An ultra-sensitive Abbott ARCHITECT® assay for the detection of hepatitis B virus surface antigen (HBsAg)

Quantitative hepatitis B core antibody and quantitative hepatitis B surface antigen: Novel viral biomarkers for chronic hepatitis B management

The management of hepatitis B virus (HBV) infection now involves regular and appropriate monitoring of viral activity, disease progression, and treatment response. Traditional HBV infection biomarkers are limited in their ability to predict clinical outcomes or therapeutic effectiveness. Quantitation of HBV core antibodies (qAnti-HBc) is a novel non-invasive biomarker that may help with a variety of diagnostic issues. It was shown to correlate strongly with infection stages, hepatic inflammation and fibrosis, chronic infection exacerbations, and the presence of occult infection. Furthermore, qAnti-HBc levels were shown to be predictive of spontaneous or treatment-induced HBeAg and HBsAg seroclearance, relapse after medication termination, re-infection following liver transplantation, and viral reactivation in the presence of immunosuppression. qAnti-HBc, on the other hand, cannot be relied on as a single diagnostic test to address all problems, and its diagnostic and prognostic potential may be greatly increased when paired with qHBsAg. Commercial qAnti-HBc diagnostic kits are currently not widely available. Because many methodologies are only semi-quantitative, comparing data from various studies and defining universal cut-off values remains difficult. This review focuses on the clinical utility of qAnti-HBc and qHBsAg in chronic hepatitis B management.

Occult HBV Infection in Patients Infected by HIV or HCV: Comparison between HBV-DNA and Two Assays for HBsAg

We investigated the frequency and serological correlates of occult hepatitis B virus infection (OBI) and the potential impact of a highly sensitive assay for HBsAg in subjects infected by human immunodeficiency virus (HIV) or hepatitis C virus (HCV), who are also at risk for hepatitis B virus (HBV) infection, often in an occult form. Samples from 499 patients with HIV, all HBsAg negative and anti-HBc positive, and 137 patients with HCV were tested for HBV-DNA, anti-HBc, anti-HBs, and HBsAg by a conventional and highly sensitive assay. HBV biomarkers were detected in 71.5% of HCV-RNA-positive, with a higher prevalence of cases positive only for anti-HBc in patients with HCV than in those with HIV. HBV-DNA was detectable in 0.6% of HIV-positive and 7.3% of HCV-RNA-positive patients. Among patients with HCV, four were positive for HBsAg and negative for HBV-DNA, bringing the rate of HBV-active infection in this group to 10.2%. Active HBV infection was not related to gender or specific patterns of HBV biomarkers but was higher in HCV patients coinfected by HIV compared to those infected only by HCV. Monitoring patients at high risk for HBV infection and reactivation may require testing for both HBV-DNA and HBsAg.

Hepatitis B Surface Antigen Isoforms: Their Clinical Implications, Utilisation in Diagnosis, Prevention and New Antiviral Strategies

The hepatitis B surface antigen (HBsAg) is a multifunctional glycoprotein composed of large (LHB), middle (MHB), and small (SHB) subunits. HBsAg isoforms have numerous biological functions during HBV infection-from initial and specific viral attachment to the hepatocytes to initiating chronic infection with their immunomodulatory properties. The genetic variability of HBsAg isoforms may play a role in several HBV-related liver phases and clinical manifestations, from occult hepatitis and viral reactivation upon immunosuppression to fulminant hepatitis and hepatocellular carcinoma (HCC). Their immunogenic properties make them a major target for developing HBV vaccines, and in recent years they have been recognised as valuable targets for new therapeutic approaches. Initial research has already shown promising results in utilising HBsAg isoforms instead of quantitative HBsAg for correctly evaluating chronic infection phases and predicting functional cures. The ratio between surface components was shown to indicate specific outcomes of HBV and HDV infections. Thus, besides traditional HBsAg detection and quantitation, HBsAg isoform quantitation can become a useful non-invasive biomarker for assessing chronically infected patients. This review summarises the current knowledge of HBsAg isoforms, their potential usefulness and aspects deserving further research.

An interesting case of isolated false-negative hepatitis B surface antigen in a blood donor

BACKGROUND AND OBJECTIVES

An important requirement for a hepatitis B surface antigen (HBsAg) screening assay is reliable detection of HBsAg mutant forms, especially in blood donation. Here we investigate and describe the case of an isolated false-negative result of commercial serology HBsAg screening assay of a blood donor.

MATERIALS AND METHODS

The current donation was routinely tested for HBsAg and hepatitis B virus (HBV) DNA in the mini-pool mode nucleic acid testing (MP-NAT of six samples), and further evaluated by individual donation ID-NAT. Finally, it was quantified and sequenced. All previous donations were found to have negative HBsAg and HBV DNA, as also the subsequent sample taken 3 months after the marked donation.

RESULTS

The current donation of the 53-year-old unvaccinated female with 14 previous donations was initially HBsAg negative and HBV DNA (MP-NAT) positive. Further testing showed HBsAg positive using other HBV serological assays, antibodies to HBV core antigen immunoglobulin M positive and HBV DNA ID-NAT positive, and contained 200 IU/mL of HBV DNA. The implicated donation carried genotype D strains, subtype ayw2 (F83S, V96A, V190A, L193S, I195T, L213S, F220L). The mutations in three positions, namely amino acids T118A, P120T, and P127T, were proven subsequently.

CONCLUSION

This unique mutation combination near the target epitope of one of the immunoassay monoclonals is a possible cause of the reduced analytical sensitivity of the serology assay.

