Occult hepatitis B virus after acute self-limited infection persisting for 30 years without sequence variation

High-sensitivity HBV DNA test for the diagnosis of occult HBV infection: commonly used but not reliable

Occult hepatitis B virus (HBV) infection (OBI) is a condition in which replication-competent viral DNA is detected in the liver (with detectable or undetectable HBV DNA in serum) of individual testing negative for HBV surface antigen (HBsAg). It is a risk factor for transfusion or transplant transmission, reactivation after immunosuppression or chemotherapy, and progression of chronic liver disease and hepatocarcinogenesis. The long-term stable presence of covalently closed circular DNA (cccDNA), which is fully replicative in the nucleus of infected hepatocytes is the molecular basis for the formation of OBI. HBV genome in liver tissue, HBV DNA and anti-HBc test in serum are the gold standard, common method and alternative markers for OBI diagnosis, respectively. Due to the stability of covalently closed circular DNA (cccDNA) and the long half-life of hepatocytes, the existence of OBI is extensive and prolonged. The low and/or intermittent replication of HBV in OBI patients, the limitations of the sensitivity of serological tests, and the non-standardized and invasive nature of liver histology render the "commonly used" serological tests are unreliable and the "gold standard" liver histology is impractical, thus the findings from studies on the formation, diagnosis and transplantation or transfusion transmission of HBV in OBI strongly suggest that the "alternative" marker, the anti-HBc test, may be the most reliable and practical approach for OBI diagnosis.

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.

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.

Hepatitis B Virus-Specific Cellular Immunity Contributes to the Outcome of Occult Hepatitis B Virus Infection

There is little known of immunologic factors leading to the occurrence of occult HBV infection (OBI). Specific cellular immune response to hepatitis B virus (HBV) core/pol peptides was compared between blood donor populations, including 37 OBIs, 53 chronic HBV infections (CHB), 47 resolved infections, and 56 non-infected controls, respectively. The rate of CD4⁺/CD8⁺ T cell proliferation in OBI or CHB carriers was higher than in HBV resolved and non-infected individuals (P < 0.05). The intensity of IFN-γ-secretion T-cell response of OBI carriers was highest, followed by CHB and resolved infections, and non-infected individuals (P < 0.05). The frequency of intracellular IFN-γ and IL-17A CD4⁺/CD8⁺ and IL-21 CD4⁺ T-cell responses was significantly higher in resolved infections than in OBI or CHB carriers (P < 0.05), while the level of extracellular IL-17A of peripheral blood mononuclear cells (PBMCs) was higher in OBI and CHB carriers than in resolved infections (P < 0.01). The frequency of intracellular IL-10 CD4⁺ T-cell response in CHB, OBI, and resolved infections was higher than in HBV non-infected individuals (P < 0.01). Intracellular IL-10 CD8⁺ T cell and extracellular IL-10 T-cell responses were higher in CHB than in OBI (P = 0.012) or HBV resolved infections (P < 0.01). In conclusion, the higher level of effective T-cell response with IFN-γ, IL-17A, and IL-21 contributes to resolved infection outcome, while higher levels of suppressive T-cell response with IL-10 result in HBV chronicity. OBI is an intermediary status between HBV resolved and chronic infections, in which IL-21 effector and IL-10 suppressor T-cell responses play an important role in directing the outcome of HBV infection.

Clinicopathological characteristics and prognosis of hepatitis B associated membranous nephropathy and idiopathic membranous nephropathy complicated with hepatitis B virus infection

The main objective of this study is to analyze the clinical and pathological features and prognosis of patients with Hepatitis B associated membranous nephropathy (HBV-MN) and idiopathic membranous nephropathy (IMN) complicated with hepatitis B virus (HBV) infection. This study will provide more basis for diagnosis and prognosis evaluation. A total of 50 patients with HBV-MN were included in this study. 56 IMN patients complicated with HBV infection diagnosed during the same period formed the control group. Parameters including blood routine, urine routine and plasma levels of albumin (ALB), serum creatinine (SCR), blood urea nitrogen (BUN), urea acid (UA), total cholesterol (T-CHO), triglycerides (TG), complement C3 and C4, glutamic pyruvic transaminase (ALT), glutamic pyruvic transaminase (AST), 24-h urinary protein quantification (24 h-TP), renal phospholipase A2 receptor (PLA₂R) and HBV related markers during the hospitalization and outpatient follow-up study period were collected for all the patients. The proportion of male patients was high in both groups. The average age of the HBV-MN group was 37.2 ± 14.187 years old, it was younger compared with the IMN group (P = 0.003). Nephrotic syndrome was the major clinical manifestation among patients. There was no significant difference between the two groups in the levels of anemia, microscopic hematuria, renal dysfunction, liver dysfunction, liver cirrhosis. The level of serum C3 and C4 in the HBV-MN group was lower compared with the IMN group (P = 0.002, P = 0.014). In the HBV-MN group, serum HBV markers were negative in 6 (12%) patients, 4 patients (8%) were positive for PLA₂R in serum, and 5 patients (10%) were positive for PLA₂R in renal tissue. Stronger IgG1 and C1q and weaker IgG4 staining were found in HBV-MN group renal tissues (P = 0.003, P = 0.025, and P = 0.001, respectively). There were no statistical differences compared with serum and renal PLA₂R between HBV-MN and IMN groups (P = 0.098, P = 0.109). During the 1-year follow-up, there was no significant difference in complete remission rate between the two groups (P = 0.7739). Renal biopsy is crucial to diagnose HBV-MN. IgG subtypes in the HBV-MN group were mainly IgG1 deposition, while those in IMN complicated with HBV infection group were mainly IgG4 deposition. When HBV-associated antigen and PLA₂R are present in renal tissue, lower level of serum C3 and C4, high intensity of renal C1q and IgG1 is more supportive of HBV-MN. The positive of PLA₂R in serum and renal tissue in differentiating HBV from IMN complicated with HBV infection remains to be discussed.

HBV-Integration Studies in the Clinic: Role in the Natural History of Infection

Hepatitis B virus (HBV) infection is a major global health problem causing acute and chronic liver disease that can lead to liver cirrhosis and hepatocellular carcinoma (HCC). HBV covalently closed circular DNA (cccDNA) is essential for viral replication and the establishment of a persistent infection. Integrated HBV DNA represents another stable form of viral DNA regularly observed in the livers of infected patients. HBV DNA integration into the host genome occurs early after HBV infection. It is a common occurrence during the HBV life cycle, and it has been detected in all the phases of chronic infection. HBV DNA integration has long been considered to be the main contributor to liver tumorigenesis. The recent development of highly sensitive detection methods and research models has led to the clarification of some molecular and pathogenic aspects of HBV integration. Though HBV integration does not lead to replication-competent transcripts, it can act as a stable source of viral RNA and proteins, which may contribute in determining HBV-specific T-cell exhaustion and favoring virus persistence. The relationship between HBV DNA integration and the immune response in the liver microenvironment might be closely related to the development and progression of HBV-related diseases. While many new antiviral agents aimed at cccDNA elimination or silencing have been developed, integrated HBV DNA remains a difficult therapeutic challenge.

