HBsAg quantification for identification of liver disease in chronic hepatitis B virus carriers

Association between intrahepatic cccDNA and the severity of liver inflammation in chronic hepatitis B virus infection patients

Background and aims

This research aimed to examine the association between hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) and liver inflammation in chronic hepatitis B (CHB) infection patients.

Methods

From August 2013 to June 2022, CHB patients at Hebei Medical University Third Hospital (Hebei, China) were recruited. Intrahepatic cccDNA was quantified and its association with liver inflammation was analyzed. Liver inflammation was assessed using the Ishak-modified histological activity index (HAI). Biochemical and viral indicators as well as hepatic inflammation biomarkers were monitored.

Results

In total, 55 CHB patients were enrolled. The average HBV-cccDNA level was markedly elevated in HBeAg+ patients compared to HBeAg patients. Intrahepatic cccDNA levels differed significantly in different liver inflammation groups and showed a positive correlation with the HAI score for hepatic inflammation.

Conclusion

HBV-cccDNA level was associated with liver inflammation.

The Relationship between Viral Replication and the Severity of Hepatic Necroinflammatory Damage Changed before HBeAg Loss in Patients with Chronic Hepatitis B Virus Infection

Background and Aims

Disease progression of chronic hepatitis B virus (HBV) infection is driven by the interactions between viral replication and the host immune response against the infection. This study aimed to clarify the relationship between HBV replication and hepatic inflammation during disease progression.

Methods

Two cross-sectional, one validation cohort, and meta-analyses were used to explore the relationship between HBV replication and liver inflammation. Spearman analysis, multiple linear regression, and logistic regression were used to explore the relationship between variables.

Results

In the cross-sectional cohorts A and B including 1,350 chronic hepatitis B patients, Spearman analysis revealed a negative relationship between HBV replication (such as HBV DNA) and liver inflammation (such as ALT) in HBeAg-positive patients with higher HBV DNA >2×106 IU/mL (rho=-0.160 and -0.042) which turned to be positive in HBeAg-positive patients with HBV DNA ≤2×106 IU/mL (rho=0.278 and 0.260) and HBeAg-negative patients (rho=0.450 and 0.363). After adjustment for sex, age, and anti-HBe, results from logistic regression and multiple linear regression showed the opposite relationship still existed in HBeAg-positive patients with different DNA levels; the opposite relationship in HBeAg-positive patients with different DNA levels was validated in a third cohort; the opposite relationship in patients with different HBeAg status was partially confirmed by meta-analysis (overall R: -0.004 vs 0.481).

Conclusions

These results suggested a negative relationship between viral replication and liver inflammation in HBeAg-positive patients with high HBV DNA, which changed to a positive relationship for those HBeAg-positive patients with DNA less than 2×106 IU/mL and HBeAg-negative patients.

Can quantitative surface antigen levels and systemic immune-inflammation index be predictive as a new indicator for the initiation of treatment in chronic hepatitis b?

OBJECTIVES

The natural history of chronic HBV infection (CHB) is generally divided into four phases: HBeAg-positive chronic HBV infection (EPCI) and -hepatitis (EPCH), HBeAg-negative chronic HBV infection (ENCI) and -hepatitis (ENCH). This study aimed to investigate changes in serum quantitative surface antigen (qHBsAg), systemic immune-inflammation index (SII) and systemic inflammatory response index (SIRI) in a large number of CHB patients.

METHOD

Three hundred seventy-two CHB patients who underwent liver biopsy between January 2015 and February 2020 were evaluated.

RESULTS

The SII-values were strongly significant between EPCI-EPCH ( P = 0.002), however, there was significant difference between ENCI-ENCH ( P = 0.025). Considering the SIRI results, there was a significant difference between both EPCI-EPCH ( P = 0.009) and ENCI-ENCH ( P = 0.118). In HBeAg-positive patients HBV-DNA, qHBsAg, and SII were found to be predictive ( P = 0.029, P = 0.039, P = 0.027, respectively) while in HBeAg-negative patients, age, AST, HBV-DNA, qHBsAg, SII, and SIRI were found to be predictive ( P = 0.047, P = 0.084, P = <0.001, P = 0.001, P = 0.012, P = 0.002, respectively). In EPCH phase, whereby accuracy rate results of HBV-DNA, qHBsAg, and SII were 75.3%, 73.4%, and 60.4%, respectively, while in the ENCH phase the accuracy rates of age, AST, HBV-DNA, qHBsAg, SII, and SIRI values were 57.8%, 65.6%, 68.3%, 63.8%, 57.3% and 53.2%, respectively.

CONCLUSION

HBV-DNA, qHBsAg, and SII are predictive in EPCH patients. Age, AST, HBV-DNA, qHBsAg, SII and SIRI are all predictive in ENCH patients. In patients with CHB, we recommend using SII to distinguish between EPCI-EPCH and ENCI-ENCH. Based on its sensitivity and features, we believe that qHBsAg and SII are suitable measuring instruments in discrimination both of EPCI-EPCH and ENCI-ENCH.

