Isolated Hepatitis B Core Antibody Positivity and Long-Term Liver-Related Mortality in Korea: A Cohort Study.

INTRODUCTION: Whether isolated hepatitis B core antibody (anti-HBc) positivity is a risk factor for long-term liver-related outcomes in hepatitis B virus (HBV)-endemic areas remains unclear. We aimed to investigate liver-related and liver cancer mortality of isolated anti-HBc positivity in Korean adults. METHODS: A cohort study comprised 609,299 Korean adults who underwent hepatitis B serologic markers, as a part of health examination. Liver-related and liver cancer mortality were determined using the National Death Records. RESULTS: During a median follow-up of 9.0 years (interquartile range, 5.5-13.7 years), 554 liver-related deaths were identified (liver-related mortality, 9.6 cases per 10 5 person-years). The prevalence of isolated anti-HBc positivity was 3.8% (n = 23,399) and was age-dependent. After adjustment for age, sex, and other confounders, hazard ratios (95% confidence interval) for liver-related mortality in isolated anti-HBc-positive and hepatitis B surface antigen-positive subjects compared with HBV-unexposed subjects were 1.69 (1.22-2.33) and 27.02 (21.45-34.04), respectively. These associations were pronounced in the analyses using liver cancer mortality as an outcome. Among isolated anti-HBc-positive patients, the risks of liver-related and liver cancer mortality were significantly higher in those with high fibrosis-4 scores compared with patients unexposed to HBV with the multivariable-adjusted hazard ratios (95% confidence interval) of 15.59 (9.21-26.37) and 72.66 (36.96-142.86), respectively. DISCUSSION: In this cohort of Korean adults, isolated anti-HBc positivity was associated with an increased risk of liver-related and liver cancer mortality, especially when accompanied by a high fibrosis score. Isolated anti-HBc positivity may be an independent risk factor for liver-related outcomes, especially in high-endemic areas.

Anti-HBc IgG Levels: A Predictor of HBsAg Seroclearance in Chronic Hepatitis B Patients with Nucleos(t)ide Analogue-Induced HBeAg Seroclearance.

BACKGROUND/AIMS: We investigated the efficiency of the indirect ratio of anti-HBc IgG at predicting HBsAg seroclearance in patients with nucleos(t)ide analogue (NA)-induced HBeAg seroclearance. METHODS: We performed a retrospective study that included 366 chronic hepatitis B patients (March 2007 to December 2016) at a single tertiary hospital. These patients were HBsAg seropositive, and experienced NA-induced HBeAg seroclearance. The indirect ratio of light absorbance of anti-HBc IgG levels were measured with chemiluminescent microparticle immunoassay using the Architect Anti-HBc assay (Abbott Laboratories, IL, USA) as a qualitative method prior to antiviral therapy. We calculated the cumulative incidences of HBsAg seroclearance based on the anti-HBc IgG levels. RESULTS: After a 10-year follow-up, 48 patients experienced HBsAg seroclearance (13.1%). Thirty-three of 179 patients who had an indirect ratio of light absorbance of anti-HBc IgG < 11 RLU (relative light unit) showed HBsAg seroclearance (18.4%); 15 of 187 patients who had an indirect ratio of light absorbance of anti-HBc IgG ≥ 11 RLU showed HBsAg seroclerance (8.0%) (p = 0.003). In multivariate analysis, age, and ALT at the time of HBeAg seroclearance were predictors of HBsAg seroclearance. Especially, the relative risk of HBsAg seroclearance in patients with baseline anti-HBc IgG levels < 11 RLU was 2.213 (95% CI, 1.220-4.014), compared to that in patients with higher levels of anti-HBc IgG at baseline (p = 0.009). CONCLUSION: Using an indirect method for anti-HBc IgG levels, baseline anti-HBc IgG levels (< 11RLU), age (≥ 50 years), and ALT (≥ 40 IU/L) might be associated with HBsAg seroclearance in patients with NA-induced HBeAg seroclearance.

Association of anti-HBc and liver inflammation in HBeAg-negative chronic hepatitis B virus-infected patients with normal ALT and detectable HBV DNA.

