Occult hepatitis B virus infection

Performance evaluation of the MAGLUMI Hepatitis B virus surface antigen chemiluminescence immunoassay

A highly sensitive and reliable Hepatitis B virus surface antigen (HBsAg) measurement is essential to universal screening, timely diagnosis, and management of Hepatitis B virus (HBV) infection. This study aimed to evaluate the performance of MAGLUMI HBsAg chemiluminescence immunoassay (CLIA). MAGLUMI HBsAg (CLIA) was compared against ARCHITECT HBsAg. 411 HBsAg positive samples, including different stages of infection, genotypes, subtypes, mutants, and 30 seroconversion panels were tested to evaluate diagnostic sensitivity. Diagnostic specificity was evaluated by testing 205 hospitalized samples and 5101 blood donor samples. Precision, limit of blank (LoB), limit of detection (LoD), and linearity were also verified. The diagnostic sensitivity of the MAGLUMI HBsAg (CLIA) was 100% with better seroconversion sensitivity than ARCHITECT HBsAg. The MAGLUMI HBsAg (CLIA) has optimal detection efficacy for HBV subgenotypes samples. The analytical sensitivity is 0.039 IU/mL. The initial diagnostic specificity is 99.63% on blood donors and 96.59% on hospitalized samples. The verification data demonstrated high repeatability, a LoB of 0.02 IU/mL, LoD of 0.05 IU/mL and an excellent linearity of 0.050-250 IU/mL (R2 = 0.9946). The MAGLUMI HBsAg (CLIA) is proved a highly sensitive and reliable assay with optimal subgenotype detection efficacy.

M133S mutation possibly involve in the ER stress and mitophagy pathway in maintenance hemodialysis patients with occult hepatitis B infection

Occult hepatitis B virus infection (OBI) is characterized by the presence of HBV DNA in the absence of detectable HBsAg. OBI is an important risk factor for cirrhosis and hepatocellular carcinoma, but its pathogenesis has not been fully elucidated. Mutations in the HBV preS/S genes can lead to impaired secretion of either HBsAg or S-protein resulting in the accumulation of defective viruses or S protein in cells. In our previous work, the M133S mutation was present in the HBV S gene of maintenance hemodialysis (MHD) patients with OBI. In this study, we investigated the potential role of amino acid substitutions in S proteins in S protein production and secretion through the construction of mutant S gene plasmids, structural prediction, transcriptome sequencing analysis, and in vitro functional studies. Protein structure prediction showed that the S protein M133S mutant exhibited hydrophilic modifications, with greater aggregation and accumulation of the entire structure within the membrane phospholipid bilayer. Differential gene enrichment analysis of transcriptome sequencing data showed that differentially expressed genes were mainly concentrated in protein processing in the endoplasmic reticulum (ER). The expression of heat shock family proteins and ER chaperone molecules was significantly increased in the wild-type and mutant groups, whereas the expression of mitochondria-associated proteins was decreased. Immunofluorescence staining and protein blotting showed that the endoplasmic reticulum-associated protein PDI, the autophagy marker LC3, and the lysosome-associated protein LAMP2 co-localized with the S proteins in the wild-type and mutant strains, and their expression was increased. The mitochondria-associated TOMM20 protein was also co-expressed with the S protein, but expression was significantly reduced in the mutant. The M133S mutation in the S gene is expressed as a defective and misfolded protein that accumulates in the endoplasmic reticulum causing secretion-impaired endoplasmic reticulum stress, which in turn triggers mitochondrial autophagy and recruits lysosomes to fuse with the autophagosome, leading to mitochondrial clearance. This study preliminarily demonstrated that the mutation of M133S in the S gene can cause OBI and is associated with disease progression, providing a theoretical basis for the diagnosis and treatment of OBI.

The seroepidemiology of isolated core antibody against hepatitis B among Taiwanese adults - A large hospital-based study

BACKGROUND/PURPOSE

This study aims to investigate the prevalence of isolated core antibodies against hepatitis B (IAHBc) in different birth cohorts using a large medical record database.

METHODS

Hepatitis B viral serological test data were collected from a chart cloud database at a medical center in Taiwan between January 2006 and December 2018. The data collected included birth year, sex, hepatitis B viral markers (HBsAg, anti-HBs or anti-HBc), and hepatitis B vaccination records. Enrolled patients were grouped according to their birth year into three categories: ≤ 1986, 1987-1992, and ≥ 1993, which correspond to no neonatal hepatitis B immunization, plasma-derived HB vaccine (PDHBV), and recombinant hepatitis B vaccine (RHBV), respectively. Prevalence of hepatitis B viral seromarkers, including IAHBc, was calculated by sex, age groups, and birth cohorts. Those who underwent repeated hepatitis B serology tests were included for further analysis to follow up their serostatus.

RESULTS

A total of 117,335 adults with complete hepatitis B serologic data were analyzed. Among them, 6641 individuals (5.7 %) were found to have IAHBc. The prevalence of IAHBc was 11.4 %, 0.8 %, and 0.3 % among those born before 1986, between 1987 and 1992, and after 1992, respectively. Among the 690 subjects with repeated blood tests and complete hepatitis B serologic data, 551 cases (79.9 %) remained IAHBc. The other cases included resolved infection status (13.9 %), seronegativity for three HB seromarkers (3 %), and carrier of hepatitis B virus (2.3 %).

CONCLUSION

The management of individuals with IAHBc should be tailored to their age, vaccination status, and risk factors for occult hepatitis B viral infection.

Effect of S-region mutations on HBsAg in HBsAg-negative HBV-infected patients

BACKGROUND

Occult HBV infection (OBI) is a special form of hepatitis B virus (HBV) infection that may cause Liver cirrhosis and hepatocellular carcinoma, causing significant harm to patients. Given the insidious nature of OBI, it is usually not easy to be detected. Most of the samples currently studied are concentrated on blood donors, however, patients in this special state have not been fully studied. This project aimed to study the effect of HBV S region mutations on HBsAg in patients with clinical OBI.

METHODS

Collect 107 HBsAg-/HBV DNA + blood samples from Beijing Youan Hospital, Capital Medical University from August 2022 to April 2023. Next, the successfully extracted and amplified HBV DNA S regions were sequenced. Construct mutant plasmids to verify the cell function of the high-frequency mutation sites and explore the possible molecular mechanism.

RESULTS

Sixty-eight HBsAg-negative samples were sequenced, revealing high-frequency amino acid substitution sites in the HBV S protein, including immune escape mutations (i.e., sY100C、sK122R、sI126T、sT131P、and sS114T) and TMD (Transmembrane domain) region substitutions (i.e., sT5A、sG10D、sF20S、and sS3N). We constructed a portion of the mutant plasmids and found that sT5A, sF20S, sG10D, sS3N, sI68T, and sI126T single point mutations or combined mutations may decrease HBsAg expression or change the antigenicity of HBsAg leading to detection failure.

CONCLUSIONS

HBsAg-negative patients may show various mutations and amino acid replacement sites at high frequency in the HBV S-region, and these mutations may lead to undetectable Hepatitis B surface antigen (HBsAg), HBsAg antigenic changes or secretion inhibition.

Occult Hepatitis B Infection among Blood Donors in Northwestern Greece

Background: Occult hepatitis B virus infection (OBI) is characterized by the presence of HBV DNA in individuals who test negative for hepatitis B surface antigen (HBsAg). It poses diagnostic challenges and contributes to chronic liver diseases. Understanding its epidemiology, pathogenesis and clinical outcomes remains essential. This study aimed to assess the prevalence and characteristics of OBI in Northwestern Greece. Methods:Serum samples were prospectively collected from 702 blood donors at the University Hospital of Ioannina, Greece, between February 2018 and September 2022. The investigation focused on the presence of hepatitis B virus (HBV) markers, utilizing the Abbott Architect HBsAg and HBcAb HB Qualitative II kit for the detection of HBsAg and anti-HBc, respectively. Further analysis was conducted on serum samples from individuals who tested negative for HBsAg but positive for anti-HBc, employing polymerase chain reaction (PCR) to detect HBV-DNA. In instances of OBI, sequencing and mutation analysis of the HBV pre-S/S gene were carried out for comprehensive characterization. Results:Screening revealed 56 cases (7.9%) with active HBV infection (HBsAg positive) and identified 144 cases (20.5%) indicative of past HBV infection (HBsAg negative, anti-HBc positive). Additionally, a prevalence of 5.4% (38/702) of OBI was detected. Among these, 36 cases exhibited a low HBV DNA load of less than 225 IU/mL. Notably, one OBI patient was co-infected with HIV. Furthermore, two cases of OBI with high HBV-DNA levels exceeding 200,000 IU/ml were detected. Sequencing analysis unveiled S- and pre-S mutations in four cases of OBI, including both instances with elevated HBV-DNA levels. Conclusion:In a region with a high proportion of immigrants from countries where HBV is endemic, a high prevalence of HBV infection and occult HBV infection (OBI) has been detected. Furthermore, mutations in the S gene were found to be associated with cases of OBI with high levels of HBV-DNA. However, additional research is needed to validate the results and understand the clinical relevance of specific OBI mutations for disease progression and treatment efficacy.