Prevalence of occult HBV infection in Western countries

Due to a lack of standardized tests, it is difficult to obtain prevalence data and define the real impact of occult HBV infection (OBI) in Western countries. The present review article addresses the prevalence of OBI, defined as presence of hepatitis B virus (HBV) DNA in liver tissue or plasma in HBsAg-negative subjects, in Western countries. This varies in different studies according to the different methodologies used (based on serology vs virology), to the sample analyzed for the diagnosis (liver tissue vs plasma), to the different populations studied, to the different geographical variations in the HBV spread, to the host characteristics (age, gender, risk factors for acquiring HBV infection) and to the presence of other parenteral infections (hepatitis C virus and/or human immunodeficiency virus [HIV] infections). Considering the different liver diseases analyzed, that is in patients with cryptogenic cirrhosis or advanced liver fibrosis, the prevalence of OBI ranges 4% to 38%. Considering the different populations studied, in the case of parenteral blood exposure it is about 45%, in patients with chronic hepatitis C it is estimated at about 52%, in HIV-infected patients it ranges from 0% to 45%, in blood donors from 0% to 22.7% and in hemodialysis patients it ranges from 0% to 54%. In conclusion, OBI is a virological entity to be considered when performing the patient's evaluation for immunosuppressive diseases, liver pathologies, or for blood transfusions. Knowing the prevalence and clinical impact of OBI will allow better patient management.

Occult hepatitis B infection and hepatocellular carcinoma: Epidemiology, virology, hepatocarcinogenesis and clinical significance

Occult hepatitis B infection (OBI) refers to a condition where replication-competent HBV DNA is present in the liver, with or without HBV DNA in the blood, in individuals with serum HBsAg negativity assessed by currently available assays. The episomal covalently closed circular DNA (cccDNA) in OBI is in a low replicative state. Viral gene expression is mediated by epigenetic control of HBV transcription, including the HBV CpG island methylation pathway and post-translational modification of cccDNA-bound histone, with a different pattern from patients with chronic HBV infection. The prevalence of OBI varies tremendously across patient populations owing to numerous factors, such as geographic location, assay characteristics, host immune response, coinfection with other viruses, and vaccination status. Apart from the risk of viral reactivation upon immunosuppression and the risk of transmission of HBV, OBI has been implicated in hepatocellular carcinoma (HCC) development in patients with chronic HCV infection, those with cryptogenic or known liver disease, and in patients with HBsAg seroclearance after chronic HBV infection. An increasing number of prospective studies and meta-analyses have reported a higher incidence of HCC in patients with HCV and OBI, as well as more advanced tumour histological grades and earlier age of HCC diagnosis, compared with patients without OBI. The proposed pathogenetic mechanisms of OBI-related HCC include the influence of HBV DNA integration on the hepatocyte cell cycle, the production of pro-oncogenic proteins (HBx protein and mutated surface proteins), and persistent low-grade necroinflammation (contributing to the development of fibrosis and cirrhosis). There remain uncertainties about exactly how, and in what order, these mechanisms drive the development of tumours in patients with OBI.

Diverse Virus and Host-Dependent Mechanisms Influence the Systemic and Intrahepatic Immune Responses in the Woodchuck Model of Hepatitis B

Woodchuck infected with woodchuck hepatitis virus (WHV) represents the pathogenically nearest model of hepatitis B and associated hepatocellular carcinoma (HCC). This naturally occurring animal model also is highly valuable for development and preclinical evaluation of new anti-HBV agents and immunotherapies against chronic hepatitis (CH) B and HCC. Studies in this system uncovered a number of molecular and immunological processes which contribute or likely contribute to the immunopathogenesis of liver disease and modulation of the systemic and intrahepatic innate and adaptive immune responses during hepadnaviral infection. Among them, inhibition of presentation of the class I major histocompatibility complex on chronically infected hepatocytes and a role of WHV envelope proteins in this process, as well as augmented hepatocyte cytotoxicity mediated by constitutively expressed components of CD95 (Fas) ligand- and perforin-dependent pathways, capable of eliminating cells brought to contact with hepatocyte surface, including activated T lymphocytes, were uncovered. Other findings pointed to a role of autoimmune response against hepatocyte asialoglycoprotein receptor in augmenting severity of liver damage in hepadnaviral CH. It was also documented that WHV in the first few hours activates intrahepatic innate immunity that transiently decreases hepatic virus load. However, this activation is not translated in a timely manner to induction of virus-specific T cell response which appears to be hindered by defective activation of antigen presenting cells and presentation of viral epitopes to T cells. The early WHV infection also induces generalized polyclonal activation of T cells that precedes emergence of virus-specific T lymphocyte reactivity. The combination of these mechanisms hinder recognition of virus allowing its dissemination in the initial, asymptomatic stages of infection before adaptive cellular response became apparent. This review will highlight a range of diverse mechanisms uncovered in the woodchuck model which affect effectiveness of the anti-viral systemic and intrahepatic immune responses, and modify liver disease outcomes. Further exploration of these and other mechanisms, either already discovered or yet unknown, and their interactions should bring more comprehensive understanding of HBV pathogenesis and help to identify novel targets for therapeutic and preventive interventions. The woodchuck model is uniquely positioned to further contribute to these advances.

Characterization of monocytic and granulocytic subsets of myeloid-derived suppressor cells in blood donors with occult hepatitis B virus infection

Myeloid-derived suppressor cells (MDSCs) accumulate from many diseases. MDSCs are rarely explored in occult hepatitis B virus infection (OBI). The frequency of monocytic MDSCs (M-MDSCs) and granulocytic MDSCs (G-MDSCs) in OBI carriers was analyzed for correlation with clinical parameters, which was no different between OBI and healthy individuals, whereas the frequency of M-MDSCs but G-MDSCs in OBI was significantly lower than that observed in chronic hepatitis B carriers (0.4% vs 0.7%, P = 0.0004). The frequency of MDSCs was not correlated with clinical parameters and viral load of OBI, suggesting that the absence of HBsAg in OBI carriers might not induce the accumulation of MDSCs.

Molecular Characterization of Near Full-Length Genomes of Hepatitis B Virus Isolated from Predominantly HIV Infected Individuals in Botswana

The World Health Organization plans to eliminate hepatitis B and C Infections by 2030. Therefore, there is a need to study and understand hepatitis B virus (HBV) epidemiology and viral evolution further, including evaluating occult (HBsAg-negative) HBV infection (OBI), given that such infections are frequently undiagnosed and rarely treated. We aimed to molecularly characterize HBV genomes from 108 individuals co-infected with human immunodeficiency virus (HIV) and chronic hepatitis B (CHB) or OBI identified from previous HIV studies conducted in Botswana from 2009 to 2012. Full-length (3.2 kb) and nearly full-length (~3 kb) genomes were amplified by nested polymerase chain reaction (PCR). Sequences from OBI participants were compared to sequences from CHB participants and GenBank references to identify OBI-unique mutations. HBV genomes from 50 (25 CHB and 25 OBI) individuals were successfully genotyped. Among OBI participants, subgenotype A1 was identified in 12 (48%), D3 in 12 (48%), and E in 1 (4%). A similar genotype distribution was observed in CHB participants. Whole HBV genome sequences from Botswana, representing OBI and CHB, were compared for the first time. There were 43 OBI-unique mutations, of which 26 were novel. Future studies using larger sample sizes and functional analysis of OBI-unique mutations are warranted.

Overt and occult hepatitis B virus infection among community children in Northwest China

Although a universal newborn hepatitis B (HB) immunization programme has been implemented in China, hepatitis B virus (HBV) breakthrough infection, including HB surface antigen (HBsAg)-positive infection and occult HBV infection (OBI), still occurs during infancy or childhood. Obtaining the actual prevalence of HBV infection in general children is important for preventing and controlling the spread of HB. Accordingly, we investigated the prevalence of overt infection and OBI in community children and compared the serological and virological characteristics of OBI and HBsAg carrier children to clarify the mechanisms related to OBI. In total, 6 706 community children <12 years of age were included from a population-based HBV seroepidemiological investigation in Northwest China. The HBsAg carrier rate in community children was 1.60% (107/6706), and the anti-HBs positive rate was 57.35% (3846/6706). Additionally, 1192 HBsAg-negative children were examined for OBI using nested PCR. The prevalence of OBI in local children was 1.26% (15/1192), and the predominant OBI genotypes were C and D. The 15 OBI children and 29 HBsAg-positive children from the same population did not have a statistical significant difference in age, gender, alanine aminotransferase (ALT), proportion of anti-HBs or anti-HBc, viral genotypes or mutations. Children with chronic overt infection had higher viral loads than OBI children (P=.004). These results suggested that HBV overt and occult infection of children was more serious in underdeveloped north-west regions. HBV neonatal immunization and catch-up programmes should be strengthened and supplemented. None of specific viral mutations or genotypes related to OBI were found. OBI may be a specific stage of HBV infection.