Hepatitis B Virus-Encoded HBsAg Contributes to Hepatocarcinogenesis by Inducing the Oncogenic Long Noncoding RNA LINC00665 through the NF-κB Pathway

Clinical and in vivo studies have demonstrated a role for hepatitis B virus (HBV)-encoded HBsAg (hepatitis B surface antigen) in HBV-related hepatocellular carcinoma (HCC); however, the underlying mechanisms remain largely unknown. Here, we investigated the role of HBsAg in regulating long noncoding RNAs (lncRNAs) involved in HCC progression. Our analysis of microarray data sets identified LINC00665 as an HBsAg-regulated lncRNA. Furthermore, LINC00665 is upregulated in liver samples from HBV-infected patients as well as in HCC, specifically in HBV-related HCC liver samples. These findings were supported by our in vitro data demonstrating that HBsAg, as well as HBV, positively regulates LINC00665 in multiple HBV cell culture models. Next, we evaluated the oncogenic potential of LINC00665 by its overexpression and CRISPR interference (CRISPRi)-based knockdown in various cell-based assays. LINC00665 promoted cell proliferation, migration, and colony formation but inhibited cell apoptosis in vitro. We then identified the underlying mechanism of HBsAg-mediated regulation of LINC00665. We used immunofluorescence assays to show that HBsAg enhanced the nuclear translocation of NF-κB factors in HepG2 cells, confirming that HBsAg activates NF-κB. Inhibition of NF-κB signaling nullified HBsAg-mediated LINC00665 upregulation, suggesting that HBsAg acts through NF-κB to regulate LINC00665. Furthermore, the LINC00665 promoter contains NF-κB binding sites, and their disruption abrogated HBsAg-induced LINC00665 upregulation. Finally, HBsAg facilitated the enrichment of the NF-κB factors NF-κB1, RelA, and c-Rel in the LINC00665 promoter. Taken together, this work shows that HBsAg can drive hepatocarcinogenesis by upregulating oncogenic LINC000665 through the NF-κB pathway, thereby identifying a novel mechanism in HBV-related HCC. IMPORTANCE Hepatitis B virus (HBV) is a major risk factor for hepatocellular carcinoma (HCC). Numerous reports indicate an oncogenic role for HBV-encoded HBsAg; however, the underlying mechanisms are not well understood. Here, we studied the role of HBsAg in regulating lncRNAs involved in hepatocarcinogenesis. We demonstrate that HBsAg, as well as HBV, positively regulates oncogenic lncRNA LINC00665. The clinical significance of this lncRNA is highlighted by our observation that LINC00665 is upregulated in liver samples during HBV infection and HBV-related HCC. Furthermore, we show LINC00665 can drive hepatocarcinogenesis by promoting cell proliferation, colony formation, and cell migration and inhibiting apoptosis. Taken together, this work identified LINC00665 as a novel gene through which HBsAg can drive hepatocarcinogenesis. Finally, we show that HBsAg enhances LINC00665 levels in hepatocytes by activating the NF-κB pathway, thereby identifying a novel mechanism by which HBV may contribute to HCC.

qHBsAg for the Identification of Liver Histological Abnormalities in HBeAg-Negative Chronic Hepatitis B Patients with Normal and Mildly Elevated ALT Levels

BACKGROUNDS

Noninvasive detection of histological abnormalities remains challenging in patients with HBeAg-negative chronic HBV infection with normal or mildly elevated levels of alanine aminotransferase (ALT). This study aimed to assess the utility of serum quantitative hepatitis B surface antigen (qHBsAg) in identifying significant histological lesions in this population.

METHODS

This is a single-center study with retrospective analysis of 392 treatment-naive patients of HBeAg-negative chronic HBV infection with normal or mildly elevated levels of ALT.

RESULTS

In this cohort, significant necroinflammation and fibrosis were found in 69.4% and 61.5% of patients, respectively. Patients with qHBsAg >1000 IU/mL (N = 236) had more hepatic inflammation of ≥G2 (75.4% vs. 60.9%, P < 0.01) or fibrosis ≥ S2 (66.1% vs. 54.5%, P < 0.05) compared to those without (N = 156). Serum HBsAg (cutoff point = 1000 IU/mL), aspartate aminotransferase (AST) level (cutoff point = 25 IU/L), age (cutoff point = 40 years), and HBV family history were identified as independent predictors of significant histological abnormalities in multivariate logistic analysis.

CONCLUSIONS

A significantly higher proportion of patients with histological abnormalities were found in patients with qHBsAg >1000 IU/mL than those without. The qHBsAg level together with age, AST, and family history of HBV infection could be used as an algorithm to help noninvasive patient selection for antiviral therapy.

Vitamin D signaling inhibits HBV activity by directly targeting the HBV core promoter

Clinical and epidemiological studies support a role for vitamin D in suppressing hepatitis B virus (HBV). This antiviral role of vitamin D is widely attributed to vitamin D receptor (VDR)/retinoid X receptor-mediated regulation of host immunomodulatory genes through vitamin D response elements (VDREs) in their promoters. Here, we investigated the ability of calcitriol (1α,25-dihydroxyvitamin D3, metabolically activated vitamin D) to directly regulate HBV activity through this signaling pathway. We observed that calcitriol selectively inhibited only the HBV core promoter without affecting the HBV-PreS1, HBV-PreS2/S, or HBx promoters. We then identified a VDRE cluster in the HBV core promoter that is highly conserved across most HBV genotypes. Disruption of this VDRE cluster abrogated calcitriol-mediated suppression of the HBV core promoter. Furthermore, we showed that VDR interacts directly with the VDRE cluster in the HBV core promoter independent of retinoid X receptor. This demonstrates that calcitriol inhibits HBV core promoter activity through a noncanonical calcitriol-activated VDR pathway. Finally, we observed that calcitriol suppressed expression of the canonical HBV core promoter transcripts, pregenomic RNA, and precore RNA in multiple HBV cell culture models. In addition, calcitriol inhibited the secretion of hepatitis B "e" antigen and hepatitis B surface antigen (HBV-encoded proteins linked to poor disease prognosis), without affecting virion secretion. Our findings identify VDR as a novel regulator of HBV core promoter activity and also explain at least in part the correlation of vitamin D levels to HBV activity observed in clinical studies. Furthermore, this study has implications on the potential use of vitamin D along with anti-HBV therapies, and lays the groundwork for studies on vitamin D-mediated regulation of viruses through VDREs in virus promoters.

