COBAS AmpliPrep-COBAS TaqMan hepatitis B virus (HBV) test: a novel automated real-time PCR assay for quantification of HBV DNA in plasma

CRISPR/Cas12b assisted loop-mediated isothermal amplification for easy, rapid and sensitive quantification of chronic HBV DNA in one-pot

BACKGROUND

Currently, millions of people suffer from undiagnosed chronic hepatitis B (CHB) infection each year, which leads to high mortality rates attributed to cirrhosis and hepatocellular carcinoma. Previously reported assays, such as PCR-based assays, have limitations in terms of convenient for CHB screening in high-burden regions and resource-limited settings. Recently, diagnosis based on CRISPR/Cas, which has been considered as a potential method of point-of-care test (POCT) in resource-limited settings, offers a significant advantage in terms of high sensitivity and specificity. Therefore, there is an urgent need for the hepatitis B virus (HBV) detection utilizing CRISPR/Cas system.

RESULTS

We have proposed a one-pot of one-step method for CRISPR/Cas12b assisted loop-mediated isothermal amplification (LAMP) to facilitate the quick, sensitive, and precise quantification of HBV DNA. This method is designed for point-of-care testing following genomic extraction or sample heat treatment. We have optimized several critical factors, such as the reaction buffer, AapCas12b-gRNA concentration, reporter and its concentration, reaction temperature, and chemical additives, to significantly enhance the performance of the one-pot assay for HBV. Importantly, it exhibited no cross-reactivity between HBV and blood-borne pathogens. Moreover, the assay is capable of quantifying HBV DNA within 1 h with a limit of detection (LOD) of 25 copies per milliliter. Additionally, when tested on 236 clinical samples, the assay demonstrated a sensitivity of 99.00 % (198/200) and a specificity of 100.00 % (36/36) at the 99 % confidence level compared to real-time quantitative PCR.

SIGNIFICANCE

The utilization of convenient and reliable point-of-care diagnostic methods is crucial for reducing the burden of CHB globally. The assay we developed was helpful to improve the ability of HBV diagnosis for practical clinical translation, especially in high-burden regions and resource-limited settings. It has great advantages for rapid screening of CHB as well as evaluation of therapeutic efficacy as a companion diagnostic method.

Overt and occult hepatitis B virus infection detected among chronic kidney disease patients on haemodialysis at a Tertiary Hospital in Ghana

Hepatitis B virus (HBV) infection is endemic in Ghana and chronic kidney disease patients on haemodialysis are a high-risk group for HBV infection. We determined the prevalence of overt and occult HBV infection among haemodialysis patients at the Korle Bu Teaching Hospital in Ghana. 104 consenting End Stage Renal Disease patients on long-term haemodialysis were recruited for the study and their socio-demographic, clinical and laboratory information were obtained using structured questionnaire. All the participants were tested for the hepatitis B surface antigen (HBsAg). The HBsAg-negative participants were re-tested for hepatitis B surface antibody (HBsAb), hepatitis B core antibody (HBcAb) and HBV DNA using chemiluminescence and Roche COBAS Ampli-Prep/TaqMan analyser and real-time polymerase chain reaction. Eight (7.7%) of the total participants were positive for HBsAg. Among the 96 HBsAg-negative participants, 12.5% (12) were HBcAb-positive, 7.3% (7) had detectable HBV DNA (mean = 98.7±53.5 IU/mL) and 40.6% (39) were positive for HBsAb. Five out of the 7 HBV DNA-positive participants were males and only one participant was negative for HBcAb. Seventy-three out of the 96 HBsAg-negative participants were vaccinated and 37 of these vaccinated individuals had significant HBsAb titres (mean = 423.21± 380.72 IU/mL). Our data demonstrated that the prevalence of overt and occult HBV infection among the haemodialysis (HD) patients was 7.7% and 7.3%, respectively, and only 50.7% of those who showed proof of vaccination were protected from HBV infection.

Rapid quantification assay of hepatitis B virus DNA in human serum and plasma by Fully Automated Genetic Analyzer μTASWako g1

Real-time monitoring of serum hepatitis B virus (HBV) levels is essential for the management of patients with chronic HBV infection in clinical practice, including monitoring the resistance of anti-HBV nucleotide analog or the detection of HBV reactivation. In this context, serum HBV deoxyribonucleic acid (DNA) quantification should be rapidly measured. A rapid HBV DNA quantification assay was established on the Fully Automated Genetic Analyzer, μTASWako g1. The assay performs automated sample preparation and DNA extraction, followed by the amplification and detection of quantitative polymerase chain reaction (PCR) combined with capillary electrophoresis (qPCR-CE) on integrated microfluidic chip. This study aimed to evaluate the analytical and clinical performance of HBV DNA assay on the μTASWako g1 platform in human serum and EDTA-plasma. The HBV DNA assay has a linear quantitative range from 20 to 108 IU/mL of HBV DNA with standard deviation (SD) of ≤0.14 log10 IU/mL. The limits of detection of the assay were 4.18 for the serum and 4.35 for EDTA-plasma. The HBV assay demonstrated the equivalent performance in both human serum and EDTA-plasma matrices. The HBV genotypes A to H were detected with an accuracy of ±0.34 log10 IU/mL. In quantification range, the HBV DNA assay was correlated with Roche cobas AmpliPrep/cobas TaqMan Ver2.0 (CAP/CTM v2) (r = 0.964). The mean difference (μTASWako g1-CAP/CTM v2) of the reported HBV DNA was -0.01 log10 IU/mL. Overall, the sensitivity, accuracy, and precision of the μTASWako g1 HBV assay were comparable to the existing commercial HBV DNA assay, and the assay can be completed within 110 min. This evaluation suggests that the HBV DNA assay on the μTASWako g1 is potentially applied for alternative method of the HBV viral load test, in particular with the advantage of the HBV DNA result availability within 2 h, improving the HBV infection management.

Development of a sensitive, multi-assay platform to monitor low levels of HBV DNA and pgRNA in patients with chronic hepatitis B virus infection

HBV cure rates remain low despite prolonged nucleos(t)ide (NrtI) therapy, likely due to persistent residual viral replication and an inability to eliminate covalently closed circular DNA (cccDNA). Therapies with novel mechanisms of action against hepatitis B virus (HBV) are being explored with the goal of achieving sustained off-treatment response and a functional cure without requiring lifelong therapy. Recent studies have indicated that serum HBV DNA levels (a biomarker for viral replication) combined with serum pregenomic RNA (pgRNA) levels (a surrogate for intrahepatic cccDNA transcriptional activity), may provide a better prediction for the risk of liver-related complications. Current HBV DNA assays, such as the COBAS AmpliPrep/COBAS TaqMan HBV test v2.0, quantitate HBV DNA down to 20 IU/mL, but are not able to monitor loss of residual virus in patients on NrtI therapy. There are no commercially available assays approved to detect serum/plasma HBV pgRNA levels. We have developed a multi-assay panel of highly sensitive nucleic acid assays designed to monitor levels of HBV DNA, pgRNA and total nucleic acids (TNA, composite DNA + pgRNA) in clinical specimens and to monitor changes during treatment with new antiviral combination regimens.

Identification of mutations in the S gene of hepatitis B virus in HIV positive Mexican patients with occult hepatitis B virus infection

INTRODUCTION AND AIM

Occult hepatitis B virus infection (OBI) is characterized by the presence of replication-competent hepatitis B virus (HBV) DNA in the liver and/or serum of patients with undetectable levels of the HBV surface antigen (HBsAg). Due to the shared infection routes HIV positive patients are at higher risk of developing OBI, thus, the aim of this study was to determine the frequency of OBI in Mexican HIV-infected patients and to identify mutations in the HBV S gene that could be associated to the development of OBI.