A Practical Model Evaluating Antiviral Cytokines by Natural Killer Cells in Treatment Naïve Patients with Chronic Hepatitis B Virus Infection

Natural killer (NK) cells play a major role in anti-viral immunity as first line defense during hepatitis B infection, particularly in untreated patients whose T cells functions are profoundly impaired. Cytokine interferon (IFN)-γ and tumor necrosis factor (TNF)-α produced by NK cells are important anti-viral factors. However, there is lack of a quantifiable model to evaluate cytokine responses by NK cells. In this study, almost half of the patients (47.9%) beyond treatment criteria had high cytokine activity, although it was lower than those recommended for antiviral therapy (78.2%). Moreover, we developed a model that low levels of HBsAg, HBcAb, and albumin and high fibrosis values predicted strong antiviral cytokine production by NK cells. Based on the cut-off score (0.361) obtained from the multivariable model, patients with 67%, 8%, 92%, and 74% in immune-active (IA), immune-tolerant (IT), immune-inactive (IC), and grey zone (GZ), respectively, showed active antiviral cytokines produced by NK cells. These results suggest that those who possess activated cytokine responses beyond the current treatment criteria may have potential implications for the timing of antiviral therapy to achieve better virus control.

Clinical study on the relationship between hepatitis B virus infection and risk of breast cancer: a large sized case-control and single center study in southwest of China

Purpose

Chronic hepatitis C virus (HCV) infection is reported to be associated with early-onset breast cancer, while, as a hepadnavirus, hepatitis B virus(HBV) infection is more common than HCV in China. In this article, it is aimed to study the relationship between HBV infection and risk of breast cancer in China.

Methods

The clinical data of 2452 cases of initially diagnosed breast cancer and 1926 cases of benign breast disease (as controls) with the consecutive reports of HBV serological markers and liver function tests, available in the Electronic Medical Records of the Breast Cancer Center of Chongqing, the southwest of China, from January 2011 to March 2015, were collected for analysis.

Results

The average age of the initially diagnosed breast cancer patients was 50.3±11.3 years with the age peaking about 40- 49yeaers (39.7%). The positive rate (8.2%) of hepatitis B surface antigen in breast cancer patients was relatively higher than that (7.8%) in controls (P>0.05). While, the positive rate (66.4%)of hepatitis B core antibody in breast cancer patients was significantly higher than that (53.7%) in controls (P<0.05), so were the similar results in the age groups of 40-49 years, after multiple layer analysis stratified by age and compare HBV markers adjusting age with binary logistic regression. Meanwhile, the status of albumin, aminotransferase and aspartate transaminase (41.4 g/L, 22.9 U/L, 22.0 U/L) in breast cancer patients were significantly poorer than those (44.1 g/L,16.8 U/L, 19.2 U/L) in controls (P<0.05).

Conclusions

Exposure to HBV infection may be a risk factor for breast cancer and may be also related to the earlier age onset of breast cancer (peaked around 40-49 years) among Chinese females.

Hepatitis B reactivation in occult viral carriers undergoing hematopoietic stem cell transplantation: A prospective study

Hepatitis B virus (HBV) reactivation in hepatitis B surface antigen (HBsAg)-negative, antibody to hepatitis B core antigen (anti-HBc)-positive patients after allogeneic hematopoietic stem cell transplantation (HSCT) has not been prospectively studied. HBsAg-negative, anti-HBc-positive patients with undetectable HBV DNA undergoing allogeneic HSCT were prospectively monitored every 4 weeks. The primary endpoint was HBV reactivation, defined as detectable HBV DNA (≥10 IU/mL). Secondary endpoints included overall survival, HBsAg positivity, and changes in liver biochemistry and antibody to HBsAg levels. Among 297 allogeneic HSCT recipients, 85 (28.7%) were HBsAg-negative, anti-HBc-positive, of whom 62 were recruited and monitored for a median of 48 (4-104) weeks. The 2-year cumulative HBV DNA detectability rate was 40.8%, occurring at a median of 44 (8-100) weeks. Multivariate analysis showed that age ≥50 years (P = 0.004, hazard ratio = 8.2) and chronic graft-versus-host disease (P = 0.010, hazard ratio = 5.3) were significantly associated with HBV reactivation. Other clinical parameters, including baseline antibody to HBsAg status, serial changes in antibody to HBsAg levels, and donor serology, were not associated with HBV reactivation. Patients <50 years old and without chronic graft-versus-host disease, compared with the remaining patient cohort, had a significantly lower 2-year cumulative HBV reactivation rate (5.6% versus 65.0%, P = 0.004). Entecavir successfully suppressed HBV DNA to undetectable levels, with no cases developing biochemical hepatitis.

CONCLUSION

HBsAg-negative, anti-HBc-positive patients had a high rate of HBV reactivation after allogeneic HSCT, with determinants of HBV reactivation including age ≥50 years and chronic graft-versus-host disease; treatment strategies based on these parameters may prevent HBV reactivation and subsequent complications. (ClinicalTrials.gov identifier NCT01481649.) (Hepatology 2017;65:1451-1461).

Association of Hepatitis B Core-Related Antigen With Hepatitis B Virus Reactivation in Occult Viral Carriers Undergoing High-Risk Immunosuppressive Therapy

OBJECTIVES

Hepatitis B core-related antigen (HBcrAg) is a novel serum marker that correlates with intrahepatic hepatitis B virus (HBV) activity. Its association with HBV reactivation in hepatitis B surface antigen (HBsAg)-negative antibody to hepatitis B core antigen (anti-HBc)-positive patients undergoing high-risk immunosuppressive therapy is undefined.

METHODS

HBcrAg was measured in HBsAg-negative, anti-HBc-positive Asian patients with undetectable HBV DNA, who participated in two prospective studies investigating HBV reactivation during rituximab-containing chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT). Patients were monitored every 4 weeks for up to 2 years, with entecavir started when HBV reactivation, defined as HBV DNA ≥10 IU ml^-1, developed.

RESULTS

One hundred and twenty-four HBsAg-negative, anti-HBc-positive patients (rituximab, N=62; allogeneic HSCT, N=62) with a median follow-up of 64 weeks (range: 4-104 weeks) were studied. HBV reactivation occurred in 31 patients, with a 2-year cumulative reactivation rate of 40.4%. Serum HBcrAg was detected in 43 (34.7%) patients. Baseline HBcrAg positivity was significantly associated with HBV reactivation (P=0.004, hazard ratio (HR): 2.94, 95% confidence interval (95% CI): 1.43-6.07). HBcrAg-positive patients had a significantly higher 2-year HBV reactivation rate than HBcrAg-negative patients (71.8 vs. 31%, P=0.002). In the rituximab cohort, the HRs for positive HBcrAg and negative antibody to HBsAg for HBV reactivation were 3.65 and 2.84, respectively (P=0.011, 95% CI: 1.35-9.86 and P=0.032, 95% CI: 1.10-7.37, respectively).

CONCLUSIONS

Serum HBcrAg positivity is a significant risk factor of HBV reactivation in HBsAg-negative, anti-HBc-positive patients undergoing high-risk immunosuppressive therapy and can potentially have a role in identifying patients who will best benefit from prophylactic nucleoside analogue treatment.