Performance Evaluation of an Improved HBsAg Assay (HBsAg NEXT) for the Detection of HBsAg Levels

Objectives  Detection of hepatitis B surface antigen (HBsAg) plays an important role in the screening and diagnosis of hepatitis B virus (HBV) infections. There is a need of highly sensitive assays with an improved lower limit of detection (LoD). Here, we evaluate the performance characteristics of the HBsAg NEXT (HBsAg new) assay in the detection of HBsAg in clinical samples. Materials and Methods  This was a cross-sectional study conducted at a tertiary care liver center in North India. The study included 439 clinical samples. The HBsAg new assay was compared to the conventional chemiluminescence-based assay (HBsAg old assay, Architect, Abbott Diagnostics, United States). The analytical sensitivity of the HBsAg new assay was evaluated by checking its performance with the second World Health Organization (WHO) international standards for HBsAg. Results  Out of 439 blood samples that were retrieved from the departmental repository stored at -80°C, 100 samples were positive and 339 samples were negative for HBsAg as per the HBsAg old assay. The HBsAg new assay showed incremental detection of HBsAg in 11 additional samples. Out of these, 5 samples were confirmed as occult HBV infection and the remaining 6 were classified as "exposed-to-virus" samples (HBV core total antibody-positive). The HBsAg new assay demonstrated a high positive significant correlation with the HBsAg old assay ( r  = 0.881, p -value < 0.001). The HBsAg new assay could effectively detect the second WHO international standards to the level of 0.0033 IU/mL. Conclusion  The HBsAg NEXT assay is a highly sensitive assay with an improved lower LoD.

Marked reduction in the incidence of transfusion-transmitted hepatitis B virus infection after the introduction of antibody to hepatitis B core antigen and individual donation nucleic acid amplification screening in Japan

BACKGROUND

In Japan, 41 million blood donations have been screened for hepatitis B virus (HBV) during the past 8.4 years using individual donation nucleic acid amplification testing (ID-NAT) and antibody to hepatitis B core antigen (anti-HBc) screening.

STUDY DESIGN AND METHODS

Transfusion-transmitted HBV infection (TT-HBV) incidence was examined. Donated blood implicated in TT-HBV was analyzed for infection stage and DNA levels. Causative HBV strains were phylogenetically analyzed.

RESULTS

Among 5162 (0.013%) ID-NAT positives, window period (WP) and occult HBV infection (OBI) accounted for 3.4% (176) and 11.5% (594), respectively. No OBI-related TT-HBV occurred. Seven blood donations caused eight TT-HBV cases, six of which were in the pre-ID-NAT WP, leaving one with an unresolved infection stage. Seven cases were caused by platelet concentrate (180 mL plasma) and one case by fresh-frozen plasma (200 mL plasma), which contained estimated infectious doses varying between 2 and 2300 HBV virions. HBV subgenotypes in five cases were HBV/A2. Complete genome sequences of the transmitting A2 strains were nearly identical (99.6%-100%) and clustered in a group that included HBV/HIV-1 coinfections and a higher proportion of donors in the acute infection phase (69%) than the other group of HBV/A2 sequences (5%).

DISCUSSION

The incidence of observed TT-HBV cases has significantly reduced to 0.19 per million in the ID-NAT screening period. OBI-related TT-HBV was eliminated by anti-HBc screening. Established TT-HBV cases were caused by blood products with large plasma volumes containing extremely low HBV concentrations derived from blood donors at a very early infection stage.

Hepatitis B Virus Genotype H: Epidemiological, Molecular, and Clinical Characteristics in Mexico

The hepatitis B virus (HBV), comprising of ten genotypes (A-J), has been a silent threat against humanity, constituting a public health problem worldwide. In 2016, the World Health Organization set forth an impressive initiative for the global elimination of viral hepatitis by 2030. As the target date approaches, many nations, particularly in the Latin American region, face challenges in designing and implementing their respective elimination plan. This review aimed to portray the state of knowledge about the epidemiological, molecular, and clinical characteristics of HBV genotype H (HBV/H), endemic to Mexico. PubMed, Scopus, Web of Science, and Google Scholar were searched to compile scientific literature over 50 years (1970-2022). A total of 91 articles were organized into thematic categories, addressing essential aspects such as epidemiological data, risk factors, HBV genotype distribution, HBV mixed infections, clinical characteristics, and vaccination. The prevalence and its associated 95% confidence interval (95% CI) were estimated using the Metafor package in R programming language (version 4.1.2). We provide insights into the strengths and weaknesses in diagnostics and prevention measures that explain the current epidemiological profile of HBV/H. Training, research, and awareness actions are required to control HBV infections in Mexico. These actions should contribute to creating more specific clinical practice guides according to the region's characteristics. Mexico's elimination plan for HBV will require teamwork among the government health administration, researchers, physicians, specialists, and civil society advocates to overcome this task jointly.

Correlation of serological and molecular markers in the screening for hepatitis B virus in blood bank in northern Brazil

INTRODUCTION

In Brazil, the blood donor screening for hepatitis B virus (HBV) includes laboratory testing for serological (HBsAg and Anti-HBc) and molecular (HBV DNA) markers. This study aims to correlate serology reactive results with HBV DNA detection among blood donors with at least one HBV infection marker detected in a blood bank in northern Brazil.

METHOD

A retrospective search for HBV reactive blood donor data from January 2017 to December 2019 was performed. Serological screening was performed by chemiluminescent microparticle immunoassays Architect HBsAg and Architect Anti-HBc, whereas molecular screening was performed by the HBV nucleic acid test (HBV NAT).

MAIN RESULTS

A total of 556 HBsAg reactive results were detected, between positive (47.66%) and inconclusive (52.34%). A total of 3,658 Anti-HBc reactive results were detected, between positive (83.71%) and inconclusive (16.29%). None of the inconclusive results were associated with HBV DNA detection. The HBV DNA detection rates were 47.55% among HBsAg positive samples and 4.08% among Anti-HBc positive samples. The signal-to-cutoff (S/CO) ratio median of HBV NAT positive samples was superior in comparison to HBV NAT negative samples (p < 0.0001). The thresholds found to optimize sensitivity and specificity were 404.15 for Architect HBsAg and 7.77 for Architect Anti-HBc. Three blood donors were in the window period and 1 occult HBV infection case was detected.

CONCLUSION

High S/CO ratios were more predictive of HBV DNA detection. However, a number of HBV NAT positive samples gave low values, while some HBV NAT negative samples showed high values, reaffirming the significance of molecular testing to enhance transfusion safety.

Versatile performance edges of HBsAg Next assay in diagnosis and therapeutic monitoring of HBV infection

BACKGROUND

HBsAg Next assay (HBsAgNx) claims improved detection of HBsAg. The aim was to investigate its performance in ascertaining HBsAg loss, ability to detect HBsAg in various phases of HBV infection, specificity and its amenability to in-house neutralization.