The role of quantitative HBsAg in patients with HBV DNA between 2000-20,000 IU/ml

AIMS

We aimed to determine the contribution of quantitative HBsAg in differentiating chronic infections from chronic hepatitis in HBeAg negative patients with HBV DNA 2000-20,000 IU/ml.

MATERIAL AND METHODS

A total of 79 untreated HBeAg negative patients were included. Patients were divided into 3 groups based on HBV DNA levels: group 1 (HBV DNA ≤ 2000 IU/ml), group 2 (HBV DNA: 2000-20,000 IU/ml) and group 3 (HBV DNA > 20,000 IU/ml). We collected serum from all patients for quantitative HBsAg analysis. We compared serum quantitative HBsAg levels with biochemical parameters, HBV DNA and liver biopsy results.

RESULTS

In this study 46 patients were female and the mean age was 42 years. Serum quantitative HBsAg levels were found to be significantly lower in chronic infections compared with chronic hepatitis. There was a positive correlation between quantitative HBsAg and HBV DNA, ALT (alanine aminotransferase), HAI score (histological activity index), fibrosis score and disease stage. The cut-off level of quantitative HBsAg was determined as 4425 IU/ml to differentiate chronic infection from chronic hepatitis. With the test specificity of 95%, we found quantitative HBsAg cut-off values 1026 IU/ml and 20,346 IU/ml for the diagnosis of chronic infection and chronic hepatitis, respectively.

CONCLUSION

Our study suggests that the quantitative HBsAg ≤ 1000 IU/ml limit value might be used for the diagnosis of chronic infection not only in HBV DNA ≤ 2000 IU/ml but also in patients with HBV DNA between 2000-20,000 IU/ml. In addition, antiviral treatment could be considered in patients with quantitative HBsAg > 20,000 IU/ml and HBV DNA > 2000 IU/ml without further examinations such as liver biopsy.

Deep sequencing of liver explant transcriptomes reveals extensive expression from integrated hepatitis B virus DNA

Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). Integration of HBV DNA into the human genome may contribute to oncogenesis and to the production of the hepatitis B surface antigen (HBsAg). Whether integrations contribute to HBsAg levels in the blood is poorly known. Here, we characterize the HBV RNA profile of HBV integrations in liver tissue in patients with chronic HBV infection, with or without concurrent hepatitis D infection, by transcriptome deep sequencing. Transcriptomes were determined in liver tissue by deep sequencing providing 200 million reads per sample. Integration points were identified using a bioinformatic pipeline. Explanted liver tissue from five patients with end-stage liver disease caused by HBV or HBV/HDV was studied along with publicly available transcriptomes from 21 patients. Almost all HBV RNA profiles were devoid of reads in the core and the 3' redundancy (nt 1830-1927) regions, and contained a large number of chimeric viral/human reads. Hence, HBV transcripts from integrated HBV DNA rather than from covalently closed circular HBV DNA (cccDNA) predominated in late-stage HBV infection, in particular in cases with hepatitis D virus co-infection. The findings support the suggestion that integrated HBV DNA can be a significant source of HBsAg in humans.

Abundance of non-circular intrahepatic hepatitis B virus DNA may reflect frequent integration into human DNA in chronically infected patients

Background

Hepatitis B virus (HBV) integration has implications for cancer development and surface antigen (HBsAg) production, but methods to quantify integrations are lacking. The aim of this study was to develop a droplet digital PCR (ddPCR) assay discriminating between circular and integrated HBV DNA, and to relate the distribution between the two forms to other HBV markers.

Methods

ddPCR with primers spanning the typical linearization breakpoint in the HBV genome allowed for quantification of the absolute copy numbers of total and circular HBV DNA, and calculation of linear HBV DNA.

Results

Analysis of 70 liver biopsies from patients with chronic HBV infection revealed that the fraction of linear HBV DNA, which includes integrations, was higher in HBeAg-negative patients than HBeAg-positive. The ratio between HBsAg and HBV DNA levels in serum correlated with the intrahepatic proportion of linear HBV DNA. Furthermore, ddPCR experiments on serum samples and experiments with nuclease indicated the contribution of encapsidated double-stranded linear DNA and replication intermediates to be limited.

Conclusions

The degree of integration of intrahepatic HBV DNA in the HBeAg-negative stage may be higher than previously anticipated, and integrated DNA may explain the persistence of high HBsAg serum levels in patients with low HBV DNA levels.

High serum levels of pregenomic RNA reflect frequently failing reverse transcription in hepatitis B virus particles

Background

Hepatocytes infected by hepatitis B virus (HBV) produce different HBV RNA species, including pregenomic RNA (pgRNA), which is reverse transcribed during replication. Particles containing HBV RNA are present in serum of infected individuals, and quantification of this HBV RNA could be clinically useful.

Methods

In a retrospective study of 95 patients with chronic HBV infection, we characterised HBV RNA in serum in terms of concentration, particle association and sequence. HBV RNA was detected by real-time PCR at levels almost as high as HBV DNA.

