Hepatitis B virus DNA in serum and liver is commonly found in Chinese patients with chronic liver disease despite the presence of antibodies to HBsAg

Occult hepatitis B virus infection in hepatitis C virus negative chronic liver diseases

Data concerning the prevalence of hepatitis B virus (HBV) occult infection (OBI) varies greatly in the different studies according to the sensitivity and specificity of the diagnostic approaches and the HBV prevalence in the different populations examined. The clinical implications of OBI are still debated. While the impact of OBI in HBV transmission as well as in HBV reactivation under immunosuppression are well established, the role of OBI in liver disease and hepatocellular carcinoma (HCC) development are still not definitively elucidated. It has been hypothesized that OBI might contribute to worsening the liver disease course when other causes of liver damage co-exist. Furthermore, much evidence suggests a role of OBI in the hepato-carcinogenesis processes through both indirect and direct oncogenic mechanisms that might favour HCC development. Data on the OBI clinical implications mainly come from studies performed in patients with hepatitis C virus (HCV) infection. However, HCV prevalence has dramatically fallen in the past years also because of the advent of specific and highly effective direct acting antivirals, with a consequent abrupt change of the worldwide scenario of chronic liver disease. Information about OBI prevalence and possible clinical impact in non-HCV-related liver disease are fragmentary, and the objective of this review is to critically summarize the available data in this field.

High Risk of HBV Infection Among Vaccinated Polytransfused Children With Malignancy

AIM OF THE STUDY

The national Egyptian hepatitis B virus (HBV) vaccination program coverage of all infants started in 1992. The study aimed to assess immunity against HBV and occurrence of HBV breakthrough infections in vaccinated polytransfused children with malignancies.

PATIENTS AND METHODS

Eighty-nine polytransfused children with malignancies were recruited; 37 were on chemotherapy (male:female 20:17; mean age 7.7±4.0 y), and there were 52 naive patients (male:female 31:21; mean age 7.6±3.2 y). In addition, 162 age-matched and sex-matched healthy controls were recruited. Patients' sera were tested for quantitative anti-hepatitis B surface (HBs) (enzyme-linked immunoassays technique), hepatitis B surface antigen (HBsAg), total anti-hepatitis B core, and HBV-DNA (nested polymerase chain reaction for surface, core, and x-regions).

RESULTS

There was a significant lower percentage of having protective anti-HBs (10 to 100 IU/L) level among those receiving chemotherapy (13.5%) than those without (44.2%) and controls (32.1%). Twenty-one (67.7%) of those on chemotherapy were HBsAg positive compared with 10 (32.2%) of those without. Overall, 46 patients were HBV-DNA positive; 38 were c-region positive, 5 were s-region positive, 2 positive for the c-region and the s-region, and 1 tested positive for the c-region and the x-region. Of 46 patients, 20 were also positive for HBsAg (overt infection), while 26 had occult HBV infection (HBsAg-negative). Anti-HBs ≥10 IU/L co-existed among 45% of patients with overt infection and in 50% of those with occult infection. There was nonsignificant impact of receiving chemotherapy on the level of HBV-DNA.

CONCLUSIONS

Vaccinated children with malignancies, especially those under chemotherapy, are at a significant risk of HBV infection. The co-existence of anti-HBs with HBsAg and/or HBV-DNA may represent a possible residual transfusion-transmission risk with mutant HBV strains.

Occult hepatitis B in kidney transplants recipients and donors from Western Mexico

BACKGROUND

Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in serum and/or liver from HBsAg-negative subjects. Our aim was to determine OBI frequency in serum and genomic DNA in patients undergoing renal transplant and their cognate donors in a selected population from Western Mexico.

METHODS

Blood samples were obtained from 94 donors and their cognate recipients (188 participants) before kidney transplantation. Identification of HBV DNA was carried-out by nested (S-region) and semi-nested (Pol-region) PCR in both genomic and serum DNA samples from 188 participants at pre-surgical stage and from a subset of 73 recipients at three-month follow-up.

RESULTS

HBV-DNA was not detected in either genomic or serum DNA samples from recipients or donors prior to transplantation. After three-months of follow-up, 2 out of 73 (2.7%, 95% CI: 0.9-11.9%) recipients were positive to HBV-DNA (Pol-region) in genomic DNA samples using a high sensitivity Taq DNA polymerase.

CONCLUSIONS

OBI incidence in recipients of kidney transplant may be higher than previously recognized. Detection of HBV-DNA was higher in genomic DNA than in serum samples using a high sensitivity Taq DNA polymerase. To the best of our knowledge, this is the first report regarding this specific topic in Mexicans.

Hepatitis B Virus Infection in the Dialysis Population: Current Perspectives

One of the major advances in the management of patients on regular dialysis has been the control of the spread of hepatitis B virus (HBV) infection in dialysis units. The rate of HBsAg positive patients on regular dialysis in the developed world is currently low, but outbreaks of HBV continue to occur. The diffusion of HBV in dialysis units in developing countries is higher, although available information is not abundant. There are limited data on the natural history of HBV in the dialysis population; they support a detrimental effect of HBV on survival in dialysis patients. The HBV viral load in HbsAg-positive dialysis patients appears low and stable over time and numerous mechanisms have been posited to explain it. Several assays for detecting HBV DNA in serum are available but they should not be used for purposes of routine screening within dialysis units. The epidemiology and clinical significance of occult HBV infection in the dialysis population needs to be addressed adequately - this remains an area of active research. Recent recommendations for the management of HBsAg chronic carriers on maintenance dialysis have been issued. No controlled trials for the treatment of hepatitis B with either interferon or lamivudine in dialysis patients are currently available.

Clinical patterns associated with the concurrent detection of anti-HBs and HBV DNA

Simultaneous detection of anti-HBs and HBV DNA is a rare serological combination and has been described in acute and chronic HBV infection. To scrutinize viral and clinical patterns associated with concurrent detection of anti-HBs and HBV DNA. Simultaneous detection of anti-HBs and HBV DNA was observed in 64/1444 (4.4%) patients treated for HBV infection at the University Hospital of Essen from 2006 to 2016 (8 with acute, 20 with reactivated, and 36 chronic HBV infection). Clinical data and laboratory parameters were analyzed. Regions of the small hepatitis B surface antigen (SHB) and the reverse transcriptase (RT) were sequenced using next generation sequencing (NGS). Among the 64 patients with detectable HBV DNA and anti-HBs, 17 were HBsAg negative (HBsAg[-]), and two had acute liver failure. Patients with acute HBV infection had fewer genotype specific amino acid substitutions in the SHB region than patients with reactivated HBV infection (4 [4.5] vs 9 [16.25], P = 0.043). However, we could observe a significantly higher number of mutations in the a-determinant region when comparing chronically infected patients to patients with acute infection (0 [1] vs 1 [1], P = 0.044). The ratio of nonsynonymous to synonymous mutations (Ka/Ks) was on average >1 for the SHB region and <1 for the RT region. The Ka/Ks ratio (>1) in the SHB region indicates that anti-HBs might have exerted selection pressure on the HBsAg. In three cases the diagnosis of acute HBV infection would have been at least delayed by only focusing on HBsAg testing.

Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants

Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult infections caused by HBV genotype C2; the variants of preS and S related to severe liver diseases among chronically infected patients were also responsible for the majority of HBV occult infections. We also reported that HBsAg variants from occult-infected Korean individuals exhibit lower HBsAg secretion capacity but not reduced HBV DNA levels. In addition, these variants exhibit increased ROS-inducing capacity compared with the wild-type strain, linking HBV occult infections to liver cell damage. Taken together, our previous reports suggest the transmission potential of distinct HBV occult infection-related variants in South Korea.