Patterns of hepatitis b virus immune escape and pol/rt mutations across clinical cohorts of patients with genotypes a, e and occult hepatitis b infection in Nigeria: A multi-centre study

Hepatitis B virus (HBV) immune escape and Pol/RT mutations account for HBV immunoprophylactic, therapeutic, and diagnostic failure globally. Little is known about circulating HBV immune escape and Pol/RT mutants in Nigeria. This study focused on narrowing the knowledge gap of the pattern and prevalence of the HBV mutants across clinical cohorts of infected patients in southwestern Nigeria. Ninety-five enrollees were purposively recruited across clinical cohorts of HBV-infected patients with HBsAg or anti-HBc positive serological outcome and occult HBV infection. Total DNA was extracted from patients' sera. HBV S and Pol gene-specific nested PCR amplification was carried out. The amplicons were further sequenced for serotypic, genotypic, phylogenetic, and mutational analysis. HBV S and Pol genes were amplified in 60 (63.2%) and 19 (20%) of HBV isolates, respectively. All the sixty HBV S gene and 14 of 19 Pol gene sequences were exploitable. The ayw4 serotype was predominant (95%) while ayw1 serotype was identified in 5% of isolates. Genotype E predominates in 95% of sequences, while genotype A, sub-genotype A3 was observed in 5%. Prevalence of HBV IEMs in the "a" determinant region was 29%. Commonest HBV IEM was S113T followed by G145A and D144E. The Pol/RT mutations rtV214A and rtI163V among others were identified in this study. This study provided data on the occurrence of existing and new HBV IEMs and Pol gene mutations in Nigeria.

The importance of triple panel testing for hepatitis B and the burden of isolated anti-hepatitis B core antibodies within a community sample

Within the United States (US), 2.4 million individuals are living with chronic hepatitis B, but less than 20% are diagnosed. Isolated anti-hepatitis B core (iAHBc) antibodies indicate serology in an individual that is positive for anti-HBc antibodies, while negative for surface antigen (HBsAg) and surface antibodies (anti-HBs). A result of iAHBc could indicate a chronic occult bloodstream infection, necessitating further testing. This study assesses the prevalence and risk factors associated with anti-HBc and iAHBc within community high-risk screening in Greater Philadelphia. Participants (n = 177) were screened for HBsAg, anti-HBs, and anti-HBc during community screening events in 2022. Chi-square tables and Firth logistic regression were used to describe the data and to assess the odds of iAHBc. The findings indicate that there was an iAHBc prevalence of 7.3% (n = 13) within our study. The odds of anti-HBc were increased for immigrants from the Western Pacific (4.5%) and Africa (11.9%). Individuals born in Africa had 7.93 greater odds for iAHBc than those born in the Americas, and these odds are multiplied by 1.01 for every 1-year increase in age. Our data show a high burden of iAHBc within high-risk and often hard-to-reach communities. Triple panel screening should be incorporated into all HBV screening programs, in accordance with current Centers for Disease Control and Prevention (CDC) universal screening recommendations, to ensure a comprehensive picture of the disease burden and reduce the risk of missing people with occult hepatitis B and those at risk for viral reactivation or liver complications.

Impact of hepatitis B virus infection on the risk of gallbladder polyps: a cohort study

BACKGROUND/AIMS

We aimed to determine whether hepatitis B virus (HBV) or hepatitis C virus (HCV) infection remains an important risk factor for gallbladder polyps (GBPs) in the current context of reduced prevalence of these infections.

METHODS

The cohort included 392,913 asymptomatic adults who underwent abdominal ultrasonography (US).

RESULTS

The prevalence of GBP sized ≥ 5 mm, ≥ 10 mm, and overall (< 5, 5-9 and ≥ 10 mm) was 2.9%, 0.1%, and 12.8%, respectively. The prevalence of hepatitis B surface antigen (HBsAg), hepatitis B core antibody (HBcAb), and hepatitis C antibody (anti-HCV) positivity was 3.2%, 26.7%, and 0.1%, respectively. The GBP risk was significantly increased in HBsAg-positive individuals, with an adjusted odds ratio of 1.66 (95% confidence interval, 1.49-1.85) for GBP ≥ 5 mm, 2.39 (1.53-3.75) for GBP ≥ 10 mm, and 1.49 (1.41-1.59) for overall, whereas there was no significant association between anti-HCV positivity and GBP risk. The GBP risk did not increase significantly in individuals who tested negative for HBsAg but positive for HBcAb.

CONCLUSION

The presence of HBsAg may be an independent risk factor for GBP development in the current context of a indecreasing prevalence of HBsAg positivity. A more comprehensive evaluation of GBP during abdominal US surveillance of HBsAg-positive individuals may be necessary.

Prevalence of occult hepatitis B virus infection in Egypt: a systematic review with meta-analysis

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is a major public health problem. The clinical importance of OBI stems from the fact that it can be transmitted to healthy individuals at extremely low viral load levels. Additionally, immunosuppression has the potential to trigger viral replication, which can result in life-threatening liver decompensation. Despite several studies examining the prevalence of OBI, the pooled prevalence of OBI in Egypt remains unknown, particularly among blood donors and high-risk individuals, to whom intervention should be targeted.

METHODS

A comprehensive literature search of the following databases was conducted from inception to October 2022 using the following keywords: occult hepatitis B virus infection or occult HBV infection or OBI and Egypt in MEDLINE [PubMed], Scopus, Google Scholar, and Web of Science. The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. I-squared and Cochran's Q were used to measure the heterogeneity between the studies, and based on the random effects model, results were reported as proportions (%) with a 95% confidence interval (CI). Analyses of subgroup analyses were conducted based on the target population. Sensitivity analyses were conducted using the leave-one-out approach to test the robustness of the results.

RESULTS

A total of 50 studies with 62 estimations of OBI were included, 19 in patients who were HBsAg-negative and anti-HBc-positive and 43 in patients who were HBsAg-negative. The highest prevalence (41%) was among multi-transfused patients according to  studies that report occult hepatitis B virus prevalence in an HBsAg-negative population, while the pooled prevalence of OBI among patients on hemodialysis, patients with chronic hepatitis C infection, patients with hepatocellular carcinoma (HCC), and patients with liver cirrhosis was 17%, 10%, 24%, and 13%, respectively. On the other hand, among studies that report OBI prevalence in HBsAg-negative and anti-HBc-positive individuals, the pooled prevalence of OBI among blood donors, patients with chronic hepatitis C infection, and patients with HCC was 12%, 15%, and 31%, respectively. Also, the majority of studies examining the genetic background of OBI have found that genotype D is the most prevalent.

CONCLUSION

 This study highlights the high prevalence in OBI among blood donors and high-risk populations in Egypt. The implementation of HBV nucleic acid amplification testing (NAT) may increase the safety of blood transfusions by excluding all HBV DNA-positive donations. However, the cost-effectiveness of these tests should be investigated.

High Prevalence of Occult Hepatitis B Virus Infection among Iranian Hemodialysis Patients

Considering the potential risks associated with occult hepatitis B virus (HBV) infection, this study was designed to investigate the magnitude and genotypic pattern of occult HBV infection among hemodialysis patients. All patients on regular hemodialysis attending the dialysis centers located in southern Iran and 277 nonhemodialysis controls were invited to participate in this study. Serum samples were tested for detection of hepatitis B core antibody (HBcAb) and hepatitis B surface antigen (HBsAg) by competitive enzyme immunoassay and sandwich ELISA, respectively. The molecular evaluation of HBV infection was conducted by two nested polymerase chain reaction (PCR) assays, targeting S, X, and precore regions of HBV genome, and sequencing by Sanger dideoxy sequencing technology. Moreover, HBV viremic samples were tested for hepatitis C virus (HCV) coinfection by HCV Ab ELISA and seminested reverse transcriptase PCR. Of 279 hemodialysis patients, five (1.8%) were positive for HBsAg, 66 (23.7%) were positive for HBcAb, and 32 (11.5%) had HBV viremia with HBV genotype D, sub-genotype D3 and subtype ayw2. Moreover, 90.6% of the hemodialysis patients with HBV viremia had occult HBV infection. Hemodialysis patients (11.5%) had significantly higher prevalence of HBV viremia than nonhemodialysis controls (1.08%; P = 0.0001). The prevalence of HBV viremia among hemodialysis patients was not statistically associated with duration of hemodialysis, age and gender distribution. In contrast, HBV viremia was significantly associated with place of residency and ethnicity, with residents of Dashtestan and Arab having had significantly higher prevalence of HBV viremia compared with the residents of other cities and Fars patients. Notably, 27.6% and 6.9% of hemodialysis patients infected with occult HBV infection were also positive for anti-HCV antibodies and HCV viremia, respectively. High prevalence of occult HBV infection was detected in hemodialysis patients, whereas 62% of patients with occult HBV infection were negative for HBcAb. Therefore, screening of all hemodialysis patients by sensitive molecular tests, regardless of the pattern of HBV serological markers, is recommended to increase the diagnosis rate of HBV infection.

Rapid detection of hepatitis B virus DNA level based on interval-point data fusion of infrared spectra

Hepatitis B is an infectious disease cause by the hepatitis B virus (HBV). In recent years, HBV-DNA level clinically gets more attention for its detailed information than other serological markers. Unfortunately, common clinical method for HBV-DNA level detection is limited for its hours consuming. This study combined infrared spectroscopy with machine learning to investigate the feasibility of near-infrared (NIR) and mid-infrared (MIR) spectra for rapid detection of HBV-DNA level. Based on partial least squares-discriminant analysis (PLS-DA) modeling method, the optimal NIR and MIR models and traditional data fusion models were constructed, respectively. Considering inequal weight between interval and point data in machine learning, interval-point data fusion method was used to compare with other traditional date fusion methods. The results of the study illustrate that interval-point data fusion of NIR and MIR spectra combined with PLS-DA modeling can provide a rapid method for HBV-DNA level detection.

