Occult Hepatitis B Virus Infection in Hemodialysis Patients: A Concept for Consideration

Hemodialysis patients potentially have an increased risk of infection with parenterally transmitted viral agents due to an impaired host immune response and multiple transfusion requirements. Viral hepatitis is considered as a problem for hemodialysis patients because 1.9% of all deaths among this population are related to the consequence of viral hepatitis. Hepatitis B virus (HBV) is one of the most important causes of transmitted infections by the parenteral route in hemodialysis patients. Occult HBV infection is characterized by presence of HBV infection without detectable hepatitis B surface antigen (HBsAg), which harbors potential risk of HBV transmission through hemodialysis. There are conflicting reports on the prevalence of occult HBV infection (OBI) in hemodialysis patients. Considering the importance of occult HBV infection in hemodialysis patients and the growing evidence on this subject, the purpose of this review is to provide comprehensive information on OBI prevalence in hemodialysis patients and highlight the most important points in this issue.     

Occult hepatitis C virus infection is more common than hepatitis B infection in maintenance hemodialysis patients

Patients of end stage renal disease on maintenance hemodialysis were enrolled to study the prevalence of occult and dual hepatitis B virus （HBV） and hepatitis C virus （HCV） infection and non-occult hepatitis B and C virus infection. One hundred and two patients were enrolled. Thirty patients had HCV infection, three of them were positive in anti-HCV. So, 27 （90%） of HCV-positive patients had occult HCV infection. Eleven （11%） patients had HBV infection. Five patients were positive in anti-HBc or HBV-DNA, but negative in HBsAg （occult HBV infection）. Three （3%） patients had dual HBV and HCV infection. None of the patients showed changes in viral markers during the follow-up of 8 mo on average （1-12 mo）.     

Occult Hepatitis B Virus Infection in Japanese Chronic Hemodialysis Patients

We investigated the prevalence of occult hepatitis B virus (HBV) infection in Japanese chronic hemodialysis patients. Hemodialysis patients (n = 1041) were screened for occult HBV. The presence of hepatitis B surface antigen (HBsAg), hepatitis B surface antibody, and hepatitis B core antibody (anti‐HBc) was determined by various chemiluminescent immunoassays. HBV‐DNA was quantified in patients positive for anti‐HBc using quantitative real‐time polymerase chain reaction. Among the 1041 patients, six (0.6%) were HBsAg‐positive and 218 (20.9%) were anti‐HBc‐positive. All HBsAg‐positive patients also tested positive for the presence of HBV DNA. Of 212 HBsAg‐negative and anti‐HBc‐positive patients, three were positive for HBV DNA. Our study showed that the prevalence of occult HBV infection in chronic hemodialysis patients from eastern Japan was 0.3%.     

Occult hepatitis B virus infection: a complex entity with relevant clinical implications

Occult hepatitis B virus(HBV) infection is a world-wide entity,following the geographical distribution of detectable hepatitis B.This entity is defined as the persistence of viral genomes in the liver tissue and in some instances also in the serum,associated to negative HBV surface antigen serology.The molecular basis of the occult infection is related to the life cycle of HBV,which produces a covalently closed circular DNA that persists in the cell nuclei as an episome,and serves as a template for gene tra...     

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 HIVpositive 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.     

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.     

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.     

Occult hepatitis B

Worldwide, chronic hepatitis B virus (HBV) infection is the primary cause of cirrhosis and hepatocellular carcinoma and is one of the ten leading causes of death. Traditionally, people with chronic HBV infection have been identified with blood tests for HBV antigens and antibodies. Recently, another group of patients with chronic HBV infection has been identified by sensitive, molecular testing for HBV DNA. Members of this group are often referred to as having occult hepatitis B because they are HBV-DNA positive, but hepatitis B surface antigen negative. Occult hepatitis B occurs in a number of clinical settings. In this review, we examine occult hepatitis B in people co-infected with hepatitis C, in whom occult hepatitis B has been associated with advanced fibrosis and diminished response to interferon alpha. Although much more research is needed, existing reports justify a heightened awareness of the medical importance and means of testing for occult hepatitis B.     

Occult HBV infection in HIV‐infected adults and evaluation of pooled NAT for HBV

The study aimed to determine the prevalence of occult hepatitis B virus infection among HIV‐infected persons and to evaluate the use of a pooling strategy to detect occult HBV infection in the setting of HIV infection. Five hundred and two HIV‐positive individuals were tested for HBV, occult HBV and hepatitis C and D with serologic and nucleic acid testing (NAT). We also evaluated a pooled NAT strategy for screening occult HBV infection among the HIV‐positive individuals. The prevalence of HBV infection among HIV‐positive individuals was 32 (6.4%), and occult HBV prevalence was 10%. The pooling HBV NAT had a sensitivity of 66.7% and specificity of 100%, compared to HBV DNA NAT of individual samples. In conclusion, this study found a high prevalence of occult HBV infection among our HIV‐infected population. We also demonstrated that pooled HBV NAT is highly specific, moderately sensitive and cost‐effective. As conventional HBV viral load assays are expensive in resource‐limited settings such as India, pooled HBV DNA NAT might be a good way for detecting occult HBV infection and will reduce HBV‐associated complications.     