Leprosy and hepatitis B coinfection in southern Brazil

To investigate the association of leprosy with hepatitis B virus (HBV) infection, as yet unknown for South Brazil, we assessed hepatitis B virus coinfection in 199 South Brazilian leprosy patients (119 lepromatous, 15 tuberculoid, 30 borderline, 12 undetermined and 23 unspecified) and in 681 matched blood donors by screening for the hepatitis B virus markers HBSAg and anti-HBc, using ELISA. Positive samples were retested and anti-HBc+ only samples were tested for the hepatitis B surface antibody (anti-HBs). There was a strong association between leprosy and hepatitis B virus infection (OR = 9.8, 95% CI = 6.4–14.7; p = 0.004·E⁻³⁰), as well as an association between HBV infection and lepromatous leprosy, compared to other forms (OR = 2.4, 95% CI = 1.2–4.8; p = 0.017). We also found that confinement due to leprosy was associated with hepatitis B virus infection (OR = 3.9, 95% CI = 2.1–7.4; p = 0.015·E⁻³). Leprosy patients are susceptible to develop hepatitis B virus infection, especially lepromatous. Institutionalized patients, who probably present a stronger Th2 response, have higher risk of being exposed to hepatitis B virus. This clearly emphasizes the need for special care to leprosy patients in preventing hepatitis B virus coinfection in South Brazil.

Occult hepatitis B virus and the risk for chronic liver disease: a meta-analysis

BACKGROUND

The role of occult hepatitis B virus infection as a cause of liver disease is still debated although many studies found a higher prevalence of this condition in subjects than those without liver disease compared. A recent meta-analysis showed an increased risk of hepatocellular carcinoma for occult hepatitis B virus infection.

AIMS

We carried out a meta-analysis of observational studies to summarize the existing evidence and assess quantitatively the association between occult hepatitis B virus infection and chronic liver disease.

METHODS

We searched the available literature on this issue published up to May 2012 using PubMed and EMBASE. All articles that provided enough information to estimate the chronic liver disease risk associated with occult hepatitis B virus infection were selected. Fourteen studies were retrieved.

RESULTS

A total of 1503 subjects with (cases) and 2052 without chronic liver disease (controls) were included. The summary odds ratio for chronic liver disease from all studies was 8.9 (95% confidence interval: 4.1-19.5). The meta-analysis restricted to 7 studies with more precise effect estimate (wt%>8%) provided a lower odds ratio estimate (odds ratio=3.9; 95% confidence interval: 1.7-9.0).

CONCLUSIONS

These findings suggest a relevant association between occult hepatitis B virus infection and chronic liver disease, confirming the hypothesis that hepatitis B virus may play a pathogenic role even in the "occult" status.

Hepatitis B virus and hepatitis C virus co-infection: a therapeutic challenge

Hepatitis B virus and hepatitis C virus are the two most common causes of chronic liver disease in the world. Dual infection with hepatitis B virus and hepatitis C virus, whose prevalence is underestimated, is characterized by a more severe liver injury, a higher probability of liver cirrhosis and a higher incidence of hepatocellular carcinoma. Treatment of these patients represents a therapeutic challenge. We report the case of an hepatitis B virus-hepatitis C virus co-infected patient, which particularly illustrates the interactions between these two viruses and therapeutic problems caused by the dual infection. HCV was initially dominant, which indicated a combination therapy by pegylated interferon and ribavirin. This treatment was associated with an early virological response of the HCV but an increase of HBV DNA occurred, requiring the use of a nucleoside analogue. A good response was obtained for the HBV but a relapse of HCV was noted, posing a problem for therapeutic decision.

Naturally occurring mutations in large surface genes related to occult infection of hepatitis B virus genotype C

Molecular mechanisms related to occult hepatitis B virus (HBV) infection, particularly those based on genotype C infection, have rarely been determined thus far in the ongoing efforts to determine infection mechanisms. Therefore, we aim to elucidate the mutation patterns in the surface open reading frame (S ORF) underlying occult infections of HBV genotype C in the present study. Nested PCRs were applied to 624 HBV surface antigen (HBsAg) negative Korean subjects. Cloning and sequencing of the S ORF gene was applied to 41 occult cases and 40 control chronic carriers. Forty-one (6.6%) of the 624 Korean adults with HBsAg-negative serostatus were found to be positive for DNA according to nested PCR tests. Mutation frequencies in the three regions labeled here as preS1, preS2, and S were significantly higher in the occult subjects compared to the carriers in all cases. A total of two types of deletions, preS1 deletions in the start codon and preS2 deletions as well as nine types of point mutations were significantly implicated in the occult infection cases. Mutations within the “a” determinant region in HBsAg were found more frequently in the occult subjects than in the carriers. Mutations leading to premature termination of S ORF were found in 16 occult subjects (39.0%) but only in one subject from among the carriers (2.5%). In conclusion, our data suggest that preS deletions, the premature termination of S ORF, and “a” determinant mutations are associated with occult infections of HBV genotype C among a HBsAg-negative population. The novel mutation patterns related to occult infection introduced in the present study can help to broaden our understanding of HBV occult infections.

T-Cell Response to Hepatitis B Core Antigen: Identification of Prior Exposure to and Confirmatory Testing for Screening for Anti-HBc

Background. During routine donor screening in the blood bank, it is not uncommon to find isolated reactivity for anti-HBc in the absence of detectable HBV DNA in a first donation but absence of reactivity to anti-HBc in subsequent donations, suggesting a false-positive result for anti-HBc. Study Design and Methods. The blood donor population was screened between January 2010 and October 2011. We selected 2,126 donations positive only for anti-HBc from a total of 125,068 donations. During the process, OBI donors were identified, and their HBcAg-specific T-cell response was analyzed and compared to donors with chronic (HBsAg positive) and recovered (anti-HBc only) infection. We analyzed correlations between signal levels (Co/s) in the competitive assay for anti-HBc and HBV DNA detection. Results. In the 21-month study period, 21 blood donors with anti-HBc alone were identified as OBI (1 in each 5955 donors). The relevant finding was the observation that anti-HBc only subjects with Co/s ≥ 0.1 did not have either HBcAg-specific T-cells or detectable HBV DNA and OBI subjects presented with Co/s ≤ 0.1 and HBcAg T-cell response. In the subset of 21 OBI subjects, 9 donors remained positive for HBcAg T-cell response after four collections. In all 9 samples, we observed HBV DNA fluctuation. Conclusion. Our data suggest that HBcAg-specific T-cell response could be used to confirm anti-HBc serological status, distinguishing previous exposure to Hepatitis B virus from anti-HBc false-positive results.

Reducing the risk of hepatitis B virus transfusion-transmitted infection

Before 1970, approximately 6% of multi-transfused recipients acquired a transfusion-transmitted Hepatitis B virus (HBV) infection. The safety improvements since then have been tremendous. From a level of a few infections per 1000 donations, the risk today, depending on the screening algorithm and additional measurements performed, has decreased to around 1:500,000 to 1:1,000,000, an improvement greater than 1000-fold compared to 50 years ago. This enormous gain in safety has been achieved through many factors, including development of increasingly more sensitive Hepatitis B antigen (HBsAg) assays; the adoption in some countries of hepatitis B core antibody (anti-HBc) screening; an improved donor selection procedure; HBV vaccination programs; and finally the introduction of HBV nucleic acid testing (NAT). Because there is a tendency in transfusion medicine to add one safety measure on top of another to approach the ultimate goal of zero risks, costs become increasingly a matter of debate. It is obvious that any new measure in addition to existing methods or measures will have very poor cost effectiveness. Therefore each country needs to perform its own calculation based on the country’s own epidemiology, resources, political and public awareness of the risks, in order to choose the correct and most cost-efficient measures. Ideally, each country would make decisions regarding implementation of additional blood safety measures in the context of both the perceived benefit and the allocation of overall health care resources.