METHODS

Analytical sensitivity was investigated using NIBSC standard (3rd WHO-IS). For clinical performance, out of 91,962 samples tested for HBsAg (Qual-II), 512 samples consisting of 170 cases with evidence of HBsAg loss during treatment (n = 116) and without treatment (n = 54), acute-hepatitis B (n = 90) and acute exacerbation of chronic-hepatitis B (n = 41), acute-hepatitis A (n = 24) and acute-hepatitis E (n = 9) positive, HIV-1 positive (n = 20), non-HBV, HAV and HEV related acute-hepatitis (n = 81) and HBsAg prozone (n = 14) as well as in-house neutralization (n = 63) were included.

RESULTS

The calculated limit of detection (LOD) was 0.004 IU/mL. Of the 170 patients with apparent HBsAg loss, 18/116 (15.5%) among treated and 15/54 (27.7%) with spontaneous clearance were positive in HBsAgNx (p < 0.0001). Additionally, it detected HBsAg in 12/95 (12.6%) and 6/34 (17.6%) patients who were HBV DNA negative in treatment experienced and spontaneous clearance groups respectively (p < 0.001). The specificity of HBsAgNx was comparable to HBsAg Qual-II. The signal-intensity of HBsAgNx was significantly higher than HBsAg Qual-II across various phases of HBV infection and prozone samples.

CONCLUSION

HBsAgNx significantly enhanced the accuracy of HBsAg detection without compromising the specificity in ascertaining HBsAg loss. The performance was superior in various phases of HBV infection including samples that exhibited prozone effect. Furthermore, it is amenable to cost-effective in-house neutralization to confirm low HBsAg levels.

An Ideal Hallmark Closest to Complete Cure of Chronic Hepatitis B Patients: High-sensitivity Quantitative HBsAg Loss

In the era of antiviral therapy, the main goal of treatment has shifted from the persistent inhibition of hepatitis B virus (HBV) replication to the pursuit of serological clearance of HBs surface antigen (HBsAg). Based on the life cycle of HBV, HBsAg originates from covalently closed circular DNA (cccDNA) and integrated HBV DNA, thus reflecting their transcriptional activity. Complete HBsAg loss may mean elimination or persistent inactivity of the HBV genome including cccDNA and integrated HBV DNA. HBsAg loss improves the recovery of abnormal immune function, which in turn, may further promote the clearance of residual viruses. Combined with functional cure and the great improvement of clinical outcomes, the continuous seroclearance of high-sensitivity quantitative HBsAg may represent the complete cure of chronic hepatitis B (CHB). For many other risk factors besides HBV itself, patients with HBsAg loss still need regular monitoring. In this review, we summarized the evolution of CHB treatment, the origin of serum HBsAg, the pattern of HBsAg seroclearance, and the effect of HBsAg loss on immune function and disease outcomes. In addition, we discuss the significance of high-sensitivity HBsAg detection and its possibility as a surrogate of complete cure.

Acute Hepatitis B Virus Infection in North American Adults

BACKGROUND & AIMS

Acute hepatitis B virus (aHBV) is thought to be self-limited with clearance of hepatitis B surface antigen (HBsAg) within 6 months. There are limited reports of the presenting features and outcomes of adults with symptomatic aHBV in the United States.

METHODS

Demographics, clinical features, and 12-month outcomes of patients with adjudicated aHBV were captured prospectively and compared with a contemporaneous cohort of chronic HBV (cHBV) patients enrolled in the Hepatitis B Research Network.

RESULTS

Between 2011 and 2018, 60 adjudicated patients with aHBV were compared with 1534 cHBV untreated controls. Although similar in age, other features were dissimilar: aHBV patients were more often male (72% vs 51%), single (72% vs 30%), and non-Hispanic whites or blacks (75% vs 24%). They also were frequently genotype A₂ (65% vs 9%), having different risk factors: sexual exposure (75% vs 16%) or injection drug use (10% vs 2%), compared with the cHBV controls. In addition to higher serum aminotransferase and bilirubin levels, acute patients had higher HBV DNA levels (4.8 vs 3.6 log₁₀ IU/mL), whereas quantitative hepatitis B e antigen (HBeAg) levels were lower (1.4 vs 3.0 log₁₀ IU/mL), despite higher rates of HBeAg (73% vs 25%). The median time to HBsAg clearance was 27 weeks and to anti-HBs appearance, 41 weeks.

CONCLUSIONS

In the current era, caucasian men infected with genotype A₂ as a result of sexual exposure or injection drug use were the predominant group in aHBV, suggesting a potential strategy for adult vaccination in North America. Strikingly, only an estimated 36% of subjects cleared HBsAg by month 6; the definition of resolution in acute hepatitis B may need to be modified. ClinicalTirals.gov number NCT01263587.

Control of occult hepatitis B virus infection

Background

The diagnosis of hepatitis B virus (HBV) infection requires HBV DNA testing and serologic testing for detection of the surface antigen (HBsAg) and the hepatitis B core antibody (anti-HBc). There is a population of patients with occult HBV infection (OBI), which is not detected by HBsAg or HBV DNA quantification in blood, despite the presence of active replication in the liver.

Scope

This document provides a definition of OBI and describes the diagnostic techniques currently used. It also addresses the detection of patients with risk factors and the need for screening for OBI in these patients.

Summary

Correct diagnosis of OBI prevents HBV reactivation and transmission. Diagnosis of OBI is based on the detection of HBV DNA in patients with undetectable HBsAg in blood.

Perspectives

A high number of patients with OBI may remain undiagnosed; therefore, screening for OBI in patients with factor risks is essential. For a correct diagnosis of OBI, it is necessary that new markers such as ultrasensitive HBsAg are incorporated, and a more comprehensive marker study is performed by including markers such as cccDNA.