DNA-guided hepatitis B treatment： Viral load is insufficient with few exceptions

In DNA-guided hepatitis B treatment, viral load is insufficient, and requires other viral markers for treatment of hepatitis B patients as in patients with acute exacerbation of chronic hepatitis B, end-stage renal disease on dialysis, human immunodeficiency virus co-infected patients. There are exceptions to this rule： a residual level hepatitis B virus （HBV） DNA at 24 wk predicts beneficial outcome and reduced resistance at i year. The genotypic viral resistance to antiviral agents and occult HBV infection can be determined by HBV-DNA levels.     

Occult hepatitis B virus infection in HIV‐infected patients: Evaluation of biochemical,virological and molecular parameters

Aim: To determine the prevalence of occult hepatitis B virus (HBV) infection in a group of human immunodeficiency virus (HIV)‐infected Brazilian patients and to investigate its association with biochemical, virological and molecular features. Methods: Sera from 43 patients positive for HBV core antibody and negative for HBV surface antigen (HBsAg) were tested for HBV DNA positivity by semi‐nested PCR. HBV loads were assessed by real‐time PCR. S gene was cloned and sequenced for HBV isolates from 3 patients. HBsAg expression of these cases was performed in HuH7 cells. Results: HBV DNA was found in 6/43 (14%) samples, all except one associated with low viral loads. Occult HBV infection was further correlated with anti‐hepatitis C virus (anti‐HCV) antibodies positivity, but not with alanine aminotransferase (ALT) elevated levels. S gene sequences derived from three patients were determined. Two of them displayed mutations that may explain HBsAg negativity. In the first one, a stop codon mutation was found at position 216 in the C‐terminal end of HBsAg. In the second patient, E164D and I195M substitutions in HBsAg, associated with lamivudine‐resistance mutations in the polymerase were identified. As expected, all clones showing those mutations displayed undetectable or very low levels of HBsAg. Conclusion: Occult HBV infection was frequent in HIV‐infected patients, was not associated with ALT elevation but significantly correlated with HCV seropositivity. The low viremia and the detection of HBsAg mutants confirm that multifactorial mechanisms are involved in occult HBV infection. HBV molecular monitoring should be employed for an adequate management of HBV/HIV co‐infected patients.     

Occult Hepatitis B Virus Infection in Hemodialysis Patients in Japan

Hepatitis B surface antigen is widely used in hepatitis B virus surveillance; patients who test negative for the antigen are judged to be uninfected. However, occult hepatitis B virus infection has been confirmed with hepatitis B virus DNA at low levels in the liver and peripheral blood in patients positive for hepatitis B core antibody or hepatitis B surface antibody, even if they test negative for hepatitis B surface antigen. To investigate the prevalence of occult hepatitis B virus in hemodialysis patients, we performed cross‐sectional analysis of 161 hemodialysis patients in two related institutions for hepatitis B surface antigen, hepatitis B core antibody, and hepatitis B surface antibody. Hepatitis B surface antigen, hepatitis B core antibody, or hepatitis B surface antibody was present in 45 patients (28.0%). Hepatitis B virus DNA was present in six patients (3.7%), all of whom also tested positive for hepatitis B core antibody. Hepatitis B surface antibody positivity was unrelated in only one of the six patients. Four of the six patients were positive for hepatitis B surface antigen; however, two (1.3%) of these with occult hepatitis B virus infection were found to be hepatitis B surface antigen negative. Occult hepatitis B virus infection may be missed in hepatitis B virus surveillance using hepatitis B surface antigen alone; therefore, routine hepatitis B core antibody screening is necessary. Patients who test positive for hepatitis B core antibody should undergo further hepatitis B virus DNA testing to enable accurate hepatitis B virus screening.     

＂Anti-HBc alone＂ in human immunodeficiency virus-positive and immuno-suppressed lymphoma patients

Hepatitis B virus （HBV） infection is endemic in various parts of the world. A proportion of patients have resolved prior exposure to HBV, as evidenced by the clearance of circulating hepatitis B surface antigen and the appearance of antibody to hepatitis B core antigen （anti-HBc）, which could produce protective antibody to hepatitis B surface antigen （anti-HBs）. With time, anti-HBs in some patients may become negative. Such patients are described as having occult HBV infection or ＂anti-HBc alone＂. In the context of immunodeficient patients, such as HIV patients or lymphoma patients undergoing immunosuppressive immunotherapy, the lack of protective anti-HBs may increase the risk of hepatitis B reactivation. Serum HBV DNA testing may be necessary in ＂anti-HBc alone＂ patients, to detect patients at a high risk of developing HBV infection allowing appropriate prophylactic management.     