MATERIALS AND METHODS

Plasma samples from 50 HIV-infected patients with undetectable levels of the HBsAg were obtained and analyzed. The Core, PreS and S genes were amplified by nested PCR and sequenced by the Sanger method. To analyze HBV diversity in the OBI-positive patients, ten sequences of 762bp from the HBV S gene were selected, cloned, and subsequently sequenced for mutational analyses.

RESULTS

OBI infection was found with a frequency of 36% (18/50). All the HBV sequences corresponded to the H genotype. The most common mutations were: C19Y, Q129H, E164D, and I195M, with a frequency of 44%, 36%, 39% and 48% respectively.

CONCLUSIONS

In this study, we report the presence of OBI in a cohort of Mexican HIV-infected patients with an overall prevalence of 36%. Mutational analyses revealed that four non-silent mutations were frequent in different regions of the HBsAg gene, suggesting that they might be associated to the development of OBI in this population, nevertheless, further studies are required to determine their role in the pathogenesis of OBI.

Endemic HBV among hospital in-patients in Bangladesh, including evidence of occult infection

Bangladesh is one of the top-ten most heavily burdened countries for viral hepatitis, with hepatitis B (HBV) infections responsible for the majority of cases. Recombinant and occult HBV infections (OBI) have been reported previously in the region. We investigated an adult fever cohort (n=201) recruited in Dhaka, to determine the prevalence of HBV and OBI. A target-enrichment deep sequencing pipeline was applied to samples with HBV DNA >3.0 log₁₀ IU ml⁻¹. HBV infection was present in 16/201 (8 %), among whom 3/16 (19 %) were defined as OBI (HBsAg-negative but detectable HBV DNA). Whole genome deep sequences (WGS) were obtained for four cases, identifying genotypes A, C and D. One OBI case had sufficient DNA for sequencing, revealing multiple polymorphisms in the surface gene that may contribute to the occult phenotype. We identified mutations associated with nucleos(t)ide analogue resistance in 3/4 samples sequenced, although the clinical significance in this cohort is unknown. The high prevalence of HBV in this setting illustrates the importance of opportunistic clinical screening and DNA testing of transfusion products to minimise OBI transmission. WGS can inform understanding of diverse disease phenotypes, supporting progress towards international targets for HBV elimination.

A High-Sensitivity Method Based on Advanced Optical Waveguide Technology to Detect HBsAg

A novel method for the detection of the hepatitis B surface antigen (HBsAg) at low concentrations, using the ultrahigh-order guided mode acting as the probe excited by a symmetrical metal-cladding waveguide, is proposed. The method using the fact of the minimum value of the absorption peaks is proportional to the concentration of the sample to be detected to realize the detection of the hepatitis B virus at extremely low concentrations. It is realized that the low concentration of the HBsAg measurement relied on the principle of the minimum value of the absorption peak and the concentration having a good linear relationship. The measurement results indicate that this new method can precisely detect HBsAg at the concentrations in the lower region of the clinical gray area (i.e., below 20 ng/mL), the lower region of the current clinical gray area of HBsAg (below 20 ng/ml) can be measured, and the resolution can be reached (2 ng/mL).

Outcome of nucleos(t)ide analog intervention in patients with preventive or on-demand therapy for hepatitis B virus reactivation

Preventive or on-demand nucleos(t)ide analog (NA) therapy can prevent severe hepatitis related to hepatitis B virus reactivation (HBV-R). However, it is unclear if NA can be safely stopped in such patients after cytotoxic therapies or during immunosuppressive therapies. We retrospectively evaluated 133 patients who initiated NA therapy between 2007 and 2018. A total of 103 patients were positive for HBV surface antigen (HBsAg) at baseline, and NA therapy was started before cytotoxic or immunosuppressive therapy (preventive group). Thirty patients with resolved HBV infection were treated with NA therapy after HBV reactivation (on-demand group). Virological relapse was defined as a serum HBV DNA level >20 IU/ml. NA therapy was stopped in 12 (12%) patients (preventive group), and in 16 (53%) patients (on-demand group). After the cessation of NA therapy, the cumulative rates of relapse were 36% and 39% at 12 and 24 months, respectively. High levels of HBsAg both at baseline and at the cessation of NA therapy were related to the occurrence of relapse. Relapse did not occur in patients with HBsAg levels <20 IU/ml (preventive group). HBV relapse occurred in five (33%) patients in the on-demand group. Relapse occurred only in anti-HBs-negative patients at the cessation of NA therapy. There were no cases of hepatitis flare after the cessation of NA therapy. HBsAg predicted HBV relapse after the cessation of NA therapy in HBsAg-positive patients. Anti-HBs could be a predictive marker for NA therapy cessation in patients with resolved HBV.

Occult Hepatitis B Virus Infection in Maintenance Hemodialysis Patients: Prevalence and Mutations in "a" Determinant

Background: Occult hepatitis B virus infection (OBI) is defined as undetectable serum hepatitis B surface antigen (HBsAg) with detectable HBV-DNA in the serum or liver. Patients with maintenance hemodialysis (MHD) are at a high risk of OBI. The prevalence of OBI in MHD patients in China is not well evaluated. In this study, we aim to assess the prevalence of OBI in MHD patients in Sichuan Province, Southwest of China and investigate the mutations in the "a" determinant of HBsAg. Methods: A total of 330 patients undergoing MHD at Sichuan Provincial People's Hospital were enrolled. Serum samples were collected for ELISA assay to test the serological markers of HBV infection, real-time PCR assay to identify the presence of HBV-DNA, and nested PCR plus sequencing analysis to investigate the gene mutations. Results: In a total of 330 MHD patients, we found that the prevalence of OBI was 4.2% (7/165) in the test group, 2.1% (7/330) in the overall dialysis cohort. After a follow-up study of 7 MHD patients with OBI for 2 years, 2 (isolated HBcAb+) of them were still detectable for HBV-DNA. By sequencing analysis, we revealed mutations at the "a" determinant of HBsAg, including Q129R, T131N, M133S, F134L and D144E. The Q129R and M133S mutations were first reported. Conclusions: Our study clarifies the prevalence of OBI in MHD patients in Sichuan Province(4.2% in the test group, 2.1% in the overall dialysis cohort), and demonstrate the mutations of Q129R and M133S in the "a" determinant of HBsAg for the first time.

Highly sensitive and specific detection of hepatitis B virus DNA and drug resistance mutations utilizing the PCR-based CRISPR-Cas13a system

OBJECTIVES

Undetectable or low-level hepatitis B virus (HBV) DNA and drug resistance mutations in patients may increase the risk of HBV transmission or cause active viral replication and other clinical problems. Here, we established a highly sensitive and practical method for HBV and drug resistance detection using a polymerase chain reaction (PCR) -based CRISPR-Cas13a detection system (referred to as PCR-CRISPR) and evaluated its detection capability using clinical samples.

METHODS

Specific CRISPR RNAs (crRNAs) are designed for HBV DNA detection and YMDD (tyrosine-methionine-aspartate-aspartate) variant identification. The HBV DNA was detected in 312 serum samples for HBV diagnosis using quantification PCR (qPCR) and PCR-CRISPR. Additionally, 424 serum samples for YMDD testing were detected by qPCR, direct sequencing, and our assay.