Update on occult hepatitis B virus infection

The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

Hepatitis B virus molecular biology and pathogenesis

As obligate intracellular parasites, viruses need a host cell to provide a milieu favorable to viral replication. Consequently, viruses often adopt mechanisms to subvert host cellular signaling processes. While beneficial for the viral replication cycle, virus-induced deregulation of host cellular signaling processes can be detrimental to host cell physiology and can lead to virus-associated pathogenesis, including, for oncogenic viruses, cell transformation and cancer progression. Included among these oncogenic viruses is the hepatitis B virus (HBV). Despite the availability of an HBV vaccine, 350-500 million people worldwide are chronically infected with HBV, and a significant number of these chronically infected individuals will develop hepatocellular carcinoma (HCC). Epidemiological studies indicate that chronic infection with HBV is the leading risk factor for the development of HCC. Globally, HCC is the second highest cause of cancer-associated deaths, underscoring the need for understanding mechanisms that regulate HBV replication and the development of HBV-associated HCC. HBV is the prototype member of the Hepadnaviridae family; members of this family of viruses have a narrow host range and predominately infect hepatocytes in their respective hosts. The extremely small and compact hepadnaviral genome, the unique arrangement of open reading frames, and a replication strategy utilizing reverse transcription of an RNA intermediate to generate the DNA genome are distinguishing features of the Hepadnaviridae. In this review, we provide a comprehensive description of HBV biology, summarize the model systems used for studying HBV infections, and highlight potential mechanisms that link a chronic HBV-infection to the development of HCC. For example, the HBV X protein (HBx), a key regulatory HBV protein that is important for HBV replication, is thought to play a cofactor role in the development of HBV-induced HCC, and we highlight the functions of HBx that may contribute to the development of HBV-associated HCC.

Asian-Pacific clinical practice guidelines on the management of hepatitis B: a 2015 update

Worldwide, some 240 million people have chronic hepatitis B virus (HBV), with the highest rates of infection in Africa and Asia. Our understanding of the natural history of HBV infection and the potential for therapy of the resultant disease is continuously improving. New data have become available since the previous APASL guidelines for management of HBV infection were published in 2012. The objective of this manuscript is to update the recommendations for the optimal management of chronic HBV infection. The 2015 guidelines were developed by a panel of Asian experts chosen by the APASL. The clinical practice guidelines are based on evidence from existing publications or, if evidence was unavailable, on the experts' personal experience and opinion after deliberations. Manuscripts and abstracts of important meetings published through January 2015 have been evaluated. This guideline covers the full spectrum of care of patients infected with hepatitis B, including new terminology, natural history, screening, vaccination, counseling, diagnosis, assessment of the stage of liver disease, the indications, timing, choice and duration of single or combination of antiviral drugs, screening for HCC, management in special situations like childhood, pregnancy, coinfections, renal impairment and pre- and post-liver transplant, and policy guidelines. However, areas of uncertainty still exist, and clinicians, patients, and public health authorities must therefore continue to make choices on the basis of the evolving evidence. The final clinical practice guidelines and recommendations are presented here, along with the relevant background information.

Optimal management of hepatitis B virus infection - EASL Special Conference

There have been great strides in the management of chronic hepatitis B virus (HBV) infection, but considerable challenges remain. The European Association for the Study of the Liver (EASL) convened a special conference focusing on all clinical aspects of the management of this disease. Immigration patterns are having a huge effect on the incidence, prevalence and genotype predominance of HBV in many European countries. In recent years there has been significant progress in our understanding of the virology and immunopathology of HBV, particularly the identification of the entry receptor for HBV conferring its hepatotropism, sodium taurocholate co-transporting polypeptide, and a better understanding of the regulation of the covalently closed circular DNA form of HBV - the major barrier to cure. However, more fundamental scientific research is needed. Serum biomarkers and transient elastography offer equivalent performance in the grading of disease stage and progression and monitoring of treatment. Occult HBV infection is often overlooked, but has many important implications for e.g., immuno-suppression, liver transplantation and the progression and severity of liver diseases from other causes. Hepatitis B e antigen positive immunotolerant patients, who are a significant source of horizontal and vertical transmission, are at risk for developing active chronic hepatitis B, but current treatment options are ineffective. Pegylated interferon therapy, given for a finite duration, offers sustained off-treatment responses in a minority of patients. Nucleos(t)ide analogues suppress the virus, improve liver histological lesions, reverse cirrhosis in the majority of cases, and improve survival, but 'cure' cannot be achieved. There is also a pressing need for novel HBV/hepatitis D virus co-infection therapies. Novel therapeutic strategies, e.g. immunomodulation, RNA interference and viral entry inhibition have demonstrated promising early results.

Asymptomatic Hepadnaviral Persistence and Its Consequences in the Woodchuck Model of Occult Hepatitis B Virus Infection

Woodchuck hepatitis virus (WHV) is molecularly and pathogenically closely related to hepatitis B virus (HBV). Both viruses display tropism towards hepatocytes and cells of the immune system and cause similar liver pathology, where acute hepatitis can progress to chronic hepatitis and to hepatocellular carcinoma (HCC). Two forms of occult hepadnaviral persistence were identified in the woodchuck-WHV model: secondary occult infection (SOI) and primary occult infection (POI). SOI occurs after resolution of a serologically apparent infection with hepatitis or after subclinical serologically evident virus exposure. POI is caused by small amounts of virus and progresses without serological infection markers, but the virus genome and its replication are detectable in the immune system and with time in the liver. SOI can be accompanied by minimal hepatitis, while the hallmark of POI is normal liver morphology. Nonetheless, HCC develops in about 20% of animals with SOI or POI within 3 to 5 years. The virus persists throughout the lifespan in both SOI and POI at serum levels rarely greater than 100 copies/mL, causes hepatitis and HCC when concentrated and administered to virus-naïve woodchucks. SOI is accompanied by virus-specific T and B cell immune responses, while only virus-specific T cells are detected in POI. SOI coincides with protection against reinfection, while POI does not and hepatitis develops after challenge with liver pathogenic doses >1000 virions. Both SOI and POI are associated with virus DNA integration into the liver and the immune system genomes. Overall, SOI and POI are two distinct forms of silent hepadnaviral persistence that share common characteristics. Here, we review findings from the woodchuck model and discuss the relevant observations made in human occult HBV infection (OBI).

Hepatitis B virus infection and risk of nasopharyngeal carcinoma in southern China

BACKGROUND

Whether or not hepatitis B virus (HBV) infection plays a role in the development of nasopharyngeal carcinoma (NPC) is largely unknown. Our study aimed to assess the association between HBV infection and the risk of NPC in Southern China.

METHODS

We conducted a case-control study including 711 NPC cases and two groups of controls. The first control group consisted of 656 individuals with other benign tumors unrelated to HBV infection and the second group consisted of 680 healthy population controls. Multivariable ORs and corresponding 95% confidence intervals (CI) for NPC were estimated by logistic regression.

RESULTS

Patients with NPC had higher prevalence of antibodies against hepatitis B core antigen-positive [anti-HBc-(+); 47.26%] compared with either benign tumor controls (39.33%; P < 0.01) or healthy controls (41.18%; P = 0.04). In multivariable models adjusting for a set of risk factors for NPC, anti-HBc-(+) was significantly associated with a higher risk of NPC [adjusted OR (AOR), 1.40; 95% CI, 1.12-1.74 compared with the benign tumor controls and AOR, 1.48; 95% CI, 1.05-2.08 compared with the healthy controls]. The association was not modified by hepatitis B surface antigen (HBsAg) status. Finally, compared with the healthy controls, individuals with both anti-HBc-(+) and EBV antibodies had largely increased risk of NPC (AOR, 141.82; 95% CI, 68.73-292.62).

