Occult HBV infection

Role of occult hepatitis B virus infection in chronic hepatitis C

The development of sensitive assays to detect small amounts of hepatitis B virus (HBV) DNA has favored the identification of occult hepatitis B infection (OBI), a virological condition characterized by a low level of HBV replication with detectable levels of HBV DNA in liver tissue but an absence of detectable surface antigen of HBV (HBsAg) in serum. The gold standard to diagnose OBI is the detection of HBV DNA in the hepatocytes by highly sensitive and specific techniques, a diagnostic procedure requiring liver tissue to be tested and the use of non-standardized non-commercially available techniques. Consequently, in everyday clinical practice, the detection of anti-hepatitis B core antibody (anti-HBc) in serum of HBsAg-negative subjects is used as a surrogate marker to identify patients with OBI. In patients with chronic hepatitis C (CHC), OBI has been identified in nearly one-third of these cases. Considerable data suggest that OBI favors the increase of liver damage and the development of hepatocellular carcinoma (HCC) in patients with CHC. The data from other studies, however, indicate no influence of OBI on the natural history of CHC, particularly regarding the risk of developing HCC.

Poor efficacy of nucleic acid testing in identifying occult HBV infection and consequences for safety of blood supply in Italy

BACKGROUND & AIMS

In Italy, DNA screening of blood donations for hepatitis B virus (HBV) was introduced to prevent the transmission of window period and occult HBV infection. Anti-HBc screening is not recommended in order to avoid shortage of the blood supply. To contain costs, donor samples are generally pooled before testing. We evaluated the safety of this national policy using a prospective repository of donors/recipient pairs.

METHODS

We used highly sensitive nucleic acid testing (NAT) assays to test repository and follow-up samples from donors who were initially classified as negative by minipool NAT assays (6-MP), but were later found to carry occult HBV DNA. When available, we also analysed recipients' pre- and post-transfusion samples, collected in the context of a repository financed by the European Commission (the BOTIA project).

RESULTS

Between 2008 and 2011 6-MP NAT assays identified 18 carriers of occult HBV infection among 12,695 donors; 28 samples from previous donations were available from 13 of these carriers. Highly sensitive HBV DNA detection methods showed that 6-MP HBV DNA screening failed to identify 14/28 (50%) viraemic donations, that were released for transfusion. HBV marker testing of such blood product recipients revealed two cases of transfusion transmitted HBV infection, documented by donor-recipient sequence identity.

CONCLUSIONS

Viraemic blood donations from occult HBV infection carriers remain undetected by current minipool HBV DNA screening, and transfusion transmission of HBV continues to occur in susceptible patients. More effective individual HBV DNA screening and/or tests for antibodies to HBV core antigen should be considered to improve blood safety.

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.

Persistence of Hepatitis C Virus Traces after Spontaneous Resolution of Hepatitis C

Hepatitis C virus (HCV) frequently causes chronic hepatitis, while spontaneous recovery from infection is infrequent. Persistence of HCV after self-limited (spontaneous) resolution of hepatitis C was rarely investigated. The current study aimed to assess incidence and robustness of HCV persistence after self-resolved hepatitis C in individuals with normal liver enzymes and undetectable virus by conventional tests. Applying high sensitivity HCV RNA detection approaches, we analyzed plasma and peripheral blood mononuclear cells (PBMC) from individuals with previous hepatitis C infection. Parallel plasma and PBMC from 24 such non-viraemic individuals followed for 0.3–14.4 (mean 6.4) years were examined. Additional samples from 9 of them were obtained 4.5–7.2 (mean 5.9) years later. RNA was extracted from 250 μl plasma and, if HCV negative, from ~5 ml after ultracentrifugation, and from ex vivo stimulated PBMC. PBMC with evidence of HCV replication from 4 individuals were treated with HCV protease inhibitor, telaprevir. HCV RNA was detected in 14/24 (58.3%) plasma and 11/23 (47.8%) PBMC obtained during the first collection. HCV RNA replicative strand was evident in 7/11 (63.6%) PBMC. Overall, 17/24 (70.8%) individuals carried HCV RNA at mean follow-up of 5.9 years. Samples collected 4.5–7.2 years later revealed HCV in 4/9 (44.4%) plasma and 5/9 (55.5%) PBMC, while 4 (80%) of these 5 PBMC demonstrated virus replicative strand. Overall, 6/9 (66.7%) individuals remained viraemic for up to 20.7 (mean 12.7) years. Telaprevir entirely eliminated HCV replication in the PBMC examined. In conclusion, our results indicate that HCV can persist long after spontaneous resolution of hepatitis C at levels undetectable by current testing. An apparently effective host immune response curtailing hepatitis appears insufficient to completely eliminate the virus. The long-term morbidity of asymptomatic HCV carriage should be examined even in individuals who achieve undetectable HCV by standard testing and their need for treatment should be assessed.

Occult HBV Infection May Be Transmitted through Close Contact and Manifest as an Overt Infection

The importance of transmission of occult HBV infection (OBI) via transfusion, organ transplantation and hemodialysis has been widely recognized. However, data regarding the transmission of OBI through close contact remain limited. In this study, serum samples were obtained from a child and his parents. The child had received the standard vaccination regimen at birth and produced protective antibody. Sera were tested for HBV serological markers. Nested PCR assays were used to detect HBV DNA and the amplicons were cloned and their sequences subjected to phylogenetic analysis. The results showed that both parents had occult infections while the child had an overt infection. Twelve, eleven and nine clones, from the father, mother and son, respectively, were sequenced. Serotypes adrq+, ayw1, ayw and ayr were found in the father and ayw1, adw2 and adwq+ in the mother; adrq+ was the only serotype in son. Genotype B, subgenotype C2 and a recombinant were identified in the father and genotype B, subgenotype C5 and three recombinants were found in the mother. Subgenotype C2 was the only genotype identified in the child. A phylogenetic tree showed that all of the child’s sequences and most of the father’s sequences clustered together. However, none of mother’s sequences clustered with those of the child. The surface gene from the child and his father had the same amino acid substitution pattern (T118K, T123N and G145A). We concluded that the father was the source of the son’s HBV infection, suggesting that occult HBV infection may be transmitted through close contact and manifest as an overt infection.