RESULTS

Using PCR-CRISPR, one copy per test of HBV DNA was detected with HBV-1 crRNA in 15 min after PCR amplification. Consistent results with qPCR were observed for 302 samples, while the remaining 10 samples with low-level HBV DNA were detectable by PCR-CRISPR and droplet digital PCR but not by qPCR. PCR-CRISPR diagnosed all 412 drug-resistant samples detected by the YMDD detection qPCR kit and direct sequencing, as well as the other 12 drug-resistant samples with low-level HBV DNA undetectable by qPCR and direct sequencing.

CONCLUSIONS

We developed a novel PCR-CRISPR method for highly sensitive and specific detection of HBV DNA and drug resistance mutations. One copy per test for HBV DNA and YMDD drug resistance mutations could be detected. This method has wide application prospects for the early detection of HBV infection, drug resistance monitoring and treatment guidance.

Sustained antiviral effects and clearance of hepatitis surface antigen after combination therapy with entecavir and pegylated interferon in chronic hepatitis B

BACKGROUND

Although the efficacy of combination therapy with lamivudine or tenofovir and pegylated interferon (PEG-IFN) has been reported in patients with chronic hepatitis B (CHB), the long-term effect of the combination based on the observation of clinical course remains to be clarified. We previously reported the efficacy of combination therapy with entecavir (ETV) and PEG-IFN. Here, we investigated the long-term effect of this combination in patients with CHB.

METHODS

We administered both ETV and PEG-IFN-α2a or -2b simultaneously to 26 patients with HBV genotype C infection. Treatment was continued for 48 weeks followed by 24 weeks of observation period; we examined the virological and biochemical responses. We also analysed characteristics related to the post-treatment relapse. Finally, we investigated the long-term therapeutic effects.

RESULTS

Average reduction of intra-hepatic cccDNA level was 1.2 log copies/μg at the completion of administration. Pretreatment hepatitis B surface antigen (HBsAg) level with more than 3.5 log U/ml was identified as a predictive factor for relapse. Furthermore, the cumulative rates of HBsAg-negative patients at 1, 3 and 5 years after the completion of administration were 3.8, 8.4 and 15%, respectively (mean follow-up period: 4.8 years).

CONCLUSIONS

Baseline HBsAg level with more than 3.5 log U/ml is a useful predictor for relapse 24 weeks after the completion of administration in patients treated with combination therapy. Combination with ETV and PEG-IFN could be an option for treatment of CHB patients especially in those with baseline HBsAg levels of less than 3.5 log U/ml.

Illumina and Nanopore methods for whole genome sequencing of hepatitis B virus (HBV)

Advancing interventions to tackle the huge global burden of hepatitis B virus (HBV) infection depends on improved insights into virus epidemiology, transmission, within-host diversity, drug resistance and pathogenesis, all of which can be advanced through the large-scale generation of full-length virus genome data. Here we describe advances to a protocol that exploits the circular HBV genome structure, using isothermal rolling-circle amplification to enrich HBV DNA, generating concatemeric amplicons containing multiple successive copies of the same genome. We show that this product is suitable for Nanopore sequencing as single reads, as well as for generating short-read Illumina sequences. Nanopore reads can be used to implement a straightforward method for error correction that reduces the per-read error rate, by comparing multiple genome copies combined into a single concatemer and by analysing reads generated from plus and minus strands. With this approach, we can achieve an improved consensus sequencing accuracy of 99.7% and resolve intra-sample sequence variants to form whole-genome haplotypes. Thus while Illumina sequencing may still be the most accurate way to capture within-sample diversity, Nanopore data can contribute to an understanding of linkage between polymorphisms within individual virions. The combination of isothermal amplification and Nanopore sequencing also offers appealing potential to develop point-of-care tests for HBV, and for other viruses.

Performance characteristics of a fast real-time PCR assay for hepatitis B virus DNA quantification

Detection of hepatitis B virus (HBV) DNA is particularly important for detection of early acute and of occult HBV infection. On the other hand, HBV DNA detection and quantification are essential to diagnose and treat chronic HBV infection. In this study, we evaluated the performance of the real-time PCR SUMASIGNAL VHB (un paso) (Immunoassay Center, Cuba). The clinical and analytical specificity of the assay was 100%. Intra-assay and inter-assay coefficients of variation ranged from 0.50 to 2.53% and from 1.23 to 3.03%, respectively. A strong correlation (r=0.926; P<0.001) with the COBAS^® AmpliPrep/COBAS^® TaqMan^® HBV Test, v2.0 (Roche Molecular Systems, Inc.) was obtained. The limit of detection using the third WHO international standard for HBV DNA was 377.47 IU/mL. The test was able to detect the most prevalent HBV genotypes (A-G) equally well. In conclusion, the SUMASIGNAL VHB (un paso) is a sensitive, specific, precise and accurate assay for the quantification of serum and plasma HBV DNA. Thus, this simple and fast real-time PCR test can be used as an aid in diagnosing an HBV infection and monitoring drug efficacy.

A novel fully automated system for quantification of Hepatitis B virus DNA using magnetic bead-based method combined with real-time PCR

BACKGROUND

Hepatitis B virus (HBV) infection is a major global health problem and causes liver damage as cirrhosis of the liver or liver cancer. Development of an accurate, sensitive and reproducible detection method for detecting and monitoring HBV DNA is very necessary and urgent.

OBJECTIVES

The aims were to evaluate the analytical performances of the fully automated Pre-NAT system comparing to domestic assay, and to explore the role of highly sensitive quantification of HBV DNA in the management of chronic HBV infection.

STUDY DESIGN

Pseudo-viral particles at high HBV DNA concentration were serially diluted to assess linear range. Accuracy and lower limit of detection were assessed by determining a panel of HBV standard substance. HBV DNA positive clinical specimen and internal quality control were measured 20 times to evaluate precision and reproducibility. 20 non HBV-infected specimens were used for the specificity assay. 96 chronic hepatitis B samples were quantified for HBV DNA to evaluating the correlation between the new test and Da-an assay. HBV serological markers were detected using ELISA method.

RESULTS

Pre-NAT quantitated HBV DNA levels covered a wide dynamic range (10 logs) with a close correlation between expected and observed values (r=0.999, P<0.05), satisfactory precision and higher specificity. The lower detection limit was 20IU/mL. Comparability assay showed Pre-NAT had a good agreement with but more sensitive than Da-an assay (t=0.149, P>0.05). HBV DNA level was partially correlated to but more reliable and sensitive than serological evidence in reflecting the viral level.

CONCLUSION

This novel fully-automated real-time PCR assay exhibits good analytical and clinical performances for highly sensitive detection of HBV DNA. It is well suited for monitoring antiviral responses and making treatment strategies according to current clinical practice guidelines for the management of chronic HBV infection.

Real-time PCR assays for hepatitis B virus DNA quantification may require two different targets

Background

Quantification Hepatitis B virus (HBV) DNA plays a critical role in the management of chronic HBV infections. However, HBV is a DNA virus with high levels of genetic variation, and drug-resistant mutations have emerged with the use of antiviral drugs. If a mutation caused a sequence mismatched in the primer or probe of a commercial DNA quantification kit, this would lead to an underestimation of the viral load of the sample. The aim of this study was to determine whether commercial kits, which use only one pair of primers and a single probe, accurately quantify the HBV DNA levels and to develop an improved duplex real-time PCR assay.

Methods

We developed a new duplex real-time PCR assay that used two pairs of primers and two probes based on the conserved S and C regions of the HBV genome. We performed HBV DNA quantitative detection of HBV samples and compared the results of our duplex real-time PCR assays with the COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. The target region of the discordant sample was amplified, sequenced, and validated using plasmid.