Updates on the treatment and outcomes of dual chronic hepatitis C and B virus infection

Dual hepatitis C virus(HCV)/hepatitis B virus(HBV)infection is found in HBV or HCV endemic areas,and in specific populations exhibiting a high risk of parenteral viral transmission.Clinical observations have revealed that HCV/HBV dually infected patients demonstrate a higher risk of liver disease progression compared with HBV or HCV monoinfected patients.The viral activity responsible for liver disease progression can be determined by examining the viral loads of HCV and HBV and by conducting liver biopsy examinations.Recent trials have confirmed that the combination therapy of peginterferon alpha-2a or 2b and ribavirin for dual hepatitis patients with HCV dominance appears to be as effective and safe as it is in patients with HCV monoinfections.Strikingly,approximately 60% of dually infected patients with inactive hepatitis B before treatment develop HBV reactivation after the clearance of the HCV.The clinical significance of this HBV reactivation and the strategy to prevent and treat this event should be determined.Furthermore,approximately 30%of dually infected patients lost hepatitis B surface antigen(HBsAg)within 5 years after the start of peginterferonbased therapy,and 40%of them harbored occult HBV infection.The underlying mechanisms of their accelerating HBsAg seroclearance and the development of occult HBV await further investigations.Moreover,the optimal treatment strategies for dually infected patients who are seropositive for the hepatitis B e antigen must be explored.Finally,the advent of new direct-acting antiviral-based anti-HCV therapy may change the optimal therapies for patients with dual hepatitis in the near future,which warrants further clinical trials.     

慢性乙型肝炎病毒感染者家族隐匿性乙型肝炎病毒感染的调查

目的 了解慢性HBV感染者家族隐匿性HBV感染的发生率及其与HBV标志物、年龄和性别等的关系.方法 ELISA方法检测慢性HBV感染者家族成员的HBV血清学标志物,套式PCR法检测136例HBsAg阴性家族成员的血清HBV DNA,并将隐匿性HBV感染者和HBsAg、HBV DNA均阴性者分别作为试验组和对照组进行HBV标志物、年龄、性别和生物化学检测结果的比较.两组均数比较采用t检验.率的比较采用χ~2检验或Fisher确切概率法检验.结果 在52个慢性HBV感染者家族中共检测到92例HBsAg阳性者和136例HBsAg阴性者,其中15例为隐匿性HBV感染者,慢性HBV感染者家族HBsAg阳性率和隐匿性HBV感染的发生率分别为40.4%和11.0%,15例隐匿性HBV感染者中有7例抗-HBc阳性(χ~2=5.341,P=0.02),但隐匿性HBV感染的存在与年龄、性别等无关.结论 HBV感染存在家庭聚集现象,且在其家族中存在隐匿性HBV感染,并在抗-HBc阳性者中发生率较高.     

Occult hepatitis B in Mexican patients with HIV, an analysis using nested polymerase chain reaction

Hepatitis B virus infection (HBV) with undetectable levels of HBsAg, has been named occult HBV infection and observed in immunosuppressed patients. The aim of this study was to determine the frequency of occult HBV infection in patients with HIV from the West of México, using a combination of serological markers and nPCR. Thirty eight HIV/AIDS patients, 32 men (84.2%) and 6 (5.8%) women, without liver damage related symptoms were studied. HBV coinfection was observed in 10 (26.3%) patients; while only 3 (7.9%) of them were positive to HBsAg. Thus, 7 (18.4%) occult HBV infected patients could be assessed in this population. One (10%) patient with occult HBV infection was positive to anti-HBs, in spite of the reinfection protection attributed to this serological marker. Anti-HBc was detected only in 2 (20%) patients with occult HBV infection. No significant association could be established between occult HBV infection and CD+4 cell count, biochemical, clinical parameters, AIDS stage, or any other risk factor. This study suggest that determination of HBV DNA utilizing highly sensitive techniques, as nPCR, should be performed to detect occult HBV infection, even in the absence of anti-HBc in HIV/ AIDS patients, in order to have a reliable diagnosis, prevent HBV dissemination and acute exacerbation of chronic hepatitis B or even fulminant hepatitis. To our knowledge this is the first study of occult HBV infection in Mexican patients with HIV. However, further studies are necessary in order to determine HBV genotypes and its relationship with evolution and clinical manifestation of the disease.     