Presence of anti-HBc is associated to high rates of HBV resolved infection and low threshold for Occult HBV Infection in HIV patients with negative HBsAg in Chile

HBV-HIV coinfection is prevalent. Frequently, anti-HBc is the only serological marker of HBV, which can be indicative of HBV resolved infection, when found together with anti-HBs reactivity; or present as "isolated anti-HBc," related to HBV occult infection with presence of detectable DNA HBV, more prevalent in HIV-positive individuals. Regional data about this condition are scarce. Anti-HBc rapid test has been used as screening, but its performance has not been described in HIV-positive patients. The aim of this study was determine prevalence of anti-HBc in HIV-positive patients, serological pattern of HBV resolved infection and isolated anti-HBc, evaluating presence of HBV occult infection. Assess anti-HBc rapid test compared to ECLIA. Methods included measurement of anti-HBc and anti-HBs in HIV-positive patients with negative HBsAg. Serum HBV DNA quantification and HBV booster vaccination to "isolated anti-HBc" individuals. Detection of anti-HBc by rapid test and ECLIA. In 192 patients, prevalence of anti-HBc was 42.7% (82/192); associated to male gender, drug use, men-sex-men, positive-VDRL, and longer time HIV diagnosis. 34.4% (66/192) had presence of anti-HBs, mean titers of 637 ui/ml. Isolated anti-HBc in 8.3% (16/192), associated to detectable HIV viral load and no-use of HAART; in them, HBV DNA was undetectable, and 60% responded to HBV vaccination booster. Anti-HBc rapid test showed low sensibility (32.9%) compared to ECLIA. These results show that prevalence of anti-HBc in HIV-positive individuals is high, in most cases accompanied with anti-HBs as HBV resolved infection. Low prevalence of "isolated anti-HBc," with undetectable HBV DNA, and most had anamnestic response to HBV vaccination; suggest low possibility of occult HBV infection. Anti-HBc rapid test cannot be recommended as screening method for anti-HBc.

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.

Chronic hepatitis B virus and hepatitis C virus infections and cancer: synergy between viral and host factors

Hepatitis B virus (HBV) or hepatitis C virus (HCV) infections represent major causes of chronic liver disease and hepatocellular carcinoma. Despite inducing shared pathological events leading to oncogenic transformation, these two viruses present profound differences in their molecular features, life cycle and interplay with host factors, which significantly differentiate the prognostic and therapeutic approach to the related diseases. In the present review, we report the main mechanisms involved in the multistep process leading from HCV/HBV infection and cancer development, discussing side-by-side the analogies and differences between the two viruses. Such events can be broadly categorized into (a) direct oncogenic effects, involving integration in the host genome (in the case of HBV) and chromosomal instability, interference with oncosuppressor pathways, induction of oxidative stress, promotion of angiogenesis, epithelial-mesenchymal transition, alterations in the epigenetic asset and interaction with non-coding RNAs; and (b) indirect activities mostly mediated by host events, including chronic inflammation sustained by peculiar cytokine networks (such as interleukin-6 and lymphotoxins), metabolic dysfunctions promoted by steatohepatitis, interplay with gut microbiota and fibrotic events (mainly in HCV infection). This scenario suggests that the integrated study of viral and host factors may lead to the successful development of novel biomarkers and targets for therapy.

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.

Chronic hepatitis B: Virology, natural history, current management and a glimpse at future opportunities

The host immune system plays an important role in chronic hepatitis B (CHB), both in viral clearance and hepatocellular damage. Advances in our understanding of the natural history of the disease have led to redefining the major phases of infection, with the "high replicative, low inflammatory" phase now replacing what was formerly termed the "immune tolerant" phase, and the "nonreplicative phase" replacing what was formerly termed the "inactive carrier" phase. As opposed to the earlier view that HBV establishes chronic infection by exploiting the immaturity of the neonate's immune system, new findings on trained immunity show that the host is already somewhat "matured" following birth, and is actually very capable of responding immunologically, potentially altering future hepatitis B treatment strategies. While existing therapies are effective in reducing viral load and necroinflammation, often restoring the patient to near-normal health, they do not lead to a cure except in very rare cases and, in many patients, viremia rebounds after cessation of treatment. Researchers are now challenged to devise therapies that will eliminate infection, with a particular focus on eliminating the persistence of viral cccDNA in the nuclei of hepatocytes. In the context of chronic hepatitis B, new definitions of 'cure' are emerging, such as 'functional' and 'virological' cure, defined by stable off-therapy suppression of viremia and antigenemia, and the normalization of serum ALT and other liver-related laboratory tests. Continued advances in the understanding of the complex biology of chronic hepatitis B have resulted in the development of new, experimental therapies targeting viral and host factors and pathways previously not accessible to therapy, approaches which may lead to virological cures in the near term and functional cures upon long term follow-up. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."

Rethinking the pathogenesis of hepatitis B virus (HBV) infection

Chronic hepatitis B virus (HBV) infection affects approximately 375 million people worldwide. Current antiviral treatment effectively controls, but rarely clears chronic HBV infection. In addition, a significant portion of chronic HBV infected patients are not suitable for currently available antiviral therapy, and still face higher risk for cirrhosis and hepatocellular carcinoma. The poorly understood pathogenesis of HBV infection is the main barrier for developing more effective treatment strategies. HBV has long been viewed as non-cytopathic and the central hypothesis for HBV pathogenesis lies in the belief that hepatitis B is a host specific immunity-mediated liver disease. However, this view has been challenged by the accumulating experimental and clinical data that support a model of cytopathic HBV replication. In this article we systematically review the pathogenic role of HBV replication in hepatitis B and suggest possible HBV replication related mechanisms for HBV-mediated liver injury. We propose that a full understanding of HBV pathogenesis should consider the following elements. I. Liver injury can be caused by high levels of HBV replication and accumulation of viral products in the infected hepatocytes. II. HBV infection can be either directly cytopathic, non-cytopathic, or a mix of both in an individual patient depending upon accumulation levels of viral products that are usually associated with HBV replication activity in individual infected hepatocytes.