Results

The results of the duplex real-time PCR were in good accordance with the commercial COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. We showed that two samples from Chinese HBV infections underestimated viral loads when quantified by the Roche kit because of a mismatch between the viral sequence and the reverse primer of the Roche kit. The HBV DNA levels of six samples were undervalued by duplex real-time PCR assays of the C region because of mutations in the primer of C region.

Conclusions

We developed a new duplex real-time PCR assay, and the results of this assay were similar to the results of commercial kits. The HBV DNA level could be undervalued when using the COBAS TaqMan HBV Test version 2 for Chinese HBV infections owing to a mismatch with the primer/probe. A duplex real-time PCR assay based on the S and C regions could solve this problem to some extent.

Comparison of the QIAGEN artus HBV QS-RGQ Assay With the Roche COBAS AmpliPrep/COBAS TaqMan HBV Assay for Quantifying Viral DNA in Sera of Chronic Hepatitis B Patients

BACKGROUND

Hepatitis B virus DNA quantification is essential for managing chronic hepatitis B (CHB). We compared the performance of artus HBV QS-RGQ (QIAGEN GmbH, Germany) and CAP/CTM v2.0 HBV assays (Roche Molecular Diagnostics, USA) in CHB patients.

METHODS

A comparative evaluation between two assays was performed with 508 clinical serum samples. Precision, linearity, and the limit of detection (LOD) of QS-RGQ assay was evaluated by using the WHO standard 97/750 and clinical samples.

RESULTS

Detection rates and viral loads as determined QS-RGQ assay were significantly lower than those from the CAP/CTM v2.0 assay (52.8% vs 60.6%; 3.55±1.77 IU/mL vs 4.18±1.89 IU/mL, P<0.0001). The kappa coefficient between qualitative results was 0.79 (95% confidence interval, 0.74 to 0.85). Bland-Altman plot found a mean difference of (QS-RGQ - CAP/CTM v2.0)=-0.63 log₁₀ IU/mL (95% limit of agreement, -1.48 to 0.22). Repeatability and total imprecision (% CV) of the QS-RGQ assay were 1.0% and 1.1% at 2,000 IU/mL, and 0.7% and 1.4% at 20,000 IU/mL, respectively. Linearity of this assay ranged from 31.6 to 1.0±10⁷ IU/mL, and the LOD was 2.95 IU/mL.

CONCLUSIONS

The artus HBV QS-RGQ assay showed good performance but significantly decreased detection rate and viral load compared with CAP/CTM v2.0 assays. This assay recommends using plasma; however, we used stored serum because of the retrospective study design. Usually HBV DNA quantification is performed in plasma or serum, but sample type and clinical relevance of quantitative values should be considered when determining the clinical application of this reagent.

No response to hepatitis B vaccine in infants born to HBsAg(+) mothers is associated to the transplacental transfer of HBsAg

BACKGROUND

No or low hepatitis B (HB) vaccine response is more frequent in infants from HBsAg(+) mothers than those from HBsAg(-). Our previous study found temporary positivity of HBsAg in infants from HBsAg(+) mothers. In this study, we hypothesized that HBsAg in infant blunt immune response to standard hepatitis B vaccination.

METHODS

A total of 328 consecutive HBsAg(+) mothers and their offspring were enrolled. Blood samples were taken from mothers and their infants and quantified for HBsAg, anti-HBs titer and HBV DNA load concentration; Placenta samples were collected to stain for HBsAg.

RESULTS

First, 6.7% infants (22/328) showed anti-HBs titer lower than 10 mIU/mL after HB vaccination (non-response to HB vaccine). HBsAg(+) newborns showed higher risk of non-response than HBsAg(-) infants (13.0% versus 5.0%, p = 0.016). Infants from high HBsAg titer mothers displayed higher risk of HBsAg positivity at birth than those from low titer mothers (45.3% versus 2.8%, p < 0.001). HBsAg titer in mothers of HBsAg(+) newborns was much higher than mothers of HBsAg(-) newborns (p < 0.001). All those data supported HBsAg can be transferred through placenta. Our hypothesis was further reinforced by immunostaining with specific antibody against HBsAg, a substantial higher prevalence (87.5% versus 30.8%, p = 0.024) and stronger immunostaining (p = 0.008) was demonstrated in HBsAg(+) group comparing with placenta of the HBsAg(-) group.

CONCLUSION

No response to HB vaccine in infants of HBsAg(+) mothers was associated to the transplacental transfer of HBsAg.

Advancing the regulatory path on hepatitis B virus treatment and curative research: a stakeholders consultation

Hepatitis B infection remains a significant disease burden around the world, with an estimated two billion individuals infected and 350 million living with chronic hepatitis B. Current antivirals are efficacious, but require lifelong treatment for the majority of infected individuals. The field is galvanised to improve diagnostics and treatment with the goal to develop shorter, finite treatments leading to viral control after treatment discontinuation. Achievement of complete and functional cure is challenged by the complexity of the virus life cycle, the lack of adequate preclinical models, the cccDNA-mediated persistence of HBV in liver cells, the lack of validated biomarkers to predict viral control and cure, and the probable need for combination treatment involving antiviral- and immune-based strategies. Experts from diverse stakeholder groups participating in the HBV Forum (a project of the Forum for Collaborative Research) contributed their expertise and perspective to resolving issues and overcoming barriers in the regulatory path for novel HBV therapeutic strategies; addressing gaps in preclinical models, diagnostics, clinical trial design, biomarkers and endpoints, and public health efforts. Interviewees highlighted the need for open and collaborative ongoing dialogues among stakeholders in a neutral space as a critical process to move the field forwards. The Forum model facilitates dialogue and deliberation of this nature, with dedicated experts from all stakeholder groups participating. The promise of an HBV cure is exciting. Now is the time to work together toward that goal.

Nationwide prospective and retrospective surveys for hepatitis B virus reactivation during immunosuppressive therapies

BACKGROUND

The significance of HBV reactivation during immunosuppressive therapy was evaluated in three nationwide cohorts including patients with previously resolved HBV (prHBV) infection.

METHODS

The clinical features of 1061 patients with acute liver failure (ALF) or late-onset hepatic failure (LOHF) were retrospectively examined, focusing on those who experienced HBV reactivation. Additionally, 420 patients with prHBV infection were prospectively enrolled: 203 received immunosuppressive therapies immediately after enrollment, while the remaining 217 were enrolled after having received immunosuppressive therapies without the occurrence of HBV reactivation. The serum HBV-DNA levels were prospectively monitored every month, and the incidences of HBV reactivation, defined as a serum HBV-DNA level of 1.3 log IU/ml or more, were evaluated.

RESULTS

In the retrospective study, persistent HBV infection was found in 90 patients, and HBV reactivation was responsible for liver injuries in 50 patients including 23 receiving immunosuppressive therapies (26 with HBs-antigen positivity, 7 with prHBV infection). None of seven patients with prHBV infection were rescued. In the prospective studies, HBV reactivation occurred in ten patients, but preemptive entecavir administration prevented liver injury. The cumulative reactivation rate was 3.2 % at 6 months, and the increase of the rate compared to that at 6 months was +1.5 % at 48 months.

CONCLUSIONS

HBV reactivation during immunosuppression was responsible for liver injuries in a quarter of the ALF/LOHF patients with persistent HBV infection. Early serum HBV-DNA monitoring may improve patient prognosis, since HBV reactivation typically occurs within 6 months of the start of immunosuppressive therapies in patients with prHBV infection.

High-dose hepatitis B immunoglobulin therapy in hepatocellular carcinoma with hepatitis B virus-DNA/hepatitis B e antigen-positive patients after living donor liver transplantation

AIM: To investigate the impact of high-dose hepatitis B immunoglobulin (HBIG) on hepatocellular carcinoma (HCC) and hepatitis B virus (HBV) recurrence and overall survival after living donor liver transplantation (LDLT).