Revisión de la infección oculta por el virus de la hepatitis B

Introducción

El diagnóstico actual del virus de la hepatitis B (VHB) está basado en la detección mediante técnicas moleculares de ADN de VHB y ensayos serológicos, como el antígeno de superficie (HBsAg) y anticuerpos frente al core VHB (anti-HBc). Existe un grupo de pacientes con infección oculta de VHB (OBI) en los que estos ensayos no son capaces de detectar el HBsAg ni la cuantificación de ADN de VHB en sangre, aunque exista replicación activa en hígado.

Contenido

El documento define la OBI, y los métodos actuales para su diagnóstico. También aborda la detección de pacientes con factores de riesgo y la necesidad de realizar el cribado de OBI en ellos.

Resumen

Un correcto diagnóstico de OBI, previene la reactivación del VHB y su transmisión. El diagnóstico de OBI actualmente está basado en la detección de ADN de VHB en pacientes con HBsAg indetectable en sangre.

Perspectivas

Un número elevado de pacientes con OBI puede permanecer sin diagnosticar. Es importante realizar el cribado de OBI en determinados pacientes con factores de riesgo. La introducción de nuevos marcadores, como el HBsAg ultrasensible, y estudios más profundos de marcadores, como el ADNccc hepático, serán necesarios para un correcto diagnóstico de OBI.

Importance of quantitative HBsAg detection in whole course management of patients with chronic hepatitis B

HBsAg is the earliest known serum marker for hepatitis B virus (HBV). It plays an important role in the pathogenesis, diagnosis, and prevention of chronic hepatitis B (CHB). In the era of antiviral therapy, the concept of functional cure is put forward. HBsAg, as an old marker of HBV infection, has been found to have more and more new applications in the management of CHB patients. Positive HBsAg is taken as the indication of antiviral treatment in special CHB patients. The level of HBsAg is conducive to the selection of treatment regimens, and the dynamics of HBsAg is conducive to the adjustment of treatment scheme. HBsAg level and its kinetics can predict the therapeutic effect and disease outcome, and guide drug withdrawal. Further research is needed on the sensitivity of HBsAg, its impact on long-term outcomes, and its value in functional cure and complete cure.

Virological Treatment Monitoring for Chronic Hepatitis B

More than 250 million people worldwide are currently infected with hepatitis B, despite the effectiveness of vaccination and other preventive measures. In terms of treatment, new therapeutic approaches are rapidly developing, promising to achieve the elimination of infected cells and the complete cure of infection. The on-treatment monitoring of these innovative antiviral treatments will require the implementation of new virological tools. Therefore, new biomarkers are being evaluated besides the traditional virological and serological assays in order to obtain information on different steps of the viral replication cycle and to monitor response to therapy more accurately. The purpose of this work is to describe both standard and innovative tools for chronic hepatitis B treatment monitoring, and to analyse their potential and feasibility.

[Safety of blood and blood products: test methods for the detection of hepatitis B, C, and E virus]

Infections with hepatitis B, C, and E virus (HBV, HCV, and HEV) can be transmitted via blood and cause severe acute or chronic liver infections. To ensure the safety of blood donations and protect recipients from virus transmissions, blood donations in Germany are tested for viral genomes using nucleic acid amplification techniques (NATs) as well as for viral antigens and antibodies by serological testing. This article describes the relevant regulations on the safety of blood and blood products in Germany and the various screening methods. The safety of blood products is assessed.Currently used NAT methods for detection of hepatitis viruses are based either on polymerase chain reaction (PCR) or isothermal methods such as transcription-mediated amplification (TMA), which enable a highly sensitive detection of viral infections and thereby contribute to the reduction of the diagnostic window. Antigen tests for the detection of viral surface protein of hepatitis B virus in blood donations were introduced in the 1970s in order to prevent potential transmissions. Since the introduction of mandatory testing for HCV-specific antibodies in 1992, HCV NAT testing in 1999, anti-HBc antibody testing in 2006, and the non-mandatory HBV NAT, which is voluntarily performed by most of the blood establishments, blood safety has increased tremendously. Only a few isolated cases of transfusion-transmitted infections in the early window period have been reported since. The success of the recent introduction of mandatory HEV NAT testing in 2020 will have to be assessed in the upcoming years. Besides blood donor screening, the system for blood safety in Germany is supplemented by additional measures for donor selection and pathogen inactivation.

Detection of the hepatitis B surface antigen in patients with occult hepatitis B using an assay with enhanced sensitivity

Patients with occult hepatitis B infection (OBI) have undetectable hepatitis B surface antigen (HBsAg) by conventional assays but detectable hepatitis B virus (HBV) DNA in blood/liver. We evaluated the key performance characteristics of a sensitive HBsAg assay (ARCHITECT HBsAg Next Qualitative Assay, referred as NEXT) with respect to HBsAg detection. Assay precision, sample carryover and seroconversion sensitivity of NEXT were evaluated. HBsAg was measured by NEXT in 1,138 individuals, including 1,038 patients who attended liver clinics in a tertiary hospital (200 HBV DNA-positive blood donors whose HBsAg was undetectable by conventional assays, and 38 patients receiving immunosuppressive therapy, 800 chronic hepatitis B patients with HBsAg seroclearance) and 100 HBsAg-negative subjects recruited from a community project. The within-run and within-laboratory coefficients of variation were <6% for the positive sample pools. In 9 seroconversion panels tested, NEXT allowed an earlier HBsAg detection than conventional assays. NEXT detected HBsAg in 10/200 (5%) HBsAg-negative blood donors, 1/20 (5%) and 0/18 HBsAg-negative patients with and without HBV reactivation respectively, and 59/800 (7.3%) patients with HBsAg seroclearance. HBsAg was detectable by NEXT in 27.8%, 8.2%, 6.9%, 3.8% and 1.9% samples at <3, 3-5, >5-8, >8-11, and >11 years after HBsAg seroclearance, respectively. Seven out of 100 HBsAg-negative community identified subjects was tested positive by NEXT. Comparing with conventional HBsAg assays, NEXT demonstrated a higher sensitivity and conferred an increment of 5-7% detection rate in patients with OBI, thereby helping in identifying HBV carriers and prevention of OBI-associated HBV transmission and reactivation.