Mutations in TP53 and CTNNB1 in Relation to Hepatitis B and C Infections in Hepatocellular Carcinomas from Thailand

Hepatocellular carcinoma (HCC) may develop according to two major pathways, one involving HBV infection and TP53 mutation and the other characterized by HCV infection and CTNNB1 mutation. We have investigated HBV/HCV infections and TP53/CTNNB1 mutations in 26 HCC patients from Thailand. HBV DNA (genotype B or C) was detected in 19 (73%) of the cases, including 5 occult infections and 3 coinfections with HCV. TP53 and CTNNB1 mutations were not mutually exclusive, and most of TP53 mutations were R249S, suggesting a significant impact of aflatoxin-induced mutagenesis in HCC development.

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.

Therapeutic effects of pegylated interferon plus ribavirin in chronic hepatitis C patients with occult hepatitis B virus dual infection

BACKGROUND AND AIM

Occult hepatitis B virus (HBV) infection is defined by the detectable serum HBV-DNA in HBV surface antigen-negative patients. This retrospective study aims to evaluate the therapeutic effects of combined pegylated interferon (PEG-IFN) plus ribavirin (RBV) in patients with concurrent occult HBV/hepatitis C virus (HCV) dual infection.

METHODS

In total, 126 consecutive chronic hepatitis C (CHC) patients who received combined PEG-IFN and RBV therapy were included. Patients were divided into the occult HBV/HCV dual infection group or the HCV-monoinfected group according to whether or not they had the detectable serum HBV-DNA. The biochemical and virological responses to combined therapy were compared between these two groups. Serum HCV-RNA and HBV-DNA were checked before treatment, at the end of treatment as well as at 6- and 12-months' follow up in the occult HBV/HCV group.

RESULT

Six patients were seropositive for HBV-DNA and were included in the occult HBV/HCV dual infection group. There were no statistical differences in the biochemical and virological responses to combined therapy between these two groups. Undetectable serum HBV-DNA was noted at the end of the treatment and the 6- and 12-months' follow up in patients with occult HBV/HCV dual infection.

CONCLUSION

Occult HBV infection in CHC patients is rare. The biochemical and virological responses to combined PEG-IFN and RBV therapy might be similar in CHC patients with or without occult HBV infection. The serum HBV-DNA level was low in patients with occult HBV/HCV dual infection who responded to combined therapy.

Influence of anti-HBc seropositivity on the risk of hepatocellular carcinoma in HCV-infected patients after adjusting for confounding factors

It is controversial whether past hepatitis B virus infection constitutes an additional risk of hepatocellular carcinoma (HCC) among patients with hepatitis C virus (HCV). The incidence of HCC between 1994 and 2004 was analysed among 1262 patients who were only positive for HCV. The cumulative incidence of HCC was assessed by Kaplan-Meier analysis and the difference between two groups was assessed by the log-rank test. The effect of anti-HBc positivity on the risk of HCC was assessed with multivariate Cox proportional analysis. Anti-HBc was positive in 522 (41.4%) patients. The proportion of male patients (56.7 vs 46.8%, P < 0.001) and mean age (60.8 vs 56.9 years, P < 0.001) were significantly higher in the anti-HBc positive group. HCC developed in 339 patients (mean follow-up 7.0 years), with cumulative incidence rates at 3, 5 and 10 years of 12.7, 24.5 and 41.9% in the anti-HBc positive group and 10.6, 17.7 and 33.4% in the negative group, respectively (P = 0.005). However, anti-HBc seropositivity did not reach statistical significance in multivariate analysis including age and gender (hazard ratio, 1.06; 95% CI, 0.85-1.31; P = 0.63). Anti-HBc positivity and HCC incidence were confounded by male gender and older age.

Comparison of clinical application of the Abbott HBV PCR kit and the VERSANT HBV DNA 3.0 test to measure serum hepatitis B virus DNA in Taiwanese patients

With an estimated 350-400 million people worldwide chronically infected with hepatitis B virus (HBV), and the subsequent serious complications caused by liver damage including cirrhosis, liver failure, and hepatocellular carcinoma, HBV infection remains a global health issue, particularly in Taiwan, an HBV-hyperendemic area. Sensitive and accurate quantification of HBV DNA is necessary to monitor patients with chronic hepatitis B who are receiving antiviral therapy to determine treatment response and adapt therapy. We evaluated and compared the clinical performance of two HBV DNA assays based on different technologies: the RealArt HBV PCR Kit (Abbott HBV DNA PCR kit, real-time polymerase chain reaction assay, detection limit: 27 IU/mL) and the VERSANT bDNA 3.0 assay (Bayer, branched DNA signal amplification assay, detection limit: 357 IU/mL). Serum levels of HBV DNA in 173 chronic HBV carriers were determined using both the RealArt HBV PCR Kit and the VERSANT bDNA 3.0 test. Of the 173 samples analyzed for baseline viral load detection, HBV DNA was quantifiable in 147 patients (82.1%) by the RealArt HBV PCR Kit, which was significantly higher than the 92 (53.2%) samples quantified by the VERSANT bDNA 3.0 assay. A total of 86 (49.7%) samples were quantifiable by both assays, whereas 25 (14.5%) were below the detection limit of both assays. The HBV DNA quantification values measured by the RealArt HBV PCR Kit and the VERSANT bDNA 3.0 assay were positively correlated (Spearman's rank correlation coefficient r = 0.932, p < 0.001). On average, the results derived from the RealArt HBV PCR Kit were 0.67 log lower than those of the VERSANT bDNA 3.0 assay. HBV DNA concentrations were significantly higher in 63 HBV e antigen (HBeAg)-seropositive patients than in 110 HBeAg-seronegative patients (5.42 +/- 2.34 logs vs. 3.21 +/- 2.27 logs, p < 0.001). The RealArt HBV PCR Kit is more sensitive and has a wider dynamic range than the VERSANT bDNA 3.0 assay in the clinical setting of chronic hepatitis B patients. The sensitivity and wide dynamic range of the PCR assay allow optimal monitoring and timely adaptation of antiviral therapy. Nevertheless, the HBV DNA values measured by the RealArt HBV PCR Kit and the VERSANT bDNA 3.0 assay were significantly correlated.

Occult hepatitis B virus infection increases hepatocellular carcinogenesis by eight times in patients with non-B, non-C liver cirrhosis: a cohort study

An impact of serum hepatitis B virus (HBV) DNA on hepatocarcinogenesis has not been investigated in a cohort of patients with non-B, non-C cirrhosis. Eighty-two consecutive Japanese patients with cirrhosis, who showed negative hepatitis B surface antigen and negative anti-hepatitis C virus, were observed for a median of 5.8 years. Hepatitis B virus core (HBc) region and HBx region were assayed with nested polymerase chain reaction. Both of HBc and HBx DNA were positive in 9 patients (11.0%) and both were negative in 73. Carcinogenesis rates in the whole patients were 13.5% at the end of the 5th year and 24.6% at the 10th year. The carcinogenesis rates in the patients with positive DNA group and negative DNA group were 27.0% and 11.8% at the end of the 5th year, and 100% and 17.6% at the 10th year, respectively (P = 0.0078). Multivariate analysis showed that men (P = 0.04), presence of HBc and HBx DNA (hazard ratio: 8.25, P = 0.003), less total alcohol intake (P = 0.010), older age (P = 0.010), and association of diabetes (P = 0.005) were independently associated with hepatocellular carcinogenesis. Existence of serum HBV DNA predicted a high hepatocellular carcinogenesis rate in a cohort of patients with non-B, non-C cirrhosis.

[Occult hepatitis B: prevalence and clinical characteristics in a population with high endemicity of hepatitis B infection in the western Brazilian Amazon region]

A persistent form of the hepatitis B virus called occult chronic hepatitis B has recently been described. Its prevalence and physiopathology are unknown. The aim of this study was to evaluate the occurrence of this clinical entity among patients in the Brazilian Amazon region. Out of 51 anti-HBc total-positive patients who were tested using the polymerase chain reaction, 17% were positive. We did not find any associations with classical risk factors for hepatitis B virus infection or with biochemical tests, hematological tests or histological patterns. However, the jaundiced and HIV-positive patients showed a statistical association with the presence of hepatitis B virus-DNA. The results demonstrated that occult hepatitis B occurred among our patients, but at prevalence rates lower than expected for this region. We believe that despite the small sample size, the occurrence might have been found to be greater if we had used primers for the S, C and X regions of the hepatitis B virus genome, thereby increasing the sensitivity of the test.