METHODS: We investigated 168 patients who underwent LDLT due to HCC, and who were HBV-DNA/hepatitis B e antigen (HBeAg) -positive, from January 2008 to December 2013. After assessing whether the patients met the Milan criteria, they were assigned to the low-dose HBIG group and high-dose HBIG group. Using the propensity score 1:1 matching method, 38 and 18 pairs were defined as adhering to and not adhering to the Milan criteria. For each pair, HCC recurrence, HBV recurrence and overall survival were analyzed by the Kaplan-Meier method and the log rank test according to the HBIG dose.

RESULTS: Among those who met the Milan criteria, the 6-mo, 1-year, and 3-year HCC recurrence-free survival rates were 88.9%, 83.2%, and 83.2% in the low-dose HBIG group and 97.2%, 97.2%, and 97.2% in the high-dose HBIG group, respectively (P = 0.042). In contrast, among those who did not meet the Milan criteria, HCC recurrence did not differ according to the HBIG dose (P = 0.937). Moreover, HBV recurrence and overall survival did not differ according to the HBIG dose among those who met (P = 0.317 and 0.190, respectively) and did not meet (P = 0.350 and 0.987, respectively) the Milan criteria.

CONCLUSION: High-dose HBIG therapy can reduce HCC recurrence in HBV-DNA/HBeAg-positive patients after LDLT.

Are current screening protocols for chronic hepatitis B virus infection adequate?

Chronic hepatitis B virus (HBV) infection screening usually includes only HBV surface antigen (HBsAg) testing; HBV core and surface antibody (anti-HBc, anti-HBs) assays, indicating resolved infection and immunity, are not routinely performed. Yet, serum HBV DNA is measurable in approximately 10% of HBsAg-negative/anti-HBc-positive cases, representing occult HBV infection (OBI). Patient blood samples from 2 Veterans Affairs medical center look-back investigations were screened for HBV infection using HBsAg enzyme immunoassays. Supplementary testing included anti-HBc and anti-HBs enzyme immunoassays. For anti-HBc-positive samples, HBV DNA testing was performed. Background OBI prevalence was further estimated at these 2 facilities based on HBV serology testing results from 1999-2012. Finally, a literature review was performed to determine OBI prevalence in the published literature. Of 1887 HBsAg-negative cohort patients, 98 (5.2%) were anti-HBc positive/anti-HBs negative; and 175 (9.3%), anti-HBc positive/anti-HBs positive. Six of 273 were HBV DNA positive, representing 0.3% of the total tested and 2.2% who were anti-HBc positive/anti-HBs negative or anti-HBc positive/anti-HBs positive. Among 32,229 general population veterans at these 2 sites who had any HBV testing, 4/108 (3.7%) were HBV DNA positive, none of whom were part of the cohort. In 129 publications with HBsAg-negative patients, 1817/1,209,426 (0.15%) had OBI. However, excluding blood bank studies with greater than 1000 patients, the OBI rate increased to 1800/17,893 (10%). OBI is not rare and has implications for transmission and disease detection. HBsAg testing alone is insufficient for detecting all chronic HBV infections. These findings may impact blood donation, patient HBV screening, follow-up protocols for patients assumed to have cleared the infection, and initiation of immunosuppression in patients with distant or undetected HBV.

Prospective long-term study of hepatitis B virus reactivation in patients with hematologic malignancy

BACKGROUND AND AIM

To elucidate the clinical characteristics of hepatitis B virus reactivation (HBV-R), we performed a prospective long-term study of patients with hematologic malignancy, including both hepatitis B virus (HBV) carriers and those with resolved HBV infection.

METHODS

Twenty-one patients with hematopoietic stem-cell transplants (HSCT) and 36 patients given rituximab-based chemotherapy were enrolled. Entecavir was administered prophylactically to eight patients with HBV surface antigen (HBsAg). HBV-DNA was measured every month in 49 patients with resolved HBV infection, and preemptive therapy was given to eight patients with HBV-R.

RESULTS

HBV-R developed in five (26%) of 19 patients with HSCT and three (10%) of 30 patients given rituximab-based chemotherapy. HBV-R occurred a median of 3 months (range: 2-10) after the end of rituximab-based chemotherapy and 22 months (range: 9-36) after HSCT. HBV-R did not develop in patients with an antibodies against HBsAg (anti-HBs) titer exceeding 200 mIU/mL at baseline. Mutations in the "a" determinant region with amino acid replacement were detected in four of the eight patients with HBV-R. Preemptive therapy prevented severe hepatitis related to HBV-R. Entecavir treatment was stopped in four patients with HBV-R. Since the withdrawal of entecavir, HBV-DNA has not been detected in two patients persistently positive for anti-HBs. No patient had fatal hepatitis.

CONCLUSIONS

Proper management of patients with HBsAg or resolved HBV infection prevented fatal hepatitis related to HBV-R in patients who received immunosuppressive or cytotoxic therapy. Entecavir could be safely discontinued in patients with HBV-R who had acquired anti-HBs.

Comparison of the Abbott RealTime HBV assay with the Roche Cobas AmpliPrep/Cobas TaqMan HBV assay for HBV DNA detection and quantification

BACKGROUND

Measurement of hepatitis B virus (HBV) DNA levels is essential in the clinical management of patients with chronic HBV infection. Performance and accuracy of quantitation for HBV DNA are therefore critical in clinical practice.

OBJECTIVES

We aimed to compare and evaluate the performance characteristics of two HBV DNA quantitative assays: Abbott RealTime HBV (RealTime assay) and Cobas AmpliPrep/Cobas TaqMan HBV assays 2.0 (TaqMan assay).

STUDY DESIGN

Serum samples from 220 HBV-infected patients were collected. Performance characteristics of the HBV DNA quantitative assays, including sensitivity, linearity, and reproducibility were measured. The assays were compared based on the viral status, including HBeAg, genotype, core promoter and pre-core region mutations.

RESULTS

The RealTime assay had a sensitivity and specificity of 98.2% and 100%, respectively. The intra-assay coefficients of variation of serum samples ranged from 0.00% to 11.25% for the RealTime assay and 1.22% to 8.22% for TaqMan assay. Paired quantitative results showed excellent correlation by linear regression analysis (R(2)=0.961), good level of agreement with a mean difference of 0.31log10IU/mL, and limits of agreement of -0.62 to 1.24log10IU/mL, irrespective of HBeAg, genotype, core promoter and pre-core region mutation-specific differences. In this study, a difference of ≥1log10IU/mL between the two assays was observed in 8.6% of the samples. Genotype B and average HBV DNA levels of <3log10IU/mL were significant associated factors of this discordance.

CONCLUSIONS

The Abbott assay delivered high performance for HBV DNA quantification and correlated extremely well with the TaqMan assay, irrespective of viral status.