Serum hepatitis B core antibody (anti-HBc) is associated with liver inflammation in chronic hepatitis B patients. This study aimed to investigate whether anti-HBc could serve as a predictor of significant liver inflammation in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infected patients with normal alanine aminotransferase (ALT) and detectable HBV DNA. Treatment-naïve HBeAg-negative chronic HBV infected patients with normal ALT and detectable HBV DNA who underwent liver biopsy were retrospectively included from two medical centers. Liver inflammation grade was evaluated using the Scheuer scoring system and significant liver inflammation was defined as ≥G2. Serum anti-HBc levels were measured by commercial immunoassays (Abbott GmbH & Co. KG). A total of 117 patients were included and 50 (42.7%) patients showed significant liver inflammation. Serum anti-HBc levels in patients with significant liver inflammation were significantly higher than patients with no or mild liver inflammation (

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.

Differences in prevalence of hepatitis B virus infection and genotypes between ethnic populations in Suriname, South America.

Epidemiological data on hepatitis B virus (HBV) are needed to benchmark HBV elimination goals. We recently assessed prevalence of HBV infection and determinants in participants attending the Emergency Department in Paramaribo, Suriname, South America. Overall, 24.5% (95%CI = 22.7-26.4%) of participants had anti-Hepatitis B core antibodies, which was associated with older age (per year, adjusted Odds Ratio [aOR] = 1.03, 95%CI = 1.02-1.04), Afro-Surinamese (aOR = 1.84, 95%CI = 1.52-2.19) and Javanese ethnicity (aOR = 1.63, 95%CI = 1.28-2.07, compared to the grand mean). 3.2% of participants were Hepatitis B surface Ag-positive, which was also associated with older age (per year, aOR = 1.02, 95%CI = 1.00-1.04), Javanese (aOR = 4.3, 95%CI = 2.66-6.95) and Afro-Surinamese ethnicity (aOR = 2.36, 95%CI = 1.51-3.71). Sex, nosocomial or culturally-related HBV transmission risk-factors were not associated with infection. Phylogenetic analysis revealed strong ethnic clustering: Indonesian subgenotype HBV/B3 among Javanese and African subgenotypes HBV/A1, HBV/QS-A3 and HBV/E among Afro-Surinamese. Testing for HBV during adulthood should be considered for individuals living in Suriname, specifically with Javanese and Afro-Surinamese ancestry.

Hepatitis B core related antigen in relation to intrahepatic and circulating viral markers, before and after combination therapy.

INTRODUCTION AND OBJECTIVES: Covalently closed circular (ccc)DNA acts as a viral reservoir in the liver of patients with a chronic hepatitis B (CHB) infection and can only be quantified in liver biopsies. Hepatitis B core-related antigen (HBcrAg) levels in plasma/serum have been proposed to reflect intrahepatic cccDNA-levels and may therefore monitor treatment efficacy. This study aimed to validate the relationship between HBcrAg and other intrahepatic and circulating viral markers in CHB patients with high viral load, before and after combination treatment. MATERIALS AND METHODS: Plasma/serum levels of HBcrAg, HBsAg, HBV-DNA, and HBV pregenomic RNA (HBV-pgRNA), and intrahepatic cccDNA and HBV-DNA levels and fibrosis scores were measured in 89 CHB patients with HBV-DNA levels of >100,000 copies/mL (17,182 IU/mL). Measurements were done before and after a 48-week treatment with pegylated interferon alfa-2a and adefovir in a prospective study (ISRCTN77073364). RESULTS: Baseline HBcrAg-values correlated strongly with intrahepatic cccDNA (ρ 0.77, p < 0.001), intrahepatic HBV-DNA (ρ 0.73, p < 0.001) and plasma/serum HBV-DNA (ρ 0.80, p < 0.001), HBV-pgRNA (ρ 0.80, p < 0.001), and to lesser extend HBsAg (ρ 0.56, p < 0.001). Baseline HBcrAg-levels could not predict functional cure (FC) but HBcrAg-levels declined more strongly in patients who developed FC or HBeAg-loss. Furthermore, most correlations persisted at the end of treatment and follow-up. CONCLUSIONS: HBcrAg reflects cccDNA transcription activity more accurately than HBsAg and may replace HBV-DNA as a marker during future treatment regimens, especially when cccDNA transcription is targeted or nucleot(s)ide analogues are included in the treatment regime.

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.

Functional Cure of Hepatitis B Virus Infection in Individuals With HIV-Coinfection: A Literature Review.