High prevalence of occult hepatitis B in hepatitis C-infected Egyptian children with haematological disorders and malignancies

OBJECTIVE

This study investigates the prevalence of occult hepatitis B virus (HBV) in children and adolescents with haematological diseases with or without hepatitis C virus (HCV) infection.

METHODS

Forty-nine children with haematological disorders (median age 11.4 years) and 51 with haematological malignancies (median age 8 years) were enrolled. Sera were tested for HCV antibodies, HCV-RNA [nested reverse transcriptase polymerase chain reaction (PCR)], HBV markers (HBsAg, anti-HBcAb IgM and total, HBeAg) and HBV-DNA (nested PCR for s, c and x regions).

RESULTS

Anti-HCV was detected among 40/49 (81.6%) children with haematological disorders (24/49; 49% HCV-RNA positive) and 9/51 (17.6%) children with malignancies (12/51; 23.5% HCV-RNA positive). HBV-DNA was positive among 38%; positive c region in 33% (15/49 and 18/51 children with haematological disorders and malignancies respectively), s region in four leukaemics and x region in one leukaemic. Twenty-one patients had occult HBV infection; one (2.6%) was HBeAg positive, four (19%) total HBcAb positive, 20 (95.2%) c region HBV-DNA positive and one was s region positive (1/21; 4.8%). HCV-RNA was the significant predictor for occult HBV (P<0.05), with an increased frequency of HBV-DNA in the HBsAg negative (HCV-RNA positive) (63.2%) compared with patients negative for HCV-RNA (25%) (P=0.009).

CONCLUSION

Occult HBV infection is not uncommon in transfused immunocompromised children with chronic HCV infection. Nucleic acid amplification should be considered in screening donors as post-transfusion hepatitis B viraemia may be substantial.

Occult hepatitis B virus infection in hepatitis B vaccinated children in Taiwan

BACKGROUND/AIMS

Presence of occult HBV infection in HBV vaccinated children remains largely unknown. The aim of this study was to investigate the prevalence of occult HBV infection among HBV vaccinated children in Taiwan.

METHODS

Forty-six HBsAg negative sera from vaccinated children were enrolled randomly. HBV serum markers were detected by ELISA, and the titers of HBV DNA were determined by quantitative real-time PCR. Pre-S, S and pre-core/core genes were amplified by nested PCR and analyzed.

RESULTS

Anti-HBs was detected in 23 (50%) children, and the positivity decreased according to age. Five (10.9%) children were classified into occult HBV infection by positivity of nested PCR in at least two regions; they had a low titer (mean titer 1.60x10(4)copies/ml). Sequence analyses of S gene showed occult isolates were variants; no G145R but C139S vaccine escape mutant was found. Variation and deletion were found in pre-S region; pre-S deletion was more frequent in 3' terminus of pre-S1 which leads to loss of immune epitopes and function sites.

CONCLUSIONS

This pilot study indicates that the prevalence of occult HBV infection is 10.9% in HBV vaccinated children. Since this is a small study, a study of a large population is needed to confirm the findings herein.

Hepatitis B virus/hepatitis C virus coinfection: epidemiology, clinical features, viral interactions and treatment

Because of the shared modes of transmission, hepatitis B virus (HBV)/hepatitis C virus (HCV) coinfection is not uncommon in highly endemic areas and among subjects with a high risk of parenteral infections. The worldwide prevalence of HBV/HCV coinfection is unknown and might be underestimated with the phenomenon of silent (occult) HBV infection. HCV superinfection in patients with chronic HBV infection was the most common clinical features of coinfection in Asia-Pacific countries. Further, most, but not all, clinical observations suggested that interference between the two viruses was more frequently characterized by an inhibition of HBV replication exerted by HCV. However, longitudinal follow-up studies have demonstrated that the virological patterns in coinfection cases are widely divergent and have dynamic profiles over time. As compared with monoinfected patients, HBV/HCV coinfected persons tend to have more severe liver injury, a higher probability of liver cirrhosis and hepatic decompensation, and a higher incidence of hepatocellular carcinoma. Detailed serological and virological evaluations are required for coinfected patients before initiation of antiviral therapy. Previous studies demonstrated that HBV/HCV coinfected patients responded poorly to interferon (IFN) monotherapy. Currently, for patients with dominant HCV infection and low level HBV viremia (<10(4) IU/mL), IFN or pegylated IFN plus ribavirin can achieve comparable sustained virus response as expected with HCV monoinfection. However, phenomenon of reciprocal viral interference can happen, and resultant "flare" of hepatitis activity may cause liver function deterioration. For coinfected patients with dually-active HBV/HCV, the optimal regimen for therapy remains unclear although adding oral nucleos(t)ide analogs to pegylated IFN and ribavirin seems a reasonable empiric option.

Occult HBV infection may represent a major risk factor of non-response to antiviral therapy of chronic hepatitis C

Occult hepatitis B virus (HBV) infection is common in chronic hepatitis C patient. However, its significance and consequences are still unclear. The aim of this study was to evaluate the prevalence of occult HBV among HCV chronic carriers in France and to assess its impact on liver histology and response to antiviral therapy. To this end a cohort of 203 patients with chronic hepatitis C without hepatitis B surface antigen (HBsAg) has been examined. Serum HBV-DNA was detected using a highly sensitive PCR with primers located in the S and X genes. HBV viraemia levels were further determined by real-time PCR. Results showed that 47 of 203 (23%) patients had occult HBV infection with a low HBV load (10(2)-10(4) copies/ml) but significantly higher HCV-RNA titers (P < 0.05). No significant difference in age, gender, serum ALT level, HCV genotypes, and the presence of anti-HBc was observed between patients with or without HBV-DNA. When compared histologically, patients with occult HBV infection had higher activity (A2-A3 in 53% vs. 38%, P < 0.01) and more advanced fibrosis (60% vs. 33%, P < 0.001) than HBV-DNA negative cases. Sustained response to combination therapy against Chronic hepatitis C was achieved in 11 (28%) of 40 HBV-DNA positive cases, compared with 65 (45%) of the 144 HBV-DNA negative cases (P < 0.05). Among the 144 HBV-DNA negative HCV patients those with genotype 1 responded less frequently to therapy as compared to other genotypes infected patients (38% vs. 55%, P < 0.05). Surprisingly, when considering all patients studied, irrespective to the HBV-DNA status no significant difference was observed in response to combination therapy regarding HCV genotypes (39% vs. 44%, P > 0.05). In conclusion, HBV-DNA is found in 1/4 of French chronic hepatitis C patients regardless of the presence of anti-HBc. Such an occult HBV co-infection is associated with more severe liver disease, higher HCV viral load and decreased response to antiviral therapy irrespective of HCV genotypes.

Occult hepatitis B virus infection

The persistence of hepatitis B virus (HBV) genomes in HBV surface antigen (HBsAg) negative individuals is termed occult HBV infection. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays, but more frequently it is due to a strong suppression of viral replication and gene expression. Occult HBV infection is an entity with world-wide diffusion, although the available data of prevalence in various categories of individuals are often contrasting because of the different sensitivity and specificity of the methods used for its detection in many studies. Occult HBV may impact in several different clinical contexts, including the transmission of the infection by blood transfusion or organ transplantation and its acute reactivation when an immunosuppressive status occurs. Moreover, much evidence suggests that it can favour the progression of liver fibrosis and above all the development of hepatocellular carcinoma.