Hepatitis B seroconversion revisited: new insights into the natural history of acute hepatitis B virus (HBV) infection from quantitative and highly sensitive assays and novel biomarkers

BACKGROUND

Hepatitis B virus (HBV) serum markers during typical acute self-limited infection are usually depicted as a composite of traditional HBV markers. The current study updates and expands our knowledge of acute hepatitis B with quantitative molecular and serological data on longitudinal samples from five plasmapheresis donors with acute HBV.

METHODS

137 longitudinal samples from five plasmapheresis donors with acute HBV were tested, four with self-limited infection and one who developed persistent infection. Testing included quantitative hepatitis B surface antigen (HBsAg), antibodies to HBV antigens, quantitative HBV e antigen (HBeAg), HBV DNA, quantitative HBV core-related antigen (HBcrAg), the highly sensitive ARCHITECT HBsAg NEXT (HBsAgNx) assay, and a quantitative research assay for HBV pregenomic RNA (pg RNA).

RESULTS

Peak levels of HBV DNA and HBsAg differed by several orders of magnitude among the panels (2.2 × 105-2.7 × 109 IU/ml for HBV DNA and 7.9-1.1 × 105 IU/ml for HBsAg). HBsAg levels peaked an average of 2.8 days after the HBV DNA peak. The overall duration of observed HBsAg positivity was increased by the more sensitive HBsAgNx assay compared to the quantitative assay in four panels. Intermittently detectable low-level HBV DNA was observed after HBsAg loss in three panels. Peak HBeAg levels occurred 2-20 days after the DNA peak and ranged from 1.1 to 4.5 × 103 IU/ml. In four panels with resolution of infection, anti-HBs levels indicating immunity (≥ 10 mIU/ml) were detected 19-317 days after the HBV DNA peak. Maximum HBcrAg concentrations ranged from 1 × 105 to > 6.4 × 106 U/ml and correlated with HBeAg values (R2 = 0.9495) and with HBV DNA values (R2 = 0.8828). Peak pgRNA values ranged from 1.6 × 103 to 1.4 × 108 U/ml and correlated with HBV DNA (R2 = 0.9013).

CONCLUSION

Traditional and new/novel HBV biomarkers were used to generate molecular and serological profiles for seroconversion panels spanning the early to late phases of acute HBV. Seroconversion profiles were heterogeneous and may be instructive in appreciating the spectrum of acute profiles relative to the typical composite representation.

Analysis of HBsAg Immunocomplexes and cccDNA Activity During and Persisting After NAP-Based Therapy

Therapy with nucleic acid polymers (NAPs), tenofovir disoproxil fumarate (TDF), and pegylated interferon (pegIFN) achieve high rates of HBsAg loss/seroconversion and functional cure in chronic hepatitis B virus (HBV) infection. The role of hepatitis B surface antigen (HBsAg) seroconversion and inactivation of covalently closed circular DNA (cccDNA) in establishing functional cure were examined. Archived serum from the REP 401 study was analyzed using the Abbott ARCHITECT HBsAg NEXT assay (Chicago, IL), Abbott research use-only assays for HBsAg immune complexes (HBsAg ICs), circulating HBV RNA, and the Fujirebio assay for hepatitis B core-related antigen (HBcrAg; Malvern, PA). HBsAg became < 0.005 IU/mL in 23 participants during NAP exposure, which persisted in all participants with functional cure. HBsAg IC declined during lead-in TDF monotherapy and correlated with minor declines in HBsAg. Following the addition of NAPs and pegIFN, minor HBsAg IC increases (n = 13) or flares (n = 2) during therapy were not correlated with HBsAg decline, hepatitis B surface antibody (anti-HBs) titers, or alanine aminotransferase. HBsAg IC universally declined during follow-up in participants with virologic control or functional cure. Universal declines in HBV RNA and HBcrAg during TDF monotherapy continued with NAP + pegIFN regardless of therapeutic outcome. At the end of therapy, HBV RNA was undetectable in only 5 of 14 participants with functional cure but became undetectable after removal of therapy in all participants with functional cure. Undetectable HBV RNA at the end of therapy in 5 participants was followed by relapse to virologic control or viral rebound. Conclusion: Anti-HBs-independent mechanisms contribute to HBsAg clearance during NAP therapy. Inactivation of cccDNA does not predict functional cure following NAP-based therapy; however, functional cure is accompanied by persistent inactivation of cccDNA. Persistent HBsAg loss with functional cure may also reflect reduction/clearance of integrated HBV DNA. Clinicaltrials.org number NCT02565719.

Blood Product (Donor) Noninfectious and Infectious Testing and Modification

Blood transfusion begins with safe donor selection and testing. In the United States, the blood supply and transfusion are highly regulated. Blood transfusion safety is multifaceted, whereby each of the elements of the blood safety value chain, spanning donor recruitment and qualification, to collection, blood processing, testing, transfusion practice, and posttransfusion surveillance, must be optimized to minimize risk. Pathogen inactivation is a promising approach to decrease bacterial contamination of platelets, inactivate parasites and viruses, and decrease risks associated with emerging and unidentified pathogens. This article offers an overview of blood donor infectious and noninfectious testing in the United States.

Molecular and Serological Characterization of Hepatitis B Virus (HBV)-Positive Samples with Very Low or Undetectable Levels of HBV Surface Antigen

BACKGROUND

Gaps remain in the detection of nucleic acid test (NAT) yield and occult hepatitis B virus (HBV) infection (OBI) by current HBV surface antigen (HBsAg) assays. The lack of detection may be due to HBsAg levels below current assay detection limits, mutations affecting HBsAg assays or HBsAg levels, or the masking of HBsAg by antibody to HBsAg (anti-HBs). In this study, we evaluate the incremental detection of NAT yield and OBI from five diverse geographic areas by an improved sensitivity HBsAg assay and characterize the samples relative to the viral load, anti-HBs status, and PreS1-S2-S mutations. Included is a comparison population with HBV DNA levels comparable to OBI, but with readily detectable HBsAg (High Surface-Low DNA, HSLD).