In individuals infected with hepatitis B virus (HBV), the loss of hepatitis B surface antigen (HBsAg) is the ultimate therapeutic goal, which defines "functional cure." For individuals living with human immunodeficiency virus (HIV), functional cure occurs roughly 2 per 100 person-years during potent anti-HBV containing antiretroviral therapy. Although this rate may be higher than expected in treated HBV mono-infected individuals, rates of functional cure widely vary between studies (0.6-10.5 per 100 person-years). Similar to HBV mono-infection, the phase of HBV infection, HBV (sub-)genotypes and hepatitis B "e" Ag-negative variants are associated with functional cure in treated HIV-HBV co-infection. In specifically HIV-HBV co-infected individuals, strong increases in CD4+ T cell counts after treatment initiation have also been linked to functional cure, yet this finding is inconsistent across studies. Several markers directly or indirectly reflecting HBV activity are being developed to predict functional cure, such as quantification of HBsAg, hepatitis B core-related antigen, HBsAg protein composition, anti-hepatitis B core antibodies and interferon-gamma-inducible protein 10. Few have been assessed during treatment in HIV-HBV co-infected individuals and none have been validated to predict functional cure. Novel therapeutics for HBV cure are essential for individuals with HIV-HBV co-infection and need to be separately evaluated in this population.

Baseline serum hepatitis B core antibody level predicts HBeAg seroconversion in patients with HBeAg-positive chronic hepatitis B after antiviral treatment.

Antibody to hepatitis B core antigen (anti-HBc) is one of the most classical serological markers of HBV infection. This study aimed to investigate the association of serum anti-HBc and HBeAg seroconversion in patients with HBeAg-positive chronic hepatitis B (CHB) after antiviral treatment. Two hundred and seventeen HBeAg-positive CHB patients treated with entecavir (ETV) or tenofovir disoproxil fumarate (TDF) for 48 weeks were retrospectively enrolled. Serological response (SR) is defined as HBeAg seroconversion at 48 weeks of antiviral treatment. Serum anti-HBc level was measured using the Abbott ARCHITECT assay. After 48 weeks of antiviral treatment, twenty-two (10.1 %) patients achieved SR. Baseline level of serum anti-HBc in the SR patients (11.8 S/CO) was significantly higher than patients with non-SR (9.6 S/CO, P < 0.001). The median anti-HBc level was significantly declined after 48 weeks of antiviral therapy (9.9 vs. 8.9 S/CO, P < 0.001). Multivariate logistic regression analysis showed baseline of serum anti-HBc was an independent predictor of SR (odds ratio [OR]: 1.462, 95 % confidence interval [CI] 1.170-1.825, P = 0.001). The area under receiver operating characteristic curve (AUROC) of baseline anti-HBc level for predicting SR was 0.781 with the cut-off of 11.1 S/CO, with a sensitivity of 77.27 % and a specificity of 72.82 %. Our findings highlighted that baseline serum anti-HBc level is a promising indictor for predicting HBeAg seroconversion in HBeAg-positive CHB patients after antiviral treatment.

Comparison of HBV RNA and Hepatitis B Core Related Antigen With Conventional HBV Markers Among Untreated Adults With Chronic Hepatitis B in North America.

BACKGROUND AND AIMS: The clinical utility of two biomarkers, hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg), as compared to conventional markers of HBV replication and disease activity, is unclear. APPROACH AND RESULTS: Untreated participants in the North American Hepatitis B Research Network Adult Cohort Study were categorized by chronic hepatitis B (CHB) phases based on HBsAg and HBeAg status and HBV DNA and alanine aminotransferase (ALT) levels. HBV RNA and HBcrAg were measured (Abbott HBV pgRNA Research Assay and Fujirebio Lumipulse Immunoassay, respectively), and cross-sectional associations with conventional CHB markers were tested. Among 1,409 participants across all CHB phases, median HBV DNA was 3.8 log10 IU/mL and ALT was 34 U/L. HBV RNA was quantifiable in 99% of HBeAg+ and 58% of HBeAg- participants; HBcrAg was quantifiable in 20% of HBeAg+ (above linear range in the other 80%) and 51% of HBeAg- participants. Both markers differed across CHB phases (P < 0.001), with higher levels in the HBeAg+ and HBeAg- immune active phases. HBV RNA and HBcrAg correlated moderately strongly with HBV DNA in both HBeAg+ and HBeAg- phases (HBV RNA: e+ ρ = 0.84; e- ρ = 0.78; HBcrAg: e+ ρ = 0.66; e- ρ = 0.56; P for all, <0.001), but with HBsAg levels among HBeAg+ phases only (HBV RNA: e+ ρ = 0.71; P < 0.001; e- ρ = 0.18; P = 0.56; HBcrAg: e+ ρ = 0.51; P < 0.001; e- ρ = 0.27; P < 0.001). Associations of higher HBV RNA and HBcrAg levels with higher ALT, APRI, and Fibrosis-4 levels were consistent in HBeAg- , but not HBeAg+ , phases. CONCLUSIONS: Despite clear relationships between HBV RNA and HBcrAg levels and CHB phases, these markers have limited additional value in differentiating CHB phases because of their strong association with HBV DNA and, to a lesser extent, with clinical disease indicators.