Occult hepatitis B virus infection and blood transfusion

Transfusion-transmitted infections including hepatitis B virus (HBV) have been a major concern in transfusion medicine. Implementation of HBV nucleic acid testing (NAT) has revealed occult HBV infection (OBI) in blood donors. In the mid-1980s, hepatitis B core antibody (HBc) testing was introduced to screen blood donors in HBV non-endemic countries to prevent transmission of non-A and non-B hepatitis. That test remains in use for preventing of potential transmission of HBV from hepatitis B surface antigen (HBsAg)-negative blood donors, even though anti-hepatitis C virus tests have been introduced. Studies of anti-HBc-positive donors have revealed an HBV DNA positivity rate of 0%-15%. As of 2012, 30 countries have implemented HBV NAT. The prevalence of OBI in blood donors was estimated to be 8.55 per 1 million donations, according to a 2008 international survey. OBI is transmissible by blood transfusion. The clinical outcome of occult HBV transmission primarily depends on recipient immune status and the number of HBV DNA copies present in the blood products. The presence of donor anti-HBs reduces the risk of HBV infection by approximately five-fold. The risk of HBV transmission may be lower in endemic areas than in non-endemic areas, because most recipients have already been exposed to HBV. Blood safety for HBV, including OBI, has substantially improved, but the possibility for OBI transmission remains.

Occult infection with HBV intergenotypic A2/G recombinant following acute hepatitis B caused by an HBV/A2 isolate

Viral and host factors leading to occult hepatitis B virus (HBV) infection (OBI) are not fully understood. Whether HBV genotype may influence the occurrence and course of OBIs is unknown. Here, we describe the case of a patient infected with HBV genotype A2 who developed symptomatic acute hepatitis and did not seroconvert after loss of HBsAg and HBeAg. The acute phase of hepatitis B was followed by a period of more than 2 years during which the DNA of an intergenotypic HBV/A2/G recombinant was intermittently detected in serum.

Occult hepatitis B virus infection predicts de novo hepatitis B infection in patients with alcoholic cirrhosis after liver transplantation

BACKGROUND & AIMS

Occult hepatitis B virus infection (OBI) in patients undergoing liver transplantation (LT) is a suspected source of de novo hepatitis B virus (HBV) infection after LT. This study aimed to investigate the prevalence of OBI in liver transplant recipients with alcoholic cirrhosis and demonstrate the association between OBI and de novo HBV infection after LT in these patients.

METHODS

Forty-three patients with alcoholic cirrhosis who were negative for HBsAg before LT were recruited in this retrospective study. DNA was extracted from paraffin-embedded native liver tissues and quantified for HBV DNA by real-time PCR. Correlation between de novo HBV infection after LT (positive HBsAg and/or detectable HBV DNA in serum) and detection of intrahepatic HBV DNA before LT was analysed.

RESULTS

Detectable HBV DNA in the explanted liver was found in 41.9% (18/43) of the patients and was thus defined as OBI, which was correlated with the presence of serum hepatitis B core antibody (P = 0.008). De novo HBV infection occurred in 18.6% (8/43) of the recipients at a median of 10 months after LT. The rate of de novo HBV infection was 38.9% (7/18) in patients with OBI, compared with 4% (1/25) in patients without OBI (P = 0.004). Furthermore, de novo HBV infection was inversely correlated with the presence of hepatitis B surface antibody in recipients with OBI (P = 0.026).

CONCLUSION

With a prevalence of 41.9% in liver transplant recipients with alcoholic cirrhosis, OBI in the native liver can predict de novo HBV infection after LT.

Occult hepatitis B virus co-infection in human immunodeficiency virus-positive patients: A review of prevalence, diagnosis and clinical significance

The prevalence of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) co-infection is high as they share similar mechanisms of transmission. The development and widespread use of highly sensitive tests for HBV diagnosis has demonstrated that a significant proportion of apparently healthy individuals with evidence of exposure to HBV continue to carry fully functional HBV DNA in their hepatocytes, a situation that predisposes them to the development of progressive liver disease and hepatocellular carcinoma. The presence of co-infections frequently influences the natural evolution of each of the participating infections present by either facilitating their virulence or competing for resources. Furthermore, the drugs used to treat these infections may also contribute to changes in the natural course of these infections, making the analysis of the impact of co-infection more difficult. The majority of studies has examined the impact of HIV on overt chronic hepatitis B, finding that co-infection carries an increased risk of progressive liver disease and the development of hepatocellular carcinoma. Although the effect of HIV on the natural history of occult hepatitis B infection (OBI) has not been fully assessed, all available data suggest a persisting risk of repeated flares of hepatitis and progressive liver disease. We describe studies regarding the diagnosis, prevalence and clinical significance of OBI in HIV-positive patients in this short review. Discrepancies in worldwide prevalence show the urgent need for the standardization of diagnostic criteria, as established by the Taormina statements. Ideally, standardized protocols for testing should be employed to enable the comparison of data from different groups. Additional studies are needed to define the differences in risk for OBI without HIV and in HIV-HBV co-infected patients with or without overt disease.

Prevention of hepatitis B virus infection: from the past to the future

About 3-5 % of the world's population is chronically infected by hepatitis B virus (HBV) and is at risk of developing liver cirrhosis or hepatocellular carcinoma. The risk of dying prematurely because of chronic HBV infection is higher in younger people. The current strategies to prevent HBV infection involve immunization (active and/or passive) and antiviral chemoprophylaxis. The vaccines available for active immunization, containing hepatitis B surface antigen, are safe and confer long-term immunity in most healthy subjects. Since the vaccination is unsatisfactory in some patients, e.g., those with chronic kidney disease, human immunodeficiency virus infection, type I diabetes mellitus, and celiac disease, new strategies of vaccination are required. The neonatal, infant, and adolescent routine program vaccination in about 180 countries has greatly decreased the disease burden. Passive immunization with specific HBV immunoglobulins is recommended after single acute exposure, in infants born to infected mothers, and in HBV-infected patients undergoing liver transplantation combined with nucleoside/nucleotide analogues (chemoprophylaxis). Chemoprophylaxis is also indicated in HBV carrier candidates for immunosuppressive treatment and in patients with occult B infection undergoing immunosuppressive therapy or hematopoietic stem cell transplantation. Since HBV is not eradicable by an immune response or by antiviral drugs developed so far, the only preventive strategy remains global neonatal vaccination in all countries, firstly in HBV-endemic countries.

