An overview of occult hepatitis B virus infection

Occult hepatitis B virus (HBV) infection (OBI), alternatively defined as occult hepatitis B (OHB), is a challenging clinical entity. It is recognized by two main characteristics: absence of HBsAg, and low viral replication. The previous two decades have witnessed a remarkable progress in our understanding of OBI and its clinical implications. Appropriate diagnostic techniques must be adopted. Sensitive HBV DNA amplification assay is the gold standard assay for detection of OBI. Viral as well as host factors...     

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,intrahepatic 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 canprevent 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 protooncogenic 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.     

Controversies about occult hepatitis B virus infection

We read with great interest the paper written by Shi et al, reviewing the molecular characteristics and stages of chronic hepatitis B virus (HBV) infection. We think that some points in the definition of occult HBV infection (OBI) and their conclusion about the management of OBI may need further considerations.     

Pathogenesis of occult chronic hepatitis B virus infection

Occult hepatitis B infection(OBI) is characterized by hepatitis B virus(HBV) DNA in serum in the absence of hepatitis B surface antigen(HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns.Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays;but more frequently it is due to a strong suppression of viral replication and gene expression.OBI is an entity with world-wide diffusion.The failure to detect HBsAg,despite the persistence of the viral DN...     

隐匿性乙型肝炎病毒感染的研究进展

隐匿性乙型肝炎病毒感染(occult HBV infection, OBI)是公共健康的一大难题,也是全球临床医学面临的挑战。由于目前检测方法以及临床实际问题的限制,不同研究中对于OBI的定义也不同。OBI的存在会影响临床诊断和输血安全,且OBI在临床高危人群中有再激活的风险,可能会导致肝硬化、肝癌和肝衰竭等终末期肝病。本文就近年OBI定义和不同人群流行率、OBI发生机制以及临床意义等研究进展进行综述。     

Influence of occult hepatitis B virus infection in chronic hepatitis C outcomes

Persistence of hepatitis B virus-DNA in the sera,peripheral blood mononuclear cells or in the liver of hepatitis B surface antigen(HBsAg) -negative patients with or without serological markers of previous exposure(antibodies to HBsAg and/or to HB-core antigen) defines the entity called occult hepatitis B infection(OBI).Co-infection with hepatitis B and hepatitis C viruses is frequent in highly endemic areas.While this co-infection increases the risk of liver disease progression,development of cirrhosis and ...     

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(HBs Ag) 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(antiHBc) in serum of HBs Ag-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.     

Long-term clinical impact of occult hepatitis B virus infection in chronic hepatitis B patients

BACKGROUND/AIMS: Long-term clinical outcomes of occult hepatitis B virus (HBV) infection were studied. METHODS: Fifteen chronic hepatitis B patients were monitored for a median of 4.4 years (range 0.9-15.3) after hepatitis B surface antigen (HBsAg) seroclearance. Serum HBV DNA was measured by real-time detection polymerase chain reaction. Thirteen patients underwent liver biopsies at the end of follow-up and liver histology was evaluated by Ishak score. Liver HBV DNA was also measured for 12 patients. RESULTS: At the end of follow-up, HBV viremia was absent in 13 (87%) patients, and antibody titers to hepatitis B core antigen showed an inverse correlation with time from HBsAg seroclearance (r=-0.554; P=0.0040). However, all patients retained liver HBV DNA and tested positive for the covalently closed circular HBV DNA replicative intermediate. The hepatic HBV DNA loads had no relation to liver histology. Paired biopsies from 11 patients disclosed that each necroinflammatory score significantly improved after HBsAg seroclearance. Amelioration of liver fibrosis was also evident in eight (73%) patients (P=0.0391 by signed rank test). CONCLUSIONS: A long-standing but strongly suppressed HBV infection may confer histological amelioration after HBsAg seroclearance.     