Results

The HBV RNA was protected from RNase and it was found in particles of similar density as particles containing HBV DNA after fractionation on a Nycodenz gradient. Sequencing the epsilon region of the RNA did not reveal mutations that would preclude its binding to the viral polymerase before encapsidation. Specific quantification of precore RNA and pgRNA by digital PCR showed almost seven times lower ratio of precore RNA/pgRNA in serum than in liver tissue, which corresponds to poorer encapsidation of this RNA as compared with pgRNA. The serum ratio between HBV DNA and HBV RNA was higher in genotype D as compared with other genotypes.

Conclusions

The results suggest that HBV RNA in serum is present in viral particles with failing reverse transcription activity, which are produced at almost as high rates as viral particles containing DNA. The results encourage further studies of the mechanisms by which these particles are produced, the impact of genotype, and the potential clinical utility of quantifying HBV RNA in serum.

Electronic supplementary material

The online version of this article (10.1186/s12985-018-0994-7) contains supplementary material, which is available to authorized users.

Impact of integrated viral DNA on the goal to clear hepatitis B surface antigen with different therapeutic strategies

A hallmark of hepatitis B virus (HBV) infection is the presence of hepatitis B surface antigen (HBsAg) in the serum of patients. Sustained loss of HBV DNA and HBsAg from the blood are main goals for treatment, and considered as functional cure. It is rarely achieved with long-term nucleoside analogue treatment though, both because cccDNA, the template for viral replication, is not completely cleared, and probably also because hepatocytes with HBV DNA integrated into their chromosomes persist and continue to produce large amounts of HBsAg. Therefore, loss of HBsAg requires that both cccDNA and integrated DNA are cleared or their expression blocked. Recent data indicate that this may be achieved in some patients by stopping nucleoside analogue treatment, and that HBsAg-levels can be reduced by using specific interfering RNA. In the future, targeted degradation or disruption of HBV DNA might be possible using genome editing techniques such as CRISPR/Cas9.

Traditional Chinese Medicine Syndrome Patterns and Their Association with Hepatitis B Surface Antigen Levels during the Natural History of Chronic Hepatitis B Virus Infection

The aim of this study is to investigate traditional Chinese medicine syndrome (TCMS) patterns and their association with hepatitis B surface antigen (HBsAg) levels during the natural history of chronic hepatitis B virus infection (CHB). Patients were categorized according to the phase of CHB, as follows: immune tolerance (ITP); immune clearance (ICP); low or nonreplication (LRP); reactivation (RAP); hepatic cirrhosis (HC); and primary liver cancer (PLC). TCMS patterns were classified among the following types: spleen-kidney deficiency (SKD); liver-qi depression (LQD); damp-heat in liver-gallbladder (LGDH); liver-kidney deficiency (LKD); and blood stasis blocking collateral (BSBC). HBsAg levels and other serological indicators were quantified for all patients and their association with TCMS was statistically analyzed and determined. Two hundred and eighty-nine patients with CHB were included. During the natural history of CHB, TCMS patterns were statistically different among the different phases (P < 0.001). The most frequently occurring syndromes among the six progressive phases were SKD, LGDH, LKD, LGDH, BSBC, and LGDH, respectively. The predominant patterns in the inactive stage (ITP + LRP), active stage (ICP + RAP), and late or advanced stage (HC + PLC) were SKD (31%), LGDH (51.8%) and BSBC (34.4%), respectively. Median HBsAg levels were also statistically different among the five patterns of TCMS (P < 0.001). The highest HBsAg levels were observed in SKD (4.48 log₁₀ IU/mL). Medium levels were in LQD (3.91 log₁₀ IU/mL) and LGDH (3.90 log₁₀ IU/mL). The lowest HBsAg levels were in LKD (3.60 log₁₀ IU/mL) and the second lowest levels in BSBC (3.81 log₁₀ IU/mL). In addition, HBsAg levels in LKD and BSBC were significantly lower than those in SKD, LQD, and LGDH (P < 0.05 or 0.001). TCMS was altered during the natural history of CHB and correlated with HBsAg titers. This study could provide further insight into the therapy of CHB.

Can quantitative hepatitis B surface antigen levels predict the severity of liver disease in genotype E Patients?

The utility of quantitative Hepatitis B surface antigen (qHBsAg) level as a marker of chronic hepatitis B (CHB)-related liver damage is not fully delineated, but is becoming increasingly relevant. Quantitative HBsAg levels are linked with progression of liver disease in HBeAg-negative genotype B and C patients, but it is not clear whether this is consistent across all HBV genotypes. In this single-centre, cross-sectional observational study, we evaluated whether qHBsAg levels can predict the severity of liver disease in genotype E patients. Demographic characteristics, viral, biochemical markers and qHBsAg levels were assessed at time of liver biopsy [all HBV DNA>2000 IU/mL and/or abnormal alanine transaminase (ALT)]. Patients were divided into three groups according to the severity of fibrosis on biopsy: mild (F0-1), moderate (F2-4), severe (F5-6) liver disease and into two groups according to the NI grading, low (NI 0-3) and high inflammation (NI ≥4). A total of 259 HBeAg-negative CHB treatment-naive genotype E patients were studied. The median age of this cohort was 38 years, and 61% were males. Advanced (severe) fibrosis patients had higher ALT, HBV DNA, and lower HBsAg level and qHBsAg/DNA ratio. Patients with NI ≥4 had higher ALT, HBV DNA, but lower qHBsAg/DNA ratio. There was no correlation between HBsAg and HBV DNA levels. Quantitative HBsAg levels were lower in more advanced liver fibrosis. There was no correlation between qHBsAg and HBV DNA levels. This may reflect discordance between viral replication and transcriptional activity or differential HBsAg expression in HBeAg-negative genotype E patients with advanced liver disease.

