Novel and highly sensitive immunoassay for total hepatitis B surface antigen, including that complexed with hepatitis B surface antibody

Incidences of new hepatitis B infection and anti-hepatitis B core-negative occult hepatitis B infection among Japanese blood donors in relation to anti-hepatitis B surface antigen levels

A transfusion-transmitted hepatitis B virus (HBV) infection caused by blood only positive for anti-hepatitis B surface antigen (anti-HBs) was reported. Occult HBV infection (OBI) with sole anti-HBs among blood donors is an issue. The incidence of HBV infection among repeat blood donors was investigated with a detailed HBV infection phase, focusing on the influence of anti-HBs level. This study followed 3 435 653 donors for HBV DNA conversion over 4 years and 9 months. Infection phase was determined based on marker changes over DNA conversion. This study identified 115 hepatitis B surface antigen (HBsAg) conversions, 72 DNA-only conversions, and 15 DNA plus anti-hepatitis B core (anti-HBc) conversions among donors all negative for HBV DNA, HBsAg, and anti-HBc. Total incidence was 2.38/100 000 person-years (PY). None of these 202 new HBV infections arose in the group with anti-HBs titer ≥ 10 mIU/mL. In total, 30 anti-HBc-negative OBIs were identified (incidence; 0.35/100 000 PY); 7 showed typical secondary anti-HBs response, and 23 showed stable anti-HBc and anti-HBs levels at DNA conversion. The HBV infection-protective ability of anti-HBs ≥ 10 mIU/mL was reinforced. In addition to new infections, the blood donor population includes anti-HBc-positive- and negative OBI with immune reactions or abortive HBV infection.

Does the ultrasensitive HBsAg Next assay enhance Hepatitis B diagnosis? An evaluation of analytical performances

BACKGROUND

Accurate laboratory confirmation for Hepatitis B diagnosis and monitoring are crucial. Recently an ultrasensitive immunoassay test, the HBsAg Next (HBsAgNx), has been reported approximately eight times more sensitive than current HBsAg assays. The aim of our study was to assess the analytical performances of this new test.

METHODOLOGY

253 clinical samples from Saint Louis University Hospital were analyzed, splitted into four panels: (1) routine prospectively screening serums (n = 196), (2) retrospective serum samples before HBV reactivation (HBV-R) (n = 18), (3) occult HBV infection (OBI) (n = 10) and (4) a selection of wild type HBV genotypes (n = 29) RESULTS: Panel 1, showed robust agreement with the HBsAg Qualitative II (HBsAgQII) assay (Cohen's kappa = 0.83). Despite this agreement, 7 false positive with the HBsAgQII assay were found negative with HBsAgNx. One OBI was detected only with HBsAgNx. Panel 2 showed potential time savings in diagnosing HBV-R using HBsAgNx among 4/18 HBsAg positives samples. Panel 3 highlighted the ability of HBsAgNx to detect HBsAg in OBI patients defined by negative for HBsAg with HBsAgQII assay and positive for HBV DNA. Furthermore, the HBsAgNx assay detected all different genotypes.

CONCLUSION

The study highlights the effectiveness of the HBsAgNx assay, showing its performance. It excels in detecting weakly positive samples and addressing challenging cases. HBsAgNx assay demonstrates promising analytical performances, with improved sensitivity and specificity compared to standard HBsAgQII assay, able to detect all genotypes. Its potential impact on early detecting and monitoring reactivations, and occult infections could be very useful in clinical practice.