Persistent occult hepatitis B virus infection： Experimental findings and clinical implications

Hepatitis B virus （HBV） is a highly pathogenic virus that causes chronic liver diseases in millions of people globally. In addition to a symptomatic, serologically evident infection, occult persistent HBV carriage has been identified since nucleic acid amplification assays of enhanced sensitivity became introduced for detection of hepadnaviral genomes and their replicative intermediates. Current evidence indicates that occult HBV infection is a common and long-term consequence of resolution of acute hepatitis B. This form of residual infection is termed as secondary occult infection （SOI）. The data from the woodchuck model of HBV infection indicate that exposure to small amounts of hepadnavirus can also cause primary occult infection （POI） where virus genome, but no serological makers of exposure to virus, are detectable, and the liver may not be involved. However, virus replicates at low levels in the lymphatic system in both these forms. We briefly summarize the current understanding of the nature and characteristics of occult hepadnaviral persistence as well as of its documented and expected pathological consequences.     

Prevalence of occult hepatitis B virus infection

Occult hepatitis B virus(HBV) infection(OBI) is characterized by the persistence of HBV DNA in the liver tissue in individuals negative for the HBV surface antigen.The prevalence of OBI is quite variable depending on the level of endemic disease in different parts of the world,the different assays utilized in the studies,and the different populations studied.Many studies have been carried out on OBI prevalence in different areas of the world and categories of individuals.The studies show that OBI prevalence...     

Diagnostic strategy for occult hepatitis B virus infection

In 2008,the European Association for the study of the liver(EASL) defined occult hepatitis B virus infection (OBI) as thepresence of hepatitis B virus(HBV) DNA in the liver(with detectable or undetectable HBV DNA in the serum) of individuals testing hepatitis B surface antigen(HBsAg) negative by currently available assays.Several aspects of occult HBV infection are still poorly understood,including the definition itself and a standardized approach for laboratory-based detection,which is the purpose of this ...     

Current and future directions for treating hepatitis B virus infection

Hepatitis B virus(HBV) persistently infects approximately 350 million people, and approximately 600000 liverrelated deaths are observed per year worldwide. HBV infection is also one of the major risk factors for hepatocellular carcinoma(HCC). The persistence of serum hepatitis B e antigen(HBe Ag) and high level of serum HBV DNA are thought to reflect a high HBV replication status in hepatocytes, causing cirrhosis, HCC and liver-related deaths. It has been reported that antiviral therapy, such as peginterferon and nucleos(t)ide analogues(NUCs), could suppress liver-related death by inhibiting the HBV DNA levels and inducing seroconversion from HBe Ag to antibody to HBe antigen. Currently, peginterferon is widely used, but there are also several disadvantages in the use of peginterferon, such as various adverse events, the administration route and duration. It is difficult to predict the effects of treatment and interferon is contraindicated for the patients with advanced fibrosis of the liver and cirrhosis. With respect to NUCs, entecavir and tenofovir disoproxil fumarate are current the first-choice drugs. NUCs can be administered orally, and their anti-viral effects are stronger than that of peginterferon. However, because cessation of NUC administration leads to high levels of viral replication and causes severe hepatitis, they must be administered for a long time. On the other hand, the use of both interferon and NUCs cannot eliminate covalently closed circular DNA of HBV. In this review, we evaluate the natural course of chronic HBV infection and then provide an outline of these representative drugs, such as peginterferon, entecavir and tenofovir disoproxil fumarate.     

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.     

Management of hepatitis B virus infection during treatment for hepatitis B virus-related hepatocellular carcinoma

Although liver resection is considered the most effective treatment for hepatocellular carcinoma (HCC), treatment outcomes are unsatisfactory because of the high rate of HCC recurrence. Since we reported hepatitis B e-antigen positivity and high serum hepatitis B virus (HBV) DNA concentrations are strong risk factors for HCC recurrence after curative resection of HBV-related HCC in the early 2000s, many investigators have demonstrated the effects of viral status on HCC recurrence and post-treatment outcomes. These findings suggest controlling viral status is important to prevent HCC recurrence and improve survival after curative treatment for HBV-related HCC. Antiviral therapy after curative treatment aims to improve prognosis by preventing HCC recurrence and maintaining liver function. Therapy with interferon and nucleos(t)ide analogs may be useful for preventing HCC recurrence and improving overall survival in patients who have undergone curative resection for HBV-related HCC. In addition, reactivation of viral replication can occur after liver resection for HBV-related HCC. Antiviral therapy can be recommended for patients to prevent HBV reactivation. Nevertheless, further studies are required to establish treatment guidelines for patients with HBV-related HCC.     