Smaller reduction of hepatitis B virus DNA in liver tissue than in serum in patients losing HBeAg

The prognosis and outcome of treatment for chronic hepatitis B virus (HBV) infection are predicted by levels of HBV DNA in serum. These levels are composed of relaxed circular DNA (rcDNA) and double stranded linear DNA in viral particles, whereas, HBV DNA in liver tissue also can be covalently closed circular DNA (cccDNA) or integrated into the human genome. The aim of this study was to investigate the quantitative relation between HBV DNA in serum and tissue, its change over time and how these markers relate to serum levels of hepatitis B surface antigen (HBsAg). Serum and liver biopsies taken from 15 patients with chronic HBV infection on two occasions during 2.7-11.1 years were analyzed retrospectively. At baseline, the median HBV DNA levels in serum were 7.76 log₁₀  IU/mL in nine hepatitis B e antigen (HBeAg) positive and 3.65 log₁₀ IU/mL in six HBeAg-negative patients. At follow-up, serum HBV DNA, serum HBsAg, and intrahepatic HBV DNA (ihDNA) levels had declined by 4.36, 0.52, and 1.47 log₁₀ units, respectively, in seven patients that lost HBeAg, whereas the corresponding reductions were 0.36, 0.30, and 0.39 log₁₀ units in eight patients with unchanged HBeAg status. We conclude that HBV DNA in liver tissue declined almost 1000 times less than HBV DNA in serum during and after loss of HBeAg. This finding raises the possibility that integrated sequences constitute a significant part of the ihDNA. Alternatively, the greater decline of HBV DNA in serum might be due to yet unknown mechanisms acting downstream of reverse transcription.

Hepatitis B virus core-related antigen as a surrogate marker for covalently closed circular DNA

BACKGROUND & AIMS

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is a key to viral persistence in chronic hepatitis B infection. Serum hepatitis B core-related antigen (HBcrAg) is a novel marker for HBV disease. We aimed to determine whether HBcrAg could be a surrogate marker for intrahepatic cccDNA.

METHODS

Three hundred and five liver biopsies and the corresponding sera collected from 138 nucleos(t)ide analogues-treated patients were analysed. 124 patients had paired liver biopsies at baseline and 1-year post-treatment, and 43 patients had a third biopsy after 6-12 years of treatment. Serum HBcrAg, HBV DNA and hepatitis B surface antigen (HBsAg), and intrahepatic HBV DNA and cccDNA were measured.

RESULTS

HBcrAg strongly correlated with cccDNA (r=.70), intrahepatic total HBV DNA (r=.67) and serum HBV DNA (r=.69; all P<.0001). In the 130 samples with undetectable serum HBV DNA, HBcrAg was detectable in 101 (78%) samples, and HBcrAg levels still correlated positively with cccDNA (r=.42, P<.0001). At ≥6 years of therapy, the median logarithmic reduction in HBcrAg was 2.7 log kU/mL, which was comparable to the magnitude of reduction in cccDNA. Twenty-one patients had undetectable cccDNA after ≥6 years of treatment, in whom 15 (71%) had detectable HBcrAg (range: 1.2-537 kU/mL).

CONCLUSIONS

Serum HBcrAg is a reliable surrogate marker for intrahepatic cccDNA. HBcrAg could be a very sensitive marker to reflect the cccDNA content and persistence of disease even with the cccDNA levels below the detection limit of assays.

Quantitative intrahepatic HBV cccDNA correlates with histological liver inflammation in chronic hepatitis B virus infection

BACKGROUND

The aim of this study was to determine the role of baseline hepatitis B virus (HBV) forming covalently closed circular DNA (HBV cccDNA) in liver inflammation in patients infected with HBV with serum alanine aminotransferase (ALT) levels under two times the upper limit of normal (2×ULN).

METHODS

After liver biopsy and serum virological and biochemical marker screening, patients diagnosed with chronic HBV infection with serum ALT levels under 2×ULN and histological liver inflammation of less than grade G2 were prospectively recruited into this study. Recruitment took place between March 2009 and November 2010 at the Center of Infectious Disease, Sichuan University. Patient virological and biochemical markers, as well as markers of liver inflammation, were monitored.

RESULTS

A total of 102 patients were recruited and 68 met the inclusion criteria; the median follow-up was 4.1 years (range 3.9-5.2 years). During follow-up, 41 patients (60.3%) exhibited signs of inflammation. Baseline HBV cccDNA >1 copy/cell (odds ratio 9.43, p=0.049) and liver inflammation grade ≥G1 (odds ratio 5.77, p=0.046) were both independent predictors of liver inflammation.

CONCLUSIONS

A higher baseline intrahepatic HBV cccDNA level may increase the risk of liver inflammation. Further investigations will be required to validate HBV cccDNA as an intrahepatic virological marker of patients who require extended outpatient management.