Hepatitis B virus prevalence in first-time blood donors in Flanders, Belgium: Impact of universal vaccination and migration.

BACKGROUND: Transfusion-transmissible infections such as hepatitis B virus (HBV) remain a major concern for the safety of blood transfusion. This cross-sectional study aimed to assess the trend of HBV prevalence and associated risk factors among a first-time donor population in a low endemic country. STUDY DESIGN AND METHODS: Between 2010 and 2018, blood samples were collected from first-time donors presented at donor collection sites of Belgian Red Cross-Flanders. They were tested for hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc), and HBV DNA, HIV and hepatitis virus C (HCV) antibodies and RNA, and syphilis antibodies. RESULTS: A total of 211,331 first-time blood donors (43.7% males, median age 25 years) were analyzed. HBsAg prevalence decreased from 0.06% in 2010 to 0.05% in 2018 (p = .004) and this declining trend was accompanied by an increased number of donors in the HBV vaccinated birth cohort (p < .001). HBsAg prevalence was 0.33% in foreign-born donors and 0.02% in Belgian natives (p < .001). Multivariate risk profiling showed that anti-HBc positivity was significantly associated with mainly foreign-born donors (odds ratio [OR] = 9.24) but also with older age (OR = 1.06), male gender (OR = 1.32), year of blood donation (OR = 0.94), and co-infections with HCV (OR = 4.31) or syphilis (OR = 4.91). DISCUSSION: The decreasing trend in HBV prevalence could mainly be explained by the introduction of the universal HBV vaccination. Being born in endemic areas was the most important predictor for HBV infection while the co-infections with syphilis suggest unreported sexual risk contacts.

Blood donor screening in the Netherlands: Universal anti-HBc screening in combination with HBV nucleic acid amplification testing may allow discontinuation of hepatitis B virus antigen testing.

BACKGROUND: In the Netherlands, blood donor screening for hepatitis B virus (HBV) consists of HBsAg screening since the 1970s, HBV DNA minipool testing (MP-NAT) since 2008, and anti-HBc screening since 2011. Anti-HBc reactivity causes deferral only if anti-HBs titers are <200 IU/mL, or when anti-HBc was acquired during follow-up. STUDY DESIGN AND METHODS: Over 5.5 million donations from 582,459 Dutch donors were screened for HBV DNA, HBsAg, anti-HBc, and, if anti-HBc positive, also for anti-HBs. The added value, expressed as the yield of (potentially) infectious and/or recent HBV infections versus unnecessary donor loss, was evaluated for each of the three HBV screening tests. RESULTS: HBV donor screening identified 89 HBV-infected donors with at least two reactive HBV markers (MP-NAT, HBsAg and/or anti-HBc). Single HBV-marker yield was: 5 MP-NAT-only, 0 HBsAg-only, and 20 anti-HBc-only donors. In addition, anti-HBc screening yielded 1,067 potentially infectious donors at risk for occult HBV infection (OBI). In total, 4,126 (0.71%) donors were anti-HBc-reactive at first-time screening, and 1,098 (0.19%) seroconverted during follow-up. Anti-HBc-related donor loss was limited to 2,627 (0.45%) donors using anti-HBs titers and two-strike programs. Donor loss due to MP-NAT and HBsAg screening was extremely low: 0 and 128 donors, respectively. CONCLUSION: HBV donor screening could be limited to MP-NAT and anti-HBc screening. MP-NAT and anti-HBc improved blood safety by intercepting infectious donations from donors with recent infection or OBI, while HBsAg did not. Unnecessary donor loss related to anti-HBc screening is substantial but does not endanger the continuity of the blood supply.