CONCLUSION

Our study suggests that HBV infection is associated with NPC risk in Southern China.

IMPACT

Prevention for HBV infection may play a role in the development of NPC.

Absence of occult hepatitis B virus infection in sera of diabetic children and adolescents following hepatitis B vaccination

BACKGROUND

The prevalence of occult hepatitis B (HB) infection (OBI) in HB-vaccinated diabetic children has not yet been tested. Here, we aimed to determine the prevalence of OBI among HB-vaccinated children and adolescents with insulin-dependent diabetes mellitus (IDDM).

RESULTS

Eighty-seven (51.2%) children had a titer for antibodies to HB surface antigen (anti-HBs) of <10 IU/L. These included 44 (70%) IDDM children and 43 (40.2%) healthy children. Eighty-three (48.8%) children had an anti-HBs titer of ≥10 IU/L; they included 19 (30%) with IDDM and 64 (59.8%) healthy children. None of the enrolled children (n = 170) were reactive for total antibody to HB core antigen (anti-HBc) as determined by enzyme-linked immunosorbent assay. HB virus DNA was not detected in HB-vaccinated IDDM or healthy children and adolescents.

METHOD

An amount of 170 HBsAg-negative sera samples from HB-vaccinated children and adolescents was included. They were classified into the IDDM group (n = 63) and the healthy control group (n = 107). HBsAg, anti-HBc, and anti-HBs were tested by enzyme-linked immunosorbent assay, and HB virus DNA was tested by nested polymerase chain reaction using 3 pairs of surface, core, and X genes.

IN CONCLUSION

Primary HB vaccination confers long-term protection against OBI in Egyptian diabetic children and adolescents. However, the number of cases tested in this study was relatively low, and further studies and long-term follow-up of large populations are needed to draw solid and convincing conclusions.

Molecular mechanisms underlying HBsAg negativity in occult HBV infection

Although genomic detection is considered the gold standard test on HBV infection identification, the HBsAg investigation is still the most frequent clinical laboratory request to diagnose HBV infection in activity. However, the non-detection of HBsAg in the bloodstream of chronic or acutely infected individuals has been a phenomenon often observed in clinical practice, despite the high sensitivity and specificity of screening assays standardized commercially and adopted in routine. The expansion of knowledge about the hepatitis B virus biology (replication/life cycle, genetic variability/mutability/heterogeneity), their biochemical and immunological properties (antigenicity and immunogenicity), in turn, has allowed to elucidate some mechanisms that may explain the occurrence of this phenomenon. Therefore, the negativity for HBsAg during the acute or chronic infection course may become a fragile or at least questionable result. This manuscript discusses some mechanisms that could explain the negativity for HBsAg in a serological profile of individuals with HBV infection in activity, or factors that could compromise its detection in the bloodstream during HBV infection.

Occult hepatitis B infection in patients with cryptogenic liver cirrhosis in southwest of iran

Background:

Chronic hepatitis B virus (HBV) infection has a broad spectrum of manifestation, ranging from silent carrier state to advanced cirrhosis and hepatocellular carcinoma. The persistence of HBV DNA in serum and hepatocytes of the cirrhotic patient could be detected by molecular techniques in spite of negative HBV serologic markers.

Objectives:

This case-control study was designed to evaluate the prevalence of occult HBV infection (OBI) in patients with cryptogenic liver cirrhosis in comparison with healthy subjects.

Patients and Methods:

Of 165 patients with liver cirrhosis, 50 consecutive patients with cryptogenic cirrhosis and 80 healthy individual without any risk factors as a control group were enrolled in this study. Their sera were tested for HBV DNA using nested PCR method.

Results:

Of 50 patients with cryptogenic cirrhotic, 36 (72%) were male. The mean age of patients was 53.34 ± 14.73 years; 80 healthy subjects were selected as control group with mean age of 32.65 ± 8.51 years; 7 (14%) of the patients with cryptogenic cirrhosis showed positive HBV DNA by PCR, while HBV DNA was negative for the control group (P = 0.0001); 4 (57%) cases with positive HBV shown by PCR were negative for anti-HBc and anti-HBs tests. The mean level of transaminases was significantly higher in patients with cirrhosis. There were no significant differences in demographic parameters, transaminases level and degree of hepatic failure among cirrhotic patients with and without OBI.

Conclusions:

The prevalence of OBI was relatively high in patients with cryptogenic cirrhosis. OBI was found among the patients above 40 years old. Prospective cohort studies are needed to evaluate the clinical significance of OBI.

Spontaneous reactivation of hepatitis B virus (HBV) infection in patients with resolved or occult HBV infection

Reactivation of a former hepatitis B virus (HBV) infection can be triggered by immunosuppressive therapy, diseases associated with an immunocompromised state, organ transplantation or the withdrawal of antiviral drugs. Despite the absence of such risk factors, a spontaneous reactivation of HBV replication occurred in two elderly patients with resolved or occult HBV infection. A 73-year-old male underwent coronary artery bypass grafting in October 2008, and was negative for HBsAg but positive for anti-HBs. In July 2009, his serum became positive for HBsAg, HBeAg and HBV DNA (6.4 log copies/ml; genotype C), but negative for anti-HBc IgM, with abrupt elevation of the liver enzymes. The entire genomic sequence of HBV recovered from this patient revealed no mutations in the core promoter and precore regions that interfere with HBeAg production. A 76-year-old male with a history of endoscopic mucosal resection for esophageal cancer in 2002 and an initial diagnosis of diabetes mellitus in 2009, at which time he was negative for HBsAg. He was found to be positive for HBsAg in September 2012 during a laboratory examination performed prior to the resection of recurrent esophageal cancer, despite a low HBV load (2.1 log copies/ml). Three months later, without the administration of any anticancer drugs, the HBV DNA (genotype B) level increased to 5.1 log copies/ml. A precore G1896A variant with high quasispecies diversity was recovered from the patient. Aging, surgical stress and complication of disease(s) associated with compromised immunity, such as cancer, arteriosclerosis and diabetes mellitus may trigger spontaneous HBV reactivation.

Hepatitis B virus-associated glomerulonephritis in HBsAg serological-negative patients

OBJECTIVE

The main objective of this study is to report the clinical and pathological characteristics of hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN) in serum hepatitis B surface antigen (HBsAg)-negative patients in China. HBV-GN is caused by the HBV's attack on the kidney tissues, but definitive diagnostic criteria are still lacking. The diagnostic criteria used in China require HBsAg positivity in the serum, but research on occult HBV infection has shown that HBV infection is also found in serum HBsAg-negative patients. Clinical and pathological characterization of HBV-GN in serum HBsAg-negative patients is required.

MATERIALS AND METHODS

Serologic and clinical findings and pathological characteristics of renal tissues in 18 HBV-GN patients (11 men and seven women) with serum HBsAg negativity were analyzed retrospectively. Thirty-three HBV-GN patients with serum HBsAg positivity and 59 patients with membranous nephropathy (MN) without any HBV infection markers in serum and renal tissues during the same period were included as controls.

RESULTS

Among the 18 HBsAg-negative patients with GN, 12 had HBsAb positivity in their sera. None of the patients was positive for serum HBeAg. Proteinuria was the major clinical manifestation and the renal histopathology was characterized as MN. Immune fluorescence deposits in renal tissues consisted mainly of HBsAg. The degree of renal injury and the decrease in the C3 level were less than those in HBsAg-positive patients and idiopathic membranous nephropathy patients.

CONCLUSION

We propose to use the HBV marker in renal tissues as a new diagnostic criterion for HBV-GN. If MN patients have HBV marker positivity in renal tissues, HBV-GN can be diagnosed even without HBsAg in the serum. This would improve the diagnostic accuracy and potential treatment efficiency.