METHODS

A total of 347 samples collected from the USA, South Africa, Spain, Cameroon, Vietnam, and Cote D'Ivoire representing NAT yield (HBsAg(-), antibody to HBV core antigen (anti-HBc)(-), HBV DNA(+), N = 131), OBI (HBsAg(-), anti-HBc(+), HBV DNA(+), N = 188), and HSLD (HBsAg(+), anti-HBc(+), HBV DNA(+), N = 28) were tested with ARCHITECT HBsAg NEXT (HBsAgNx) (sensitivity 0.005 IU/mL). The sequencing of the PreS1-S2-S genes from a subset of 177 samples was performed to determine the genotype and assess amino acid variability, particularly in anti-HBs(+) samples.

RESULTS

HBsAgNx detected 44/131 (33.6%) NAT yield and 42/188 (22.3%) OBI samples. Mean HBV DNA levels for NAT yield and OBI samples were lower in HBsAgNx(-) (50.3 and 25.9 IU/mL) than in HBsAgNx(+) samples (384.1 and 139.5 IU/mL). Anti-HBs ≥ 10 mIU/mL was present in 28.6% HBsAgNx(+) and 45.2% HBsAgNx(-) OBI, and in 3.6% HSLD samples. The genotypes were A1, A2, B, C, D, E, F, and H. There was no significant difference between HBsAgNx(-) and HBsAgNx(+) in the proportion of samples harboring substitutions or in the mean number of substitutions per sample in PreS1, PreS2, or S for the NAT yield or OBI (p range: 0.1231 to >0.9999). A total of 21/27 (77.8%) of HBsAgNx(+) OBI carried S escape mutations, insertions, or stop codons. HSLD had more PreS1 and fewer S substitutions compared to both HBsAgNx(-) and HBsAgNx(+) OBI. Mutations/deletions associated with impaired HBsAg secretion were observed in the OBI group.

CONCLUSIONS

HBsAgNx provides the improved detection of NAT yield and OBI samples. Samples that remain undetected by HBsAgNx have exceptionally low HBsAg levels below the assay detection limit, likely due to low viremia or the suppression of HBsAg expression by host and viral factors.

Detection of the serological markers hepatitis B virus surface antigen (HBsAg) and hepatitis B core IgM antibody (anti-HBcIgM) in the diagnosis of acute hepatitis B virus infection after recent exposure

The serological diagnosis of acute hepatitis B virus (HBV) infection after recent exposure has been established by the hepatitis B virus surface antigen (HBsAg) and anti-hepatitis B core IgM antibody (anti-HBcIgM) detection in serum, sometimes accompanied by the detection of hepatitis B "e" antigen (HBeAg). Despite this characteristic serological profile, misdiagnosis can occur in cases of unexpected or atypical behavior of the serological markers in the bloodstream, or if the true meaning of its expression is not properly investigated, or even if there is a possibility of interference from factors not necessarily linked to the infectious process, in the detection of these markers. This review discusses the influence of these variables on laboratory results for these two serological markers and, therefore, the potential risk of these variables compromising the correct diagnosis of acute infection after recent HBV exposure.

Novel Biomarkers of Hepatitis B Virus and Their Use in Chronic Hepatitis B Patient Management

Even though an approved vaccine for hepatitis B virus (HBV) is available and widely used, over 257 million individuals worldwide are living with chronic hepatitis B (CHB) who require monitoring of treatment response, viral activity, and disease progression to reduce their risk of HBV-related liver disease. There is currently a lack of predictive markers to guide clinical management and to allow treatment cessation with reduced risk of viral reactivation. Novel HBV biomarkers are in development in an effort to improve the management of people living with CHB, to predict disease outcomes of CHB, and further understand the natural history of HBV. This review focuses on novel HBV biomarkers and their use in the clinical setting, including the description of and methodology for quantification of serum HBV RNA, hepatitis B core-related antigen (HBcrAg), quantitative hepatitis B surface antigen (qHBsAg), including ultrasensitive HBsAg detection, quantitative anti-hepatitis B core antigen (qAHBc), and detection of HBV nucleic acid-related antigen (HBV-NRAg). The utility of these biomarkers in treatment-naïve and treated CHB patients in several clinical situations is further discussed. Novel HBV biomarkers have been observed to provide critical clinical information and show promise for improving patient management and our understanding of the natural history of HBV.

Paradoxical HBsAg and anti-HBs coexistence among Chronic HBV Infections: Causes and Consequences

Hepatitis B surface antigen (HBsAg) and Hepatitis B surface antibody (anti-HBs) were reported simultaneously among Hepatitis B virus (HBV) infections. HBsAg is a specific indicator of acute or chronic HBV infections, while anti-HBs is a protective antibody reflecting the recovery and immunity of hosts. HBsAg and anti-HBs coexist during seroconversion and then form immune complex, which is rare detected in clinical cases. However, with the promotion of vaccination and the application of various antiviral drugs, along with the rapid development of medical technology, the coexistence of HBsAg and anti-HBs has become more prevalent. Mutations in the viral genomes, immune status and genetic factors of hosts may contribute to the coexistence. Novel HBsAg assays, with higher sensitivity and ability to detect mutations or immune complexes, can also yield HBsAg/anti-HBs coexistence. The discovery of coexistence has shattered the idea of traditional serological patterns and raised questions about the effectiveness of vaccines. Worth noting is that HBsAg/anti-HBs double positivity is strongly associated with progressive liver diseases, especially hepatocellular carcinoma. In conclusion, viral mutations, host factors, and methodology impacts can all lead to the coexistence of HBsAg and anti-HBs. This coexistence is not an indicator of improvement, as an increased risk of adverse clinical outcomes still exists.

The contribution of more sensitive hepatitis B surface antigen assays to detecting and monitoring hepatitis B infection

BACKGROUND

Hepatitis B surface antigen (HBsAg) remains the main viral marker for screening and monitoring hepatitis B virus (HBV) infection. The quantification limit of most current HBsAg assays is around 0.05 IU/mL. The Lumipulse-G-HBsAg-Quant assay (Fujirebio) claims to obtain a tenfold improvement in sensitivity. This study aimed to assess the performance of this assay in detecting low HBsAg levels in clinical samples.