Epidemiology of HBV infection in Asian blood donors: Emphasis on occult HBV infection and the role of NAT

Hepatitis B virus (HBV) infection is endemic in many Asian countries. Among many transmission routes, transfusion is the one that should be prevented. The first major success in enhancing transfusion safety came with the implementation of hepatitis B surface antigen (HBsAg) in the early 1970s. However, the studies quoted in this review demonstrate that transmission by blood components negative for HBsAg can still occur in the acute phase of infection during the seronegative window period, or during chronic stages of infection (i.c. "occult" HBV infection, OHB). OHB is defined as the presence of HBV DNA in blood or liver tissues in patients negative for HBsAg, with or without any HBV antibodies. Because of limitations in current blood screening practices, OHB is an overlooked source of HBV transmission. For policy development on screening for HBV infection in blood donors, it would be useful to assess the relative contribution of the above two sources of transfusion-transmitted HBV infection from HBsAg-negative donations. New screening policy should be evaluated on the basis of available data or newly designed studies. While anti-HBc screening can climinate residual risk of occult HBV transmission by transfusion in low-endemic areas, it would not be practical in most parts of the world where the prevalence of anti-HBc is >10% as too many otherwise healthy donors will be ineligible. On the contrary, studies mentioned in this paper indicate that nucleic acid amplification test (NAT) or new HBsAg tests of enhanced sensitivity would be effective in the screening of blood donors for OHB in highly endemic countries. However, the cost-effectiveness of blood screening tests is a major concern in Asia. We therefore have systemically reviewed the literature on prevalence and infectivity of OHB in Asian countries and the possible role of NAT for identifying blood donors in the pre-HBsAg window phase or in later stages of OHB.

Changing patterns of hepatitis B infection in Italy and NAT testing for improving the safety of blood supply

In Italy, as in most industrialized countries, the burden of hepatitis B has progressively declined in recent decades as a consequence of general improvements in hygiene and standard of living, the introduction of several public health measures, refinement in blood screening and the implementation of specific vaccination programmes. Universal hepatitis B vaccination for all infants and adolescents as well as individuals at increased risk has resulted in considerable progress towards prevention and control of HBV infection. The residual risk of transmitting blood-borne viruses through transfusion is currently very low. Nucleic acid testing can shorten the window period and, consequently, further reduce the risk of viral transmission. Blood donor screening for HCV by NAT was initiated in Italy in 2001 and became mandatory in June 2002. NAT for HIV is currently mandatory in four regions, not mandatory but almost universally performed in another thirteen regions, and not yet introduced in the remaining four regions. NAT for HBV is currently mandatory in four regions and under evaluation in the remaining. NAT for HBV may be a useful tool in detecting acute viral infections in the window phase as well as the occult infections. Its efficacy in improving the safety of blood supply is expected to be higher in countries with intermediate/high endemicity, where anti-HBc antibody screening cannot be routinely performed. There is agreement that, at present, the implementation of HBV DNA testing will not allow for discontinuation of screening for HBsAg.

Occult hepatitis B virus infection is associated with the development of hepatocellular carcinoma in chronic hepatitis C patients

BACKGROUND

Occult hepatitis B virus (HBV) infection frequently occurs in patients with HBV surface antigen (HBsAg)-negative chronic liver disease, and much evidence suggests that it is a risk factor for hepatocellular carcinoma (HCC) development. However, to the authors' knowledge, no follow-up study has been performed to date evaluating HCC occurrence over time in chronic hepatitis patients with or without occult HBV infection.

METHODS

A cohort of the 380 HBsAg-negative chronic hepatitis patients attending the study institution between 1991-2000 were evaluated and tested for occult HBV DNA by analysis of liver biopsy specimens.

RESULTS

There were 135 patients (35.5%) with occult HBV and 245 patients (64.5%) without occult HBV. Cirrhosis was significantly associated with occult HBV infection (P = 0.01). One hundred thirty-four of these patients were followed for a minimum of 50 months (median, 82.8 +/- 32.6 mos). Fifty-three patients (39%) were occult HBV carriers and 81 (61%) were not. Nine patients developed HCC during the follow-up; eight were positive and one was negative for occult HBV (P = 0.002).

CONCLUSIONS

The current observational cohort study showed that, among the HBsAg-negative patients with chronic hepatitis, HCC develops for the most part in carriers of occult HBV. Therefore, the evaluation of HBV genomes in chronic hepatitis patients appears to be a powerful tool for the identification of individuals at higher risk of HCC development.

Fibrosis progression in chronic hepatitis C patients with occult hepatitis B co-infection

Occult hepatitis B virus (HBV) infection in individuals without hepatitis B surface antigen (HBsAg) can be identified in hepatitis C virus (HCV) infected patients. However, its role in fibrosis progression remains uncertain. This retrospective study compared the fibrosis progression (defined as fibrosis progression by at least one stage) and progression to severe fibrosis (fibrosis stage 3 or 4) in HCV patients with occult HBV infection. Occult HBV infection was diagnosed by the detection of HBV DNA in the serum of 74 consecutive anti-HCV positive patients by PCR. Thirty-one patients (41.9%) had occult HBV infection. All 74 patients had a median of 2 (range 2-3) liver biopsies. The median time between the first and last liver biopsy was 57.7 (range 15.0-132.8) months. Eleven of the 31 patients with occult HBV infection compared with 12 of the 43 patients without occult HBV infection had fibrosis progression (35.5% versus 27.9%, respectively, p=0.608). Six of the 31 patients with occult HBV infection compared with 8 of the 43 patients without occult HBV infection developed severe fibrosis (19.4% versus 18.6%, respectively, p=0.946). In conclusion, chronic HCV patients with occult HBV co-infection does not seem to progress more than patients without occult HBV infection. However, more large-scale studies are needed before a definite conclusion can be obtained.

Occult hepatitis B virus infection in a North American community-based population

BACKGROUND/AIMS

Occult hepatitis B virus (HBV) infection [HBV-DNA detection in hepatitis B surface antigen (HBsAg)-negative individuals] may cause acute and/or chronic liver disease. The objective of this study was to document the prevalence of occult HBV in an isolated, North American Inuit community.

METHODS

Four hundred and eighty seven HBsAg negative sera (61% of the community population) were available for HBV-DNA testing by real time PCR. Of these, 80 (Group 1) had serologic evidence of resolved HBV infection and 407 (Group 2) were HBV-seronegative.

RESULTS

HBV-DNA was detected in 14/80 (18%) and S-variants in 12/14 (86%) samples from Group 1. In Group 2, HBV-DNA was detected in 33/407 (8.1%) and S-variants in 17/33 (52%). In all cases (Groups 1 and 2) viral loads were low (<10(5) viral copies/ml) and clinical or biochemical features did not distinguish HBV-DNA positive from negative individuals. However, S-variants were more common (P<0.0001) in older age groups.

CONCLUSIONS

The results of this study indicate that in this community-based population; (1) the prevalence of occult HBV infection is 18% in those with serologic evidence of previous HBV infection and 8.1% in HBV seronegative individuals, (2) age, gender and liver biochemistry findings do not identify those with occult HBV and (3) S-variants are present in the majority of individuals with occult HBV.

Occult hepatitis B virus infection: implications in transfusion

Hepatitis B virus (HBV) presents a higher residual risk of transmission by transfusion than hepatitis C virus (HCV) or human immunodeficiency virus (HIV). While most infectious blood units are removed by screening for hepatitis B surface antigen (HBsAg), there is clear evidence that transmission by HBsAg-negative components occurs, in part, during the serologically negative window period, but more so during the late stages of infection. Donations negative for HBsAg, but positive for HBV DNA, with or without the presence of HBV antibodies, correspond to 'occult' HBV infection (OBI). The frequency of OBI depends on the relative sensitivity of both HBsAg and HBV DNA assays. It also depends on the prevalence of HBV infection in the population. OBI may follow recovery from infection, displaying antibody to hepatitis B surface antigen (anti-HBs) and persistent low-level viraemia, escape mutants undetected by the HBsAg assays, or healthy carriage with antibodies to hepatitis B e antigen (anti-HBe) and to hepatitis B core antigen (anti-HBc). Over time, in the latter situation, anti-HBe and, later, anti-HBc may become undetectable. The critical question is whether or not OBI is infectious by transfusion. All forms have been shown to be infectious in immunocompromised individuals, such as organ- or bone marrow-transplant recipients. In immunocompetent recipients, there is no evidence that anti-HBs-containing components (even at low titre) are infectious. Anti-HBc only, with HBV DNA, can be associated with infectivity, as can rare cases of HBV DNA without any serological HBV marker. If HBV nucleic acid amplification technology (NAT) is considered, the OBI viral load would usually be < 500 IU/ml, making testing of plasma pools unsuitable unless the sensitivity of NAT significantly increases by genome enrichment or test improvement.