Spontaneous HBsAg loss in Korean patients: relevance of viral genotypes, S gene mutations, and covalently closed circular DNA copy numbers

Background/Aims

Occult HBV infection can persist following HBsAg loss and be transmitted, but the virological features are not well defined.

Methods

Here we investigated 25 Korean patients who lost HBsAg during follow up, either spontaneously or subsequent to therapy.

Results

Whereas subtype adr (genotype C) was found in 96% of HBsAg positive patients, 75 % of patients who lost HBsAg spontaneously were seemed to be infected with the ayw subtype with sequence similar to genotype D. Mutations in the major hydrophilic region (MHR) of HBsAg were found in 7 patients who lost HBsAg spontaneously. The mutations include T123S, M125I/N, C139R, D144E, V177A, L192F, and W196L, some of which have not been reported before. Functional analysis via transfection experiments indicate that the C139R and D144E mutations drastically reduced HBsAg antigenicity, while the Y225del mutation found in one interferon-treated patient impaired HBsAg secretion.

Conclusions

Lack of detectable HBsAg in patient serum could be explained by low level of ccc DNA in liver tissue, low antigenicity of the surface protein, or its secretion defect.

The intracellular HBV DNAs as novel and sensitive biomarkers for the clinical diagnosis of occult HBV infection in HBeAg negative hepatocellular carcinoma in China

This study aimed to investigate the virological status in liver (both tumor and adjacent non-tumor tissue), the clinical features and the contribution of occult HBV infection (OBI) to postoperative prognosis in HBeAg-negative(−) hepatocellular carcinoma (HCC) patients in China. Using quantitative TaqMan fluorescent real-time PCR assays, HBV covalently closed circular DNA (cccDNA) and total DNA (tDNA) were both quantified in 11 (HBsAg(−)) and 57 (HBsAg-positive(+)) pairs of tumor tissue (TT) and adjacent non-tumor tissue (ANTT) obtained from HBeAg(−) HCC patients who received no antiviral treatment and were negative for anti-HCV before surgical treatment. Of 11 HBsAg(−) patients, 36% were with HBsAb(+) HBeAb(+) HBcAb(+). However, only 9% of the HBsAg(−) patients were HBsAb(−) HBeAb(+) HBcAb(+), which accounted for the majority (93%) in the HBsAg(+) group. TT and ANTT HBV tDNAs in 11 HCC patients with HBsAg (−) and HBeAg (−) were all detectable. HBV cccDNA and tDNA were all lower in the HBsAg(−) group than those in the HBsAg(+) group. By Kaplan-Meier analysis, patients with OBI were associated with a lower risk of cirrhosis and better overall survival (OS). The intracellular HBV DNAs, such as HBV cccDNA and tDNA are valuable biological markers for the diagnosis of occult HBV infection in HCC patients. This would assist the clinical implementation of a more personalized therapy for viral re-activation control and improve the survival rate of OBI patients.

Anti-HBc-positive/HBsAg-negative liver donors pose a higher risk of occult HBV infection but do not cause severe histological damage in liver grafts

BACKGROUND

The use of serum anti-hepatitis B core antibody (HBc)-positive/hepatitis B surface antigen (HBsAg)-negative liver donors for patients with hepatitis B virus (HBV)-related liver disease (HBRLD) is a promising means of expanding the organ donor pool and does not increase the risk of HBV recurrence. However, whether such donors will compromise the histology of the liver grafts is unclear.

METHODS

Among 84 patients who underwent transplantation for HBRLD and who did not have post-transplant HBV recurrence (non-detectable serum HBsAg and HBV DNA), 19 underwent liver biopsy (eight received anti-HBc-positive/HBsAg-negative liver grafts; 11 received anti-HBc-negative liver grafts) and were included in the study. Intrahepatic total HBV DNA and covalently closed circular DNA (cccDNA) were detected using real-time polymerase chain reaction; histological characteristics were evaluated with the Batts-Ludwig semi-quantitative scoring system.

RESULT

Of the 19 recipients, nine (47.4%) were positive for intrahepatic HBV DNA; 82.5% (7/8) received grafts from anti-HBc-positive donors and 18.2% (2/11) received grafts from anti-HBc-negative donors (P=0.003). HBV cccDNA was not detectable in the liver grafts of the 19 recipients. Ten patients had mild inflammation and minimal fibrosis in the portal area: four of the eight in the anti-HBc-positive group and six of the 11 in the anti-HBc-negative group (P>0.05).

CONCLUSION

Anti-HBc-positive/HBsAg-negative donors for HBRLD pose a higher risk of occult HBV infection post-liver transplant but do not cause liver damage. Thus, anti-HBc-positive grafts may be considered an effective and safe means of expanding the pool of liver donors for patients with HBRLD.

[Definition, diagnosis, and prevalence of occult hepatitis B virus infection]

Occult HBV infection is characterized by the absence of serum HBsAg with persistence of low level of intrahepatic HBV DNA. Several suggested mechanisms for the origin of occult HBV infection include strong suppression of viral replication and gene expression, mutation in the regulatory regions of HBV genome, formation of immunoglobulin-bound HBsAg, viral interference, and blockage of HBsAg secretion from infected hepatocytes. Standardized assays are not yet available, and sensitive HBV DNA amplification assay is necessary for the diagnosis of cryptic infection. Detection rate of HBV DNA is highest in IgG anti-HBc positive population. However, neither anti-HBc nor anti-HBs can be detected in a significant proportion of infected persons. Occult HBV infection occurs in a number of clinical settings and is highly prevalent in HCV-infected patients as well as in patients with cryptogenic chronic liver disease including hepatocellular carcinoma.

[Occult hepatitis B virus infection in chronic hepatitis C]

Occult HBV infection is defined as the presence of HBV DNA in the liver (with or without detectable or undetectable HBV DNA in the serum) of individuals testing negative for HBsAg. Studies on occult HBV infection in hepatitis C patients have reported highly variable prevalence, because the prevalence of occult HBV infection varies depending on the hepatitis B risk factors and methodological approaches. The most reliable diagnostic approach for detecting occult HBV detection is through examination of liver DNA extracts. HCV has been suspected to strongly suppress HBV replication up to the point where it may be directly responsible for occult HBV infection development. However, more data are needed to arrive at a definitive conclusion regarding the role of HCV in inducing occult HBV infection. Occult HBV infection in chronic hepatitis C patients is a complex biological entity with possible relevant clinical implications. Influence of occult HBV infection on the clinical outcomes of chronic hepatitis C may be considered negative. However, recent studies have shown that occult HBV infection could be associated with the development of hepatocellular carcinoma and contribute to the worsening of the course of chronic liver disease over time in chronic hepatitis C patients. Nevertheless, the possible role of occult HBV infection in chronic hepatitis C is still unresolved and no firm conclusion has been made up until now. It still remains unclear how occult HBV infection affects the treatment of chronic hepatitis C. Therefore, in order to resolve current controversies and understand the pathogenic role and clinical impacts of occult HBV infection in chronic hepatitis C patients, well-designed clinical studies are needed.

Occult hepatitis B virus and hepatocellular carcinoma

Occult hepatitis B virus (HBV) infection (OBI) is a challenging pathobiological and clinical issue that has been widely debated for several decades. By definition, OBI is characterized by the persistence of HBV DNA in the liver tissue (and in some cases also in the serum) in the absence of circulating HBV surface antigen (HBsAg). Many epidemiological and molecular studies have indicated that OBI is an important risk factor for hepatocellular carcinoma (HCC) development. OBI may exert direct pro-oncogenic effects through the activation of the same oncogenic mechanisms that are activated in the course of an HBsAg-positive infection. Indeed, in OBI as in HBV-positive infection, HBV DNA can persist in the hepatocytes both integrated into the host genome as well as free episome, and may maintain the capacity to produce proteins-mainly X protein and truncated preS-S protein - provided with potential transforming properties. Furthermore, OBI may indirectly favor HCC development. It has been shown that the persistence of very low viral replicative activity during OBI may induce mild liver necro-inflammation continuing for life, and substantial clinical evidence indicates that OBI can accelerate the progression of liver disease towards cirrhosis that is considered the most important risk factor for HCC development.