METHODS

Three panels of stored frozen samples were selected on the basis of HBV-DNA and HBsAg values obtained previously with routine techniques. Panels 1 (n=13) and 2 (n=52) consisted of DNA-positive/HBsAg-negative samples from individuals in the window period and with occult HBV infection respectively. Panel 3 comprised 23 samples with low or discrepant HBsAg screening results. All these samples were tested retrospectively with the DiaSorin and Fujirebio HBsAg assays.

RESULTS

Sixteen out of 65 samples (25 %), initially screened HBsAg negative, were reactive only with the Fujirebio assay (median value= 0.015 IU/mL; IQR= 0.012): three (23 %) samples from panel 1 and 13 (25 %) from panel 2. Thirteen of these 16 (81 %) had HBsAg values below 0.03 IU/mL with the DiaSorin assay. In panel 3, 22 (96 %) samples were quantified successfully with the Fujirebio assay (median: 0.32 IU/mL; IQR: 1.20) and 19 (83 %) with the DiaSorin assay (median: 0.31 IU/mL; IQR: 0.65). Concentrations obtained with the two assays showed good correlations (r=0.893, Spearman).

CONCLUSIONS

HBsAg assays with enhanced analytical sensitivity could improve HBV serological profile interpretation with possible consequences on clinical management of infected patients, and on blood transfusion safety.

A hook-effect-free homogeneous light-initiated chemiluminescence assay: is it reliable for screening and the quantification of the hepatitis B surface antigen?

Background

Hepatitis B virus (HBV) infection remains a threat to global public health. As a hallmark of HBV infection, hepatitis B surface antigen (HBsAg) has been used to screen for HBV infection for decades, and quantitative assays are also being clinically rejuvenated to predict the disease outcome and monitor the antiviral response. Herein, we developed and evaluated a hook-effect-free homogeneous quantitative HBsAg assay based on the light-initiated chemiluminescence immunoassay (LICA).

Methods

A hook-effect-free LICA algorithm was established by measuring the relative light units (RLUs) of two time points during the immunoreaction. The precision was assessed using low- and high-level controls. Consecutive clinical serum samples were tested using the LICA and Abbott Architect assay; samples producing inconsistent results were retested using supplementary assays including the HBsAg neutralization, HBV DNA, and Roche Elecsys HBsAg assays for further confirmation. The consistency, sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. For the quantitative results, the correlation was analyzed. The coverage of different genotypes and mutations by the LICA was evaluated. Moreover, serial on-treatment and follow-up samples from chronic hepatitis B patients were also measured using the two assays.

Results

The LICA had better within-run and within-laboratory precisions than the Architect assay. In total, 5,176 clinical samples were tested. The two assays showed a consistency of 99.63%. The LICA showed greater specificity (99.95% vs. 99.77%) and PPV (99.75% vs. 98.77%) than the Architect assay, whereas the Architect assay showed greater sensitivity (100.00% vs. 99.01%) and NPV (100.00% vs. 99.82%). The two assays displayed an excellent correlation independent of genotypes and mutations. The LICA hook-free algorithm recognized 100% of the underestimated results. Furthermore, similar HBsAg dynamics were demonstrated using the LICA and Architect HBsAg assay.

Conclusions

The hook-free LICA provides a reliable tool for screening for HBV infection and quantifying HBsAg.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference‡

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic HBV treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilising cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase III trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity for the prediction of sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive or negative chronic hepatitis, who are treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with an increase in bilirubin or international normalised ratio should prompt temporary or permanent cessation of an investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase III trials for HDV coinfection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalisation of alanine aminotransferase is considered an intermediate goal. In conclusion, regarding HBV 'functional cure', the primary goal is sustained HBsAg loss with undetectable HBV DNA after completion of treatment and the intermediate goal is sustained undetectable HBV DNA without HBsAg loss after stopping treatment.

Detection of hepatitis B virus infection in German blood donors 2008-2015

BACKGROUND AND OBJECTIVES

Assessment of HBV-NAT testing compared to HBsAg and anti-HBc screening in German blood establishments for the period 2008-2015.

MATERIALS AND METHODS

Blood donations screened for HBsAg and anti-HBc along with HBV-NAT were evaluated. Sensitivity of HBsAg and HBV-NAT tests was compared in 30 HBV seroconversion panels and with the viral load of the NAT-only cases. Residual risk for HBV in the WP was modelled.

RESULTS

A total of 45 270 111 donations were evaluated. There were 29 NAT-only cases in the HBsAg-negative HBV-WP, one by ID-NAT and 28 by MP-NAT. MP-NAT, on average, showed higher sensitivity than HBsAg testing: MP-NAT-LoD of 146 IU/ml vs. 362 IU/ml HBV DNA for positive HBsAg detection (range 135-1502 IU/ml), resulting in 3·1 days (range 2·0-4·8 days) earlier HBV detection. Viral loads of the NAT-only cases confirmed the sensitivity of the HBV tests in the seroconversion study. One HBsAg-negative case was due to a new HBsAg mutant combination. There was one HBsAg-reactive only case. In addition, HBV incidence in the HBV-WP included 41 HBsAg-/HBV-NAT-positives and three HBV transmission cases. The residual risk for HBsAg was estimated to be 1:1 619 419-1 268 474 compared to 1:2 793 365-2 134 702 for MP-NAT. Within chronic HBV (HBsAg-/anti-HBc-positive and MP-NAT-negative) 70% were ID-NAT positive at low viral load (median 20 IU/ml). Among anti-HBc-only, supplementary ID-NAT detected 23 occult HBV infections.

CONCLUSIONS

In the HBV-WP, MP-NAT provided a higher sensitivity than HBsAg testing, obtained a considerably higher yield and reduced the risk for HBV transmission. In later HBV stages, anti-HBc screening and HBV-ID-NAT intercepted potentially infectious donations.