Harnessing the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated Cas9 system to disrupt the hepatitis B virus

The current therapies to treat hepatitis B virus (HBV) infection are limited. Recently, clustered regularly interspaced short palindromic repeat (CRISPR) systems, originally identified in bacteria and archaea, have been found to consist of an RNA-based adaptive immune system that degrades complimentary sequences of invading plasmids and viruses. Here, we studied the effects of the CRISPR/CRISPR-associated Cas9 system that was targeted to the surface antigen (HBsAg)-encoding region of HBV, both in a cell culture system and in vivo. The HBsAg levels in the media of the cells and in the sera of mice were analyzed by a quantitative enzyme-linked immunosorbent assay. The HBV DNA levels were assessed by quantitative PCR and HBsAg expression in mouse livers was assessed by an immunohistochemical assay. The amount of HBsAg secreted in the cell culture and mouse serum was reduced by CRISPR/Cas9 treatment. Immunohistochemistry analyses showed almost no HBsAg-positive cells in the liver tissue of CRISPR/Cas9-S1+X3-treated mice. The CRISPR/Cas9 system efficiently produced mutations in HBV DNA. Thus, CRISPR/Cas9 inhibits HBV replication and expression in vitro and in vivo and may constitute a new therapeutic strategy for HBV infection.

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.

Occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host’s strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI.

Hepatitis B virus infection in post-vaccination South Africa: occult HBV infection and circulating surface gene variants

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the prevalence of occult hepatitis B virus (HBV) infection and the HBV surface (S) gene variants circulating in the South African population after nearly two decades of universal hepatitis B vaccination.

STUDY DESIGN

From a previous serosurvey, 201 serum samples with serological evidence of exposure to HBV were identified and these were stratified into post- and pre-vaccine introduction populations. For all samples, HBV DNA was screened and quantified using a real-time PCR assay and results analysed together with HBV serological markers. Where HIV results were available, subset analysis was performed. The HBV S gene was PCR-amplified and sequences analysed for a total of 37 isolates.

RESULTS

The prevalence of occult HBV infection reduced from 70.4% in the pre-vaccine introduction era to 66.0% post-vaccine introduction. There was an association between HIV infection and an increase in prevalence of occult HBV infection within the post-vaccine introduction population, although this was not statistically significant. Furthermore, sequence analysis revealed the following HBV subgenotypes; A1 (n=34), A2 (n=2) and a rare D4 isolate. HBV S gene variants, including diagnostic escape mutants were isolated.

CONCLUSION

There was a decline in the prevalence of occult HBV infection in post-vaccination South Africa, although the disease burden remains significant in the HIV co-infected population. After nearly two decades of a universal hepatitis B vaccination programme, no positive selection of vaccine escape mutants were observed.

Epidemiology, risk factors and genotypes of HBV in HIV-infected patients in the northeast region of Colombia: high prevalence of occult hepatitis B and F3 subgenotype dominance

INTRODUCTION

Chronic hepatitis B virus (HBV) infection is an increasing cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected individuals. HIV-positive patients are commonly co-infected with HBV due to shared routes of transmission.

OBJECTIVES

Our aim was to determine the risk factors, prevalence, genotypes, and mutations of the Surface S gene of HBV, and occult hepatitis B infection (OBI) among patients infected with HIV in a northeastern Colombian city.

METHODS

A cross-sectional study was conducted with 275 HIV-positive patients attending an outpatient clinic in Bucaramanga, Colombia during 2009-2010. Blood samples were collected and screened for serological markers of HBV (anti-HBs, anti-HBc and HBsAg) through ELISA assay. Regardless of their serological profile, all samples were tested for the HBV S gene by nested-PCR and HBV genotypes were determined by phylogenetic inference. Clinical records were used to examine demographic, clinical, virological, immunological and antiretroviral therapy (ART) variables of HIV infection.

RESULTS

Participants were on average 37±11 years old and 65.1% male. The prevalence of HIV-HBV coinfection was 12% (95%CI 8.4-16.4) of which 3.3% had active HBV infection and 8.7% OBI. The prevalence of HIV-HBV coinfection was associated with AIDS stage and ART treatment. Sequence analysis identified genotype F, subgenotype F3 in 93.8% of patients and genotype A in 6.2% of patients. A C149R mutation, which may have resulted from failure in HBsAg detection, was found in one patient with OBI.

CONCLUSIONS

The present study found a high prevalence of HIV-HBV coinfection with an incidence of OBI 2.6-fold higher compared to active HBV infection. These findings suggest including HBV DNA testing to detect OBI in addition to screening for HBV serological markers in HIV patients.

Characterization and risk of blood-borne virus transmission in organ transplantation: what are the priorities?

ABSTRACT 

Blood-borne virus transmission through organ transplantation, although rare, has been associated with severe complications in recipients. There are few data available to ascertain the risk of infection in organ transplantation for known and emerging pathogens, as most information comes from events of transmission, which are rare and not always well characterized. The balance between quality of life through organ transplantation and the risks of donor-derived infection can be improved through advances in donor screening, enhanced monitoring and a multidisciplinary approach to improving donor assessment and recipient biosurveillance. The involvement of investigators with clinical, laboratory, surveillance and policy expertise is critical to bridge research knowledge and clinical practice.

Prediction of occult hepatitis B virus infection in liver transplant donors through hepatitis B virus blood markers

BACKGROUND

Occult hepatitis B virus infection is defined as detectable HBV-DNA in liver of HBsAg-negative individuals, with or without detectable serum HBV-DNA. In deceased liver donors, results of tissue analysis cannot be obtained prior to allocation for liver transplantation.

AIMS

we investigated prevalence and predictability of occult hepatitis B using blood markers of viral exposure/infection in deceased liver donors.

METHODS

In 50 consecutive HBsAg-negative/anti-HBc-positive and 20 age-matched HBsAg-negative/anti-HBc-negative donors, a nested-PCR assay was employed in liver biopsies for diagnosis of occult hepatitis B according to Taormina criteria. All donors were characterized for plasma HBV-DNA and serum anti-HBs/anti-HBe.