Epidemiology of Hepatitis B Virus Infection in China: Current Status and Challenges

The prevalence of hepatitis B is high in China. Based on the National Disease Supervision Information Management System of China, the mean reported incidence of hepatitis B was 84.3 per 100,000 in China between 2005 and 2010. There are differences in population distribution based on region and ethnic group. Here, risk factors, virological characteristics, and prophylaxis of hepatitis B in China are reviewed. Although the prevalence of HBV infection is gradually declining, there are many challenges in HBV infection control, including higher prevalence in floating population, poor compliance of antiviral therapy, and high disease burden.

MicroRNAs may solve the mystery of chronic hepatitis B virus infection

Hepatitis B virus (HBV) infection is a global public health problem that causes persistent liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. A large amount of people die annually from HBV infection. However, the pathogenesises of the HBV-related diseases are ill defined and the therapeutic strategies for the diseases are less than optimum. The recently discovered microRNAs (miRNAs) are tiny noncoding RNAs that regulate gene expression primarily at the post-transcriptional level by binding to mRNAs. miRNAs contribute to a variety of physiological and pathological processes. A number of miRNAs have been found to play a pivotal role in the host-virus interaction including host-HBV interaction. Numerous studies have indicated that HBV infection could change the cellular miRNA expression patterns and different stages of HBV associated disease have displayed distinctive miRNA profiles. Furthermore, the differential expressed miRNAs have been found involved in the progression of HBV-related diseases, for instance some miRNAs are involved in liver tumorigenesis and tumor metastasis. Studies have also shown that the circulating miRNA in serum or plasma might be a very useful biomarker for the diagnosis and prognosis of HBV-related diseases. In addition, miRNA-based therapy strategies have attracted increasing attention, indicating a promising future in the treatment of HBV-related diseases.

Occult hepatitis B virus infection in anti-HBs-positive infants born to HBsAg-positive mothers in China

Objective

To investigate the prevalence of occult HBV infection (OBI) among children and to characterize virology of occult HBV, we conducted an epidemiological survey.

Methods

186 HB-vaccinated infants born to HBsAg-positive mothers were included in the study. Serological tests for HBV markers were performed using commercial ELISA kits. Real-time quantitative PCR and nested PCR were used to detect HBV DNA. PCR products of the C and pre-S/S regions were sequenced and analyzed.

Results

1.61% (3/186) infants were HBsAg positive, and 4.92% (9/183) infants were considered as occult infection. The viral load of mothers was associated with occult infection (P = 0.020). Incomplete three-dose injections of HB vaccine was associated with HBV infection (P = 0.022). Six OBI infants were positive for anti-HBs, but their titers were not greater than 100 mIU/mL. Seven isolated HBV pre-S/S sequences were obtained from nine OBI infants. Three of the sequences were genotype C, and four of the sequences were genotype C/D. Escape mutation S143L was found in the four sequences of genotype C/D. All seven sequences lacked G145R and other escape mutation in S region.

Conclusions

Occult HBV infection was detected in anti-HBs positive infants born to HBsAg-positive mothers in China. Occult infection was associated with absent anti-HBs or with low anti-HBs level, high maternal viral loads and escape mutations in the S gene.

Study of hepatitis B prevalence in parallel with the most frequent HBV genotype in South Iranian blood donors

BACKGROUND

Hepatitis B virus (HBV) is one of the leading causes of acute and chronic liver diseases and in turn responsible for a million of worldwide annual deaths. HBV has been classified into eight main groups, designated as A-H with different geographical distribution. Some genotypes are associated with different clinical outcomes and particular viral mutations. Current study was aimed to investigate the genotype and prevalence of HBV in blood donors of south of Iran.

METHODS

This experimental study investigated the prevalence of HBV positivity in 198,289 Iranian blood donors from south of Iran by both ELISA- and PCR-based methods. Within 198,289 donors, 120 HBsAg(+) cases were selected, HBV-DNA was extracted, and the p gene sequences were amplified by nested-PCR. The HBV genotypes were determined by direct sequencing of the polymerase gene of HBV. Phylogenetic trees also were constructed by the neighbor-joining (NJ) method.

RESULTS

Findings of this study indicated that 0.184%, 0.329%, and 0.215% of blood donors were HBsAg(+) among Isfahan, Kerman, and Yazd provinces, respectively. Only 69 (57.5%) cases of 120 HBsAg(+) donors were HBV-DNA(+) . Sequencing analysis revealed that all of HBV-infected donors had the D genotype of HBV.

CONCLUSIONS

In conclusion, the prevalence of genotype D was 100% in Iranian HBV blood donors. These findings may have an impact on the immunological and genetic diagnosis of HBV, selection of diagnostic kits, and viral quality control panels to evaluate diagnostic methods.

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.

Molecular biology of the hepatitis B virus for clinicians

Hepatitis B virus (HBV) infection is one of the major global health problems, especially in economically under-developed or developing countries. HBV infection can lead to a number of clinical outcomes including chronic infection, cirrhosis and liver cancer. It ranks among the top 10 causes of death, being responsible for around 1 million deaths every year. Despite the availability of a highly efficient vaccine and potent antiviral agents, HBV infection still remains a significant clinical problem, particularly in those high endemicity areas where vaccination of large populations has not been possible due to economic reasons. Although HBV is among the smallest viruses in terms of virion and genome size, it has numerous unique features that make it completely distinct from other DNA viruses. It has a partially double stranded DNA with highly complex genome organization, life cycle and natural history. Remarkably distinct from other DNA viruses, it uses an RNA intermediate called pregenomic RNA (pgRNA) and reverse transcriptase for its genome replication. Genome replication is accomplished by a complex mechanism of primer shifting facilitated by direct repeat sequences encoded in the genome. Further, the genome has evolved in such a manner that every single nucleotide of the genome is used for either coding viral proteins or used as regulatory regions or both. Moreover, it utilizes internal in-frame translation initiation codons, as well as different reading frames from the same RNA to generate different proteins with diverse functions. HBV also shows considerable genetic variability which has been related with clinical outcomes, replication potential, therapeutic response etc. This review aims at reviewing fundamental events of the viral life cycle including viral replication, transcription and translation, from the molecular standpoint, as well as, highlights the clinical relevance of genetic variability of HBV.

The prevalence and long term outcome of occult hepatitis B virus infections in community based populations

Features of occult hepatitis B infection in community-based populations have yet to be described. In this study we documented: (1) the prevalence and demographics, (2) associated serology and viral loads, and (3) clinical outcomes of occult hepatitis B infection in community-based populations. Hepatitis B surface antigen (HBsAg)-negative sera collected from three Northern Canadian communities (HBsAg prevalences: 11-12%) in 1983-1985 were tested for HBV-DNA by nested stage polymerase chain reaction. Of 706 HBsAg negative sera, 9 (1.3%) were HBV-DNA positive. The median age of occult hepatitis B infected patients at the time of sampling was 9.8 years (range 3.1-50.4 years) and six (67%) were female. Two (22%) individuals were anti-HBs positive (in the absence of prior vaccination). Viral loads were undetectable in all but two samples (2.40 and 2.86  log₁₀ IU/ml). Only one of the five (20%) patients who were assessed clinically, remained HBV-DNA positive at 25-30 year follow-up. There was no clinical, biochemical or radiologic evidence of chronic hepatitis, cirrhosis or hepatocellular carcinoma in these individuals or on review of the charts from the remaining four infected patients. The results of this study suggest that in community-based populations: (1) occult hepatitis B infection is not as common as HBsAg positive infection, (2) the majority of infected subjects are young females, (3) a minority are anti-HBs positive, (4) viral loads are either undetectable or low, and (5) in the absence of concurrent liver disease, occult hepatitis B infection does not appear to be associated with long term adverse clinical outcomes.