Heart Retransplantation From an Hepatitis B Core Antibody (Anti-HBcore)-Positive Donor: A Case Report.

Heart transplantation is performed in patients with end-stage heart failure. The number of suitable donors for patients on the urgent heart transplantation waiting list is still low, and effort has been made to increase the number of suitable donors, including extended-criteria donors. We present a case report of heart retransplantation because of graft failure from an hepatitis B core antibody (anti-HBcore-positive, HBcAb [+]) and HBs antigen-negative (HBsAg [-]) donor to a seronegative recipient. We show that the procedure, with the use of antiviral prophylaxis, is a safe option for the recipient. Based on anatomopathologic and histopathologic examination of the explanted graft, we also suggest that acute cellular rejection in the transplanted heart may exist despite negative findings in right-sided endomyocardial biopsy.

Pre-transplant donor HBV DNA+ and male recipient are independent risk factors for treatment failure in HBsAg+ donors to HBsAg- kidney transplant recipients.

BACKGROUND: In order to reduce the burden on organ shortage around the world, using potential infectious donor might be an option. However, scarce evidences have been published on kidney transplantation (KTx) from hepatitis B surface antigen (HBsAg) + donors to HBsAg- recipients [D (HBsAg+)/R(HBsAg-)] without hepatitis B virus (HBV) immunity. Here, we reported the results of D(HBsAg+/HBV DNA- or +)/R(HBsAg-) living KTx recipients with or without HBV immunity. METHODS: We retrospectively identified 83 D(HBsAg+)/R(HBsAg-) living KTx recipients, and 83 hepatitis B core antibody (HBcAb) + living donors to HBcAb- recipients [D(HBcAb+)/R(HBcAb-)] were used as control group by reviewing medical archives and propensity score matching. Treatment failure (defined as any HBV serology conversion, liver injury, graft loss, or recipient death) is the primary endpoint. RESULTS: Twenty-four donors (28.9%) were HBV DNA+, and 20 recipients had no HBV immunity in the D(HBsAg+)/R(HBsAg-) group pre-transplantation. HBV prophylaxis was applied in all D(HBsAg+)/R(HBsAg-) recipients, while none was applied in the D(HBcAb+)/R(HBcAb-) group. We observed a significant higher treatment failure in D(HBsAg+)/R(HBsAg-) than D(HBcAb+)/R(HBcAb-) group (21.7% vs. 10.8%, P < 0.001). Interestingly, no significant difference was found between groups on HBV seroconversion, liver and graft function, rejection, infection, graft loss, or death. However, 2/20 recipients without HBV immunity in the D(HBsAg+)/R(HBsAg-) group developed HBV DNA+ or HBsAg+, while none observed in the D(HBcAb+)/R(HBcAb-) group. HBV DNA+ donor and male recipient were significant risk factors for treatment failure. CONCLUSION: D(HBsAg+)/R(HBsAg-) should be considered for living kidney transplantation, but with extra caution on donors with HBV DNA+ and male candidates.

Characterization and Application of Precore/Core-Related Antigens in Animal Models of Hepatitis B Virus Infection.

BACKGROUND AND AIMS: The hepatitis B core-related antigen (HBcrAg), a composite antigen of precore/core gene including classical hepatitis B core protein (HBc) and HBeAg and, additionally, the precore-related antigen PreC, retaining the N-terminal signal peptide, has emerged as a surrogate marker to monitor the intrahepatic HBV covalently closed circular DNA (cccDNA) and to define meaningful treatment endpoints. APPROACH AND RESULTS: Here, we found that the woodchuck hepatitis virus (WHV) precore/core gene products (i.e., WHV core-related antigen [WHcrAg]) include the WHV core protein and WHV e antigen (WHeAg) as well as the WHV PreC protein (WPreC) in infected woodchucks. Unlike in HBV infection, WHeAg and WPreC proteins were N-glycosylated, and no significant amounts of WHV empty virions were detected in WHV-infected woodchuck serum. WHeAg was the predominant form of WHcrAg, and a positive correlation was found between the serum WHeAg and intrahepatic cccDNA. Both WHeAg and WPreC antigens displayed heterogeneous proteolytic processing at their C-termini, resulting in multiple species. Analysis of the kinetics of each component of the precore/core-related antigen, along with serum viral DNA and surface antigens, in HBV-infected chimpanzees and WHV-infected woodchucks revealed multiple distinct phases of viral decline during natural resolution and in response to antiviral treatments. A positive correlation was found between HBc and intrahepatic cccDNA but not between HBeAg or HBcrAg and cccDNA in HBV-infected chimpanzees, suggesting that HBc can be a better marker for intrahepatic cccDNA. CONCLUSIONS: In conclusion, careful monitoring of each component of HBcrAg along with other classical markers will help understand intrahepatic viral activities to elucidate natural resolution mechanisms as well as guide antiviral development.