RESULTS

In liver tissue, occult hepatitis B was present in 30/50 anti-HBc-positive (60%) and in 0/20 anti-HBc-negative donors (p<0.0001). All anti-HBc-positive donors with detectable HBV-DNA in plasma (n=5) or anti-HBs>1,000 mIU/mL (n=5) eventually showed occult infection, i.e, 10/30 occult hepatitis B-positive donors which could have been identified prior to transplantation. In the remaining 40 anti-HBc-positive donors, probability of occult infection was 62% for anti-HBe-positive and/or anti-HBs ≥ 58 mIU/mL; 29% for anti-HBe-negative and anti-HBs<58 mIU/mL.

CONCLUSIONS

In deceased donors, combining anti-HBc with other blood markers of hepatitis B exposure/infection allows to predict occult hepatitis B with certainty and speed in one third of cases. These findings might help refine the allocation of livers from anti-HBc-positive donors.

Occult hepatitis B virus infection among Mexican human immunodeficiency virus-1-infected patients

AIM: To determine the frequency of occult hepatitis B infection (OHBI) in a group of human immunodeficiency virus (HIV)-1+/ hepatitis B surface antigen negative (HBsAg)- patients from Mexico.

METHODS: We investigated the presence of OHBI in 49 HIV-1+/HBsAg- patients. Hepatitis B virus (HBV) DNA was analyzed using nested PCR to amplify the Core (C) region and by real-time PCR to amplify a region of the S and X genes. The possible associations between the variables and OHBI were investigated using Pearson’s χ² and/or Fisher’s exact test.

RESULTS: We found that the frequency of OHBI was 49% among the group of 49 HIV-1+/HBsAg- patients studied. The presence of OHBI was significantly associated with the HIV-1 RNA viral load [odds ratio (OR) = 8.75; P = 0.001; 95%CI: 2.26-33.79] and with HIV-antiretroviral treatment with drugs that interfere with HBV replication (lamivudine, tenofovir or emtricitabine) (OR = 0.25; P = 0.05; 95%CI: 0.08-1.05).

CONCLUSION: The OHBI frequency is high among 49 Mexican HIV-1+/HBsAg- patients and it was more frequent in patients with detectable HIV RNA, and less frequent in patients who are undergoing HIV-ARV treatment with drugs active against HBV.

No evidence for occult HBV infection in hepatitis B vaccine non-responders

BACKGROUND AND OBJECTIVE

Although hepatitis B vaccine immunogenicity is high, certain risk factors such as age, tobacco consumption, obesity and genetic background have been associated with low responsiveness to HBV vaccine. We aimed to evaluate the role of occult hepatitis B virus (HBV) infection in non-responder adults to HBV vaccine in a low endemic area for HBV.

MATERIAL AND METHODS

A total of 52 subjects who were non-responder to HBV vaccine were enrolled in the study. HBsAg, anti-HBs and anti-HBc were tested in all subjects. The presence of HBV-DNA was determined in plasma samples by real-time PCR.

RESULTS

A total of 52 cases with median age 34 years were enrolled in the study. 63.5% of patients were male and 36.5% were female. Isolated anti-HBc (HBsAg negative, anti-HBs negative and anti-HBc positive) was detected in 3.8% of cases. HBV-DNA was not detected in our cases.

CONCLUSION

This study showed no evidence of occult HBV infection in our HBV vaccine non-responders even in cases with isolated anti-HBc.

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.

Occult hepatitis B virus infection in liver transplant patients in a Brazilian referral center

Estimates of occult hepatitis B virus (HBV) infection prevalence varies among different studies depending on the prevalence of HBV infection in the study population and on the sensitivity of the assay used to detect HBV DNA. We investigated the prevalence of occult HBV infection in cirrhotic patients undergoing liver transplantation in a Brazilian referral center. Frozen liver samples from 68 adults were analyzed using a nested polymerase chain reaction assay for HBV DNA. The specificity of the amplified HBV sequences was confirmed by direct sequencing of the amplicons. The patient population comprised 49 (72.1%) males and 19 (27.9%) females with a median age of 53 years (range=18-67 years). Occult HBV infection was diagnosed in three (4.4%) patients. The etiologies of the underlying chronic liver disease in these cases were alcohol abuse, HBV infection, and cryptogenic cirrhosis. Two of the patients with cryptic HBV infection also presented hepatocellular carcinoma. Markers of previous HBV infection were available in two patients with occult HBV infection and were negative in both. In conclusion, using a sensitive nested polymerase chain reaction assay to detect HBV DNA in frozen liver tissue, we found a low prevalence of occult HBV infection in cirrhotic patients undergoing liver transplant, probably due to the low prevalence of HBV infection in our population.

Hepatitis B virus PreS/S gene variants: pathobiology and clinical implications

The emergence and takeover of hepatitis B virus (HBV) variants carrying mutation(s) in the preS/S genomic region is a fairly frequent event that may occur spontaneously or may be the consequence of immunoprophylaxis or antiviral treatments. Selection of preS/S mutants may have relevant pathobiological and clinical implications. Both experimental data and studies in humans show that several specific mutations in the preS/S gene may induce an imbalance in the synthesis of the surface proteins and their consequent retention within the endoplasmic reticulum (ER) of the hepatocytes. The accumulation of mutated surface proteins may cause ER stress with the consequent induction of oxidative DNA damage and genomic instability. Viral mutants with antigenically modified surface antigen may be potentially infectious to immune-prophylaxed patients and may account for cases of occult HBV infection. In addition, preS/S variants were reported to be associated with cases of fulminant hepatitis as well as of fibrosing cholestatic hepatitis, and they are associated with cirrhosis and hepatocellular carcinoma development.

Serological characterization of occult hepatitis B virus infection among blood donors in India

INTRODUCTION

Discovery of hepatitis B infections characterized by the presence of viral genome without detectable HBsAg (Occult Hepatitis; OBI) has initiated a considerable amount of research in this regard. Our study is a serological and molecular characterization of OBI among the donors who donated at our blood bank during the study period.

MATERIAL AND METHOD

During the study period HBsAg ELISA non reactive ID-NAT reactive donors samples were screened for presence of antibody against HBc, HBs and HBe. Molecular analysis of these NAT yield samples was undertaken for detection of the viral load and genotyping.