Impact of peginterferon alpha-2b and entecavir hydrate combination therapy on persistent viral suppression in patients with chronic hepatitis B

The ideal approach to treat chronic hepatitis B remains controversial. This pilot study aimed to evaluate the effectiveness of peginterferon (PEG-IFN) α-2b and entecavir hydrate (ETV) as a combination therapy for patients with chronic hepatitis B, particularly in the context of virological response and the reduction of intrahepatic covalently closed circular DNA (cccDNA). A total of 17 patients with hepatitis B virus (HBV) genotype C were enrolled in this study. All subjects were treated with this combination therapy for 48 weeks and observed for an additional 24 weeks. All patients underwent liver biopsy before and after the therapy period. Changes in cccDNA levels and liver histology were monitored between biopsies. Among the 11 patients who exhibited pre-therapy hepatitis B e antigen (HBeAg), 8 (73%) showed evidence of HBeAg seroconversion by the end of the follow-up period. Serum HBV DNA levels decreased by 5.2 and 3.3 log copies/ml (mean) by the end of the therapy and follow-up periods, respectively. In addition, intrahepatic cccDNA decreased significantly to 1.4 log copies/µg (mean) by the end of the therapy period. Among the 11 patients who did not experience viral relapse, only 2 (18%) exhibited high levels of cccDNA (>4.5 log copies/µg) by the end of the treatment period. In contrast, all relapsed subjects exhibited significantly higher levels of cccDNA than subjects who did not relapse (P  = 0.027). The combination regimen is a promising approach to treat chronic hepatitis B and may achieve significant reduction in serum HBV DNA and intrahepatic cccDNA. Wiley Periodicals, Inc.

Detection of occult hepatitis B virus infection among blood donors in Sudan

BACKGROUND

Sudan is classified among countries with a high hepatitis B surface antigen (HBsAg) endemicity of more than 8%. Cross-sectional studies have showed a marked increase in the prevalence of occult hepatitis B infection (OBI) in patients with cirrhosis or hepatocellular carcinoma. In terms of OBI infectivity by transfusion, it is largely unknown whether residual risk estimates translate into true rates of infection.

AIM

The current study aimed to determine the frequency of OBI among blood donors in Sudan.

MATERIALS AND METHODS

This study was carried out during the period between 2011 and 2012. It included 100 HBsAg-negative blood donors who attended the Central Blood Bank in Sudan. Sera collected from all donors were tested for HBsAg, antibodies against hepatitis B core antigen (anti-HBc), antibodies against hepatitis Be antigen (anti-HBe), and antibodies against hepatitis B surface antigen (anti-HBs) by enzyme-linked immunosorbant assay. Anti-HBc-positive patients were tested for hepatitis B virus (HBV)-DNA.

RESULTS

The anti-HBc was detected in 42% of the blood donors, among whom 90.5% were positive for HBV-DNA. Two main profiles have been detected, namely, the presence of the three genes (S, C, and X genes) together in 35.7% of the blood donors or the presence of the X gene in addition to the core gene.

CONCLUSION AND RECOMMENDATIONS

With the use of HBsAg as the sole detection marker for HBV, there is a danger of HBV transmission through blood transfusion. Anti-HBc testing should be added to the routine blood donor screening test if occult hepatitis B is to be diagnosed.

Need for nucleic Acid testing in countries with high prevalence of transfusion-transmitted infections

Introduction. In India, family/replacement donors still provide more than 45% of the collected blood. With increasing voluntary blood donation and the still-prevalent infectious diseases in donors, we need to augment transfusion-transmitted infections (TTIs) testing before use. Our study was aimed to know the seroprevalence of TTIs among the donors of Rajasthan and the need for newer technologies like nucleic acid testing (NAT). Materials and Methods. Enhanced chemiluminescence immunoassay (ECi) was used for detection of HBsAg, anti-HIV, and anti-HCV in donor serum. 50% of the blood units which were negative on ECi were randomly selected and subjected to NAT testing for HBV, HCV, and HIV. Results. The total seroprevalence of TTIs is 2.62%. Of the randomly selected donor units negative by ECi, 8 turned out to be reactive on NAT testing: 4 were voluntary and 4 were family/replacement donors. Combined NAT yield (NAT reactive/seronegative) for HIV, HCV, and HBV was 0.034% (1 in 2972 donations). All the 8 reactive samples were positive for HBV DNA. Conclusion. In countries with a high prevalence of TTIs like India there are likely to be a significant number of window period donations that can be identified by NAT which may be implemented in blood centers allover India with serological testing to provide safe blood and cost alone should not be a deterrent to the government and implementing agencies.

Development of a new duplex real-time polymerase chain reaction assay for hepatitis B viral DNA detection

BACKGROUND

Quantification of hepatitis B virus (HBV) DNA can be used for diagnosing HBV infection and monitoring the effect of antiviral therapy. However, probably because of mismatches between the template and primer/probe, HBV DNA in some HBV infections could not be detected using currently available commercial assays with single primer/probe. By aligning the HBV sequences, we developed a duplex real-time polymerase chain reaction (PCR) assay using two sets of primers/probes and a specific armored DNA as internal control (IC).

RESULTS

The limit of the duplex real-time PCR assay was 29.5 IU/ml, whereas the specificity was 100%. The within-run precision coefficient of variation (CV) ranged from 1.02% to 2.73%, while the between-run CV ranged from 0.83% to 1.25%. The optimal concentration of armored DNA IC in the HBV DNA duplex real-time PCR assay was 1 000 copies/ml. Data from 69 serum samples with HBV infection showed that the performance of the duplex real-time PCR assay was comparable to that of the COBAS Ampliprep/Cobas Taqman (CAP/CTM) HBV assay and was superior to those of the domestic commercial HBV assays.

CONCLUSIONS

The duplex real-time PCR assay is sufficiently sensitive, specific, accurate, reproducible and cost-effective for the detection of HBV DNA. It is suitable for high throughput screening and frequent HBV DNA level monitoring.

Prospective study of reactivation of hepatitis B virus in patients with rheumatoid arthritis who received immunosuppressive therapy: evaluation of both HBsAg-positive and HBsAg-negative cohorts

BACKGROUND

Screening and prophylactic treatment for hepatitis B virus (HBV) reactivation is recommended for patients who receive immunosuppressive or cytotoxic therapy. The aim of this study was to clarify the prevalence of HBV reactivation in rheumatoid arthritis (RA) patients who had received more than 1 year of immunosuppressive therapy. This study also evaluated guidelines for determining HBV reactivation in patients with RA.

METHODS

This was a prospective non-randomized, non-controlled study. We enrolled 50 patients with RA who had antibodies against hepatitis B core antigen (anti-HBc) and who had started treatment with disease-modifying anti-rheumatic drugs, including those who had additionally received anti-tumor necrosis factor-α (anti-TNF-α). HBV DNA levels were measured every 2-3 months by a real-time, polymerase chain reaction-based method. Entecavir was administered to patients with HBV DNA levels >2.1 log/ml.

RESULTS

The mean observation period was 23 months (range 12-32 months). HBV reactivation occurred in 2 of 5 patients with HBV surface antigen (HBsAg) and in 1 of 45 patients without HBsAg. In patients who received anti-TNF-α therapy, antibodies against HBsAg decreased significantly. Entecavir therapy inhibited HBV amplification and prevented HBV-associated flares of hepatitis.

CONCLUSIONS

The incidence of HBV reactivation was low in RA patients in whom HBV infection had been resolved. Screening for HBV reactivation and prophylactic therapy with entecavir were effective means of preventing HBV-associated hepatic failure in patients with HBsAg, as well as in those with only anti-HBc who received immunosuppressive therapy for RA.