Development of HBc virus-like particles as modular nanocarrier by intein-mediated trans-splicing.

Hepatitis B virus core protein (HBc) spontaneously assembles as Virus-like particles (VLPs) in Escherichia coli (E. coli) which is extensively used as a nanocarrier to boost antigen immunogenicity. Genetic fusion of cargo protein with HBc occasionally forms inclusion bodies instead of properly assembled VLPs. To this end, we devised HBc VLPs as a modular nanocarrier for antigen delivery by intein-mediated trans-splicing (TS). We introduced split inteinC (intC) to the C-terminus of split HBc N-core to employ intein-mediated TS technology to HBc VLPs. Split HBc with the insertion of intC at N-core C-terminus (designated as HBc N-intC-C) existed in inclusion bodies. Interestingly, introduction of a soluble tag, gb1, to intC C-terminus remarkably improved the solubility of recombinant protein (named HBc N-intC-gb1-C). Moreover, newly designed recombinant spontaneously assembled as VLPs and endowed efficiently coupling two different model antigens onto HBc N-intC-gb1-C VLPs. Furthermore, model antigens delivered by HBc VLPs induced a dramatically enhanced antigen-specific immune responses. Antigen proteins mainly elicited Th2 IgG responses while antigens delivered by HBc VLPs steered Th1/Th2 balanced IgG responses. Taken together, intein-mediated TS was amenable to decorate HBc VLPs with antigens and showed good potential for antigen delivery.

HBV vaccination and HBV infection induces HBV-specific natural killer cell memory.

OBJECTIVE: Vaccination against hepatitis B virus (HBV) confers protection from subsequent infection through immunological memory that is traditionally considered the domain of the adaptive immune system. This view has been challenged following the identification of antigen-specific memory natural killer cells (mNKs) in mice and non-human primates. While the presence of mNKs has been suggested in humans based on the expansion of NK cells following pathogen exposure, evidence regarding antigen-specificity is lacking. Here, we demonstrate the existence of HBV-specific mNKs in humans after vaccination and in chronic HBV infection. DESIGN: NK cell responses were evaluated by flow cytometry and ELISA following challenge with HBV antigens in HBV vaccinated, non-vaccinated and chronic HBV-infected individuals. RESULTS: NK cells from vaccinated subjects demonstrated higher cytotoxic and proliferative responses against autologous hepatitis B surface antigen (HBsAg)-pulsed monocyte-derived dendritic cells (moDCs) compared with unvaccinated subjects. Moreover, NK cell lysis of HBsAg-pulsed moDCs was significantly higher than that of hepatitis B core antigen (HBcAg)-pulsed moDCs (non-vaccine antigen) or tumour necrosis factor α-activated moDCs in a NKG2D-dependent manner. The mNKs response was mediated by CD56dim NK cells coexpressing CD57, CD69 and KLRG1. Further, mNKs from chronic hepatitis B patients exhibited greater degranulation against HBcAg-pulsed moDCs compared with unvaccinated or vaccinated patients. Notably, mNK activity was negatively correlated with HBV DNA levels. CONCLUSIONS: Our data support the presence of a mature mNKs following HBV antigen exposure either through vaccination or infection. Harnessing these antigen specific, functionally active mNKs provides an opportunity to develop novel treatments targeting HBV in chronic infection.

Prognostic value of anti-HBc quantification in hepatitis B virus related acute-on-chronic liver failure.