Occult Hepatitis B Infection and its Possible Impact on Chronic Hepatitis C Virus Infection

As a well-recognized clinical phenomenon, persistent detectable viral genome in liver or sera in the absence of other serological markers for active hepatitis B virus (HBV) replication is called occult HBV infection. The main mechanism through which occult infection occurs is not completely understood and several possible explanations, such as integration into human genome and maintenance in peripheral mononuclear cells, exist. Occult HBV infection has been reported in different populations, especially among patients with Hepatitis C (HCV) related liver disease. The probable impact of occult HBV in patients with chronic HCV infection has been previously investigated and the evidence suggests a possible correlation with lower response to anti-viral treatment, higher grades of liver histological changes, and also developing hepatocellular carcinoma. However, in the absence of conclusive results, further studies should be conducted to absolutely assess the impact of occult HBV contamination on the HCV related liver disease.     

Outcomes and management of viral hepatitis and human immunodeficiency virus co-infection in liver transplantation

Liver transplantation for human immunodeficiency virus(HIV)positive patients with viral hepatitis co-infection is increasingly offered in many North American and European liver transplant centers.Prior studies have demonstrated acceptable post-transplant outcomes and no increased risk of HIV complications in patients coinfected with hepatitis B virus(HBV).However,liver transplantation in HIV positive patients with hepatitis C virus(HCV)has poorer outcomes overall,requiring careful selection of candidates.This review aims to summarize the published literature on outcomes after transplant in HIV patients with HBV or HCV related end-stage liver disease and recommendations for management.In particular the pre-transplant factors impacting outcomes in HCV/HIV co-infected candidates and importance of multidisciplinary management will be discussed.     

Occult hepatitis B virus infection is not associated with disease progression of chronic hepatitis C virus infection

AIM To clarify the prevalence of occult hepatitis B virus(HBV) infection(OBI) and the association between OBI and liver disease progression, defined as development of liver cirrhosis or hepatocellular carcinoma(HCC), worsening of Child-Pugh class, or mortality in cases of chronic hepatitis C virus(HCV) infection. METHODS This prospective cohort study enrolled 174 patients with chronic HCV infection(chronic hepatitis, n = 83; cirrhosis, n = 47; HCC, n = 44), and evaluated disease progression during a mean follow-up of 38.7 mo. OBI was defined as HBV DNA positivity in 2 or moredifferent viral genomic regions by nested polymerase chain reaction using 4 sets of primers in the S, C, P and X open reading frame of the HBV genome. RESULTS The overall OBI prevalence in chronic HCV patients at enrollment was 18.4%, with 16.9%, 25.5% and 13.6% in the chronic hepatitis C, liver cirrhosis and HCC groups, respectively(P = 0.845). During follow-up, 52 patients showed disease progression, which was independently associated with aspartate aminotransferase 40 IU/L, Child-Pugh score and sustained virologic response(SVR), but not with OBI positivity. In 136 patients who were not in the SVR state during the study period, OBI positivity was associated with neither disease progression, nor HCC development. CONCLUSION The prevalence of OBI in chronic HCV patients was 18.4%, and OBI was not associated with disease progression in South Koreans.     

Occult Hepatitis B Virus Infection in Hemodialysis Patients With Isolated Hepatitis B Core Antibody: A Multicenter Study

Occult hepatitis B virus (HBV) infection is characterized by presence of HBV infection with undetectable hepatitis B surface antigen (HBsAg). Occult HBV infection harbors potential risk of HBV transmission through hemodialysis (HD). The aim of this study was to assess the occult HBV infection in hemodialysis patients with isolated hepatitis B core antibody (anti-HBc). A total of 289 HD patients from five dialysis units in Tehran, Iran, were included in this study. Hepatitis B surface antigen (HBsAg), Hepatitis B surface antibody (anti-HBs), anti-HBc, Hepatitis C antibody (anti-HCV), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were tested in all subjects. The presence of HBV-DNA was determined quantitatively in plasma samples of HD patients with isolated anti-HBc (HBsAg negative, anti-HBs negative and anti-HBc positive) by real-time PCR using the artus HBV RG PCR kit on the Rotor-Gene 3000 real-time thermal cycler. Of 289 patients enrolled in this study, 18 subjects (6.2%, 95% confidence interval (CI), 3.5%–8.9%) had isolated anti-HBc. HBV-DNA was detectable in 9 of 18 patients (50%, 95% CI, 27%–73%) who had isolated anti-HBc. Plasma HBV-DNA load was less than 50 IU/ml in all of these patients. Our study showed that detection of isolated anti-HBc could reflect unrecognized occult HBV infection in HD patients. The majority of these infections are associated with low viral loads.