Low Risk of Occult Hepatitis B Infection among Vietnamese Blood Donors

Occult hepatitis B infection (OBI) is characterized by the presence of low levels of hepatitis B virus (HBV) DNA and undetectable HBsAg in the blood. The prevalence of OBI in blood donors in Asia ranges from 0.013% (China) to 10.9% (Laos), with no data available from Vietnam so far. We aimed to investigate the prevalence of OBI among Vietnamese blood donors. A total of 623 (114 women and 509 men) HBsAg-negative blood donors were screened for anti-HBc and anti-HBs by ELISA assays. In addition, DNA from sera was isolated and nested PCR was performed for the HBV surface gene (S); a fragment of the S gene was then sequenced in positive samples. The results revealed that 39% (n = 242) of blood donors were positive for anti-HBc, and 70% (n = 434) were positive for anti-HBs, with 36% (n = 223) being positive for both anti-HBc and anti-HBs. In addition, 3% of blood donors (n = 19) were positive for anti-HBc only, and 34% (n = 211) had only anti-HBs as serological marker. A total of 27% (n = 170) were seronegative for any marker. Two of the blood donors (0.3%) were OBI-positive and sequencing revealed that HBV sequences belonged to HBV genotype B, which is the predominant genotype in Vietnam.

Role of S Protein Transmembrane Domain Mutations in the Development of Occult Hepatitis B Virus Infection

Occult HBV infection (OBI) is a special infection status during Hepatitis B virus (HBV) infection. The underlying mechanism of its occurrence remains unclear. This study conducted sequencing analysis on 104 OBI plasma samples and 524 HBsAg positive samples from 29 blood centres, and searched for high-frequency mutations in transmembrane domain (TMD) of S protein in the OBI population. Plasmids with TMD high-frequency mutations were constructed, in vivo and in vitro functional experiments were performed to investigate possible molecular mechanisms of OBI occurrence. We found 22 high-frequency TMD mutations in genotype B OBI strains. Among them, five mutations can lead to impairment of HBsAg secretion; seven mutations had accumulated intracellular HBsAg while extracellular HBsAg didn’t decrease compared to wildtype. This study chose C85R from TMD2, F220C, and F220Y from TMD4 for further exploration. Protein structure predication showed these three mutant HBsAg displayed changed hydrophilic properties and tended to accumulate in the phospholipid bilayer of cell membrane. Mutant HBsAg’s secretion disorder may induce OBI. On the other hand, V168A + V177A from TMD3 expressed increased HBsAg both in intracellular and extracellular levels. This mutation had most unstable natural conformation and may be inclined to transition into V177A or V168A + S174N + V177A. These three mutations were more prone to mixed infection, presenting a state of coexistence, thus approaching the impaired secretion pattern of OBI. This study demonstrated TMD mutations could contribute to the occurrence of OBI and provided a theoretical basis for OBI study and the functional cure of chronic hepatitis B virus infection.

Liver fibrosis progression in a cohort of young HIV and HIV/ HBV co-infected patients: A longitudinal study using non-invasive APRI and Fib-4 scores

Background

The risk of liver fibrosis increases over time in HIV and HIV-HBV individuals even under antiretroviral treatment (ART), warranting a rigorous and periodic monitorization. Given the lower availability of transient elastography, we aimed to assess the longitudinal variation of two non-invasive liver fibrosis scores, APRI and Fib-4, in cases with HIV monoinfection, HIV-HBV co-infection and individuals with HBsAg-seroclearance.

Methods

We performed an observational retrospective study between 2013 and 2019 on 212 HIV patients including 111 individuals with HIV mono-infection, 62 individuals with HIV-HBV co-infection and positive HBsAg and 39 cases with HIV-HBV infection and HBsAg-loss. The groups were followed at 36, 48, and 60 months. Liver fibrosis was indicated by an APRI >0.5 or Fib-4≥1.45 score and advanced fibrosis by an APRI score >1.5 or Fib-4 >3.25. Logistic regression with generalized estimating equations (GEE) was used to assess the predictors for the presence of liver fibrosis over time.

Results

During a median follow-up of 58.5 months the prevalence of liver fibrosis in all patients increased with 0.5% reaching 11.3% using an APRI score and with 0.9% reaching 10.8% using the Fib-4 score. At the visit corresponding to 60 months the prevalence of liver fibrosis was higher in all HIV-HBV patients compared with individuals with HIV mono-infection, namely: 16.1% on APRI and 12.9% on the Fib-4 score in HIV-HBV/HBsAg-positive individuals, 12.8% on both APRI and Fib-4 scores in HIV-HBV/HBsAg-negative individuals vs. 8.1 and 9%, respectively in HIV mono-infection. The presence of liver fibrosis over the study period was independently associated with plasma HIV RNA, CD4+T cell counts, HIV-HBV co-infection (for APRI >0.5) and ART non-adherence (for Fib-4 >1.45). At the final visit, non-adherence to ART and CD4+T cell counts remained associated with liver fibrosis.

Conclusions

The study found a slow progression of APRI and Fib-4 scores over time in young PLWH with extensive ART. Liver fibrosis scores continued to increase in patients with HIV mono-infection yet remained lower than in HIV-HBV patients irrespective on the presence of HBsAg. The periodic follow-up using non-invasive scores on the long-term could help improve the surveillance in low-income settings and high scores should be followed by additional diagnostic methods.

Occult Hepatitis B Virus Infection: An Update

Occult hepatitis B virus (HBV) infection (OBI) refers to a condition in which replication-competent viral DNA is present in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for the HBV surface antigen (HBsAg). In this peculiar phase of HBV infection, the covalently closed circular DNA (cccDNA) is in a low state of replication. Many advances have been made in clarifying the mechanisms involved in such a suppression of viral activity, which seems to be mainly related to the host's immune control and epigenetic factors. OBI is diffused worldwide, but its prevalence is highly variable among patient populations. This depends on different geographic areas, risk factors for parenteral infections, and assays used for HBsAg and HBV DNA detection. OBI has an impact in several clinical contexts: (a) it can be transmitted, causing a classic form of hepatitis B, through blood transfusion or liver transplantation; (b) it may reactivate in the case of immunosuppression, leading to the possible development of even fulminant hepatitis; (c) it may accelerate the progression of chronic liver disease due to different causes toward cirrhosis; (d) it maintains the pro-oncogenic properties of the "overt" infection, favoring the development of hepatocellular carcinoma.

Molecular investigation of occult hepatitis B virus infection in a reference center in Northern Brazil

The goal of this study was to investigate the prevalence of occult HBV infection in a reference center for the Northern Brazil from 2005 to 2015 and to identify mutations associated with occult hepatitis B. Molecular analysis was performed on 110 serum samples in which anti-HBc was the only positive serological marker. Regions of the HBV genome were amplified by polymerase chain reaction to detect HBV DNA. A prevalence of 4.1% (793/18,889) for anti-HBc alone was identified. Molecular analysis revealed a prevalence of occult HBV infection of 0.04%. HBV DNA detected were identified in individuals who underwent hemodialysis, infected with the hepatitis C virus and from area of high endemicity for HBV. Direct DNA nucleotide sequencing and phylogenetic analysis identified that genotypes A and D and mutations E164D, I195M, P217L and P120S were associated with occult HBV infection in the S gene. This study contributed with epidemiological and molecular information on Northern Brazil samples with a suggestive profile of occult HBV infection in addition to reinforcing the importance of molecular diagnosis in this type of infection.

Global prevalence of occult hepatitis B: A systematic review and meta-analysis

The study aimed to investigate the prevalence and risk factors associated with occult hepatitis B virus (HBV) infection (OBI) in the global population. We searched PubMed, Embase, CINAHL, Cochrane and Web of Science from database inception through 27 Dec, 2018. Studies reporting HBV-DNA serological data in previously undiagnosed hepatitis B patients were included. The data were further categorized according to the presence of risk factors. After an initial screening of 2,325 records, we finally included 98 articles about the prevalence of OBI from 34 countries and regions. The OBI prevalence was 0.82% (95% CI:0.69-0.96) in the general population, 16.26% (95% CI:10.97-22.34) in HIV patients, 13.99% (95% CI:8.33-20.79) in patients with other liver diseases, 4.25% (95% CI:1.64-7.87) in haemodialysis patients and 5.14% (95% CI:2.26-9.01) patients with other risk factors. In conclusion, OBI prevalence varies significantly across different populations and nations, which deserve attention from the public health authorities. Our results generate further epidemiological data to identify the population with OBI, which has important clinical implications in finding these high-risk populations to design preventive and management strategies.

