HBV RNA profile and its correlation with other viral markers in patients with chronic hepatitis B who are treatment-naïve and patients receiving nucleos(t)ide analogues (NA). APPROACH AND RESULTS: Biomarkers, including HBV RNA and hepatitis B core-related antigen (HBcrAg), were measured in 388 patients. Of these, 246 were treatment-naïve and were categorized into HBeAg-positive chronic infection (n = 41), HBeAg-positive chronic hepatitis (n = 81), HBeAg-negative chronic infection (n = 39), HBeAg-negative chronic hepatitis (n = 66), and HBsAg seroclearance (n = 19). These biomarkers were also measured in 142 patients who were NA-treated receiving tenofovir or entecavir at baseline, week 48, and week 96. The pattern of serum HBV RNA levels mirrored HBV DNA (1-2 logs higher than HBV RNA) and HBcrAg in patients who were treatment-naïve. HBV RNA correlated best with HBcrAg (r = 0.84) and to a lesser extent with HBV DNA (r = 0.737) (both P < 0.001). In patients with HBsAg seroclearance, 15.8% and 15.8% had detectable serum HBV RNA and HBcrAg, respectively. NA treatment reduced serum HBV RNA by 1.46 logs and 1.77 logs at weeks 48 and 96, respectively. At week 96 of NA therapy, only 19.1% patients who were tenofovir-treated and 25.7% patients who were entecavir-treated had unquantifiable HBV RNA (P > 0.05). In patients who were treated and had undetectable HBV DNA, 77.5% and 30% had quantifiable HBV RNA and HBcrAg, respectively. CONCLUSIONS: HBV RNA showed distinct and corresponding profiles in patients with HBV in different disease phases. HBV RNA and HBcrAg could be used to monitor residual transcriptional activities in patients with HBsAg seroclearance. NA led to reduction of serum HBV RNA. Monitoring of viral activities can still be achieved in patients with undetectable HBV DNA by serum HBV RNA.

Cryptic HBV Replicative Activity Is Frequently Revealed in Anti-HBc-Positive/HBsAg-Negative Patients with HIV Infection by Highly Sensitive Molecular Assays, and Can Be Predicted by Integrating Classical and Novel Serological HBV Markers.

The anti-HBc-positive/HBsAg-negative status is frequent in HIV-infection and correlates with poor survival. Here, by highly-sensitive assays, we evaluate cryptic HBV replication and factors correlated with its detection in 81 anti-HBc-positive/HBsAg-negative HIV-infected patients. Patients were treated for >12 months with HBV-active modern combined antiretroviral-therapy (cART) and had serum HBV-DNA < 20 IU/mL by commercial Real-Time PCR. Serum HBV-DNA was quantified by droplet digital PCR, serum HBV-RNA by an Abbott research assay, and anti-HBc titer (proposed to infer intrahepatic cccDNA) by Lumipulse/Fujirebio. Cryptic serum HBV-DNA was detected in 29.6% of patients (median (IQR): 4(1-15) IU/mL) and serum HBV-RNA in 3.7% of patients despite HBsAg-negativity and HBV-active cART. Notably, cryptic serum HBV-DNA correlated with an advanced CDC-stage (p = 0.01) and a lower anti-HBs titer (p = 0.05), while serum HBV-RNA correlated with lower nadir CD4+ cell-count (p = 0.01). By analyzing serological HBV-markers, the combination of anti-HBs < 50 mIU/mL (indicating lower immune response) plus anti-HBc > 15COI (reflecting higher HBV replicative activity) was predictive of cryptic serum HBV-DNA (OR: 4.7(1.1-21.7), p = 0.046, PPV = 62.5%, and NPV = 72%). In conclusion, cryptic HBV-replication (not detected by classical assays) characterizes a conspicuous set of anti-HBc-positive HIV-infected patients despite HBsAg-negativity and HBV-active combined antiretroviral therapy (cART). The integration of classical and novel markers may help identify patients with cryptic HBV-replication, thus optimizing the monitoring of anti-HBc-positive/HBsAg-negative HIV-infected patients.

Author Correction: Development and performance of prototype serologic and molecular tests for hepatitis delta infection.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Chronic Human Pegivirus 2 without Hepatitis C Virus Co-infection.

Most human pegivirus 2 (HPgV-2) infections are associated with past or current hepatitis C virus (HCV) infection. HPgV-2 is thought to be a bloodborne virus: higher prevalence of active infection has been found in populations with a history of parenteral exposure to viruses. We evaluated longitudinally collected blood samples obtained from injection drug users (IDUs) for active and resolved HPgV-2 infections using a combination of HPgV-2-specific molecular and serologic tests. We found evidence of HPgV-2 infection in 11.2% (22/197) of past or current HCV-infected IDUs, compared with 1.9% (4/205) of an HCV-negative IDU population. Testing of available longitudinal blood samples from HPgV-2-positive participants identified 5 with chronic infection (>6 months viremia in >3 timepoints); 2 were identified among the HCV-positive IDUs and 3 among the HCV-negative IDUs. Our findings indicate that HPgV-2 can establish chronic infection and replicate in the absence of HCV.