RESULT

We studied 28,134 HBsAg ELISA non reactive donor samples. On testing them with ID-NAT, HBV DNA was detected in 25 samples. Eighteen samples out of these 25 NAT yield were further worked up. The 66.6% of the NAT yield samples (12 out of 18) were reactive for antibody against HBc. The 25% (3 out of 12) of these NAT yield samples having antibody against core antigen also had antibody against HBs. The 27.7% (5 out of 18) of NAT yield detected by ID-NAT did not have any detectable serological marker in blood. Four out of 12 core antibody positive NAT yield samples had genotype A HBV infection.

CONCLUSION

As per our study molecular detection of HBV DNA by ID-NAT, we were able to analyze 18 HBV NAT yield cases among 28,134 HBsAg ELISA non reactive donors. Out of 18, 12 donors were OBI whereas the rest (6) were in window period (WP yield) of HBV infection. One out of every 3.6 NAT yield detected by ID-NAT was non reactive for all serological markers.

Therapy of occult hepatitis B virus infection and prevention of reactivation

Occult hepatitis B virus infection (OBI) is highly prevalent worldwide. In some cases, it is a consequence of infection with variant viruses mutated in the S gene and producing a surface antigen not recognized by diagnostic kits. In most cases, OBI is due to a strong inhibition of hepatitis B virus (HBV) activities exerted by host defense mechanisms. OBI may reactivate in patients undergoing immunosuppressive therapy and/or chemotherapy with the possibility of a consequent development of acute hepatitis that may lead to hepatic failure. Hematological malignancies and therapeutic schedules including rituximab are the conditions most frequently associated with OBI reactivation. However, this event may occur in a large number of additional clinical and therapeutic settings. Identification of patients prone to undergo reactivation is of great importance for promptly starting a proper antiviral therapy that may stop the HBV reactivation and prevent its clinical sequelae.

[Occult hepatitis B virus infection: transmission and reactivation]

Occult HBV infection (OBI) is defined as presence of HBV DNA in the liver tissue in patients with serologically undetectable HBsAg. There are differences in virologic and serological profiles of OBI. Majority of OBI are positive for anti-HBs and/or anti-HBc and minor portion are negative for all HBV markers. However, there are no HBV mutations in the surface and its regulatory regions. HBV infection persists by the presence of covalently closed circular DNA (cccDNA) within the infected hepatocytes, which serves as a reservoir for future infection. OBI increases the risk of HBV transmission through transfusion, hemodialysis, and organ transplantation. Therefore effective measures should be employed to screen OBI. Antiviral therapy is needed in HBsAg-negative transplant patients who are anti-HBc positive to prevent the recurrence of HBV infection. Since HBV replication is strongly suppressed by immune surveillance system in OBI patients, immunosuppression results in massive HBV replication. This leads to acute hepatitis and sometimes mortality when immune surveillance is recovered after stopping immunosuppressive drugs/anticancer chemotherapy. Therefore, narrow surveillance is required to recognize the viral reactivation and start antiviral agents during immunosuppressive therapy/anticancer chemotherapy in patients with OBI.

Sequence variations of full-length hepatitis B virus genomes in Chinese patients with HBsAg-negative hepatitis B infection

BACKGROUND

The underlying mechanism of HBsAg-negative hepatitis B virus (HBV) infection is notoriously difficult to elucidate because of the extremely low DNA levels which define the condition. We used a highly efficient amplification method to overcome this obstacle and achieved our aim which was to identify specific mutations or sequence variations associated with this entity.

METHODS

A total of 185 sera and 60 liver biopsies from HBsAg-negative, HBV DNA-positive subjects or known chronic hepatitis B (CHB) subjects with HBsAg seroclearance were amplified by rolling circle amplification followed by full-length HBV genome sequencing. Eleven HBsAg-positive CHB subjects were included as controls. The effects of pivotal mutations identified on regulatory regions on promoter activities were analyzed.

RESULTS

22 and 11 full-length HBV genomes were amplified from HBsAg-negative and control subjects respectively. HBV genotype C was the dominant strain. A higher mutation frequency was observed in HBsAg-negative subjects than controls, irrespective of genotype. The nucleotide diversity over the entire HBV genome was significantly higher in HBsAg-negative subjects compared with controls (p = 0.008) and compared with 49 reference sequences from CHB patients (p = 0.025). In addition, HBsAg-negative subjects had significantly higher amino acid substitutions in the four viral genes than controls (all p<0.001). Many mutations were uniquely found in HBsAg-negative subjects, including deletions in promoter regions (13.6%), abolishment of pre-S2/S start codon (18.2%), disruption of pre-S2/S mRNA splicing site (4.5%), nucleotide duplications (9.1%), and missense mutations in "α" determinant region, contributing to defects in HBsAg production.

CONCLUSIONS

These data suggest an accumulation of multiple mutations constraining viral transcriptional activities contribute to HBsAg-negativity in HBV infection.

Modification of the hepatitis B virus envelope protein glycosylation pattern interferes with secretion of viral particles, infectivity, and susceptibility to neutralizing antibodies

The envelope proteins of hepatitis B virus (HBV) bear an N-linked glycosylation site at N146 within the immunodominant a-determinant in the antigenic loop (AGL) region. This glycosylation site is never fully functional, leading to a nearly 1/1 ratio of glycosylated/nonglycosylated isoforms in the viral envelope. Here we investigated the requirement for a precise positioning of N-linked glycan at amino acid 146 and the functions associated with the glycosylated and nonglycosylated isoforms. We observed that the removal of the N146 glycosylation site by mutagenesis was permissive to envelope protein synthesis and stability and to secretion of subviral particles (SVPs) and hepatitis delta virus (HDV) virions, but it was detrimental to HBV virion production. Several positions in the AGL could substitute for position 146 as the glycosylation acceptor site. At position 146, neither a glycan chain nor asparagine was absolutely required for infectivity, but there was a preference for a polar residue. Envelope proteins bearing 5 AGL glycosylation sites became hyperglycosylated, leading to an increased capacity for SVP secretion at the expense of HBV and HDV virion secretion. Infectivity-compatible N-glycosylation sites could be inserted at 3 positions (positions 115, 129, and 136), but when all three positions were glycosylated, the hyperglycosylated mutant was substantially attenuated at viral entry, while it acquired resistance to neutralizing antibodies. Taken together, these findings suggest that the nonglycosylated N146 is essential for infectivity, while the glycosylated form, in addition to its importance for HBV virion secretion, is instrumental in shielding the a-determinant from neutralizing antibodies.