Occult Hepatitis B Virus Infection among β-Thalassemia Major Patients in Ahvaz City, Iran

Occult Hepatitis B Infection (OBI) is a critical risk factor for triggering post-transfusion hepatitis (PTH), cirrhosis, hepatocellular carcinoma, and hepatitis B virus (HBV) reactivation, which β-thalassemia major (BTM) patients are at risk of it due to multiple blood transfusions. This study was aimed at determining the prevalence of OBI among BTM patients from Khuzestan Province, Iran. In this cross-sectional study, 90 thalassemia patients, who have received blood 36 to 552 times, participated referred to the Shafa hospital of Ahvaz city from January 2018 to April 2019. ELISA for determining serological markers (HBsAg, anti-HBc, anti-HBs, and anti-HCV) and real-time PCR for detecting HBV-DNA were performed; Nested PCR was conducted for DNA sequencing and determining the genotype of OBI case. Phylogenetic and statistical analyses were done by R package. Of 90 subjects enrolled in this study; 95.5% (86/90) were HBsAg negative, and the frequency of OBI among them was 1.16% (1/86). The anti-HBs, anti-HBc, and anti-HCV were detected in 80.00%, 7.78%, and 12.2% of patients, respectively. HBV-DNA was assessed at four HBsAg-positive subjects as well, and all of them were negative. The phylogenetic analysis showed that the detected HBV DNA in the OBI case belongs to the genotype D. This research, for the first time, demonstrated that OBI is present among β-thalassemia patients in Iran. Also, further studies are necessary to determine the actual prevalence of OBI among BTM patients in Iran to decisions concerning OBI screening, especially in transfusion centers.

E2 Site Mutations in S Protein Strongly Affect Hepatitis B Surface Antigen Detection in the Occult Hepatitis B Virus

The mechanism of occult hepatitis B infection (OBI) has not yet been fully clarified. Our previous research found that novel OBI-related mutation within S protein, E2G, could cause the hepatitis B surface antigen (HBsAg) secretion impairment, which resulted in intracellular accumulation in OBI of genotype B. Here, to further explore the role of E2 site mutations in the occurrence of OBI, we analyzed these site mutations among 119 OBI strains identified from blood donors. Meanwhile, 109 wild-type HBV strains (HBsAg positive/HBV DNA positive) were used as control group. Furthermore, to verify the E2 site mutations, two conservative 1.3-fold full-gene expression vectors of HBV genotype B and C (pHBV1.3B and pHBV1.3C) were constructed. Then, the E2 mutant plasmids on the basis of pHBV1.3B or pHBV1.3C were constructed and transfected into HepG2 cells, respectively. The extracellular and intracellular HBsAg were analyzed by electrochemical luminescence and cellular immunohistochemistry. The structural characteristics of S proteins with or without E2 mutations were analyzed using relevant bioinformatics software. E2 mutations (E2G/A/V/D) existed in 21.8% (26/119) of OBIs, while no E2 mutations were found in the control group. E2G/A/V/D mutations could strongly affect extracellular and intracellular level of HBsAg (p < 0.05). Notably, unlike E2G in genotype B that could cause HBsAg intracellular accumulation and secretion decrease (p < 0.05), E2G in genotype C could lead to a very significant HBsAg decrease both extracellularly (0.46% vs. pHBV1.3C) and intracellularly (11.2% vs. pHBV1.3C) (p < 0.05). Meanwhile, for E2G/A mutations, the relative intracellular HBsAg (110.7-338.3% vs. extracellular) and its fluorescence intensity (1.5-2.4-fold vs. with genotype-matched pHBV1.3B/C) were significantly higher (p < 0.05). Furthermore, N-terminal signal peptides, with a typical cleavage site for peptidase at positions 27 and 28, were exclusively detected in S proteins with secretion-defective mutants (E2G/A). Our findings suggest that: (1) E2G/A/V/D mutations were confirmed to significantly influence the detection of HBsAg, (2) the underlying mechanism of OBI caused by E2G mutation is quite different between genotype B and genotype C, and (3) E2G/A could produce a N-terminal truncated S protein, which might attribute to the HBsAg secretion impairment in the OBIs.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

Interpretation of HBV Serologies

Hepatitis B was discovered by researchers who were investigating jaundice associated with blood transfusions as well as parenterally administered medications. Through trial and error, the HBV was identified. There are specific tests that detect HBV infection, whether it is a previous exposure or active infection. The various HBV serologies are reviewed in this work as well. Hepatitis B surface antigen has emerged as a tool in defining treatment endpoint and its significance is reviewed. HBV genotypes are distributed uniquely throughout the world, in particular, genotype C is associated with higher rates of hepatocellular carcinoma. Various HBV genotypes and their impact on the clinical course are discussed. The relationship of HBV serologies and HBV DNA to disease progression is outlined. There are specific recommendations on monitoring those infected with HBV and this is reviewed here. HBV mutations have an impact on the disease course and those of significance are also discussed.

[Residual risk for transfusion-transmitted hepatitis B virus infection due to occult hepatitis B virus infection in donors living in Yaoundé, Cameroon]

Introduction

l´infection virale au virus de l´hépatite B reste la plus importante transmise par transfusion sanguine. Bien que la recherche de l´antigène de surface (AgHBs) du virus de l´hépatite B (VHB) dans les banques de sang ait considérablement réduit le risque de transmission de l´infection du virus par transfusion, il subsiste un risque résiduel transfusionnel de transmission dû aux donneurs porteurs d´une hépatite B occulte. Les poches de sang contenant l´AcHBc avec ou sans l´AcHBs et l´ADN viral peuvent être infectieuses et représenter une menace pour la sécurité transfusionnelle là où l´AcHBc n´est pas dépisté. L´objectif de cette étude était de déterminer le risque résiduel de la transmission par transfusion du virus de l´hépatite B à l´hôpital central de Yaoundé (HCY) et le Centre Hospitalier Dominicain Saint Martin de Porres (CHDSMP) à Yaoundé au Cameroun.

Méthodes

une étude transversale a été effectuée sur des donneurs de sang de l´Hôpital Central de Yaoundé (HCY) et le Centre Hospitalier Dominicain Saint Martin de Porres (CHDSMP) chez lesquels la recherche de l´AcHBc et/ou AcHBs était faite par immunochromatographie. La recherche de l´ADN du VHB sur les échantillons testés positifs aux AcHBc et/ou AcHBs était faite par PCR en utilisant des amorces spécifiques.

Résultats

sur les 193 donneurs de sang négatifs aux marqueurs sérologiques des infections à VIH, VHB (AgHBs), VHC et tréponème retenus dans cette étude, nous avons obtenu une séroprévalence globale des AcHBc et/ou AcHBs de 9,84% (19/193). Sur les 19 donneurs potentiellement infectieux, l´ADN du virus a été détecté chez 03 individus dont 02 porteurs de l´AcHBc et 01 porteur à la fois de l´AcHBc et de l´AcHBs, soit une prévalence de l´hépatite B occulte de 15,79% (3/19) [IC95% =3,38%-39,58%] et un risque résiduel de transmission par transfusion de l´infection à VHB de 1,55% (3/193) [IC95% = 0,32%-4,48%].

Conclusion

il ressort de cette étude que le risque résiduel de transmission par transfusion sanguine de l´infection du VHB est faible. Toutefois il est recommandé de rechercher les AcHBc et/ou AcHBs lors de la qualification des dons de sang.

Liver failure from delayed hepatitis B reactivation in anti-HBc-positive patient following rituximab for B-cell lymphoma

A 93-year-old man was admitted with 1 week of frank jaundice and abdominal pain. His medical history included diffuse large B-cell lymphoma treated with rituximab and cyclophosphamide, hydroxydaunomycin, oncovin and prednisolone (R-CHOP) chemotherapy 10 months prior. His investigations revealed marked hyperbilirubinemia with a total bilirubin of 355 μmol/L, along with a 17-fold elevation in alanine transaminase and impaired hepatic synthetic function. He tested hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (HBsAb) negative, hepatitis B core antibody (HBcAb) positive and had elevated hepatitis B virus DNA level at 13 691 IU/L. This was in the setting of radiological evidence of suspected cirrhosis. He was later found to have tested positive for HBcAb and negative for HBsAg and HBsAb prior to chemotherapy, but had not received antiviral prophylaxis. He was diagnosed with fulminant hepatitis secondary to delayed hepatitis B reactivation in the setting of rituximab. Hepatitis B reactivation and the role of screening and antiviral prophylaxis in isolated HBcAb-positive patients is reviewed.

Cryptic HBV Replicative Activity Is Frequently Revealed in Anti-HBc-Positive/HBsAg-Negative Patients with HIV Infection by Highly Sensitive Molecular Assays, and Can Be Predicted by Integrating Classical and Novel Serological HBV Markers

The anti-HBc-positive/HBsAg-negative status is frequent in HIV-infection and correlates with poor survival. Here, by highly-sensitive assays, we evaluate cryptic HBV replication and factors correlated with its detection in 81 anti-HBc-positive/HBsAg-negative HIV-infected patients. Patients were treated for >12 months with HBV-active modern combined antiretroviral-therapy (cART) and had serum HBV-DNA < 20 IU/mL by commercial Real-Time PCR. Serum HBV-DNA was quantified by droplet digital PCR, serum HBV-RNA by an Abbott research assay, and anti-HBc titer (proposed to infer intrahepatic cccDNA) by Lumipulse/Fujirebio. Cryptic serum HBV-DNA was detected in 29.6% of patients (median (IQR): 4(1-15) IU/mL) and serum HBV-RNA in 3.7% of patients despite HBsAg-negativity and HBV-active cART. Notably, cryptic serum HBV-DNA correlated with an advanced CDC-stage (p = 0.01) and a lower anti-HBs titer (p = 0.05), while serum HBV-RNA correlated with lower nadir CD4+ cell-count (p = 0.01). By analyzing serological HBV-markers, the combination of anti-HBs < 50 mIU/mL (indicating lower immune response) plus anti-HBc > 15COI (reflecting higher HBV replicative activity) was predictive of cryptic serum HBV-DNA (OR: 4.7(1.1-21.7), p = 0.046, PPV = 62.5%, and NPV = 72%). In conclusion, cryptic HBV-replication (not detected by classical assays) characterizes a conspicuous set of anti-HBc-positive HIV-infected patients despite HBsAg-negativity and HBV-active combined antiretroviral therapy (cART). The integration of classical and novel markers may help identify patients with cryptic HBV-replication, thus optimizing the monitoring of anti-HBc-positive/HBsAg-negative HIV-infected patients.