BACKGROUND AND AIM: It has been reported that serum quantification of anti-HBc (qAnti-HBc) could predict antiviral response in chronic hepatitis B (CHB) patients, while its role in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) remains unclear. Its implication in HBV-ACLF was evaluated in this study. METHODS: Baseline serum qAnti-HBc levels were retrospectively detected in HBV-ACLF and CHB patients using recently developed double-sandwich immunoassay. The association of qAnti-HBc level with clinical outcomes was evaluated by multiple logistic regression. Nomogram was adopted to formulate an algorithm incorporating qAnti-HBc for the prediction of survival in HBV-ACLF. The post-hospitalization of HBV-ACLF patients were followed-up for 1 year. RESULTS: Eighty-eight HBV-ACLF as training set, 80 HBV-ACLF as validation set and 216 CHB cases were included. Serum qAnti-HBc level was significantly higher in HBV-ACLF (4.95 ± 0.54 log10  IU/mL) than CHB patients (4.47 ± 0.84 log10  IU/mL) (P < 0.01). Among HBV-ACLF cases, both in training and validation set, patients with poor outcomes had lower qAnti-HBc level. Area under receiver operating characteristic curve of the novel qAnti-HBc inclusive model was 0.82, superior to 0.73 from model for end-stage liver disease scores (P = 0.018), which was confirmed in validation set. During follow-up, the qAnti-HBc level declined at month 3 and month 6, then plateaued at 3.84 log10  IU/mL. CONCLUSIONS: Serum qAnti-HBc level was associated with disease severity and might be served as a novel biomarker in the prediction of HBV-ACLF clinical outcomes. The underlying immunological mechanism warrants further investigation.

Low risk of hepatitis B reactivation in patients with severe COVID-19 who receive immunosuppressive therapy.

A significant proportion of patients infected with SARS-CoV-2 develop severe respiratory symptoms due to an excessive immune response. Treatment of this condition may include immunosuppressive therapies, such as IL-6 receptor antagonists and corticosteroids, which pose a risk for patients with active or past hepatitis B virus (HBV) infection. In this prospective cohort study, we analysed the risk of HBV reactivation in patients with severe COVID-19 and resolved HBV infection undergoing immunosuppressive therapy. From 15th March to 30th April 2020, 600 patients with severe COVID-19 were admitted to our hospital and treated with immune modulators. Data regarding HBV infection were available in 484, of whom 69 (14%) were HBsAg negative/anti-HBc positive. For these patients, HBV reactivation prophylaxis with entecavir was strongly recommended. Complete follow-up was available in 61 patients: 72% were male, median age was 67 years, and anti-HBs was >10 IU/mL in 72%. The immunosuppressive drug most used was tocilizumab (72%). Despite HBV prophylaxis recommendation, 38 (62%) patients received entecavir and 23 (38%) did not. Baseline features of both groups were similar. At follow-up, we found no cases of HBsAg seroreversion and only 2 (3%) patients (no prophylaxis group) had detectable serum HBV-DNA (<15 IU/mL). Both were anti-HBs negative and had normal aminotransferase levels. Our data show that the risk of HBV reactivation in patients with severe COVID-19 and resolved HBV infection undergoing immunosuppressive treatment is low. However, if a systematic follow-up after hospital discharge is unfeasible in patients without anti-HBs, a short course of antiviral prophylaxis may be a safe option.

Identification of the association between HBcAg-specific T cell and viral control in chronic HBV infection using a cultured ELISPOT assay.

Hepatitis B virus (HBV)-specific T cells play a critical role in determining the outcome of HBV infection. However, T cell response induced by predominant Ag in chronic infection is hardly detectable owing to the lack of a suitable assay. We herein established an optimized method to enumerate HBV-specific T cells and assessed the association between HBV surface Ag (HBsAg) and HBV DNA. Sixty chronic HBV infection patients were enrolled. HBV-specific T cells were expanded by using overlapping peptide pools covering the entire sequence of HBV genotypes B and C. IFN-γ-producing HBV-specific T cells were detected by a cultured enzyme-linked immunospot (ELISPOT) assay, ex vivo ELISPOT assay, or flow cytometry staining. The association between HBV-specific T cells and serum levels of HBsAg and HBV DNA were analyzed. Cultured ELISPOT assay had a higher sensitivity than ex vivo ELISPOT in the detection of HBV-specific T cells. Moreover, consistent results were acquired by flow cytometry analysis and cultured ELISPOT assay, but the latter required only a limited number of cells for detection. Interestingly, HBV core peptide pool induced a robust HBV-specific T cell response in patients with lower levels of HBV DNA and HBsAg. Specifically, the frequency of HBV core Ag-specific IFN-γ+ spot-forming cells was inversely correlated with serum levels of HBV DNA and HBsAg. An optimized cultured ELISPOT assay reveals the association between HBV core Ag-induced T cell response and HBV control; this method may favor the investigation of HBV-specific T cell in chronic HBV infection.