A real-time quantitative assay for hepatitis B DNA virus (HBV) developed to detect all HBV genotypes

Hepatitis B virus (HBV) is a major cause of chronic liver disease worldwide. Besides genotype, quantitative analysis of HBV infection is extensively used for monitoring disease progression and treatment. Affordable viral load monitoring is desirable in resource-limited settings and it has been already shown to be useful in developing countries for other viruses such as Hepatitis C virus (HCV) and HIV. In this paper, we describe the validation of a real-time PCR assay for HBV DNA quantification with TaqMan chemistry and MGB probes. Primers and probes were designed using an alignment of sequences from all HBV genotypes in order to equally amplify all of them. The assay is internally controlled and was standardized with an international HBV panel. Its efficacy was evaluated comparing the results with two other methods: Versant HBV DNA Assay 3.0 (bDNA, Siemens, NY, USA) and another real-time PCR from a reference laboratory. Intra-assay and inter-assay reproducibilities were determined and the mean of CV values obtained were 0.12 and 0.09, respectively. The assay was validated with a broad dynamic range and is efficient for amplifying all HBV genotypes, providing a good option to quantify HBV DNA as a routine procedure, with a cheap and reliable protocol.

Detection and quantitation of HBV DNA in miniaturized samples: multi centre study to evaluate the performance of the COBAS ® AmpliPrep/COBAS ® TaqMan ® hepatitis B virus (HBV) test v2.0 by the use of plasma or serum specimens

Laboratory analysis of blood specimens is an increasingly important tool for rapid diagnosis and control of therapy. So, miniaturization of test systems is needed, but reduced specimens might impair test quality. For rapid detection and quantitation of HBV DNA, the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HBV test has proved a robust instrument in routine diagnostic services. The test system has been modified recently for application of reduced samples of blood plasma and for blood serum, too. The performance of this modified COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HBV v2.0 (HBV v2.0 (this test is currently not available in the USA)) test was evaluated by comparison with the former COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HBV v1.0 (HBV v1.0) test. In this study a platform correlation of both assay versions was done including 275 HBV DNA positive EDTA plasma samples. Comparable results were obtained (R(2)=0.97, mean difference -0.03 log(10)IU/ml). The verification of equivalency of the sample matrix (plasma vs. serum samples tested in HBV v2.0 in the same run) showed comparable results for all 278 samples with a R(2)=0.99 and a mean difference of 0.06 log(10)IU/ml. In conclusion, the new test version HBV v2.0 is highly specific and reproducible and quantifies accurately HBV DNA in EDTA plasma and serum samples from patients with chronic HBV infection.

Molecular characterization of hepatitis B virus and a 9-year clinical profile in a patient infected with genotype I

An unusual hepatitis B virus (HBV) variant, assigned provisionally to genotype I, was recently reported, characterized by an anomalous genotyping pattern and putative recombination; however, the natural history of this unusual strain is unknown. This study analyzed longitudinal sera collected over a 9-year period from a patient infected with this variant to investigate the clinical profile and intrahost viral evolution over time. The patient, who had immigrated to Canada in 1998 from Vietnam, was treated with lamivudine in 2000. Approximately 4-5 years following the withdrawal of lamivudine therapy, a genomic "shift" occurred coincident with ALT flares and increasing HBV viral load, resulting in numerous stable nucleotide substitutions within the core coding region, suggesting altered immune control that may provide a selective advantage to the virus. Analysis of quasispecies diversity over time demonstrated further this shift, with two sequence clusters associated with time points either prior to or following relapse observed, including increased diversity among quasispecies prior to relapse. In keeping with the complex nature of genotype I strains, majority population genomes had a mean genetic distance from genotype C of 7.6 +/- 0.1%, although large genomic segments lacked significant homology with any HBV genotype. Further study is needed to understand the evolutionary origin and natural history of infection with this unique HBV variant.

Monitoring of therapy in patients with chronic hepatitis B virus

OBJECTIVE

The aims of this study were to evaluate therapy with lamivudine (LAM) and adefovir dipivoxil (ADV) monotherapy in chronic hepatitis B virus (HBV)-infected patients with frequent measurements of DNA levels, to characterize HBV genotypes, and to determine the emergence of nucleos(t)ide analogue mutants before and during the therapy by direct-sequencing the reverse transcriptase region and by INNO-LiPA HBV DR v3.

MATERIALS AND METHODS

A total of 15 chronic HBV patients were analysed: 11 were treated with ADV and four were treated with LAM.

RESULTS

Viral genotype was determined, showing the presence of genotype D (73%) in 11 patients and genotype A (27%) in four patients. In the viral response to treatment, three patients developed substitutions at rtM204I associated with LAM resistance and one of these patients presented rtM204V/I plus rtL180M mutation. In contrast, of the 11 patients treated with ADV, three patients developed mutations (rtN236T; rtA181V; rtA181V plus rtN236T). With regard to this case, the same results were observed by INNO-LiPA HBV DR v3 and direct sequencing, but by direct sequencing we detected an extra mutation rtQ215S that was present in two patients: one patient who was on treatment with LAM had an rtQ215S mutation in addition to an rtM204I, and the second patient treated with ADV had rtA181V.

CONCLUSION

Direct sequence analysis is an essential tool to optimize therapeutic management of HBV chronic infection in clinical practice to choose the appropriate nucleos(t)ide analogues and to detect extra mutations that are not included in the commercial kit.

Establishment of a novel quantitative hepatitis D virus (HDV) RNA assay using the Cobas TaqMan platform to study HDV RNA kinetics

Determination of hepatitis D virus (HDV) viremia represents the "gold standard" for the diagnosis of HDV infection. Hepatitis B virus (HBV)-HDV coinfection frequently leads to end-stage liver disease and hepatocellular carcinoma. No commercial assay for HDV RNA quantification that includes automated nucleic acid extraction is available, and in-house PCR tests are not well standardized. However, knowledge of HDV RNA levels may give important information for patient management and could be a useful tool for monitoring the response to antiviral therapies. One platform that is widely used for HBV DNA or HCV RNA quantification is the Cobas Ampliprep/TaqMan system. Using the utility channel of this platform, we established a novel protocol for TaqMan-based HDV RNA quantification after automatic extraction of RNA by the Ampliprep system. The assay was specific and showed linearity over a wide range from 3 x 10(2) to 10(7) copies/ml. Reproducibility was demonstrated by determination of the interrun and intrarun variabilities, which were similar to those achieved with the commercially available Cobas TaqMan assays for HCV RNA and HBV DNA. HDV RNA levels were stable in whole blood (n = 4), plasma (n = 3), and serum (n = 3) samples at room temperature for up to 6 days. Importantly, HDV RNA viremia showed only minor fluctuations, with the log(10) coefficient of variation being between 1.3 and 11.2% for hepatitis delta patients studied every 2 weeks for up to 3 months (n = 6), while a rapid viral decline was observed early during treatment with pegylated alfa-2a interferon (n = 6). In conclusion, this novel automated HDV RNA assay is a useful tool for monitoring HDV-infected patients both before and during antiviral therapy.

Longitudinal evaluation of viral interactions in treated HIV-hepatitis B co-infected patients with additional hepatitis C and D virus

Virological interactions of hepatitis B (HBV), hepatitis C (HCV) and hepatitis D (HDV) viruses in HIV-infected patients have been poorly characterized especially under treatment influences. Undetection rates of hepatitis viruses were longitudinally analyzed in a 3-year cohort of 308 HIV-HBV co-infected patients and compared using Generalized Estimating Equation models adjusted for age, HIV-RNA, CD4 cell-count and antiviral treatment. Chronic hepatitis co-infection in HIV-infected patients (age years, SD) was: 265 HBV (40.7, 8.2); 19 HBV-HCV (39.7, 4.1); 12 HBV-HDV (35.2, 9.9); 12 HBV-HCV-HDV (39.2, 5.2). At inclusion, treatment with lamivudine/tenofovir was not significantly different between co-infection groups. HBV suppression was significantly associated with HDV (aOR = 3.85, 95%CI 1.13-13.10, P = 0.03) and HCV tri-infection (aOR = 2.65, 95%CI 1.03-6.81, P = 0.04), but marginally associated with HIV-HBV-HCV-HDV (aOR = 2.32, 95%CI 0.94-5.74, P = 0.07). In quad-infection, lower HDV-undetectability (vs HIV-HBV-HDV, P = 0.2) and higher HCV-undetectability (vs HIV-HBV-HCV, P = 0.1) were demonstrated. The degree of HBV suppression varied between visits and co-infection groups [range of aOR during follow-up (vs HIV-HBV co-infection): HIV-HBV-HCV = 2.23-5.67, HIV-HBV-HDV = 1.53-15.17]. In treated co-infected patients, HDV expressed continuous suppression over HCV- and HBV-replications. Peaks and rebounds from undetectable hepatitis B, C and/or D viremia warrant closer follow-up in this patient population. HDV-replication was uncontrolled even with antiviral treatment.