Hepatitis B virus genotypes, phylogeny and occult infection in a region with a high incidence of hepatocellular carcinoma in China

AIM: To determine the genotypes and phylogeny of hepatitis B viruses (HBVs) in asymptomatic HBV carriers, and the prevalence of occult HBV infection in Long An County, Guangxi Zhuang Autonomous Region, an area with a high incidence of hepatocellular carcinoma.

METHODS: A nested polymerase chain reaction (nPCR) was used for detection of HBV DNA in serum samples from 36 blood donors with asympmatic HBV infection, and in serum samples from 52 HBsAg negative family members of the children who did not receive hepatitis B vaccination in Long An County. PCR products were sequenced, and the genotype of each HBV sequence was determined by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases using the BLAST programme. Phylogenetic trees were constructed by the quartet maximum likelihood analysis using the TreePuzzle software.

RESULTS: Twenty (55.56%) of 36 HBV asymptomatic carriers were positive for HBV DNA. They were all genotype C by comparison with sequences of known genotypes in the GenBank and EMBL nucleotide databases. The full-length HBV DNA sequence isolated from the sample No. 624 contained 3215 bases. No interesting mutations were found in this isolate. The homology analysis showed that this strain was closer to the Vietnamese HBV genotype C strain, with a homology of 97%, compared its relation to the same genotype of HBV isolated in Shanghai. Six (11.5%) of the 52 HBsAg negative family members were positive for HBV DNA. A point mutation was found in the sample No. 37, resulting in the substitution of amino acid glycine to arginine in the “a” determinant. Other samples with positive HBV DNA did not have any unusual amino acid substitutions in or around the “a” determinant, and were attributed to the wild-type HBV.

CONCLUSION: The HBVs isolated from asymptomatic carriers of Long An County were all identified as genotype C, and the prevalence of occult HBV infection in the population of the county is as high as 11.5%. It is suggested that genotype C and persistent occult HBV infection may play an important role in the development of HCC in the county.

Occult hepatitis B virus infection in Greek patients with chronic hepatitis C and in patients with diverse nonviral hepatic diseases

Occult hepatitis B virus (HBV) infection has been reported in patients with chronic hepatitis C who are negative for HBV surface antigen (HBsAg). However, the significance of 'silent' HBV in hepatitis C virus (HCV) infection is unknown. We investigated 540 subjects for the presence of occult HBV in Greek HCV patients, patients with nonviral liver diseases and healthy donors in an attempt to determine the frequency and importance of this phenomenon. One hundred and eighty-seven anti-HCV(+)/HBsAg(-) patients' sera were investigated for the presence of HBV-DNA by polymerase chain reaction. Two hundred and eighty-two selected blood donors (positive for antibodies to HBV core antigen) and 71 patients with various nonviral hepatic diseases consisted the control groups [both controls were anti-HCV(-)/HBsAg(-)]. HBV-DNA was detected in 26.2% of HCV-infected patients vs 8.5% of patients with nonviral diseases (P = 0.003) and 0/282 of donors (P = 0.0000). HBV-DNA was neither associated with HBV markers, nor with the clinical status of HCV and nonHCV patients. Neither epidemiological, histologic and virologic data nor the response to therapy were associated with the HBV-DNA detection. Hence one quarter of HCV-infected patients had occult HBV infection. Similar findings were not found in both control groups. Occult HBV infection in Greek patients with chronic hepatitis C does not seem to modify the progression of chronic liver disease. Further studies of longer duration are needed in order to clarify the role of 'silent' HBV infection in HCV-infected patients.

Virological significance of low-level hepatitis B virus infection in patients with hepatitis C virus associated liver disease

The clinical and virological significance of low-level viremia by hepatitis B virus (HBV) in hepatitis C virus (HCV)-infected patients remains unclear. HBV-DNA and HCV-RNA were, therefore, quantitatively analyzed in livers and sera from co-infected patients. HBV-DNA and HCV-RNA were quantitated using real-time detection of polymerase chain reaction (RTD-PCR), based on Taq-Man chemistry, in 220 non-HCV-infected healthy volunteers and 93 HCV-infected patients without detectable HBsAg. Serum HBV-DNA was detected in 4 (1.8%) of 220 non-HCV-infected healthy volunteers and 32 (34.4%) of 93 HCV-infected patients without detectable HBsAg. HCV-infected patients displayed higher frequency of HBV infection than healthy volunteers (P < 0.0001). Hepatocellular carcinoma (HCC) was more frequent among co-infected patients than among HCV mono-infected patients (P < 0.001). However, quantities of HBV-DNA in sera from co-infected patients were very low (8-19,000 copies/ml). HBV-DNA was detected in liver tissue from co-infected patients at 2-20 copies per 100 hepatocytes, accounting for 1/1,000 to 1/10,000 of HBsAg positive patients. In livers of patients with HCC and HCV or HBV mono-infection, the viruses existed predominantly in non-cancerous tissue, with levels 10- to 1,000-fold and 1- to 100-fold higher than in cancerous tissue, respectively. In contrast, patients co-infected with HCV and HBV displayed decreased HBV levels in non-cancerous tissue, but no change in cancerous tissue. These results indicate that low-level HBV infection exists in HCV-infected patients. HCC was more common among HCV/HBV co-infected patients than among HCV mono-infected patients. HCV might initiate hepatocarcinogenesis, but does not necessarily determine progression to HCC.

Clinical evaluation of the COBAS Amplicor HBV monitor test for measuring serum HBV DNA and comparison with the Quantiplex branched DNA signal amplification assay in Taiwan

AIMS

To evaluate the performance characteristics and clinical usefulness of the COBAS Amplicor HBV monitor (COBAS-AM) test in Taiwan and to examine its correlation with the Quantiplex branched DNA signal amplification (bDNA) assay for measuring serum hepatitis B virus (HBV) DNA concentrations.

METHODS

HBV DNA was measured by the COBAS-AM test in 149 sera from chronic HBV infected patients that had previously been analysed by the bDNA assay.

RESULTS

The COBAS-AM test showed good reproducibility, with acceptable intra-assay and interassay coefficients of variation (1.6% and 0.9%, respectively) and good linearity (r2=0.98). The overall sensitivity of the COBAS-AM test was significantly higher than that of the bDNA assay (95.3% v 83.2%): 69.6% of samples with HBV DNA below the detection limit of the bDNA assay could be measured by the COBAS-AM test. There was a significant correlation between the results of the two assays (r=0.901; p<0.0001). On average, the results derived from the COBAS-AM test were 0.55 log lower than those of the bDNA assay. HBV DNA concentrations were significantly higher among HBV e antigen (HBeAg) positive patients than negative ones, and higher among patients with abnormal alanine aminotransferase (ALT) concentrations than those with normal ALT concentrations (p=0.0003).

CONCLUSIONS

The COBAS-AM assay, more sensitive in HBeAg negative samples than the bDNA assay, can effectively measure HBV DNA concentrations in Taiwanese patients. HBV DNA values measured by the COBAS-AM test and bDNA assay correlate significantly.

