Clinical usefulness of a newly developed high-sensitive hepatitis B surface antigen (HBsAg) assay for monitoring hepatitis B reactivation

Positivity of high-sensitivity HBsAg test, not previous HBV infection, indicates poor prognosis in patients with non-HBV-related HCC

BACKGROUND AND AIMS

The prognostic impact of previous-HBV-infection (pHBV) in non-HBV-related hepatocellular carcinoma (non-HBV-related-HCC) and the prevalence, characteristics and significance of recently developed high-sensitivity HBs antigen positivity (hHBsAg+) in these patients remain unclear. We aimed to close these gaps.

METHODS

We retrospectively screened patients with newly diagnosed non-HBV-related-HCC (standard HBsAg-test negative) at Hokkaido University. Patients with complete clinical information and preserved serum for hHBsAg+ were included. We evaluated the prevalence, characteristics and prognostic impact of pHBV and hHBsAg+ in non-HBV-related-HCC.

RESULTS

A total of 401 non-HBV-related-HCC patients were included (288 with pHBV/113 without pHBV). In non-HBV-related-HCC, pHBV did not affect overall survival (OS). Among non-HBV-related-HCC patients with pHBV, 11.8% (34/288) were hHBsAg+ and had more advanced stages of HCC, higher AFP levels, higher vascular invasion rates, and significantly shorter OS than others (OS: 19.3 vs. 61.4 months, p = 0.012). Comparison of OS among non-HBV-related-HCC patients without pHBV (group 1), those with pHBV and without hHBsAg+ (group 2), and those with pHBV and hHBsAg+ (group 3) revealed significantly shorter OS in group 3 (19.3, 56.6 and 66.4 months in groups 1, 2 and 3, respectively; p = 0.036). Multivariate Cox regression indicated that compared with group 1, only group 3 was significantly and independently associated with shorter OS (HR: 2.044, p = 0.011). Subgroup analysis revealed that this association was particularly evident in non-HBV-related-HCC patients with non-B-non-C aetiology and advanced HCC.

CONCLUSIONS

In non-HBV-related-HCC patients, hHBsAg+, not pHBV, is significantly and independently associated with poor prognosis.

An overview of occult hepatitis B infection (OBI) with emphasis on HBV vaccination

Background

The prevalence of chronic hepatitis B virus (HBV) poses a significant threat to the lives of 257 million individuals globally, potentially resulting in severe outcomes such as liver cirrhosis or hepatocellular carcinoma. Among the existing preventive measures, yeast-derived vaccines have proven to be the most efficacious approach in combatting hepatitis B. Nonetheless, as scientific inquiries focus more on occult HBV infection (OBI) in vaccinated persons and the lingering risk of vertical transmission affecting 10-30 % of babies born to HBsAg-positive mothers, there is a growing apprehension regarding the inability of HBV vaccines to ensure complete immunity. This study aims to offer a more comprehensive understanding of the implications of widespread HBV vaccination initiatives on OBI while tackling the primary limitations associated with current vaccine formulations.

Methods

The exploration was conducted on PubMed, Scopus, and Web of Science databases to pinpoint research on OBI within vaccinated cohorts. A sum of 76 suitable studies was recognized.

Discussion

Multiple studies have documented the occurrence of OBI in fully vaccinated individuals, including both the general population and high-risk groups, such as newborns born to HBsAg-positive mothers. Factors contributing to vaccine failures include low-level anti-HBs antibodies, high maternal viral loads in mother-to-child transmission cases, as well as the presence of vaccine escape mutants and heterologous HBV genotypes. However, further research is needed to precisely understand the impact of active immunization on the emergence of OBI in vaccinated populations. Nonetheless, it is apparent that the advancement of more effective HBV vaccines could potentially lead to the extinction of HBV.

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.

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.

Novel strategies for the early diagnosis of hepatitis B virus reactivation

Hepatitis B virus (HBV) reactivation under systemic chemotherapy or immunosuppressive therapy is a serious complication among HBV-resolved patients. Some medications, such as more than 2 weeks of corticosteroid therapy, can influence HBV reactivation; therefore, screening tests that measure hepatitis B surface antigen (HBsAg), hepatitis B core antibody, and hepatitis B surface antibody before therapy are required. Additionally, because HBV reactivation has been reported in patients positive for HBsAg treated with immune checkpoint inhibitors (ICIs), the prophylactic administration of nucleos(t)ide analogues prior to administering ICIs is recommended for HBsAg-positive patients. Under these circumstances, highly sensitive novel biomarkers are expected to be used for the early diagnosis of HBV reactivation. A fully automated high-sensitivity HBsAg assay (detection limit: 5 mIU/ml) by Lumipulse HBsAg-HQ, with 10-fold higher sensitivity than that of conventional assays, is currently used. Furthermore, ultra-sensitive HBsAg assays using a semi-automated immune complex transfer chemiluminescence enzyme immunoassay (ICT-CLEIA; detection limit: 0.5 mIU/ml) have been developed. Recently, a fully automated, novel high-sensitivity hepatitis B core-related antigen assay (iTACT-HBcrAg; cut-off value: 2.1 Log U/mL) has been developed and reported. The utility of ICT-CLEIA and iTACT-HBcrAg for the diagnosis of HBV reactivation appears comparable to the use of HBV DNA. In this review, we provide the latest information related to medications that influence HBV reactivation and recently developed novel biomarkers that predict and monitor HBV reactivation.