Novel hepatitis B virus surface antigen mutations associated with occult genotype B hepatitis B virus infection affect HBsAg detection

The causative factors of occult hepatitis B infection are complicated and not yet been fully elucidated. Mutations in hepatitis B virus (HBV) S gene are one of the factors may contributing to occult infection. In this study, 89 blood donors with genotype B occult HBV infection were investigated. Fifty-seven hepatitis B surface antigen (HBsAg)-positive/HBV DNA-positive blood donors served as control group for comparison. Occult HBV-related mutations with a high incidence (P < .05) in the S gene were identified. To further verify these occult infection-related mutations, a conservative full-gene expression vector of HBV B genotype (pHBV1.3B) was constructed. Then, the mutant plasmids on the basis of pHBV1.3B were constructed and transfected into HepG2 cells. Extracellular as well as intracellular HBsAg was analysed by electrochemical luminescence and cellular immunohistochemistry. Ten occult infection-related mutations (E2G, Q101R, K122R, M133T, D144E, G145R, V168A, S174N, L175S and I226S) were significantly more frequent in the occult infection group (P < .05). Five of the ten mutations (E2G, D144E, G145R, V168A and S174N) strongly decreased extracellular HBsAg level (P < .05) in the transfection system. Notably, the E2G mutation had the most significant impact on the ratio of extracellular HBsAg (3.8% vs pHBV1.3B) and intracellular HBsAg (239.3% vs pHBV1.3B) (P < .05), and the fluorescence density of E2G mutant HBsAg was significantly higher than that of pHBV1.3B (P < .0001). Hence, ten mutations were associated with genotype B occult HBV infection; E2G and V168A were novel mutations which we confirmed significantly affect HBsAg detection. E2G might cause HBsAg secretion impairment that results in intracellular accumulation and a decrease in HBsAg secretion.

Patients with tuberculous meningitis and hepatitis B co-infection have increased risk for antituberculosis drug-induced liver injury and poor outcomes

BACKGROUND

Tuberculous meningitis (TBM) is one of the most severe forms of tuberculosis. Previous studies reported that hepatitis B virus (HBV) infection could increase the risk of antituberculosis drug-induced liver injury (ATB-DILI) in pulmonary tuberculosis patients. To date, only a few studies exist on the effect of HBV on TBM.

METHODS

This inpatient study retrospectively analyzed the medical records of patients who were diagnosed with TBM between June 2002 and June 2018. Statistical analysis was used to reveal the difference between the HBV and non-HBV groups. Univariate analysis and multivariate regression analysis were performed on data to determine the prognostic factors of TBM.

RESULTS

A total of 386 patients were enrolled in our study, 57 of whom were included in the HBV group and 329 in the non-HBV group. The HBV group showed a higher frequency of ATB-DILI (HBV group: 14.0% versus non-HBV group: 3.3%, p < .001) and a higher risk of poor outcomes (i.e. death during inpatient period or neurological deficit at discharge, HBV group: 31.6% versus non-HBV group: 19.8%, p = .045) than the non-HBV group. The multivariate regression analysis identified ATB-DILI, scores of 3-8 on the Glasgow Coma Scale and hydrocephalus as independent predictors of poor outcomes in TBM patients.

CONCLUSIONS

Our study demonstrated that HBV co-infection could increase the incidence of ATB-DILI and the risk of poor outcomes as identified by three predictors in TBM patients.

THE IMPACT OF POSITIVE ANTI-HBC MARKER ON PERMANENT DEFERRAL OF VOLUNTARY BLOOD DONORS IN EASTERN CROATIA AND ESTIMATION OF OCCULT HEPATITIS B VIRUS INFECTION RATE

Recently an increase has been reported in the number of HBV transmissions from anti-HBc positive blood donors that were repeatedly negative in HBsAg and nucleic acid testing using the most sensitive tests available. The aim of the study was to show the effect of anti-HBc antibody testing performed in 2006 on permanent deferral of voluntary blood donors (VBDs), and to estimate occult hepatitis B infection (OBI) rate in this population after the introduction of mandatory molecular testing in the 2013-2016 period. More than 30,000 blood donations collected during the 2005-2007 period and more than 14,000 VBDs having donated blood during the 2013-2016 period after the introduction of molecular testing from eastern Croatia were included in the study. Serologic testing was performed with HBsAg assay throughout the study period, and anti-HBc assay was only performed in 2006. As part of the confirmatory algorithm testing, all HBsAg positive and unclear results were tested with molecular tests. Anti-HBc prevalence among VBDs in 2006 was 1.5%, with a rate of 1:197, whereas HBsAg prevalence was stable from 2005 to 2007 (0.04%, 0.1% and 0.1%, respectively). The calculated OBI rate from 2013 to 2016 was 1:30,250. Ten of 161 (12.4%) VBDs had serologic anti-HBc-only pattern. Anti-HBc testing in 2006 resulted in statistically more deferrals of VBDs compared to 2005 and 2007, and to the rest of Republic of Croatia. The strategy of universal anti-HBc testing of VBDs in addition to the existing HBsAg and molecular screening could be an additional measure to prevent HBV transmission by blood and blood components.

Surveillance and impact of occult hepatitis B virus, SEN virus, and torque teno virus in Egyptian hemodialysis patients with chronic hepatitis C virus infection

OBJECTIVES

Egypt ranks first regarding the prevalence of hepatitis C virus (HCV) infection. Many patients have concomitant diseases like kidney disorders requiring hemodialysis, a procedure carrying the hazard of transmitting other hepatitis viruses. The purpose of this study was to investigate for occult hepatitis B virus (HBV), SEN virus (SENV), and torque teno virus (TTV) among chronic HCV patients on maintenance hemodialysis to identify their impacts.

METHODS

A total of 325 hemodialysis patients were enrolled and divided into two groups based on HCV RNA testing results. Blood samples were collected before hemodialysis. Sera were tested for hepatitis B core antibodies (anti-HBc) and hepatitis B surface antibodies (anti-HBs) using ELISA. HBV, SENV, and TTV DNA were detected by PCR. The serum alanine aminotransferase (ALT) level was measured.

RESULTS

Anti-HBc and HBV DNA were detected in 73.1% and 50.8% of group 1 versus 36.4% and 22.6% of group 2. The serum ALT level was higher in group 1 than group 2. SENV was detected in 11.5% of group 1 versus 8.2% of group 2. TTV was detected in 29% of group 1 versus 27% of group 2.

CONCLUSIONS

There is an increased prevalence of occult HBV in our locality among chronic HCV patients undergoing hemodialysis. The existence of SENV and TTV viremia has no clinical impact.

Prevalence and characteristics of occult hepatitis B virus infection in Japanese human immunodeficiency virus-infected patients

Occult hepatitis B virus (HBV) infection (OBI) is hepatitis B surface antigen (HBsAg) negative but with detectable HBV DNA. Although HIV infection has been reported to be a risk factor for OBI, the prevalence and clinical features of OBI in Japanese HIV infected patients have not been documented. This retrospective, single-center study was conducted to determine the prevalence and characteristic of OBI in Japanese antiretroviral therapy (ART) naïve HIV infected patients. OBI was defined as the presence of serum HBV DNA but without detectable HBsAg. Of the 147 ART naïve HIV infected patients, OBI was detected in 9 (6.1%) patients; 2 (4.3%) of 47 with both anti-HBs and anti-HBc positive, 6 (27.3%) of 22 with anti-HBc alone, and 1 (2.0%) of 50 with both anti-HBs and anti-HBc negative. The mean HBV DNA level was low at 28.7 ± 18.2 IU/mL. The proportion of OBI patients with anti-HBc alone was significantly higher than that of non-OBI patients (66.7% vs 14.5%, P = 0.001). In addition, the prevalence of AIDS (acquired immunodeficiency syndrome)-defining illnesses in the OBI group was significantly higher than in the non-OBI group (77.8% vs 35.5%, P = 0.001). No significant difference was found in the CD4 count or alanine aminotransferase levels of these two groups. This is the first study to reveal the prevalence and clinical features of OBI in Japanese HIV-infected patients. The persistence of anti-HBc alone and AIDS-defining illnesses were associated with the occurrence of OBI in these patients.

Outcomes after hepatectomy of patients with positive HBcAb Non-B Non-C hepatocellular carcinoma compared to overt hepatitis B virus hepatocellular carcinoma

PURPOSE

Hepatitis B core antibody (HBcAb) positivity is regarded as a sensitive marker for occult and prior hepatitis B virus (HBV) infection. However, the prognosis of patients with HBcAb-positive in non-B, non-C hepatocellular carcinoma (NBNC-HCC) remains unclear. The study aimed to compare the clinicopathological characteristics of patients with HBcAb-positive NBNC-HCC to those with overt HBV (hepatitis B surface antigen positive) HCC.

METHODS

306 HCC patients underwent hepatectomy were divided into two groups: an overt HBV-HCC group and HBcAb-positive NBNC-HCC group. Then patients were analyzed using propensity score matching (PSM) to reduce selection bias. Clinicopathological characteristics and survival outcomes were compared between the two groups. Univariate and multivariate analysis for risk factors were also evaluated.