Hepatitis B core-related antigen: A novel and promising surrogate biomarker to guide anti-hepatitis B virus therapy

The current requirement for biomarkers to detect hepatitis B virus (HBV) infection is polarized. One is a fully-automated and highly sensitive measurement system; the other is a simple system for point-of-care testing (POCT) in resource-limited areas. Hepatitis B core-related antigen (HBcrAg) reflects intrahepatic covalently closed circular DNA and serum HBV DNA. Even in patients with undetectable serum HBV DNA or HBsAg loss, HBcrAg may remain detectable. Decreased HBcrAg levels are associated with reduction of the occurrence of hepatocellular carcinoma (HCC) in chronic hepatitis B. Recently, a fully-automated, novel high-sensitivity HBcrAg assay (iTACT-HBcrAg, cut-off value: 2.1 logIU/mL) has been developed. This attractive assay has been released in Japan very recently. iTACT-HBcrAg can be useful for monitoring HBV reactivation and prediction of HCC occurrence, as an alternative to HBV DNA. Moreover, monitoring HBcrAg may be suitable for determining the therapeutic effectiveness of approved drugs and novel drugs under development. Presently, international guidelines recommend anti-HBV prophylaxis for pregnant women with high viral loads to prevent mother-to-child transmission of HBV. However, >95% of HBV-infected individuals live in countries where HBV DNA quantification is not available. Worldwide elimination of HBV needs the scaling-up of examination and medication services in resource-limited areas. Based on this situation, a rapid and easy HBcrAg assay as a POCT is valuable. This review provides the latest information regarding the clinical use of a new surrogate marker, HBcrAg, in HBV management, based on iTACT-HBcrAg or POCT, and introduces novel agents targeting HBV RNA/protein.

Kinetics of HBcrAg and HBsAg using highly sensitive iTACT assays in chronic hepatitis B patients with HBsAg seroclearance

Two novel assays have been developed, iTACT-hepatitis B core-related antigen (iTACT-HBcrAg) and iTACT-hepatitis B surface antigen (iTACT-HBsAg) assays. We investigated the longitudinal profiles of iTACT-HBcrAg- and -HBsAg in patients with HBsAg seroclearance (SC) (<0.05 IU/mL). This study comprises 60 HBV-infected patients with HBsAg SC, 27 in chronic hepatitis/liver cirrhosis (CH/LC) group and 33 in inactive carrier (IC) group. Longitudinal profiles of iTACT-HBcrAg and -HBsAg were examined using stored serum samples. The median period from HBsAg SC to iTACT-HBcrAg loss or to the last observation was longer in the CH/LC group than the IC group (39 vs. -3 months, p = 0.004), but this tendency was not observed in that by iTACT-HBsAg. Comparing the times of iTACT-HBcrAg and -HBsAg loss, the rate of patients who lost HBcrAg first was significantly higher in the IC group (p = 0.008). The cumulative incidence rate of iTACT-HBcrAg loss after HBsAg SC was higher in the IC group that the CH/LC group (p = 0.002). Patients in the CH/LC group had higher rates of detectable iTACT-HBcrAg than those in the IC group after HBsAg SC, suggesting that the presence of HBcrAg possibly contribute to the progression of chronic hepatitis B.

A longitudinal study to detect hepatitis B surface and core-related antigens in chronic hepatitis B patients with hepatitis B surface antigen seroclearance using highly sensitive assays

BACKGROUND

This study aimed to evaluate the usefulness of two novel assays, namely the iTACT-hepatitis B surface antigen (iTACT-HBsAg) and iTACT-hepatitis B core-related antigen (iTACT-HBcrAg) assays, in chronic hepatitis B (CHB) patients with HBsAg seroclearance (SC) documented by standard assays.

METHODS

HBsAg and HBcrAg were measured by the two iTACT-assays in 556 serial sera collected from 96 CHB patients at 7 different time points spanning from 5 years before to 10 years after SC and 120 HBsAg-negative, anti-HBc-positive individuals. As controls, 60 seronegative individuals, who were negative for HBsAg, anti-HBc and anti-HBs, were tested.