Pregenomic HBV RNA and Hepatitis B Core-Related Antigen Predict Outcomes in Hepatitis B e Antigen-Negative Chronic Hepatitis B Patients Suppressed on Nucleos(T)ide Analogue Therapy.

BACKGROUND AND AIMS: A dichotomous separation of hepatitis B viral DNA and hepatitis B surface antigen (HBsAg) concentrations occurs during the natural history and treatment of chronic hepatitis B. We have evaluated the ability of hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) as surrogates of silencing of covalently closed circular DNA (cccDNA), to characterize this dissociation, and virological outcomes. APPROACH AND RESULTS: Three cohorts of hepatitis B e antigen (HBeAg)-negative patients were studied: cohort A: 66 HBeAg-negative patients on long-term nucleos(t)ide analogue (NA) therapy; cohort B: 23 antibodies against hepatitis B e antigen (anti-HBe)-positive patients who stopped treatment; and Cohort C: 19 anti-HBe-positive patients on long-term NA treatment who achieved HBsAg loss and in whom treatment was withdrawn. Concentrations of HBV serological/virological biomarkers (HBV DNA, HBsAg, HBcrAg, and HBV RNA) were measured in sequential samples at different time points on/off therapy. Cohort A: After 3 years of antiviral therapy, 33% and 30% had detectable HBcrAg and HBV RNA, respectively, despite all being HBV-DNA negative. After 5 years' therapy with NA, 27% and 14% had detectable HBcrAg and HBV RNA. Detectable HBcrAg and HBV RNA at the time of treatment withdrawal was only observed in those patients who developed a severe aminotransferase flare. Only those patients with HBV reactivation in cohort C had detectable HBV RNA at treatment withdrawal, but HBcrAg and HBV DNA were not detected. CONCLUSIONS: HBcrAg and HBV RNA are sensitive biomarkers of continued transcription of cccDNA in HBeAg-negative patients despite marked HBV-DNA suppression by NA. These markers were predictors of severe alanine transaminase flares, after treatment withdrawal, and HBV-DNA reactivation. Their measurement during the natural history of hepatitis B, and on treatment with current and new agents, could characterize residual HBV-RNA transcription from cccDNA and assist drug development and disease management.

Hepatitis B Virus Serum DNA andRNA Levels in Nucleos(t)ide Analog-Treated or Untreated Patients During Chronic and Acute Infection.

Treatment of chronic hepatitis B (CHB) patients with nucleos(t)ide analogs (NAs) suppresses hepatitis B virus (HBV) DNA synthesis but does not affect synthesis of HBV pregenomic RNA (pgRNA). Hepatitis B virus pgRNA is detectable in the serum during NA treatment and has been proposed as a marker of HBV covalently closed circular DNA activity within the infected hepatocyte. We developed an automated assay for the quantification of serum HBV pgRNA using a dual-target real-time quantitative PCR approach on the Abbott m2000sp/rt system. We demonstrate accurate detection and quantification of serum HBV RNA. Hepatitis B virus DNA was quantified using the Abbott RealTime HBV viral load assay. We further compared serum nucleic acid levels and kinetics in HBV-positive populations. Samples included on-therapy CHB samples (n = 16), samples (n = 89) from 10 treatment naïve CHB subjects receiving 12 weeks of NA treatment with 8-week follow-up, hepatitis B surface antigen-positive blood donor samples (n = 102), and three seroconversion series from plasmapheresis donors (n = 79 samples). Conclusion: During NA treatment of CHB subjects, we observed low correlation of HBV DNA to pgRNA levels; pgRNA concentration was generally higher than HBV DNA concentrations. In contrast, when NA treatment was absent we observed serum pgRNA at concentrations that correlated to HBV DNA and were approximately 2 log lower than HBV DNA. Importantly, we observe this trend in untreated subject samples from both chronic infections and throughout seroconversion during acute infection. Results demonstrate that the presence of pgRNA in serum is part of the HBV lifecycle; constant relative detection of pgRNA and HBV DNA in the serum is suggestive of a linked mechanism for egress for HBV DNA or pgRNA containing virions.

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.

Development of the Abbott RealTime ZIKA assay for the qualitative detection of Zika virus RNA from serum, plasma, urine, and whole blood specimens using the m2000 system.

Zika virus is an arthropod-borne flavivirus that has rapidly developed into a world-wide concern. Discovered in 1947, the virus was relatively obscure until an outbreak occurred in 2007 in the Yap islands and spread eventually to the Americas in 2015. Only 20% of patients infected with Zika virus develop symptoms. However, there can be serious consequences of infection including birth defects in developing fetuses and links to Guillain-Barré syndrome. The swift rise in infections has necessitated the development of diagnostic tests for both the detection of viral RNA and the presence of virus-specific antibodies. Abbott has developed a dual target RT-PCR assay for the detection of Zika virus RNA within serum, plasma, whole blood, and urine using the automated m2000 system for sample extraction to result reporting. The Abbott RealTime ZIKA assay has a limit of detection of 30 copies per mL in serum, 40 copies per mL in plasma and urine, and 120 copies per mL in whole blood and demonstrates high specificity against challenges from closely related infectious agents.