End Joining-Mediated Gene Expression in Mammalian Cells Using PCR-Amplified DNA Constructs that Contain Terminator in Front of Promoter

Mammalian gene expression constructs are generally prepared in a plasmid vector, in which a promoter and terminator are located upstream and downstream of a protein-coding sequence, respectively. In this study, we found that front terminator constructs-DNA constructs containing a terminator upstream of a promoter rather than downstream of a coding region-could sufficiently express proteins as a result of end joining of the introduced DNA fragment. By taking advantage of front terminator constructs, FLAG substitutions, and deletions were generated using mutagenesis primers to identify amino acids specifically recognized by commercial FLAG antibodies. A minimal epitope sequence for polyclonal FLAG antibody recognition was also identified. In addition, we analyzed the sequence of a C-terminal Ser-Lys-Leu peroxisome localization signal, and identified the key residues necessary for peroxisome targeting. Moreover, front terminator constructs of hepatitis B surface antigen were used for deletion analysis, leading to the identification of regions required for the particle formation. Collectively, these results indicate that front terminator constructs allow for easy manipulations of C-terminal protein-coding sequences, and suggest that direct gene expression with PCR-amplified DNA is useful for high-throughput protein analysis in mammalian cells.

Mechanisms downstream of reverse transcription reduce serum levels of HBV DNA but not of HBsAg in chronic hepatitis B virus infection

BACKGROUND

Hepatitis B virus (HBV) DNA in serum of chronically infected patients declines by 3-4 log10 units at loss of HBe antigen (HBeAg) from serum. The mechanisms behind this decline, and the much smaller decline of surface antigen (HBsAg) levels, are still not well known. The aim of this study was to get a better understanding of this process by analysing both serum and intrahepatic markers of HBV replication.

METHODS

Levels of HBV DNA and HBsAg in serum, and covalently closed circular DNA (cccDNA), pregenomic RNA (pgRNA) and S-RNA and total intrahepatic HBV DNA (ihDNA) in liver biopsies from 84 chronically infected patients (16 positive and 68 negative for HBeAg) were analysed.

RESULTS

Lower HBV DNA levels within HBeAg-positive stage reflected lower levels of cccDNA and pgRNA with strong correlation. In HBeAg-negative patients, ihDNA levels were greater and HBV DNA levels in serum lower than expected from pgRNA levels. A lower HBV DNA/HBsAg ratio corresponded with lower pgRNA/cccDNA (p < 0.01) and higher S-RNA/cccDNA (p < 0.0001) ratios, suggesting that in HBeAg-negative patients transcription of pgRNA, but not of S-RNA, becomes suppressed.

CONCLUSIONS

The marked reduction of HBV DNA in serum after loss of HBeAg appears to be due to combined reduction of cccDNA, pgRNA and yet unidentified mechanisms downstream of reverse transcription. Such mechanisms include faster clearance of circulating virus or blocked secretion of virions, the latter supported by the observed relative increase of ihDNA in HBeAg-negative patients. The smaller reduction of S-RNA than of pgRNA partly explains why HBsAg remain high in the HBeAg-negative stage, supporting the possibility of HBsAg synthesis from integrated HBV DNA.

Nationwide large survey on hepatitis B surface antigen quantification use in real-life clinical practice

BACKGROUND AND AIM

Hepatitis B surface antigen quantification (qHBsAg) is a relevant biomarker assay in the therapeutic management of hepatitis B virus-infected patients; however, little is known about its use in France. The aim of this study was to describe the knowledge of qHBsAg use and the indications for the prescription of qHBsAg in France.

METHODS

From March 2014 to May 2014, 135 questionnaires were sent to hepatologists and gastroenterologists from several health centers (private practice, public practice, and outlying health centers). There were 20 items in each questionnaire on the use of qHBsAg.

RESULTS

Seventy-six percent of the practitioners had previously used qHBsAg, among whom 88% had prescribed the use of qHBsAg before treatment, 73% had prescribed the use of qHBsAg in combination with hepatitis B virus viral load, 64% had prescribed the use of qHBsAg at week 12 or week 24 of treatment, 62% had prescribed the use of qHBsAg for stopping rules, and 49% had prescribed the use of qHBsAg to identify inactive carriers. The reason for nonprescription of qHBsAg was mainly because of difficulty accessing the test (50% of the practitioners), followed by nonreimbursement of the test (27%); 97% of the practitioners who did not prescribe qHBsAg indicated an interest in accessing the test.

CONCLUSION

This survey describes the characteristics of the prescription of qHBsAg in France. More than three out of four practitioners have previously used qHBsAg. The use of the qHBsAg just before treatment was the main reason for prescription. The main reason for nonprescription was because of difficulty in accessing the test.

Can serum level of HBsAg differentiate HBeAg-negative chronic hepatitis B from inactive carrier state?

Hepatitis B envelope antigen (HBeAg)-negative hepatitis B virus (HBV) infection exerts both inactive carrier (IC) state and chronic hepatitis B (CHB), which are sometimes difficult to be differentiated. We aimed to assess the role of hepatitis B surface antigen (HBsAg) level in differentiation of CHB and IC among a group of chronic HBeAg-negative HBV-infected patients. A total of 251 HBeAg-negative HBV-infected patients were enrolled. Serum HBV DNA and HBsAg levels were determined for each patient. HBV DNA quantification with cutoff value 2000IU/mL for diagnosis of CHB had 99.0% sensitivity and 74.1% specificity. A cutoff value of HBsAg level at 1000IU/mL was more reliable for diagnosis of CHB with 82.7% sensitivity and 66.2% specificity than other HBsAg cutoff values. There was a positive correlation between HBV DNA and HBsAg levels in both CHB (r=0.42, P<0.001) and IC (r=0.43, P<0.001) groups. Single-point HBsAg quantification did not have enough sensitivity and specificity for differentiation of HBeAg-negative CHB and IC state.