RESULTS

Using the iTACT-assays, HBsAg was detectable in 154/418 (36.8%) samples collected after SC. HBcrAg was detectable in 78.3% and 65.9% of samples collected before and after SC, respectively. The detectability rates of both HBsAg and HBcrAg progressively decreased over time after SC. At 10 years after SC, 20.4% and 64.5% of the patients still had detectable HBsAg and HBcrAg, respectively. 66 (71%) patients had detectable HBsAg and/or HBcrAg. Among the 120 HBsAg-negative, anti-HBc-positive individuals, 11 (9.2%) and 4 (3.3%) had detectable HBsAg and HBcrAg respectively. Both HBsAg and HBcrAg were undetectable in the controls.

CONCLUSION

The iTACT assays detected a low level of HBsAg and/or HBcrAg in >70% of patients even at 10 years after SC, suggesting that CHB patients with SC still harbour a low level of HBV protein expression. The clinical significance of detectable viral proteins after SC with regard to disease progression and HBV reactivation deserves further investigations.

Circulating immune complexes and mutations of HBsAg are associated with the undetectable HBsAg in anti-HBs and HBeAg positive occult hepatitis B virus infection

Introduction

Occult hepatitis B virus infection (OBI) is an HBsAg negative state in HBV infection with usually inactive HBV replication. However, there were a minority of individuals with positive HBeAg and anti-HBs among OBI blood donors and few studies have focused on this unusual serological pattern.

Methods

2022 plasma of blood donors that preliminary screened reactive for HBV DNA and non-reactive for HBsAg were collected from 16 provinces in China from 2015 to 2018. HBV DNA and HBsAg in these samples were retested using the Cobas TaqScreen MPX test and ARCHITECT HBsAg Quantitative II assay. Lumipulse HBsAg-HQ assay and polyethylene glycol (PEG)-double precipitation following HCl and trypsin digestion were performed to detect HBsAg from HBsAg-anti-HBs circulating immune complexes (CICs).

Results

1487 of 2022 samples were positive for Cobas HBV DNA test and non-reactive for ARCHITECT HBsAg assay, while 404 of them were positive using Lumipulse HBsAg-HQ assay. 10 HBsAg-/anti-HBs+/HBeAg+ OBI blood donor samples were further dissociated and HBsAg-CICs were detected in 7 samples. Sequencing analysis showed that D44N, N98T, G73S, Del 56-116, and I161T occurred in the pre-S region, and immune escape mutations such as P127T, F134L, G145R, V168A, and I126T/S in the S region were found.

Discussion

In conclusion, there were a minority of HBsAg-/anti-HBs+/HBeAg+ individuals in OBI blood donors. The undetectable HBsAg in these individuals was mainly due to HBsAg-CICs. Immune escape-associated mutations also happened under the host’s selective pressure. HBsAg dissociation methods or Lumipulse HBsAg-HQ assay is recommended to distinguish these individuals.

Clinical usefulness of a novel high-sensitivity hepatitis B core-related antigen assay to determine the initiation of treatment for HBV reactivation

BACKGROUNDS

A fully automated, novel, high-sensitivity hepatitis B core-related antigen assay (iTACT-HBcrAg) has been developing. The purpose of this study is to evaluate the efficacy of measuring HBcrAg, using that assay, to diagnose HBV reactivation in a multi-center setting, compared with ultra-high-sensitivity HBsAg (iTACT-HBsAg) and HBV DNA assays.

METHODS

Forty-four patients with HBV reactivation from 2008 to 2020 were enrolled in four hospitals. Serial serum specimens from the patients were assessed retrospectively for their HBcrAg levels by iTACT-HBcrAg (lower limit of detection; 2.0 log U/mL) and HBsAg levels by iTACT-HBsAg (lower limit of detection; 0.0005 IU/mL); these were compared to the HBV DNA levels. HBV reactivation was defined as detection of serum HBV DNA, including unquantifiable detection.