Occult hepatitis B virus infection

The detection of HBV DNA without HBsAg with or without the presence of HBV antibodies outside the acute phase window period defines occult HBV infection. This condition has been described in hepatocellular carcinoma (HCC), chronic hepatitis B, healthy HBV carriage and recovered infection, chronic hepatitis C and individuals without serological markers of HBV. The frequency of the diagnosis depends on the relative sensitivity of both HBsAg and HBV DNA assays. It also depends on the prevalence of HBV infection in the population. Occult HBV in blood donors has a wide range of potential origins within the natural history of the infection. It may originate from recovered infections with anti-HBs and persistent, low-level, viral replication, escape mutants undetected by the HBsAg assays or healthy chronic carriage. The last situation is mostly found with anti-HBc only. Over time, antibody markers may become undetectable leaving HBV DNA as the only marker of the infection. In all cases, the viral load is low, mostly below 10(4) IU/ml, often below 100 IU/ml. At these levels, nucleic acid testing (NAT) in pools is likely to be largely ineffective. Is occult HBV transmissible by transfusion? Carriers of anti-HBs or anti-HBc only were shown infectious in immunosuppressed organ or bone marrow transplant recipients. In immunocompetent recipients, there is no evidence that anti-HBs-containing components are infectious, even in low titre. Donations carrying anti-HBc only and HBV DNA can be infectious and this is a threat where anti-HBc is not screened. Anti-HBc screening identifies most occult HBV infection but not all. HBV NAT needs either extreme sensitivity or to be performed on individual donations to eliminate HBV DNA-containing units.

Hepatitis B virus maintains its pro-oncogenic properties in the case of occult HBV infection

BACKGROUND AND AIMS

Occult hepatitis B virus (HBV) infection is characterized by persistence of HBV DNA into the tissue of hepatitis B surface antigen-negative individuals. The clinical relevance of this peculiar infection is still under debate. In particular, the impact of occult HBV infection in cases of hepatocellular carcinoma (HCC) is uncertain. We investigated the prevalence and molecular status of occult HBV in patients with HCC.

METHODS

We tested tumor tissues from 107 patients with HCC and the corresponding nontumor liver tissue from 72 of these patients for HBV DNA. We also examined liver specimens from 192 patients with chronic hepatitis. All cases were hepatitis B surface antigen negative. Covalently closed circular HBV genomes, HBV transcripts, and viral integrated forms were investigated in cases of HCC found positive for occult HBV.

RESULTS

Viral DNA was detected in 68 of 107 cases of HCC (63.5%) and in 63 of 192 cases of chronic hepatitis (32.8%) (P < 0.0001; odds ratio, 3.6; 95% confidence interval, 2.2-5.9). The significant association of occult HBV with HCC was irrespective of age, sex, and contemporary hepatitis C virus infection. Both integrated viral DNA and covalently closed circular HBV genomes were detected in patients with occult HBV. Moreover, the presence of free HBV genomes was associated with persistence of viral transcription and replication.

CONCLUSIONS

Our findings provide clear evidence that occult HBV is a risk factor for development of HCC and show that the potential mechanisms whereby overt HBV might induce tumor formation are mostly maintained in cases of occult infection.

Detection of hepatitis B virus in seropositive and seronegative patients with chronic liver disease using DNA amplification by PCR

BACKGROUND

The aim of this study was to detect DNA of hepatitis B virus (HBV) for reliable diagnosis of HBV infection in sera by means of a validated polymerase chain reaction (PCR) using a 5' oligonucleotide (primer) previously described and a 3' primer designed by our investigation group.

METHODS

Sera samples collected from patients with chronic liver disease (CLD) related to HBV infection and negative to hepatitis C virus (HCV) infection were analyzed. Patients were both positive and negative to HBV by serum markers detected by ELISA immunoassay. A 146-base pair (bp) fragment was amplified from highly conserved precore-core region. This procedure enabled us to search for DNA HBV-positive cases.

RESULTS

Viral replicative state in negative hepatitis B e antigen (HBeAg) (15.7%) cases was verified by PCR technique. This detected infection by HBV in 100% of immunoassay-positive samples. Additionally, sequences of expected size in patients bearing atypical markers in their sera (7.1%) and those with negative serology (4.8%) for HBV markers were detected.

CONCLUSIONS

In this study we have improved a PCR technique successfully applied in hepatitis B prevalence studies in northeastern Mexico. Prevalence of hepatitis B in this region of Mexico is intermediate compared to countries of the northern hemisphere where prevalence is lower, and to countries of Southeast Asia and the Mediterranean region where it is highly endemic.

Occult hepatitis B virus infection and clinical outcomes of patients with chronic hepatitis C

Although occult hepatitis B virus (HBV) infections in individuals without detectable hepatitis B surface antigen (HBsAg) may occur and have been reported to be common in patients with chronic hepatitis C, the clinical relevance remains controversial. We searched for serum HBV DNA in 210 HBsAg-negative patients with hepatitis C virus (HCV)-related liver disease (110 patients with chronic hepatitis, 50 patients with cirrhosis, and 50 patients with hepatocellular carcinoma) by PCR. Most of the patients had detectable antibodies to HBsAg or HBV core antigen. All of the 110 chronic hepatitis C patients were treated with a combination therapy consisting of interferon plus ribavirin. In addition, 100 HBsAg-negative healthy adults served as controls. Thirty-one of the 210 patients (14.8%) had HBV DNA in their sera, as did 15 of the 100 healthy controls (15%). HBV DNA was not detected in the sera of those negative for serological markers of HBV infection. In patients with chronic HCV infection, the prevalence of occult HBV infection did not parallel the severity of liver disease (14.5% in patients with chronic hepatitis, 8% in patients with liver cirrhosis, and 22% in patients with hepatocellular carcinoma). In addition, the sustained response to combination therapy against hepatitis C was comparable between patients with and without occult HBV infection (38 versus 39%). In conclusion, these data suggest that occult HBV infection does not have clinical significance in chronic hepatitis C patients residing in areas where HBV infection is endemic.

Sequence analysis of pre-S/surface and pre-core/core promoter genes of hepatitis B virus in chronic hepatitis C patients with occult HBV infection

Although occult hepatitis B virus (HBV) infection in individuals without detectable hepatitis B surface antigen (HBsAg) may occur and has been reported to be common in patients with chronic hepatitis C, the related molecular mechanisms remain unknown. With the polymerase chain reaction, serum HBV DNA was sought in 100 HBsAg-negative patients with chronic hepatitis C virus (HCV)-infection. In those with occult HBV infection, possible genomic variability of HBV was evaluated by amplification and direct sequencing of pre-S, surface, and pre-core/core promoter genes. In total, 10 of the 100 patients (10%) had detectable serum HBV DNA, documenting an occult HBV infection. A deletion mutant in the pre-S gene was found in one patient and mutations of the a determinant of HBsAg were observed in 2. In addition, a novel core promoter mutant (a dinucleotide substitution: T-to-C at nucleotide 1,802 and T-to-G at nucleotide 1,803, T1802C/T1803G) was found frequently in patients with occult HBV infection as compared to sex- and age-matched HBsAg-positive patients (80 vs. 10%, P < 0.001). In conclusion, the data suggest occult HBV infection is not uncommon in chronic hepatitis C patients in Taiwan, and a novel core promoter mutant may be associated with the absence of circulating HBsAg in these patients.

Occult hepatitis B virus infection and its clinical implications

Occult hepatitis B virus (HBV) infection is characterized by presence of HBV infection with undetectable hepatitis B surface antigen (HBsAg). Serum HBV level is usually less than 104 copies/mL in these patients. Diagnosis of occult HBV infection requires sensitive HBV-DNA PCR assay. Several possibilities have been hypothesized as the mechanisms of occult HBV infection. These include: (i) mutations of HBV-DNA sequence; (ii) integration of HBV-DNA into host's chromosomes; (iii) infection of peripheral blood mononuclear cells by HBV; (iv) formation of HBV-containing immune complex; (v) altered host immune response; and (vi) interference of HBV by other viruses. The precise prevalence of occult HBV infection remains to be defined. The clinical implications of occult HBV infection involve different clinical aspects. First of all, occult HBV infection harbours potential risk of HBV transmission through blood transfusion, haemodialysis, and organ transplantation. Second, it may serve as the cause of cryptogenic liver disease, contribute to acute exacerbation of chronic hepatitis B, or even fulminant hepatitis. Third, it is associated with development of hepatocellular carcinoma. Fourth, it may affect disease progression and treatment response of chronic hepatitis C. Most of the previous studies utilized retrospective observation without control groups, and lacked direct association of occult HBV infection with specific pathological changes and disease progression. Highly sensitive, quantitative, and functional molecular analyses of HBV, combined with a well-designed prospective clinical assessment will provide the best approach for the future study of occult HBV infection.