RESULTS

HBcAb-positive NBNC-HCC group showed comparable survival outcomes to the overt HBV-HCC group (3-year overall survival rates 66% vs 62%, 69% vs 53%; 3-year recurrence-free survival rates 49% vs 40%, 47% vs 37%; P > 0.05) before and after PSM. Patients with HBcAb-positive NBNC-HCC were older, had more complications, higher proportions of vascular invasion, and larger tumor sizes but lower proportions of cirrhosis, elevated alanine aminotransferase and prothrombin time.

CONCLUSIONS

HBcAb-positive NBNC-HCC group had more advanced tumors, but their prognosis was relatively comparable to that of the other group. Therefore, we believe that screening is also necessary in HBcAb-positive patients for early detection of HCC, especially in the elderly.

The prevalence and significance of isolated hepatitis B core antibody (anti-HBc) in endemic population

OBJECTIVE

There are three major serologic markers for hepatitis B virus (HBV) infection: hepatitis B surface antigen (HBsAg); hepatitis B surface antibody (anti-HBs); and hepatitis B core antibody (anti-HBc). HBV screening programs, however, often test only HBsAg and anti-HBs, missing those individuals who have anti-HBc as the only detectable marker. Isolated anti-HBc can represent chronic infection in which HBsAg is not detectable by serology. We, therefore, investigated the prevalence of isolated anti-HBc in an ethnic community at moderate to high risk for HBV infection.

RESULTS

Of 7157 Korean American adults in New Jersey, 2736 (38.2%) lacked anti-HBs, potentially susceptible to HBV. Of these 2736 subjects, 771 subjects had anti-HBc. The prevalence of isolated anti-HBc increased with age: 0.8% (age 21-30); 2.4% (age 31-40); 6.05% (age 41-50); 11.7% (age 51-60); 18.3% (age 61-70); and 24.5% (age 71-91). Similarly, the percentage of the individuals with isolated anti-HBc in anti-HBs lacking subjects showed a striking age dependence. We conclude that serologic HBV screening should include anti-HBc to accurately assess the prevalence of HBV exposure. Serologic screening with only HBsAg and anti-HBs may overestimate the prevalence of non-immune population. It can also underestimate the prevalence of HBV and increase the risk of HBV reactivation during immunosuppression.

Current progress in the prevention of mother-to-child transmission of hepatitis B and resulting clinical and programmatic implications

There is currently no cure for hepatitis B chronic infections. Because new hepatitis B infections result mainly from perinatal transmission, preventing mother-to-child transmission is essential to reach by 2030 the goal of hepatitis B elimination set by the World Health Organization. The universal administration of hepatitis B vaccine to all infants, regardless of maternal status, starting with the birth dose, is the cornerstone of the strategy for elimination. Additional interventions, such as hepatitis B immune globulin administered to newborns and antiviral prophylaxis administered to hepatitis B infected pregnant women, may contribute to reaching the goal earlier. Hepatitis B immune globulin may remain out for reach of many pregnant women in low- and middle-income countries due to cost and logistic issues, but antivirals are cheap and do not require a cold chain for distribution. However, it has been observed that some viruses harbor mutations associated with escape from vaccine-elicited antibodies following immunization or administration of hepatitis B immune globulin. Also, resistance associated mutations have been described for several drugs used for treatment of hepatitis B infected patients as well as for the prevention of mother-to-child transmission. Whether these mutations have the potential to compromise the prevention of mother-to-child transmission or future treatment of the mother is a question of importance. We propose a review of important recent studies assessing tenofovir disoproxil fumarate for the prevention of mother-to-child transmission, and provides detailed information on the mutations possibly relevant in this setting.

Molecular and serological characterization of occult hepatitis B virus infection among patients with hemophilia

BACKGROUND

The occult hepatitis B virus infection (OBI) is a health concern among high-risk groups and immunosuppressed individuals. There is still a paucity of data regarding the occult hepatitis B virus infection among hemophilic patients. With this in mind, we aimed to evaluate the molecular prevalence of OBI among clients with hemophilia.

METHODS

Totally, 87 hemophilic patients were selected to be studied. To detect OBI, nested polymerase chain reaction test was used to amplify HBV-S, X, and Core regions. Viral load was determined using an in-house real-time PCR assay. Finally, sequence of S gene was used for genotyping and analysis of mutations.

RESULTS

The mean age of patients was 28.4 ± 5.3 years old, with 90.7% of whom were men. HBV-DNA was detected in eight subjects (9.3%). The rate of OBI was much higher in anti-HBs seronegative subjects than that in other patients (P = 0.019). All OBI cases had HBV genotype D, subgenotype D1. In addition, five out of eight cases (62.5%) showed detectable viral loads (a mean viral load of 4.5 × 10 ² copies/mL). sR73H, sI110L, sP120A, sP127T, sQ129H, sG130R, and sC137S were shown to be the most determinant escape mutation and OBI-relevant mutants.

CONCLUSION

The rate of OBI among the studied population of hemophilia seems to be remarkable. Therefore, screening for OBI must be a routine practice in patients with hemophilia and also patients undergoing immunosuppressive treatments. Amino acid substitutions were observed in the major hydrophilic region. However further investigations are needed for analysis of exact function.

Occult hepatitis B virus infection in patients with leprosy

Leprosy patients may present with immune system impairment and have a higher hepatitis B virus (HBV) seroprevalence, justifying the investigation of occult HBV infection in these individuals. The aim of this study was to verify the frequency and the clinical factors associated with occult HBV infection in leprosy patients. Between 2015 and 2016, leprosy patients from a reference center in Brazil were interviewed to assess clinical data. Blood samples were collected for the screening of HBV serological markers using enzyme-linked immunosorbent assay. Patients with negative hepatitis B surface antigen (HBsAg) that had positive anti-HBc and/or anti-HBs were selected for HBV DNA detection using real-time polymerase chain reaction. SPSS was used for data analysis. Among 114 selected patients, six were identified with occult infection (5.3%) and five of them with multibacillary leprosy. Three patients with occult infection had a history of a type 2 reaction (P = 0.072; OR, 4.97; 95% CI, 0.87-28.52). Only two patients with occult infection had isolated anti-HBc, while three had isolated anti-HBs, including those with the highest HBV DNA titers. In conclusion, in leprosy patients with negative HBsAg and positive anti-HBc and/or anti-HBs, occult HBV infection occurs in 5.3% and can be found even in patients with isolated anti-HBs.

Epidemiology, risk factors, and molecular characterization of occult hepatitis B infection among anti-hepatitis B core antigen alone subjects

OBJECTIVES

Features of occult hepatitis B virus (HBV) infection among the anti-hepatitis B core antigen (anti-HBc) positives have yet to be described in more details. This study aimed to determine the molecular prevalence of occult HBV infection (OBI), and association to risk factors among seropositives for anti-HBc.

METHODS

This was part of a community-based screening project that included 5234 cases. All participants completed a questionnaire on demographic and socio-epidemiological information. Then, the blood samples were collected and tested for anti-HBc and HBsAg using ELISA method. To identify OBI, nested-polymerase chain reaction (PCR) assays were performed for HBV-S and X genes, and viral load was determined using an in-house real-time PCR. Sequencing and phylogenetic analysis have been implemented for genotyping.

RESULTS

Overall, 596 cases, positive only for anti-HBc were included in the study. OBI was detected among 61 cases (10.2%). The genotype and subgenotype of HBV among all of them was D1, except one that was D4. Most of them had low viral loads ranged from 1.2 × 10² to 1.34 × 10 ³  copies/mL; 19.6% had undetectable viral loads. Important mutations in surface protein and reverse transcriptase were sI92T, sQ129H, rtL80I, rtS85F, rtL91I. The prevalence of OBI was related to some risk factors, such as tattooing (P = 0.02), sexual activities (P = 0.009), and diabetes (P = 0.031).

CONCLUSION

Our study suggests that OBI should be considered among anti-HBc seropositive subjects. This form of HBV infection was accompanied with some mutations, risk factors, and diseases. However, further investigations are needed to determine virological importance of documented mutations.

Detection of Hepatitis B Virus DNA among Chronic and potential Occult HBV patients in resource-limited settings by Loop-Mediated Isothermal Amplification assay

Transmission of Hepatitis B Virus (HBV) usually occurs due to the transfusion of blood or blood products from chronic HBV (CHB) or occult HBV-infected (OBI) patients. Besides serological tests, e.g. HBsAg and anti- HBc (total), detection of HBVDNA is necessary for the diagnosis of OBI patients. Different nucleic acid tests (NATs) including real- time-Polymerase Chain Reaction (qPCR) are used to detect HBV- DNA. The NATs are expensive and require technical expertise which are barriers to introduce them in resource-limited settings. This study was undertaken to evaluate the use of Loop-Mediated Isothermal Amplification (LAMP) assay as an alternative to qPCR for the detection of HBV-DNA in CHB and potential OBI patients in resource-limited settings. Following the published protocols with some modifications, a LAMP assay was developed for detection of HBV-DNA by either using a heat block followed by detection in an agarose gel or using a qPCR thermocycler. The LAMP assay was applied to supernatant prepared from heat-treated serum collected from CHB and potential OBI patients. HBV viral load in serum was measured by qPCR using a single-step HBV-DNA quantification kit. Among 200 samples tested, qPCR was capable to detect HBV-DNA in 25.5% of cases, whereas LAMP assay detected HBV-DNA in 43.5% cases. The qPCR was able to detect 11 (9.16%) potential OBI cases, whereas LAMP assay identified HBV-DNA in 43 (35.83%) cases. In addition to tests for HBsAg and/or anti-HBc (total), detection of HBV-DNA by LAMP assay may aid in preventing post-transfusion HBV infection in resource-limited settings.