RESULTS

At HBV reactivation and/or thereafter, HBV DNA levels were quantified (≥ 1.3 log IU/mL) in the sera of 27 patients, and were below the level of quantification (< 1.3 log IU/mL) in the sera of 17 patients. Of the 27 patients with HBV reactivation and whose serum HBV DNA was quantified, the sera of 26 and 24 patients (96.3% and 88.9%) were positive by iTACT-HBcrAg and iTACT-HBsAg, respectively. HBcrAg was detectable by iTACT-HBcrAg before HBV DNA was quantifiable in 15 of the 27 patients. Of the 11 patients with HBV reactivation and undetectable HBcrAg by iTACT-HBcrAg at HBV reactivation and/or thereafter, 10 had unquantifiable HBV DNA and none developed HBV reactivation-related hepatitis.

CONCLUSIONS

The iTACT-HBcrAg assay is useful for monitoring HBV reactivation to determine the initiation of treatment with nucleos(t)ide analogues.

Global prevalence of occult hepatitis B: A systematic review and meta-analysis

The study aimed to investigate the prevalence and risk factors associated with occult hepatitis B virus (HBV) infection (OBI) in the global population. We searched PubMed, Embase, CINAHL, Cochrane and Web of Science from database inception through 27 Dec, 2018. Studies reporting HBV-DNA serological data in previously undiagnosed hepatitis B patients were included. The data were further categorized according to the presence of risk factors. After an initial screening of 2,325 records, we finally included 98 articles about the prevalence of OBI from 34 countries and regions. The OBI prevalence was 0.82% (95% CI:0.69-0.96) in the general population, 16.26% (95% CI:10.97-22.34) in HIV patients, 13.99% (95% CI:8.33-20.79) in patients with other liver diseases, 4.25% (95% CI:1.64-7.87) in haemodialysis patients and 5.14% (95% CI:2.26-9.01) patients with other risk factors. In conclusion, OBI prevalence varies significantly across different populations and nations, which deserve attention from the public health authorities. Our results generate further epidemiological data to identify the population with OBI, which has important clinical implications in finding these high-risk populations to design preventive and management strategies.

A Novel Thyroglobulin Immunoassay Using the Specimen-Pretreatment Process Improves the Accuracy of Thyroglobulin Measurements in Anti-Thyroglobulin Positive Specimens

BACKGROUND

Recently, second-generation thyroglobulin (Tg) sandwich immunoassays have been used in clinical laboratories to measure the serum Tg levels, which is a tumor marker used to monitor postoperative patients with differentiated thyroid cancers. However, these immunoassays are often subject to Tg autoantibody (TgAb) interference. TgAb interference is inevitable for almost all Tg immunoassays, resulting in unreliable Tg measurement values of TgAb-positive samples.

METHODS

To address TgAb interference, we have developed a novel immunoassay based on a fully automated chemiluminescent enzyme immunoassay system using the effective specimen-pretreatment process to inactivate TgAb in blood and evaluated its assay performance.

RESULTS

The developed assay was traceable to BCR457 IRMM reference material with a limit of quantification of 0.03 ng/mL. The pretreatment process inactivated almost all TgAb in specimens and allowed accurate Tg measurements in TgAb-positive samples in which TgAb interference was observed using the immunoassays. Size-exclusion chromatography analysis of immunoreactive Tg molecule in a TgAb-positive serum verified disruption of the Tg-TgAb immune complex by the pretreatment process. Good correlation of Tg values in TgAb-negative specimens was observed between the new Tg immunoassay and the second-generation sandwich immunoassays. However, there were numerous discrepant samples on bias plots between the new Tg immunoassay and the second-generation sandwich immunoassays for TgAb-positive specimens.

CONCLUSIONS

This study indicates the new Tg immunoassay with the specimen-pretreatment process is both robust and free from interference by TgAb. Thus, this novel assay is superior to second-generation sandwich immunoassays and gives accurate Tg concentrations even for TgAb-positive cases.