Occult HBV infection

The long-lasting persistence of hepatitis B virus (HBV) genomes in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for the HBV surface antigen (HBsAg) is termed occult HBV infection (OBI). Although in a minority of cases the lack of HBsAg detection is due to infection with variant viruses unrecognized by available assays (S-escape mutants), the typical OBI is related to replication-competent HBVs strongly suppressed in their replication activity. The causes of HBV suppression are not yet well clarified, although the host's immune surveillance and epigenetic mechanisms are likely involved. OBI is a worldwide diffused entity, but 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. OBI may have an impact in several different clinical contexts. In fact, it can be transmitted (i.e., through blood transfusion and liver transplantation) causing classic forms of hepatitis B in newly infected individuals. The development of an immunosuppressive status (mainly by immunotherapy or chemotherapy) may induce OBI reactivation and development of acute and often severe hepatitis. Finally, evidence suggests that OBI can favor the progression of liver fibrosis, in particular in HCV-infected patients. The possible contribution of OBI to the establishment of cirrhosis also implies its possible indirect role in the development of hepatocellular carcinoma. On the other hand, OBI may maintain most of the direct transforming properties of the overt HBV infection, such as the capacity to integrate in the host's genome and to synthesize pro-oncogenic proteins.

Genomic analysis of hepatitis B virus reveals antigen state and genotype as sources of evolutionary rate variation

Hepatitis B virus (HBV) genomes are small, semi-double-stranded DNA circular genomes that contain alternating overlapping reading frames and replicate through an RNA intermediary phase. This complex biology has presented a challenge to estimating an evolutionary rate for HBV, leading to difficulties resolving the evolutionary and epidemiological history of the virus. Here, we re-examine rates of HBV evolution using a novel data set of 112 within-host, transmission history (pedigree) and among-host genomes isolated over 20 years from the indigenous peoples of the South Pacific, combined with 313 previously published HBV genomes. We employ Bayesian phylogenetic approaches to examine several potential causes and consequences of evolutionary rate variation in HBV. Our results reveal rate variation both between genotypes and across the genome, as well as strikingly slower rates when genomes are sampled in the Hepatitis B e antigen positive state, compared to the e antigen negative state. This Hepatitis B e antigen rate variation was found to be largely attributable to changes during the course of infection in the preCore and Core genes and their regulatory elements.

Clinical significance of occult hepatitis B virus infection in chronic hepatitis C patients

Background/Aims

We investigated the frequency of occult hepatitis B virus (HBV) infection in anti-hepatitis C virus (HCV)-positive individuals and the effects of occult HBV infection on the severity of liver disease.

Methods

Seventy-one hepatitis B virus surface-antigen (HBsAg)-negative patients were divided according to their HBV serological status into groups A (anti-HBc positive, anti-HBs negative; n=18), B (anti-HBc positive, anti-HBs positive; n=34), and C (anti-HBc negative, anti-HBs positive/negative; n=19), and by anti-HCV positivity (anti-HCV positive; n=32 vs. anti-HCV negative; n=39). Liver biopsy samples were taken, and HBV DNA was quantified by real-time PCR.

Results

Intrahepatic HBV DNA was detected in 32.4% (23/71) of the entire cohort, and HBV DNA levels were invariably low in the different groups. Occult HBV infection was detected more frequently in the anti-HBc-positive patients. Intrahepatic HBV DNA was detected in 28.1% (9/32) of the anti-HCV-positive and 35.9% (14/39) of the anti-HCV-negative subjects. The HCV genotype did not affect the detection rate of intrahepatic HBV DNA. In anti-HCV-positive cases, occult HBV infection did not affect liver disease severity.

Conclusions

Low levels of intrahepatic HBV DNA were detected frequently in both HBsAg-negative and anti-HCV-positive cases. However, the frequency of occult HBV infection was not affected by the presence of hepatitis C, and occult HBV infection did not have a significant effect on the disease severity of hepatitis C.

Molecular analysis of hepatitis B virus (HBV) in an HIV co-infected patient with reactivation of occult HBV infection following discontinuation of lamivudine-including antiretroviral therapy

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is characterized by HBV DNA persistence even though the pattern of serological markers indicates an otherwise resolved HBV infection. Although OBI is usually clinically silent, immunocompromised patients may experience reactivation of the liver disease.

CASE PRESENTATION

We report the case of an individual with human immunodeficiency virus (HIV) infection and anti-HBV core antibody positivity, who experienced severe HBV reactivation after discontinuation of lamivudine-including antiretroviral therapy (ART). HBV sequencing analysis showed a hepatitis B surface antigen escape mutant whose presence in an earlier sample excluded reinfection. Molecular sequencing showed some differences between two isolates collected at a 9-year interval, indicating HBV evolution. Resumption of ART containing an emtricitabine/tenofovir combination allowed control of plasma HBV DNA, which fell to undetectable levels.

CONCLUSION

This case stresses the ability of HBV to evolve continuously, even during occult infection, and the effectiveness of ART in controlling OBI reactivation in HIV-infected individuals.

Detection of HBV genotypes of tumor tissues and serum by a fluorescence polarization assay in north-western China's hepatocellular carcinoma patients

BACKGROUND

The understanding of the distribution of hepatitis B virus genotypes and the occult hepatitis B virus infection in hepatocellular carcinoma may shed light into the prevention and treatment of hepatocellular carcinoma. The purpose of the study is to investigate hepatitis B virus genotypes distribution, the high-risk genotypes and the occult infection in north-western China's hepatocellular carcinoma patients.

METHODS

Hepatitis B virus genotypes A-D of hepatocellular carcinoma tumor tissues and serum samples in 268 north-western China hepatocellular carcinoma patients were detected by fluorescence polarization assay. The hepatitis B virus genotypes in serum and matched primary tumor tissue samples were compared. Hepatitis B surface antigen and α-fetoprotein in serum were detected. Occult hepatitis B virus infections were analyzed. The relationship between hepatitis B virus genotypes and clinicopathologic characteristics were analyzed statistically using SPSS v.10.0.

RESULTS

Intrahepatic hepatitis B virus DNA was detected in 83.6% of 268 patients, whereas serum hepatitis B virus DNA was detected in 78.7%. The hepatitis B virus genotypes in serum were consistent with the results in matched tumor tissue. Intrahepatic hepatitis B virus genotype B and C were detected respectively in 11.6% and 54.5% of the patients. Mixed intrahepatic hepatitis B virus genotypes were detected in 13.4% of 268 patients. There was not mixed hepatitis B virus infection in Edmondonson grade I. The patients with mixed HBV genotypes exhibited statistically significant different Edmondson grade than the patients with single type HBV infection (p < 0.05). Hepatitis B surface antigens were positive in 77.2% of 268 patients. Hepatitis B virus genotype C was detected in 64.7% of occult infected patients. There was no significant differences of patients' ages and α-fetoprotein level in different groups of intrahepatic hepatitis B virus genotypes (p > 0.05).

CONCLUSIONS

Hepatitis B virus genotype C was associated closely with the development of hepatocellular carcinoma and the occult hepatitis B virus infection in patients in north-western China. There was a relatively high prevalence of mixed hepatitis B virus infection in Edmondonson grade III-IV.