Virological profiles in patients with chronic hepatitis C and overt or occult HBV infection

OBJECTIVES

The virological profiles of hepatitis B and C viruses (HBV and HCV) and their interplay in cases of coinfection are undefined. A suppressed and occult HBV infection may occur in hepatitis B surface antigen (HBsAg) negative patients with chronic hepatitis C. The HCV core protein is able to inhibit HBV "in vitro," and serines at positions 99 and 116 are essential for such inhibition. We aimed to assess the HBV and HCV virological profiles in cases of coinfection and to evaluate the relationship between HCV core gene variability and HBV activity.

METHODS

Eighty-two anti-HCV positive patients were examined: 35 cases were HBsAg positive, 24 were HBsAg negative with "occult" HBV infection, and 23 were HBV negative. HBV and HCV viremia levels were evaluated in all cases. HCV genomic region coding for the aminoacid sequence 99-116 of core protein was amplified and sequenced in all HCV RNA positive cases. The entire core gene was amplified and sequenced in three randomly selected cases.

RESULTS

Serum HCV RNA was detected in all cases but 13, all HBsAg positive individuals; HCV viremia levels of the other 22 HBsAg positive subjects were similar to those detected in HBsAg negative patients with or without occult HBV infection. Among the 35 HBsAg positive patients both HBV DNA and HCV RNA were detected in five cases, HCV RNA alone in 17, and HBV DNA alone in six, whereas seven cases had undetectable levels of both viruses. Sequencing analyses showed that the HCV core gene was highly preserved in all patients.

CONCLUSION

A wide spectrum of HCV and HBV virological patterns may occur in a case of coinfection. HCV core variability is not related to HBV activity "in vivo."

Prevalence of vaccine-induced escape mutants of hepatitis B virus in the adult population in China: a prospective study in 176 restaurant employees

BACKGROUND AND AIM

Hepatitis B virus (HBV) variants with mutations in the S gene would pose a substantial risk to the community as current HBV vaccines are not effective in preventing infection with them. The majority of such vaccine escape mutants so far reported have been found while studying vertical transmission of HBV; the vaccine failure rate in connection with vaccine escape mutants in adults is not clear at the moment. The purpose of this study was to evaluate the efficacy of immunization against HBV in the adult population by analysis using polymerase chain reaction (PCR) to detect HBV-DNA, and also to elucidate the type of mutation encountered in vaccine failure cases.

METHOD

A total of 176 adult restaurant employees in China, who had been vaccinated according to the food epidemic law, were enrolled in a standard vaccination program. Their serum HBV-DNA was determined before and 1 year after the completion of the vaccination program. In those infected with HBV, despite having received the HBV vaccine, direct sequencing within the S gene of the amplified samples was conducted.

RESULTS

Although only two cases were found to be hepatitis B surface antigen (HBsAg) positive 1 year after the completion of the vaccination program, six subjects (3.4%) were found to be HBV-DNA positive assessed by a nested PCR. Four out of these six cases had a point mutation within the 'a' determinant; they were Gly-145-Ala, and Ile/Thr-126-Asn/Ser.

CONCLUSION

The HBV vaccine failure rate assessed by using PCR analysis was 3.4% (six of 176) in the Chinese adult population undergoing the HBV vaccination program. Hepatitis B virus variants with missense mutation within the 'a' determinant were responsible in most cases.

Hepatitis B virus and hepatocellular carcinoma

Chronic hepatitis B virus (HBV) infection is a major global cause of hepatocellular carcinoma (HCC). Individuals who are chronic carriers have a greater than 100-fold increased relative risk of developing the tumour. Several mechanisms of HBV-induced HCC have been proposed. Integration of HBV DNA into the genome of hepatocytes occurs commonly, although integration at cellular sites that are important for regulation of hepatocyte proliferation appears to be a rare event. Functions of the HBx protein are also potentially oncogenic. These include transcriptional activation of cellular growth regulatory genes, modulation of apoptosis and inhibition of nucleotide excision repair of damaged cellular DNA. The effects of HBx are mediated by interaction with cellular proteins and activation of cell signalling pathways. Variations in HBV genome sequences may be important in hepatocarcinogenesis, although their significance has not yet been completely elucidated. Necroinflammatory hepatic disease, which often accompanies chronic HBV infection, may contribute indirectly to hepatocyte transformation in a number of ways, including by facilitating HBV DNA integration, predisposing to the acquisition of cellular mutations and generating mutagenic oxygen reactive species. Although HCC is a malignancy with a poor prognosis, the availability of an effective vaccine against HBV infection, and its inclusion in the Expanded Programme of Immunization of many countries, augurs well for the eventual elimination of HBV-associated HCC.

Hepatitis B virus DNA in serum of healthy black African adults positive for hepatitis B surface antibody alone: possible association with recombination between genotypes A and D

In some patients with chronic liver disease induced by hepatitis B virus, viral DNA is known to persist in low concentration in serum after seroconversion to hepatitis B surface antibody-positivity. This phenomenon has, however, not been documented in asymptomatic black African carriers of hepatitis B virus. Using nested amplification by the polymerase chain reaction, we detected low concentrations of hepatitis B virus DNA in the serum of 6 of 23 (26%) healthy black African adults with normal liver function and with hepatitis B virus surface antibody as the only serological marker of the virus. This finding offers one explanation for the earlier observation of integrated hepatitis B virus DNA in hepatocellular carcinomas in black Africans whose serum was positive for surface antibody alone. A number of genetic changes were found in the six isolates that might be responsible for evasion of the immune response and persistence of the virus. Isolated mutations were detected in the "a" determinant of the surface gene and in the encapsidation signal. In all five isolates sequenced in the core promoter, mutations were present in the upstream regulatory region. Recombination between genotypes A and D was present in three of the isolates, including both of those in which the entire genome was sequenced. This change in genotype also overlapped the amino end of the polymerase domain and may result in sufficiently low levels of replication to allow viral persistence. Topoisomerase 1 specific trinucleotides were concentrated in the vicinity of the recombination breakpoints.

Hepatitis B virus and hepatocellular carcinoma

Chronic hepatitis B virus (HBV) infection is a major global cause of hepatocellular carcinoma (HCC). Individuals who are chronic carriers have a greater than 100-fold increased relative risk of developing the tumour. Several mechanisms of HBV-induced HCC have been proposed. Integration of HBV DNA into the genome of hepatocytes occurs commonly, although integration at cellular sites that are important for regulation of hepatocyte proliferation appears to be a rare event. Functions of the HBx protein are also potentially oncogenic. These include transcriptional activation of cellular growth regulatory genes, modulation of apoptosis and inhibition of nucleotide excision repair of damaged cellular DNA. The effects of HBx are mediated by interaction with cellular proteins and activation of cell signalling pathways. Variations in HBV genome sequences may be important in hepatocarcinogenesis, although their significance has not yet been completely elucidated. Necroinflammatory hepatic disease, which often accompanies chronic HBV infection, may contribute indirectly to hepatocyte transformation in a number of ways, including by facilitating HBV DNA integration, predisposing to the acquisition of cellular mutations and generating mutagenic oxygen reactive species. Although HCC is a malignancy with a poor prognosis, the availability of an effective vaccine against HBV infection, and its inclusion in the Expanded Programme of Immunization of many countries, augurs well for the eventual elimination of HBV-associated HCC.