Real Time Polymerase Chain Reaction for Hepatitis B Screening in Donor Corneas in the Central Eye Bank of Iran

PURPOSE

The aim of this study was to report the results of the use of real-time polymerase chain reaction (PCR) for the diagnosis of hepatitis B virus (HBV) infection in cornea donors at the Central Eye Bank of Iran.

METHODS

Between 2014 and 2016, all cornea donors that had negative screening serologic results for hepatitis B (HB) surface antigen, HB surface antibody (Ab), hepatitis C virus Ab, human immune deficiency virus Ab, human T-cell leukemia virus Ab, and syphilis, and positive serology for HB core Ab were subjected to real-time PCR with a detection limit of 400 IU/mL to identify HBV DNA. Positive results for HBV DNA were considered occult HBV infections in these donors.

RESULTS

Over the 3-year period, 122 out of 10448 cornea donors had negative screening serologic tests outside of HB core Ab. Of which, 90 cases were subjected to real-time PCR. Occult HBV was detected in 11 cases (12.2%), resulting in the rejection of the corresponding corneas. The remaining 79 cases (87.8%) had negative results for HBV DNA and the corresponding corneas were used for transplantation.

CONCLUSION

Implementation of PCR for the detection of occult HBV in cornea donors is necessary to not only increase the security level of cornea donation but also minimize the rejection rate of donors that have isolated HB core Ab reactivity.

Current evidence on the management of hepatitis B in pregnancy

Hepatitis B virus (HBV) infection is one of the main public health problems across the globe, since almost one third of the world population presents serological markers of contact with the virus. A profound impact on the epidemiology has been exerted by universal vaccination programmes in many countries, nevertheless the infection is still widespread also in its active form. In the areas of high endemicity (prevalence of hepatitis B surface antigen positivity > 7%), mother-to-child transmission represents the main modality of infection spread. That makes the correct management of HBV in pregnancy a matter of utmost importance. Furthermore, the infection in pregnancy needs to be carefully assessed and handled not only with respect to the risk of vertical transmission but also with respect to gravid women health. Each therapeutic or preventive choice deserves to be weighed upon attentively. On many aspects evidence is scarce or controversial. This review will highlight the latest insights into the paramount steps in managing HBV in pregnancy, with particular attention to recommendations from recent guidelines and data from up-do-date research syntheses.

The dynamics of integration, viral suppression and cell-cell transmission in the development of occult Hepatitis B virus infection

BACKGROUND

Out of several phases of HBV infection, the least understood phase is occult hepatitis B virus infection. The paucity of data due to non-availability of biological tissues and the prerequisite of ultra-sensitive assays for the detection of occult hepatitis B virus infection prompted us to utilize mathematical modeling in determining mechanisms that lead to occult hepatitis B virus infection and characteristics of HBV infection during occult hepatitis B virus infection.

METHODS

We proposed two mathematical models (M1 and M2), considering two different phenomenon for episomal maintenance and accumulation of covalently closed circular DNA (cccDNA) in infected hepatocytes: (i) M1 - recirculation of the relaxed circular DNA/double-stranded linear DNA from cytoplasm to the nucleus, and (ii) M2 - reinfection of infected hepatocytes with virions. We further incorporated the dynamics of integrated Hepatitis B virus DNA (iHBV) to investigate its role in the development of occult hepatitis B virus infection.

RESULTS

The analysis showed that the main mechanism for the spread of infection during occult hepatitis B virus infection is cell-to-cell transmission and not cell-free virus transmission. A significant viral suppression (of at least 99% from its peak production values) was essential but not sufficient in the development of occult hepatitis B virus infection under M1; however under M2, the viral suppression was neither sufficient nor essential as the inhibition of the production of HBsAg without viral suppression can also explain the development of occult hepatitis B virus infection. Our analysis also revealed that occult hepatitis B virus infection seropositive cases are more likely to progress into liver cirrhosis compared to occult hepatitis B virus infection seronegative cases. The iHBV was found to be mostly silent (by either being absent or non-productive for HBsAg) during occult hepatitis B virus infection.

CONCLUSION

The viral suppression is neither essential nor sufficient to explain the development of occult hepatitis B virus infection on its own. Not only the viral suppression but the inhibition -of the production and the export of HBsAg from cccDNA and iHBV also plays an important role in the development of occult hepatitis B virus infection. This is the first study, which incorporates the dynamics of iHBV and shows that HBV primarily spreads via cell-cell transmission during occult hepatitis B virus infection.

Occult Hepatitis B Virus Infection in Hyperlipidemia Patients

Chronic hepatitis B virus (HBV) infection is associated with lower prevalence of hyperlipidemia (HLP). However, occult HBV infection (OBI) in HLP patients has not yet been explored. OBI is defined as the presence of detectable HBV DNA in serum or liver tissue but undetectable HBV surface antigen in serum. In this study, 1,036 HLP patients and 1,134 replacement blood donor controls were recruited. Among them, 252 HLP patients and 255 blood donors with antibody to HBV core positive were selected and analyzed. HBV DNA was confirmed by nucleic acid testing assays, and nucleotide mutations were analyzed. OBI was detected in 9.5% (24/252) of HLP patients and 2.4% (6/255) of blood donors, respectively (P < 0.001). In HLP population, 41.7% of OBI and 13.6% of non-OBI carriers were associated with daily alcohol consuming > 30 g/day (P < 0.01), while in control population those rates were not statistically different between OBI and non-OBI carriers (P > 0.05). Viral load of OBI in HLP patients was higher than that of OBI in blood donors (P < 0.05), which was a positive correlation between total cholesterol and HBV viral load levels (r = 0.474 P = 0.019). HBV vaccination rate was found significantly lower in OBI HLP patients than that in non-OBI HLP patients (P < 0.01). Importantly, mutations were found in basic core promoter region of HBV among OBI HLP patients. In conclusion, the frequency of OBI is significantly higher in HLP patients, especially those patients with heavy daily alcohol consumption.

The prevalence of occult hepatitis B in chronic hepatitis C patients treated with interferon-based antiviral therapy

BACKGROUND AND STUDY AIMS

Occult hepatitis B infection (OBI) is known to be mostly prevalent in chronic hepatitis C (CHC) patients and OBI reactivation might be life-threatening in patients undergoing interferon (IFN)-free direct acting antiviral (DAA) therapy. As previous studies have revealed a relationship between OBI and non-response to IFN-based antiviral therapy, the aim of the current study was to determine if there was a higher prevalence of OBI in IFN non-responders than responders.

PATIENTS AND METHODS

This retrospective cross-sectional study was conducted in CHC patients who had previously received IFN-based antiviral therapy. Serum samples of 100 HBsAg negative CHC patients were tested for HBV DNA, anti-HBc IgG, anti-HBs, ALT and AST. The presence of OBI was compared between 50 IFN responders and 50 IFN non-responders. Patients with a history of previous HBV infection, patients with evidence of cirrhosis and patients who had received IFN therapy within the last one year were excluded from the study.

RESULTS

Anti-HBc IgG positivity was determined in 53% of the patients. HBV DNA positivity, indicating OBI was determined in 1 (1%) patient. This patient was anti-HBc IgG positive, anti-HBs negative, ALT and AST levels were normal. The HBV DNA and anti-HBc IgG positivity rates were higher in the non-responder group than in the responder group, but the difference was not statistically significant (p = 0.31 and p = 0.07 respectively).

CONCLUSION

According to the results of this study, the prevalence of OBI is lower than expected amongst CHC patients in Turkey and it may not be necessary to apply routine screening to IFN non-responders for OBI infection before DAA therapy. However, there is a need for multicentre studies with larger patient series.

Prevalence and natural course of occult hepatitis B virus infection in residents of 2 communities of Wuwei City, Gansu Province, China

Occult hepatitis B infection (OBI) is characterized by serum hepatitis B surface antigen (HBsAg) negative and hepatitis B virus (HBV) DNA positive (HBsAg-/HBV DNA+). Occult hepatitis B infection in community-based populations has been scarcely investigated, and OBI outcomes remain unclear, especially in Wuwei, a region located in Northwest China. This region is one of the areas in China that has the highest prevalence of chronic HBV infection. A prospective study was performed in the general population of 2 towns of Wuwei from June 2011 to May 2014. A questionnaire was used to collect demographic and medical data, and serum samples were collected from the participants and stored until analysis. DNA was detected using quantitative PCR (qPCR) or nested PCR, the HBV DNA from HBV DNA-positive or possible positive (below the detection limit) subjects was extracted and amplified by nested PCR, and the PCR products were sequenced. Sequence analysis was performed using the Mega 6.0 program and CLC sequence viewer software. Hepatitis B virus DNA was detected in 90 of 3,080 HBsAg-negative subjects, and the prevalence of OBI in the study population was 2.92% (90/3,080, 95% CI: 2.33%-3.51%). Hepatitis B virus genomes in 51 of 80 objects (63.75%) contained mutations in the "a" determinant of HBsAg. After 2 years follow-up, 42 of 90 HBV DNA of OBI subjects remained positive, and the natural clearance rate of OBI subjects was 53.3%. Occult hepatitis B infection prevalence in this cohort was much lower than chronic HBV infection in the same region. HBV DNA was cleared in most OBI subjects during the 2 year period. Our data suggest that some OBI may represent a late stage of resolving the HBV infection process.