IMPORTANCE

At the surface of HBV particles, the immunodominant a-determinant is the main target of neutralizing antibodies and an essential determinant of infectivity. It contains an N-glycosylation site at position 146, which is functional on only half of the envelope proteins. Our data suggest that the coexistence of nonglycosylated and glycosylated N146 at the surface of HBV reflects the dual function of this determinant in infectivity and immune escape. Hence, a modification of the HBV glycosylation pattern affects not only virion assembly and infectivity but also immune escape.

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.

Potential mutations associated with occult hepatitis B virus status

CONTEXT

Occult hepatitis B virus (HBV) status (OHBS) is simply defined as the presence of HBV DNA in the liver (with or without detectable HBV DNA in the serum), in the absence of serum HBV surface antigen (HBsAg). Importance of OHBS is mostly clinical, related to its possible role in spreading through blood transfusion and liver transplantation; causing classic forms of HBV. Mechanisms underlying this entity are poorly defined. Several possibilities have been suggested, with major classification into two groups: defective host immune response and viral replication activity through mutations of HBV DNA sequence. Mutations are extensively investigated in all four overlapping open reading frames (ORFs) of HBV genome, to define their possible role in the pathogenesis of OHBS. Some of these mutations like S-escape mutants could not be detected by the routine available assays, making them difficult to diagnosis. Therefore, trying to detect this covert condition could be more helpful for defining better preventive and therapeutic strategies.

EVIDENCE ACQUISITION

In the present study we provided an in-depth review of the most important new data available on different mutations in HBV genome of patients with OHBS, which may play a role in the pathogenesis of OHBS. The data were collected through reviewing the full-text articles, identified by the PubMed search, using the following keywords and their different combinations: occult hepatitis B, HBV genome, "a" determinant, HBV open reading frames, S mutations, X mutations, P mutations and C mutations.

RESULTS

Variants within the major hydrophilic region (MHR) of the HBsAg, deletions in the pre-S1region, codon stop in the S open reading frames (ORF), sporadic non common mutations, some mutations affecting the posttranslational production of HBV proteins in the S ORF like deletion mutations, mutations in start codon and nucleotide changes in the X ORF, deletion and point mutations in P ORF and sometimes, nucleotide substitution in the C ORF are among the assumed mutations detected to have a role in OHBS appearance.

CONCLUSIONS

Studies mostly lacked a control group and the whole-length HBV sequencing was scant with conflicting results, suggesting that OHBS is often a result of multiple mechanisms. Additional studies on full-length HBV genomes from occult and non-occult HBV cases may shed more light on the interplay between different mechanisms involved in the pathogenesis of OHBS.

Reactivation of hepatitis B virus in rheumatoid arthritis patients treated with biological disease-modifying antirheumatic drugs

OBJECTIVE

To examine the incidence of hepatitis B virus (HBV) reactivation in patients with rheumatoid arthritis (RA) receiving biological disease-modifying antirheumatic drugs (DMARDs).

METHODS

We retrospectively reviewed RA patients treated with biological DMARDs at our institution from July 2010 to December 2012. Patients with antibodies for hepatitis B core antigen and/or hepatitis B surface antigen were regarded as having prior HBV infection. Clinical data on these patients, including HBV-DNA levels, were retrieved from the medical records.

RESULTS

During the study period, 251 patients were administered various biological DMARDs. Six patients with a history of HBV vaccination and one patient with positive HBV surface antigen were excluded from the study. Fifty-seven of the remaining 244 patients (23.4%) had prior HBV infection. These patients were followed for a median of 18 months (range: 2-27 months) and HBV-DNA was examined a median of seven times (range: 2-27). HBV-DNA was detected in three patients (5.3%), comprising two receiving tocilizumab and one receiving etanercept. However, HBV-DNA levels were below the quantitation limit (<2.1 log copies mL(-1) ) in all three patients. HBV-DNA became negative again within several months in all three patients, while biological DMARDs were continued and liver function tests remained normal throughout.

CONCLUSION

HBV-DNA reactivation occurred in 5.3% of RA patients with prior HBV infection during treatment with biological DMARDs, but there were no associated clinical manifestations. Accordingly, it seems that biological DMARDs can be used safely in patients with RA.

Occult hepatitis B virus infection and hepatocellular carcinoma: a systematic review

Occult hepatitis B (OHB) infection has been reported to play an important role in the development of hepatocellular carcinoma (HCC). In this systematic review, a significantly higher prevalence of OHB was observed in patients with HCC in the presence or absence of HCV infection when compared with control populations without HCC. Correspondingly, among adequately designed prospective studies, the cumulative probability of developing HCC was significantly greater among patients with OHB than among HBV DNA-negative patients in the presence or absence of HCV infection. Study design, inclusion criteria, treatment options, methodology and potential confounding variables were evaluated, and immunopathogenic mechanisms that could be involved in OHB as a risk factor in HCC were reviewed. From this analysis, we conclude that although OHB is an independent risk factor in HCC development in anti-HCV-negative patients, a synergistic or additive role in the occurrence of HCC in HCV-coinfected patients is more problematic due to the HCC risk attributable to HCV alone, especially in patients with advanced fibrosis and cirrhosis.

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.

The clinical significance of occult HBV infection

The presence of hepatitis B virus (HBV) DNA in HBV surface antigen (HBsAg)-negative individuals is defined as occult HBV infection (OBI). OBI is related in some cases to infection with variant viruses (S-escape mutants) undetectable by HBsAg commercial kits. More frequently, however, it is due to infection with wild-type viruses that are strongly suppressed in their replication activity. OBI may be involved in different clinical contexts, including the transmission of the infection by blood transfusion or liver transplantation and its acute reactivation when an immunosuppressive status occurs. Moreover, much evidence suggests that it may contribute to the development of cirrhosis and may have an important role in hepatocarcinogenesis.