Clinical performance of a new hepatitis B surface antigen quantitative assay with automatic dilution

Hepatitis B virus surface antigen (HBsAg) levels reflect disease status and can predict the clinical response to antiviral treatment; however, the emergence of HBsAg mutant strains has become a challenge. The Abbott HBsAg quantification assay provides enhanced detection of HBsAg and HBsAg mutants. We aimed to evaluate the performance of the Abbott HBsAg quantification assay with automatic sample dilutions (shortened as automatic Architect assay), compared with the Abbott HBsAg quantification assay with manual sample dilutions (shortened as manual Architect assay) and the Roche HBsAg quantification assay with automatic sample dilutions (shortened as Elecsys). A total of 130 sera samples obtained from 87 hepatitis B virus (HBV)-infected patients were collected to assess the correlation between the automatic and manual Architect assays. Among the 87 patients, 41 provided 42 sera samples to confirm the linearity and reproducibility of the automatic Architect assay, and find out the correlation among the Elecsys and two Architect assays. The coefficients of variation (0.44-9.53%) and R(2) = 0.996-1, which were both determined using values obtained from the automatic Architect assay, showed good reproducibility and linearity. Results of the two Architect assays demonstrated a feasible correlation (n = 130 samples; R = 0.898, p < 0.01). With regard to subgroups, correlations between the two Architect assays were better in the hepatitis B e antigen (HBeAg)-negative group (HBeAg-negative group vs. HBeAg-positive group: R = 0.885 vs. R = 0.865, both p < 0.01) and low HBV DNA group (low DNA group vs. high DNA group: R = 0.886 vs. R = 0.844, both p < 0.01). Significant correlations were also found between the results of the Elecsys and Architect assays (R > 0.93 in all cases). In conclusion, the correlation between the automatic and manual dilution Architect assays was feasible, particularly in the HBeAg-negative and low DNA groups. With lower labor costs and less human error than the manual version, the Abbott automatic dilution Architect assay provided a good clinical performance with regard to the HBsAg levels.

High levels of hepatitis B surface antigen are associated with poorer survival and early recurrence of hepatocellular carcinoma in patients with low hepatitis B viral loads

PURPOSE

Recurrence is a disastrous outcome in patients with hepatitis-related hepatocellular carcinoma (HCC) who have undergone curative resection, and little is known about whether high levels of hepatitis B surface antigen (HBsAg) increase the risk of HCC recurrence.

PATIENTS AND METHODS

This retrospective study included 1,360 HBsAg-positive postoperative HCC patients with hepatitis B viral (HBV) DNA levels < 2000 IU/mL, including 298 patients in a training cohort and 1,062 patients in a validation cohort. The prognostic value of the HBsAg level was evaluated using Cox regression and Kaplan-Meier analyses.

RESULTS

We demonstrated that 1,000 IU/mL, but not 10 or 100 IU/mL, was a meaningful cutoff level for significantly discriminating these patients into an HBsAg(Low) group and an HBsAg(High) group based on correlations between the HBsAg level and liver cirrhosis (p = 0.028), tumor size (p = 0.039), and hepatitis B e antigen level (p < 0.001). The postoperative 1-, 3-, and 5-year overall survival (OS) rates of HCC patients in the HBsAg(Low) group were significantly higher than those of HCC patients in the HBsAg(High) group. Accordingly, the 5-year recurrence-free survival (RFS) rates of patients in the HBsAg(Low) group were markedly higher than those of HCC patients in the HBsAg(High) group. The HBsAg level was a prognostic indicator for OS (p = 0.014) and RFS (p = 0.01).

CONCLUSION

HBsAg level is correlated with more aggressive tumor behavior and serves as a prognostic indicator in patients with surgically resected HCC with low HBV load.

Hepatitis B surface antigen levels during natural history of chronic hepatitis B: A Chinese perspective study

AIM: To determine the baseline hepatitis B surface antigen (HBsAg) levels during the different phases of chronic hepatitis B (CHB) patients in China.

METHODS: Six hundred and twenty-three hepatitis B virus or un-infected patients not receiving antiviral therapy were analyzed in a cross-sectional study. The CHB patients were classified into five phases: immune-tolerant (IT, n = 108), immune-clearance (IC, n = 161), hepatitis B e antigen negative hepatitis (ENH, n = 149), low-replicative (LR, n = 135), and liver cirrhosis (LC, n = 70). HBsAg was quantified (Abbott ARCHITECT assay) and correlated with hepatitis B virus (HBV) DNA, and serum alanine aminotransferase/aspartate aminotransferase (ALT/AST) in each phase of CHB was also determined.

RESULTS: Median HBsAg titers were different in each phase of CHB (P < 0.001): IT (4.85 log₁₀ IU/mL), IC (4.36 log₁₀ IU/mL), ENH (2.95 log₁₀ IU/mL), LR (3.18 log₁₀ IU/mL) and LC (2.69 log₁₀ IU/mL). HBsAg titers were highest in the IT phase and lowest in the LC phase. Serum HBsAg titers showed a strong correlation with HBV viral load in the IC phase (r = 0.683, P < 0.001). No correlation between serum HBsAg level and ALT/AST was observed.

CONCLUSION: The mean baseline HBsAg levels differ significantly during the five phases of CHB, providing evidence on the natural history of HBV infection. HBsAg quantification may predict the effects of immune-modulator or oral nucleos(t)ide analogue therapy.