Nuclease-resistant double-stranded DNA controls or standards for hepatitis B virus nucleic acid amplification assays

BACKGROUND

Identical blood samples tested using different kits can give markedly different hepatitis B virus (HBV) DNA levels, which can cause difficulty in the interpretation of viral load. A universal double-stranded DNA control or standard that can be used in all commercial HBV DNA nucleic acid amplification assay kits is urgently needed. By aligning all HBV genotypes (A-H), we found that the surface antigen gene and precore-core gene regions of HBV are the most conserved regions among the different HBV genotypes. We constructed a chimeric fragment by overlapping extension polymerase chain reaction and obtained a 1,349-bp HBVC+S fragment. We then packaged the fragment into lambda phages using a traditional lambda phage cloning procedure.

RESULTS

The obtained armored DNA was resistant to DNase I digestion and was stable, noninfectious to humans, and could be easily extracted using commercial kits. More importantly, the armored DNA may be used with all HBV DNA nucleic acid amplification assay kits.

CONCLUSIONS

The lambda phage packaging system can be used as an excellent expression platform for armored DNA. The obtained armored DNA possessed all characteristics of an excellent positive control or standard. In addition, this armored DNA is likely to be appropriate for all commercial HBV DNA nucleic acid amplification detection kits. Thus, the constructed armored DNA can probably be used as a universal positive control or standard in HBV DNA assays.

Evaluation of the patient with hepatitis B

The initial evaluation of a patient with hepatitis B virus infection should attempt to assess the disease activity and stage in the context of the known natural history of this infection and to properly assess the needs for treatment and surveillance. In addition to a medical history and focused physical examination, the initial evaluation usually requires serological, biochemical, and virological tests to confirm the diagnosis as well as an imaging study to establish a baseline for future monitoring. A liver biopsy is generally not needed but can provide useful information on prognosis, need for surveillance for hepatocellular carcinoma (HCC), and whether to recommend therapy. Follow-up monitoring is aimed at determining disease progression, development of complications, and reassessing the need for treatment. Monitoring frequency should be determined based on the activity and stage of disease. Initiation of screening for HCC should be based on age, race, sex, family history, and stage and duration of disease. The current recommended method of screening and surveillance for HCC is by ultrasonography and alpha-fetoprotein measurements every 6-12 months. Prospective studies are needed to evaluate the role of longitudinal application of noninvasive assays of fibrosis, such as serum fibrosis markers and transient elastography. Better biomarkers and imaging modalities are needed for early detection of HCC. Finally, studies are needed to better refine the indications and to balance the risks and benefits of antiviral therapy.

How I treat and monitor viral hepatitis B infection in patients receiving intensive immunosuppressive therapies or undergoing hematopoietic stem cell transplantation

Hepatitis B virus (HBV) reactivation is a serious but preventable complication of immunosuppression. Full HBV serologic profile must be obtained from all patients receiving intensive immunosuppressive therapy. In general, preemptive anti-HBV therapy is more effective than giving treatment after development of reactivation. Prompt lamivudine therapy should be given to at-risk patients who are hepatitis B surface antigen (HBsAg)-positive. It is recommended that lamivudine be continued until at least 6 months after the cessation of immunosuppression. Some patients requiring a longer duration of lamivudine therapy are at risk of developing drug resistance. The newer anti-HBV agents are effective in overcoming lamivudine resistance. Early use of these agents may be considered. HBV reactivation was observed in HBsAg-negative patients with occult HBV infection (HBV DNA-positive) who are on heavy immunosuppression. The optimal management of this group of patients is unclear. For patients receiving allogeneic HSC transplants, the HBV status of the donors requires special attention. To minimize the risk of transmission of infection to recipients, HBsAg-positive donors should receive adequate anti-HBV therapy before HSC donation. As the result of adoptive immune transfer, clearance of HBsAg is observed in HBsAg-positive patients receiving HSC transplants from donors who are positive for hepatitis B surface and core antibodies.

Hepatitis B reactivation after chemotherapy: two decades of clinical research

Hepatitis due to hepatitis B virus reactivation after cytotoxic or immunosuppressive therapy is a serious cause of liver-related morbidity and mortality. With the characterization of the underlying pathogenesis, much progress in the management of this important clinical problem has been made in the past 2 decades. By year 2008, it is mandatory to screen for hepatitis B surface antigen status before initiating intensive chemotherapy or immunosuppressive therapy. All those who are hepatitis B surface antigen positive should be started on preemptive nucleos(t)ide analogues. However, there remains important issues, such as the type and duration of nucleos(t)ide analogue therapy, which need to be understood. As not all hepatitis B surface antigen-positive patients will suffer from HBV reactivation, it is therefore useful to identify risk factors related to HBV reactivation so that patients will not be treated unnecessarily with nucleos(t)ide analogues. To date, a high baseline level of viral replication, as reflected by high serum HBV DNA level, positive serum hepatitis B e antigen, and a high intrahepatic covalently closed circular DNA level, is the most important predictor for HBV reactivation. Recently, there has been an increased awareness of reactivation of occult hepatitis B virus, especially in hepatitis B virus endemic area, such as the Asia-Pacific region. Careful epidemiological study will be needed to clarify the impact of occult hepatitis B infection in patients treated with cytotoxic or immunosuppressive therapy.

Performance of the Cobas AmpliPrep/Cobas TaqMan real-time PCR assay for hepatitis B virus DNA quantification

Hepatitis B virus (HBV) DNA quantification is used to establish the prognosis of chronic HBV-related liver disease, to identify those patients who need to be treated, and to monitor the virologic response and resistance to antiviral therapies. Real-time PCR-based assays are gradually replacing other technologies for routine quantification of HBV DNA in clinical practice. The goal of this study was to evaluate the intrinsic characteristics and clinical performance of the real-time PCR Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) platform for HBV DNA quantification. Specificity was satisfactory (95% confidence interval, 98.1 to 100%). Intra-assay coefficients of variation ranged from 0.22% to 2.68%, and interassay coefficients of variation ranged from 1.31% to 4.13%. Quantification was linear over the full dynamic range of quantification of the assay (1.7 to 8.0 log(10) IU/ml) and was not affected by dilution. The assay was accurate regardless of the HBV genotype. Samples containing HBV DNA levels above 4.5 log(10) IU/ml were slightly underestimated relative to another accurate assay based on branched-DNA technology, but this is unlikely to have noteworthy clinical implications. Thus, the CAP/CTM HBV DNA assay is sensitive, specific, and reproducible, and it accurately quantifies HBV DNA levels in patients chronically infected by HBV genotypes A to F. Samples with HBV DNA concentrations above the upper limit of quantification need to be diluted and then retested. Broad use of fully automated real-time PCR assays should improve the management of patients with chronic HBV infection.