Ultrasensitive Assay for Hepatitis B Core-Related Antigen Predicts Hepatocellular Carcinoma Incidences During Entecavir

Serum hepatitis B core‐related antigen (HBcrAg) and surface antigen (HBsAg) are surrogate markers of intrahepatic covalently closed circular DNA. The measurement range of the current HBcrAg assay is relatively narrow. Thus, we examined the potential of HBcrAg and HBsAg measured by ultrasensitive assays for predicting hepatocellular carcinoma (HCC) development in patients with chronic hepatitis B treated with entecavir (ETV). We conducted a retrospective cohort study of 180 patients who received ETV for >1 year. All patients had hepatitis B e‐antigen negativity at baseline. Serum HBcrAg and HBsAg levels at baseline and year 1 were measured in all patients by ultrasensitive assays using immunoassay for total antigen including complex by pretreatment (iTACT) technology. During the median follow‐up of 11.0 years, 22 patients developed HCC (11.8/1,000 person‐years). Baseline HBsAg levels were not associated with HCC development during ETV treatment. However, high HBcrAg levels at baseline and at year 1 were significantly associated with HCC development (log‐rank test; P < 0.001). In 110 patients (61.1%) with ≥4.0 log U/mL at baseline (high HBcrAg cohort), HBcrAg declined to ≤2.9 log U/mL at year 1 in 25 patients (22.7%). The adjusted hazard ratio for HCC incidence was significantly lower in patients with HBcrAg ≤2.9 log U/mL at year 1 than in those in the high HBcrAg cohort. Conclusion: Measurement of HBcrAg by ultrasensitive assay has better potential for predicting HCC during antiviral treatment than the current HBcrAg assay.

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.

Potential of ultra-highly sensitive immunoassays for hepatitis B surface and core-related antigens in patients with or without development of hepatocellular carcinoma after hepatitis B surface antigen seroclearance

AIMS

Hepatitis B surface antigen (HBsAg) seroclearance indicates a "functional cure" in chronic hepatitis B (CHB) virus infection. However, several cases of hepatocellular carcinoma (HCC) development have been reported after HBsAg seroclearance. We evaluated the potential of HBsAg and hepatitis B core-related antigen (HBcrAg), measured by the ultra-highly sensitive assays, in cases with HCC development after HBsAg seroclearance.

METHODS

We enrolled 17 patients with CHB who achieved HBsAg seroclearance, defined by the conventional assay using Architect HBsAg QT kit (five HCC patients and 12 non-HCC patients). HBsAg and HBcrAg were measured in their stored serum samples using ultra-highly sensitive assays featuring "immunoassay for total antigen including complex via pretreatment (iTACT)" technology.

RESULTS

All five patients who developed HCC were positive for HBsAg or HBcrAg by iTACT-HBsAg or iTACT-HBcrAg at all follow-up points. HBcrAg levels in the HCC group, using iTACT-HBcrAg, were significantly higher than those in the non-HCC group at HBsAg seroclearance (3.6 LogU/ml (2.8-4.2) versus 2.6 (<2.1-3.8), p = 0.020). The best cutoff value of iTACT-HBcrAg for predicting HCC development was 2.7 LogU/ml by receiver operating characteristic curve analysis. The prevalence of HBcrAg ≥2.7 in the HCC group was significantly higher than that in non-HCC group (100% [5/5] versus 33% [4/12], p = 0.029).

CONCLUSIONS

Residual low viral antigen might predict HCC development even if HBsAg seroclearance was achieved according to a conventional assay. The results suggest that iTACT assays of HBsAg and HBcrAg would be useful for monitoring CHB patients.

Neonatal hepatitis B vaccination protects mature adults from occult virus infection

BACKGROUND

Among elder children/young adults who received hepatitis B virus (HBV) vaccination during infancy, the serological status of HBsAg-negative and anti-HBc-positive [HBsAg(-)/anti-HBc(+)] was frequently reported, indicating potential occult HBV infection (OBI). It is required to define the long-term protection of neonatal vaccination against OBI in their mature adulthood.