Baseline HBsAg predicts response to pegylated interferon-α2b in HBeAg-positive chronic hepatitis B patients

AIM: To evaluate the predictive effect of baseline hepatitis B surface antigen (HBsAg) on response to pegylated interferon (PEG-IFN)-α2b in hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients.

METHODS: This retrospective analysis compared the treatment efficacy of PEG-IFN-α2b alone in 55 HBeAg-positive CHB patients with different baseline HBsAg levels. Serum HBV DNA load was measured at baseline, and at 12, 24 and 48 wk of therapy. Virological response was defined as HBV DNA < 1000 IU/mL. Serum HBsAg titers were quantitatively assayed at baseline, and at 12 and 24 wk.

RESULTS: Eighteen patients had baseline HBsAg > 20 000 IU/mL, 26 patients had 1500-20000 IU/mL, and 11 patients had < 1500 IU/mL. Three (16.7%), 11 (42.3%) and seven (63.6%) patients in each group achieved a virological response at week 48, with a significant difference between groups with baseline HBsAg levels > 20000 or < 20000 IU/mL (P = 0.02). Thirteen patients had an HBsAg decline > 0.5 log₁₀ and 30 patients < 0.5 log₁₀ at week 12; and 6 (46.2%) and 10 (33.3%) in each group achieved virological response at week 48, with no significant difference between the two groups (P = 0.502). Eighteen patients had an HBsAg decline > 1.0 log₁₀ and 30 patients < 1.0 log₁₀ at week 24, and 8 (44.4%) and 11 (36.7%) achieved a virological response at week 48, with no significant difference between the two groups (P = 0.762). None of the 16 patients with HBsAg > 20000 IU/mL at week 24 achieved a virological response at week 48.

CONCLUSION: Baseline HBsAg level in combination with HBV DNA may become an effective predictor for guiding optimal therapy with PEG-IFN-α2b against HBeAg-positive CHB.

HBeAg negative variants and their role in the natural history of chronic hepatitis B virus infection

Molecular virology methods including polymerase chain reaction, cloning and sequencing have revolutionised our understanding of viral genome variation. In the case of hepatitis B virus (HBV), sequencing studies have identified a number of virus variants normally found during the natural course of chronic infection. The appearance of the precore stop codon (with G-for-A substitution at position 1896) and basal core promoter (BCP) (with A-for-T and G-for-A, at positions 1762 and 1764, respectively) variants which reduce or abrogate hepatitis B e antigen (HBeAg) production, heralds the initiation of the seroconversion phase from HBeAg to anti-HBe positivity. The gradual removal of the tolerogenic effect of HBeAg leads to the awakening of the immune response (immune clearance phase). Most patients after HBeAg seroconversion become “inactive HBsAg carriers”. However during the course of infection precore and/or BCP variants may emerge and be selected leading to HBeAg negative chronic hepatitis B (CHB) with high viremia levels (reactivation phase). The prevalence of HBeAg negative CHB has been increasing over the last few decades and has become the commonest type of HBV infection in many countries of the world. This probably reflects the aging of existing HBV carriers and the effective prevention measures restricting new HBV infections. Frequent acute exacerbations accompanied by high viral replication, elevated alanine aminotransferase levels and histological activity are a common feature of HBeAg negative CHB leading to cirrhosis much faster than in HBeAg positive CHB patients.

Analysis of hepatitis B virus intrahepatic covalently closed circular DNA and serum viral markers in treatment-naive patients with acute and chronic HBV infection

Background

This study aimed to investigate the relationships of intrahepatic cccDNA with serum HBsAg and with HBV DNA in treatment-naive patients throughout acute and chronic HBV infection.

Methods

A total of 120 patients who had a liver biopsy were enrolled, including 19 with acute hepatitis B (AHB), and 101 patients with chronic HBV infection (CHB) of whom were 10 in immune-tolerant (IT) phase, 59 in immune-clearance (IC) phase, 8 in low-replicative (LR) phase, and 24 in HBeAg-negative hepatitis (ENH) phase. Intrahepatic cccDNA, serum HBsAg and serum HBV DNA levels were comparatively analyzed.

Results

The median intrahepatic cccDNA levels were 0.18 4.80, 3.81, 0.22 and 0.97 copies/cell for patients with AHB, CHB-IT, CHB-IC, CHB-LR, and CHB-ENH, respectively. In AHB patients, intrahepatic cccDNA was positively correlated with serum HBsAg (r = 0.665, P = 0.003), as well as serum HBV DNA (r = 0.536, P = 0.022). In CHB patients, intrahepatic cccDNA was positively correlated with serum HBsAg in the IC phase (r = 0.392, P = 0.005), and with serum HBV DNA in the IC phase (r = 0.301, P = 0.036) and ENH phase (r = 0.588, P = 0.013). HBV replicative efficiency, defined as the ratio of serum HBV DNA to intrahepatic cccDNA, was obviously lower in AHB and CHB-LR patients than in CHB-IT, CHB-IC and CHB-ENH patients (0.70 and 0.53 vs. 1.12, 1.09 and 0.99, P<0.001, values were logarithmic transformed for analysis). In CHB-IC patients, HBV replicative efficiency was positively correlated with histological activity index of liver inflammation (r = 0.308, P = 0.009).

Conclusion

Serum HBsAg and HBV DNA levels may reflect the amount of active intrahepatic cccDNA in treatment-naive AHB and CHB-IC patients. Reduced intrahepatic cccDNA and HBV replicative efficiency may imply effective immune control of HBV infection.