Persistence of hepatitis C virus during and after otherwise clinically successful treatment of chronic hepatitis C with standard pegylated interferon α-2b and ribavirin therapy

Resolution of chronic hepatitis C is considered when serum HCV RNA becomes repeatedly undetectable and liver enzymes normalize. However, long-term persistence of HCV following therapy with pegylated interferon-α/ribavirin (PegIFN/R) was reported when more sensitive assays and testing of serial plasma, lymphoid cells (PBMC) and/or liver biopsies was applied. Our aim was to reassess plasma and PBMCs collected during and after standard PegIFN/R therapy from individuals who became HCV RNA nonreactive by clinical testing. Of particular interest was to determine if HCV genome and its replication remain detectable during ongoing treatment with PegIFN/R when evaluated by more sensitive detection approaches. Plasma acquired before (n = 11), during (n = 25) and up to 12–88 weeks post-treatment (n = 20) from 9 patients and PBMC (n = 23) from 3 of them were reanalyzed for HCV RNA with sensitivity <2 IU/mL. Clone sequencing of the HCV 5′-untranslated region from plasma and PBMCs was done in 2 patients. HCV RNA was detected in 17/25 (68%) plasma and 8/10 (80%) PBMC samples collected from 8 of 9 patients during therapy, although only 5.4% plasma samples were positive by clinical assays. Among post-treatment HCV RNA-negative plasma samples, 9 of 20 (45.3%) were HCV reactive for up to 59 weeks post-treatment. Molecularly evident replication was found in 6/12 (50%) among PBMC reactive for virus RNA positive strand collected during or after treatment. Pre-treatment point mutations persisted in plasma and/or PBMC throughout therapy and follow-up. Therefore, HCV is not completely cleared during ongoing administration of PegIFN/R otherwise capable of ceasing progression of CHC and virus commonly persists at levels not detectable by the current clinical testing. The findings suggest the need for continued evaluation even after patients achieve undetectable HCV RNA post-treatment.

Impact of occult hepatitis B virus infection on the outcome of chronic hepatitis C

BACKGROUND & AIMS

Occult hepatitis B virus infection (OBI) frequently occurs in patients with hepatitis C virus (HCV) related chronic hepatitis (CHC), but the influence of OBI on the CHC outcome is still uncertain. This observational cohort study evaluated the clinical evolution of CHC patients according to their OBI status.

METHODS

From 1991 to 2000, 326 hepatitis B surface antigen negative CHC patients were tested for OBI by the analysis of liver biopsy DNA extracts. A total of 128/326 cases (39.2%) tested OBI positive and 198/326 (60.8%) OBI negative. Ninety-four of 326 patients (37 OBI positive, 57 OBI negative) were followed-up for a median time of 11 years (range 5-19 years). During the follow-up, 79/94 patients underwent anti-HCV treatments and 25 [corrected] achieved a sustained virological response that occurred independently of their OBI status

RESULTS

Eighteen patients (13/37 OBI positive, 5/57 OBI negative, p < 0.01) developed hepatocellular carcinoma (HCC). Among the 76 non-HCC individuals, 15 subjects (8/24 OBI positive, 7/52 OBI negative, p < 0.05) developed advanced forms of cirrhosis. Eighteen patients died during follow-up and 2 underwent liver transplantation. OBI positive individuals had a cumulative survival rate significantly shorter than OBI negative individuals (p = 0.003). Liver-related deaths were more frequently found in OBI positive than OBI negative patients (12/37 OBI positive vs. 6/57 OBI negative patients respectively, p < 0.01). Finally, non-response to anti-HCV therapy was significantly associated with lower survival (p = 0.02).

CONCLUSIONS

Among CHC patients, occult HBV co-infected individuals are a category at high risk of progression toward cirrhosis, HCC development, and lower survival.

Viral hepatitis markers in liver tissue in relation to serostatus in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) incidence is increasing in the United States. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major causes of HCC. Hepatitis infection in patients with HCC is generally diagnosed by serology, which is not always consistent with the presence of HBV and HCV in the liver. The relationship of liver viral status to serostatus in hepatocarcinogenesis is not fully understood.

METHODS

HBV and HCV were evaluated in formalin-fixed, paraffin-embedded liver tissue specimens in a retrospective study of 61 U.S. HCC cases of known serologic status. HBV DNA and HCV RNA were detected by PCR, reverse transcription PCR (RT-PCR), and pyrosequencing, and HBsAg and HBcAg were evaluated by immunohistochemistry.

RESULTS

Viral markers were detected in the liver tissue of 25 of 61 (41%) HCC cases. Tissue viral and serologic status were discordant in 27 (44%) cases, including those with apparent "occult" infection. Specifically, HBV DNA was detected in tissue of 4 of 39 (10%) serum HBsAg (-) cases, including 1 anti-HCV(+) case; and HCV RNA was detected in tissue of 3 of 42 (7%) anti-HCV seronegative cases, including two with serologic evidence of HBV.

CONCLUSIONS

Viral hepatitis, including HBV-HCV coinfection, may be unrecognized in up to 17% of patients with HCC when based on serology alone. Further research is needed to understand the clinical significance of viral makers in liver tissue of patients with HCC in the absence of serologic indices.

IMPACT

The contribution of HBV and HCV to the increasing incidence of HCC in the United States may be underestimated.

Non-B, non-C hepatocellular carcinoma (Review)

Although most hepatocellular carcinoma (HCC) is related to viral infection, there is a substantial population of HCC patients (5-20%) who are negative for both markers of hepatitis B virus and hepatitis C virus infection [non-B, non-C (NBNC) hepatitis] in Japan and the incidence of NBNC-HCC has recently tended to increase. The most common cause of liver disease in developed countries is non‑alcoholic fatty liver disease (NAFLD), which includes non‑alcoholic steatohepatitis (NASH) and its related complications. Increased body mass index and diabetes mellitus are associated with developing NAFLD and NASH, which is a severe form of NAFLD. Furthermore, increasing clinical evidence supports the fact that NAFLD and NASH can progress to liver cirrhosis and even HCC. A detailed understanding of the epidemiology, etiology, molecular mechanism, clinical features and prognosis of NBNC-HCC could improve our screening and therapy of this disease. In this review, we primarily focus on clinical aspects of NBNC-HCC and refer to our current knowledge of this cancer.