METHODS

Building upon the 1983-1990 established Qidong Hepatitis B Intervention Study, we sampled 10% of the 28-35-year-old participants, who remained in the cohort by 2012. Each participant was tested for serological markers of HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc. HBV-DNA and relaxed circular DNA (rcDNA) were determined in some HBsAg(-)/anti-HBc(+) individuals.

RESULTS

Totally, 3615 individuals from the neonatal vaccination group and 3100 individuals from the control group donated blood samples, respectively. In the vaccination group, the prevalence of HBsAg was 1.58% (57/3615), HBsAg(-)/anti-HBc(+) was 4.70% (170/3615), significantly lower than in the control group, which was 7.45% (231/3100) and 19.48% (640/3100) respectively (all p < 0.001). With aging, HBsAg(-)/anti-HBc(+) prevalence increased in the sampled participants from the control group (p_{for trend} < 0.001), but uncertain from the vaccination group. Of HBsAg(-)/anti-HBc(+), HBV-DNA was detected in 13.08% (17/130) from the vaccination group, and in 4.18% (12/287) from the control group. HBV rcDNA was detected in most sera that were tested positive for HBV-DNA.

CONCLUSIONS

OBI occurred in some vaccinated adults. However, neonatal HBV vaccination kept the effective protection against OBI in mature adults.

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.

The complement system in liver diseases: Evidence-based approach and therapeutic options

Complement is usually seen to largely originate from the liver to accomplish its tasks systemically - its return to the production site has long been underestimated. Recent progress in genomics, therapeutic effects on complement, standardised possibilities in medical laboratory tests and involvement of complosome brings the complement system with its three major functions of opsonization, cytolysis and phagocytosis back to liver biology and pathology. The LOINC™ system features 20 entries for the C3 component of complement to anticipate the application of artificial intelligence data banks algorythms of which are fed with patient-specific data connected to standard lab assays for liver function. These advancements now lead to increased vigilance by clinicians. This reassessment article will further elucidate the distribution of synthesis sites to the three germ layer-derived cell systems and the role complement now known to play in embryogenesis, senescence, allotransplantation and autoimmune disease. This establishes the liver as part of the gastro-intestinal system in connection with nosological entities never thought of, such as the microbiota-liver-brain axis. In neurological disease etiology infectious and autoimmune hepatitis play an important role in the context of causative viz reactive complement activation. The mosaic of autoimmunity, i.e. multiple combinations of the many factors producing varying clinical pictures, leads to the manifold facets of liver autoimmunity.

Update of the statements on biology and clinical impact of occult hepatitis B virus infection

In October 2018 a large number of international experts with complementary expertise came together in Taormina to participate in a workshop on occult hepatitis B virus infection (OBI). The objectives of the workshop were to review the existing knowledge on OBI, to identify issues that require further investigation, to highlight both existing controversies and newly emerging perspectives, and ultimately to update the statements previously agreed in 2008. This paper represents the output from the workshop.

Clinical evaluation of a novel and highly sensitive immunoassay for anti-hepatitis B core antigen using a fully automated immunochemical analyzer

AIM

Recently, the measurement of hepatitis B surface antigen and anti-hepatitis B core antigen (HBcAb) and/or anti-hepatitis B surface antigen has been recommended before various therapies to identify patients at risk of hepatitis B virus (HBV) reactivation. However, a recent study reported that HBV reactivation occurred in HBcAb-negative patients, indicating that it is challenging to identify patients with a history of HBV infection using conventional HBcAb reagent. We developed a highly sensitive HBcAb (HBcAb-HS) assay for reducing the risk of HBV reactivation.

METHODS

The HBcAb-HS assay is an automated chemiluminescent enzyme immunoassay system, which is suitable for clinical use. The cut-off was set at 0.020 IU/mL from the distribution patterns of HBcAb-negative specimens, and we evaluated the performance of this assay compared with conventional reagents.