Occult hepatitis B virus infection in Egypt

The emerging evidence of the potentially clinical importance of occult hepatitis B virus (HBV) infection (OBI) increases the interest in this topic. OBI may impact in several clinical contexts, which include the possible transmission of the infection, the contribution to liver disease progression, the development of hepatocellular carcinoma, and the risk of reactivation. There are several articles that have published on OBI in Egyptian populations. A review of MEDLINE database was undertaken for relevant articles to clarify the epidemiology of OBI in Egypt. HBV genotype D is the only detectable genotype among Egyptian OBI patients. Higher rates of OBI reported among Egyptian chronic HCV, hemodialysis, children with malignant disorders, and cryptogenic liver disease patients. There is an evidence of OBI reactivation after treatment with chemotherapy. The available data suggested that screening for OBI must be a routine practice in these groups of patients. Further studies needed for better understand of the epidemiology of OBI among Egyptian young generations after the era of hepatitis B vaccination.     

自身免疫性胆管炎合并隐匿性乙型肝炎1例

自身免疫性胆管炎临床上少见,合并隐匿性乙型肝炎更为罕见,由于本例患者合并上述两种疾病,治疗上存在矛盾因素,通过综合治疗后取得较好疗效.     

Clinical significance of occult hepatitis B virus infection

Occult hepatitis B virus(HBV) infection(OBI) is defined as the presence of HBV DNA in the liver(with or without detectable HBV DNA in serum) for individuals testing HBV surface antigen negative.Until recently,the clinical effect of OBI was unclear on the progression of liver disease;on the development of hepatocellular carcinoma;and on the risk for reactivation or transmission of HBV infection.Several studies suggest a high prevalence of OBI among patients with cryptogenic chronic liver disease,but its role...     

Clinical impact of occult hepatitis B virus infection in immunosuppressed patients

Occult hepatitis B infection(OBI), is characterized by low level hepatitis B virus(HBV) DNA in circulating blood and/or liver tissue. In clinical practice the presence of antibody to hepatitis B core antigen in hepatitis B surface antigen(HBsAg)-/anti-HBs-negative subjects is considered indicative of OBI. OBI is mostly observed in the window period of acute HBV infection in blood donors and in recipients of blood and blood products, in hepatitis C virus chronic carriers, in patients under pharmacological immunosuppression, and in those with immunodepression due to HIV infection or cancer. Reactivation of OBI mostly occurs in anti-HIV-positive subjects, in patients treated with immunosuppressive therapy in onco-hematological settings, in patients who undergo hematopoietic stem cell transplantation, in those treated with anti-CD20 or anti-CD52 monoclonal antibody, or anti-tumor necrosis factors antibody for rheumatological diseases, or chemotherapy for solid tumors. Under these conditions the mortality rate for hepatic failure or progression of the underlying disease due to discontinuation of specific treatment can reach 20%. For patients with OBI, prophylaxis with nucleot(s)ide analogues should be based on the HBV serological markers, the underlying diseases and the type of immunosuppressive treatment. Lamivudine prophylaxis is indicated in hemopoietic stem cell transplantation and in onco-hematological diseases when high dose corticosteroids and rituximab are used; monitoring may be indicated when rituximab-sparing schedules are used, but early treatment should be applied as soon as HBsAg becomes detectable. This review article presents an up-to-date evaluation of the current knowledge on OBI.     

Fulminant hepatitis due to reactivation of chronic hepatitis B virus infection after allogeneic bone marrow transplantation

Summary A case of hepatitis B reactivation following bone-marrow transplantation for leukemia in a previously healthy HB_sAg carrier is reported. A number of changes in HBV serum markers were contemporary to the acute episode. All of them (increase of HB_sAg concentration, conversion from anti-HB_e to HB_eAg, appearance of anti-HB_c IgM, and of serum HBV-DNA) were suggestive of a switching-on of viral replication. Institution of corticosteroid treatment at the onset of the acute phase did not prevent the fatal outcome.