Guidance for design and endpoints of clinical trials in chronic hepatitis B - Report from the 2019 EASL-AASLD HBV Treatment Endpoints Conference

Representatives from academia, industry, regulatory agencies, and patient groups convened in March 2019 with the primary goal of developing agreement on chronic hepatitis B virus (HBV) treatment endpoints to guide clinical trials aiming to 'cure' HBV. Agreement among the conference participants was reached on some key points. 'Functional' but not sterilizing cure is achievable and should be defined as sustained HBsAg loss in addition to undetectable HBV DNA 6 months post-treatment. The primary endpoint of phase 3 trials should be functional cure; HBsAg loss in ≥30% of patients was suggested as an acceptable rate of response in these trials. Sustained virologic suppression (undetectable serum HBV DNA) without HBsAg loss, 6 months after discontinuation of treatment would be an intermediate goal. Demonstrated validity in predicting sustained HBsAg loss was considered the most appropriate criterion for the approval of new HBV assays to determine efficacy endpoints. Clinical trials aimed at HBV functional cure should initially focus on patients with HBeAg-positive and HBeAg-negative chronic hepatitis, treatment-naïve or virally suppressed on nucleos(t)ide analogues. A hepatitis flare associated with increase in bilirubin or INR should prompt temporary or permanent cessation of investigational treatment. New treatments must be as safe as existing nucleos(t)ide analogues. The primary endpoint for phase 3 trials for hepatitis D virus (HDV) co-infection should be undetectable serum HDV RNA 6 months after stopping treatment. On treatment HDV RNA suppression associated with normalization of ALT is considered an intermediate goal. CONCLUSION: For HBV 'functional cure', sustained HBsAg loss with undetectable HBV DNA after completion of treatment is the primary goal and sustained undetectable HBV DNA without HBsAg loss after stopping treatment an intermediate goal.

Improved detection of early acute, late acute, and occult Hepatitis B infections by an increased sensitivity HBsAg assay

BACKGROUND

Hepatitis B surface antigen (HBsAg) is the primary marker for diagnosis of acute and chronic hepatitis B. Although HBsAg assays have undergone continuous improvement, gaps remain in the detection of early and late acute infection and occult hepatitis B infection (OBI).

OBJECTIVES

The performance of a prototype, improved sensitivity HBsAg assay run on the ARCHITECT and Alinity instruments was evaluated for detection of early and late acute infection and OBI.

STUDY DESIGN

Seventy seven early acute samples [positive only for hepatitis B viral DNA (HBV DNA)], twelve seroconversion panels spanning late acute infection, and 101 occult samples (HBsAg negative, positive for HBV DNA and anti-HBc) were tested with the prototype assay and ARCHITECT HBsAg Qualitative II. HBsAg gene sequencing was performed to determine genotype and mutations in the immunodominant region.

RESULTS

Compared with ARCHITECT HBsAg Qualitative II, the prototype assay showed increased detection of NAT yield samples (28/77, 36.4%,), late acute samples (≥13 days longer detection of HBsAg for 6/12 panels), and OBI samples (11/101, 10.9%). HBsAg sequence data were obtained for 62 samples. Genotypes represented were A1, A2, B2, B4, C1, C2, C5, D3, E, and H. HBsAg escape mutations were found in 4.8% of NAT yield and 38.9% of OBI samples sequenced. Prototype assay values for 188 samples were equivalent on the ARCHITECT and Alinity instruments.

CONCLUSIONS

The new prototype HBsAg assay will be of diagnostic value in providing improved detection of early acute, late acute, and occult HBV infections.

Non-invasive biomarkers for chronic hepatitis B virus infection management

Chronic hepatitis B virus (HBV) infection remains a major health burden with over 250 million cases worldwide. This complex infection can lead to chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Complete recovery is seldom achieved due to the persistence in infected hepatocytes of covalently closed circular (ccc)DNA, which is not targeted by current antiviral therapies. Routine circulating biomarkers used for clinical monitoring of patients do not accurately reflect the cccDNA pool and transcriptional activity. New biomarkers, such as serum HB core-related Ag and circulating HBV RNAs, are under development. In this review, we discuss surrogate non-invasive biomarkers for evaluating intrahepatic cccDNA abundance and transcriptional activity. We also present their relevance for improving the classification of patients with regards to their natural history and for evaluating novel compounds to assess target engagement and to define new virological endpoints.

Molecular and serological characterization of hepatitis B vaccine breakthrough infections in serial samples from two plasma donors

Background

Although vaccines for hepatitis B virus (HBV) are highly effective, HBV infections in vaccinees occur. Index samples of breakthrough infections are typically anti-HBc negative but HBV DNA positive with protective anti-HBs levels while HBsAg detection may be delayed or absent. HBsAg mutations have been associated with some vaccine breakthrough cases.

Methods

This research characterizes the serological and molecular profiles of vaccine breakthrough infections in serial samples from two commercially available plasma donor panels. Samples were tested with commercially available assays for HBV antigens and antibodies: HBsAg, HBeAg, anti-HBc, anti-HBc IgM, anti-HBe, and anti-HBs. Different immunoassay approaches for earlier detection of breakthrough infection were explored including hepatitis B core-related antigen (HBcrAg), a research assay for preS2 antigen, and a new prototype ARCHITECT HBsAg assay with improved sensitivity. The prototype HBsAg assay is fully automated and involves no sample pre-treatment. Molecular testing included HBV DNA quantitation and sequencing of preS1, preS2, surface, and basal core promoter/core promoter genes.

Results

Although the research preS2 antigen assay allowed earlier detection of the breakthrough infections than current HBsAg assays and HBcrAg, the new prototype ARCHITECT HBsAg assay provided the earliest serologic detection. The ability of the new prototype HBsAg assay to detect HBsAg in the presence of anti-HBs was investigated using known concentrations of native HBsAg mixed with anti-HBs from a vaccinee. The results demonstrated that the prototype ARCHITECT assay is more sensitive in detecting HBsAg in the presence of anti-HBs than current HBsAg assays. Sequencing revealed multiple substitutions in preS1, preS2, and S regions for one panel including a rare D144N substitution associated with vaccine breakthrough that emerged with increasing frequency as the breakthrough infection developed.

Conclusions

When compared with other immunoassay approaches, the new prototype ARCHITECT HBsAg assay allows earlier detection of vaccine breakthrough infections and more sensitive detection of HBsAg in the presence of anti-HBs. Molecular characterization of longitudinal samples demonstrated the progressive appearance of a rare HBsAg mutation associated with vaccine breakthrough.