RESULTS

This new assay showed a 27-81-fold greater sensitivity than conventional HBcAb reagents; the quantified measurement range was from 0.005 IU/mL to 1.500 IU/mL, and it showed excellent quantitative performance and correlated well with two conventional assays, using the HBcAb-positive specimens. Moreover, it showed 100% specificity for the 469 purchased HBcAb-negative specimens. Notably, this newly developed HBcAb-HS assay showed positivity in the preserved specimens before HBV reactivation, for which conventional HBcAb reagents gave negative results, and the HBcAb-HS assay could detect the lower HBcAb levels even after intensive immunosuppressive therapies, including autologous hematopoietic stem cell transplantation.

CONCLUSIONS

The clinical efficacy of the newly developed, highly sensitive HBcAb assay would enable the identification of patients at risk of HBV reactivation more accurately.

Serum autotaxin is a useful liver fibrosis marker in patients with chronic hepatitis B virus infection

AIM

Autotaxin (ATX) is a secreted enzyme that is considered to be associated with liver damage as well as fibrosis. This study assessed the ability of ATX to diagnose liver fibrosis in patients with chronic hepatitis B virus (HBV) infection.

METHODS

Serum ATX levels were retrospectively evaluated in 101 treatment-naïve patients with HBV-related chronic hepatitis or cirrhosis, all of whom had undergone liver biopsy at our hospital.

RESULTS

Serum ATX concentration increased significantly according to liver fibrosis stage in overall (r = 0.46, P < 0.0001), male (r = 0.55, P < 0.0001), and female (r = 0.52, P = 0.0006) patient groups. When analyzed by gender, serum ATX was one of the most reliable markers for all fibrosis stages compared with other tested non-invasive markers, which included hyaluronic acid, type IV collagen 7S, aspartate aminotransferase-to-platelet ratio index, and fibrosis index based on four factors, according to receiver operating characteristic curve analysis.

CONCLUSION

Based on this histologically proven data, ATX represents a novel non-invasive biomarker for liver fibrosis in HBV-infected patients.

Analysis of hepatitis B surface antigen (HBsAg) using high-sensitivity HBsAg assays in hepatitis B virus carriers in whom HBsAg seroclearance was confirmed by conventional assays

AIM

We investigated the utility of high-sensitivity hepatitis B surface antigen (HBsAg) assays compared with conventional HBsAg assays.

METHODS

Using serum samples from 114 hepatitis B virus (HBV) carriers in whom HBsAg seroclearance was confirmed by conventional HBsAg assays (cut-off value, 0.05 IU/mL), the amount of HBsAg was re-examined by high-sensitivity HBsAg assays (cut-off value, 0.005 IU/mL). Cases negative for HBsAg in both assays were defined as consistent cases, and cases positive for HBsAg in the high-sensitivity HBsAg assay only were defined as discrepant cases.

RESULTS

There were 55 (48.2%) discrepant cases, and the range of HBsAg titers determined by high-sensitivity HBsAg assays was 0.005-0.056 IU/mL. Multivariate analysis showed that the presence of nucleos(t)ide analog therapy, liver cirrhosis, and negative anti-HBs contributed to the discrepancies between the two assays. Cumulative anti-HBs positivity rates among discrepant cases were 12.7%, 17.2%, 38.8%, and 43.9% at baseline, 1 year, 3 years, and 5 years, respectively, whereas the corresponding rates among consistent cases were 50.8%, 56.0%, 61.7%, and 68.0%, respectively. Hepatitis B virus DNA negativity rates were 56.4% and 81.4% at baseline, 51.3% and 83.3% at 1 year, and 36.8% and 95.7% at 3 years, among discrepant and consistent cases, respectively. Hepatitis B surface antigen reversion was observed only in discrepant cases.

CONCLUSIONS

Re-examination by high-sensitivity HBsAg assays revealed that HBsAg was positive in approximately 50% of cases. Cumulative anti-HBs seroconversion rates and HBV-DNA seroclearance rates were lower in these cases, suggesting a population at risk for HBsAg reversion.