Genetic polymorphism and decreased expression of HLA class II DP genes are associated with HBV reactivation in patients treated with immunomodulatory agents

Hepatitis B virus (HBV) reactivation can be triggered by immunosuppressive chemotherapy. HLA class II molecules may play a role in HBV reactivation. Genetic polymorphism and mRNA expression of HLA class II were examined in patients with latent HBV infection treated with immunosuppressive therapies. Subjects with resolved HBV infection who had undergone treatment with immunosuppressive chemotherapies were retrospectively enrolled (n = 42) and divided into reactivated (n = 9) and non-reactivated groups (n = 33). Patients were genotyped for 17 single nucleotide polymorphisms (SNPs) within HLA class II DPA1, and DPB1, and mRNA expression levels of HLA class II genes were assessed. The frequency of the AA genotype of rs872956, a SNP in HLA-DPB1, was significantly higher in the reactivated group than in the non-reactivated group (55.6% vs 12.1%, P < 0.05). The frequencies of the T allele and non-AA genotypes (AT/TT) of rs3116996 (located in DPB1) were significantly higher in the reactivated group (T allele frequency: 16.7% vs 0.0% [P < 0.01], non-AA genotype frequency: 22.2% vs 0.0% [P < 0.05]). Multivariate logistic regression identified the AA genotype of rs872956 as an independent protective factor against HBV reactivation (odds ratio [OR] = 18.1, 95% confidence interval [CI] = 2.6-126.7, P < 0.01). mRNA expression of HLA-DPB1 was lower in the HBV reactivated group than in the non-reactivated group (median 276.1 ± 165.6/β-actin vs 371.4 ± 407.5/β-actin [P < 0.05]). These results suggest the involvement of HLA class II molecules in HBV reactivation after treatment with immunomodulatory agents.

First report of occult hepatitis B infection among ART naïve HIV seropositive individuals in Maputo, Mozambique

Background

The prevalence of hepatitis B virus (HBV) infection and human immunodeficiency virus (HIV) infection in Mozambique is one of the highest in the world, though in spite of this the prevalence of occult hepatitis B infection (OBI) is unknown.

Objectives

This study was conducted with the aim to investigate the prevalence of OBI and frequency of isolated hepatitis B core antibody (anti-HBc alone) among antiretroviral (ART) naïve HIV-positive patients in Mozambique.

Methods

A cross-sectional study was conducted in two health facilities within Maputo city. All ART-naive HIV seropositive patients attending outpatient clinics between June and October 2012 were consecutively enrolled. Blood samples were drawn from each participant and used for serological measurement of HBV surface antigen (HBsAg), antibodies against HBV surface antigen (anti-HBs) and antibodies against core antigen (anti-HBc) using ELISA. Quantification of HBV DNA was performed by real time PCR. A questionnaire was used to obtain demographics and clinical data.

Results

Of the 518 ART-naive HIV-positive subjects enrolled in the study, 90.9% (471/518) were HBsAg negative. Among HBsAg negative, 45.2% (213/471) had isolated anti-HBc antibodies, and the frequency of OBI among patients with anti-HBc alone was 8.3% (17/206). OBI was not correlated either with CD4⁺ T cells count or transaminases levels. A total of 11.8% of patients with OBI presented elevated HBV DNA level. Frequency of individuals with APRI score > 2 and FIB-4 score > 3.25 was higher in patients with OBI as compared not exposed, immune and anti-HBc alone patients.

Conclusion

Our data demonstrate for the first time that OBI is prevalent among HIV patients in Mozambique, and will be missed using the commonly available serological assays that measures HBsAg.

[Occult hepatitis B reactivation in a patient with homozygous sickle cell disease: clinical case and literature review]

Occult Hepatitis B corresponds to the presence of hepatitis B virus-deoxyribonucleic acid (HBV-DNA) in serum and/or in liver of a patient despite HBsAg negativity. Clinically, it is usually asymptomatic. Its reactivation is rare and commonly occurs in immunosuppressed individuals. We report the case of a 21-year old patient from Senegal, with homozygous sickle cell disease, presenting with cholestatic jaundice. Laboratory tests showed reactivation of occult Hepatitis B. This study emphasizes the need to systematically investigate the presence of occult Hepatitis B in patients with sickle cell disease suffering from acute liver disease.

The correlation between renal transplantation and liver carcinoma: a meta-analysis

OBJECTIVE

Much of the related researches have reported the correlation between renal transplantation and different tumors in the post transplant recipients. However, there are not exact essays revealed that renal transplantation is definite causation for liver carcinoma, thus we systematically evaluated the association between renal transplantation and the risk of liver carcinoma in this meta-analysis from all available researches.

METHODS

All useful data were collected through searching of PubMed and Web of Science until the date of 31 September 2015. Random-effects model were adopted to calculate the standardized incidence ratio and 95% confidence interval (CIs) of the risk of liver carcinoma among renal transplant recipients. Other statistical analyses like heterogeneity tests, sensitivity analysis and publication bias were also performed in this meta-analysis.

RESULTS

Among 17,4256 kidney transplant cases and 25,6736 patients-years observation, 9136 post-transplant cancers were diagnosed. We identified a 2.08-fold higher standardized incidence rate (SIR) (95% confidence interval (CI): 1.24-3.47, P=0.005) of liver carcinoma following renal transplantation compared with the general population. Observation and publication bias were not observed in this study.

CONCLUSION

This study suggested that the risk of liver carcinoma among renal transplant recipients with chronic hepatic disease is higher than general population. Such results alert clinical doctors the importance of anti-virus therapy with chronic virus hepatitis and enough attention of periodic liver screening with chronic liver diseases in renal transplant recipients.

Detection and molecular characterisation of a diagnosis escape variant associated with occult hepatitis B virus in Brazil

BACKGROUND

Many studies have identified mutations in the hepatitis B surface antigen (HBsAg) as important factors limiting the ability of commercial serological assays to detect this viral antigen. However, an association between mutations in the HBsAg gene and the occurrence of occult HBV infection (OBI) in patients has not been established.

OBJECTIVES

To detect hepatitis B virus (HBV) DNA in patients with anti-HBc as a unique serological marker, a previously published, cost-effective TaqMan-based real-time polymerase chain reaction (PCR) test with minor groove binding probes was adapted for use in this study. The current study also aimed to investigate HBsAg mutations and genotypes of HBV in OBI at the Viral Hepatitis Ambulatory Clinic in Rio de Janeiro to determine any possible association.

METHODS

Intra-assay and inter-assay reproducibility were determined, and the mean coefficient of variation values obtained were 2.07 and 3.5, respectively. Probit analysis indicated that the 95% detection level was 25 IU/mL. The prevalence of OBI was investigated in 35 serum samples with an ‘anti-HBc alone’ profile from individuals who attended our clinic between 2011 and 2013.

FINDINGS

HBV DNA was detected in only one sample, resulting in an OBI rate of 2.9%. Nucleotide sequencing of the pre-S/S region was performed to genotype and analyse mutations within the HBsAg gene of this HBV DNA. The HBV in the OBI case was classified as sub-genotype A1, and a sequence analysis of the small S gene revealed 12 mutations in the major hydrophilic region compared to the consensus A1 sequence. Most of these mutations occurred in amino acid residues that have been reported as clinically relevant because they have been implicated in vaccine escape and/or inability to detect HBsAg by commercial serological assays.

MAIN CONCLUSIONS

Our study suggests the importance of specific HBsAg mutations, different from those in D, B, and C genotypes, in sub-genotype A1 HBV associated with OBI.

Occult hepatitis B virus infection in Greek patients with congenital bleeding disorders

Occult Hepatitis B Infection (OBI) is a form of chronic HBV infection characterized by low level HBV DNA, without detectable HBV surface antigen (HBsAg). OBI is frequently associated with the presence of anti-HBc and in some cases also with anti-HBs. Patients, who formerly received non-inactivated factor concentrates, can potentially be considered at high risk for OBI, especially since these patients usually are HIV or HCV co-infected. This study aimed to assess the prevalence of occult HBV infection in Greek patients with hereditary bleeding disorders. The study sample comprised of 114 patients from a single haemophilia center. All patients were screened for HBV serum markers and individually tested for HBV DNA using a qualitative PCR. Presence of HBV DNA was further confirmed by quantification of viral load with an ultrasensitive in-house real time PCR. 88 and 21 patients with haemophilia A and B, respectively, 4 patients with von Willebrand Disease and 1 patient with severe factor VII deficiency were screened for the presence of OBI. Anti-HBc were detected in 53 (46.5%) subjects; 18 of them were anti-HBs(-) and 35 anti-HBs(+). Anti-HBe were present in 26 subjects. Two out of 114 patients were HBsAg(+). Of the remaining 112 HBsAg(-) patients tested, two (1.8%) were found HBsAg(-), HBV DNA(+), anti-HBc(+) and anti-HBs(-) and were identified as potential OBI cases. Both cases exhibited very low DNA levels; 38.2IU/mL in patient A and 14.2IU/mL in patient B. Both patients were HBeAg(-), but patient A had HBe antibodies. Patient B was also HIV/HCV co-infected. In conclusion, two cases of OBI with low HBV viraemia were identified among patients with congenital bleeding disorders. Although the incidence in our sample is moderately low (1.8%), close monitoring of these infections is of great clinical significance, especially in patients with co-infections and concomitant immunosuppression.