Prevalence of occult HBV infection among subjects with normal serum ALT levels in Korea

Estimates of the prevalence of occult HBV infection in Asia: a systematic review and meta-analysis

PURPOSE

Occult Hepatitis B virus infection (OBI) is of great significance to the transmission of Hepatitis B virus (HBV) and the evolution of the patient's clinical outcome. We conducted a systematic review and meta-analysis to estimate the prevalence of OBI in Asia.

METHODS

Literature search was conducted in PubMed, Cochrane Library database, Web of Science and Embase with the keywords of 'Hepatitis B virus', 'occult infection', 'prevalence'. 70 studies were included in the meta-analysis. Meta-analysis was performed using random-effects models to calculate the pooled prevalence of OBI and 95% confidence interval (CI). The data were analyzed in R 4.1.2.

RESULTS

The overall prevalence of OBI was 4% (95%CI: 0.03-0.06) in Asia. Subgroup analysis based on geographic region showed a prevalence of 3% (95%CI 0.02-0.06) in East Asia, 9% (95%CI 0.05-0.15) in West Asia, 3% (95%CI 0.01-0.11) in Southern Asia and 9% (95%CI 0.05-0.15) in Southeast Asia. Subgroup analysis demonstrated a prevalence of 1% (95%CI 0.00-0.02) in general population, 5% (95%CI: 0.03-0.08) in high-risk population, 9% (95%CI: 0.03-0.22) in the human immunodeficiency virus (HIV)-infected patient, 18% (95%CI: 0.09-0.32) in the hepatopathy patients.

CONCLUSION

Based on the meta-analysis of the prevalence of OBI in different populations, we concluded that the prevalence of OBI in the high-risk population, hepatopathy patients, and HIV-infected patients was higher than that in the general population. A systematic review showed that OBI was associated with disease progression and prognosis. Therefore, these populations should be routinely screened for OBI and promptly intervened to avoid promoting disease progression.

Occult Hepatitis B Virus Infection and Its Risks of Cryptic Transmission in Southern Ethiopia

BACKGROUND

The detection of hepatitis B virus surface antigen (HBsAg) in serum remains the mainstay in diagnosing and screening of hepatitis B virus (HBV) in most developing countries. The absence of HBsAg in the blood may not indicate the absence of circulating HBV and might be infectious. Thus, this study aimed to estimate the burden and its cryptic transmission risks of occult hepatitis B infection (OBI) among HBsAg negative healthy individuals in Southern Ethiopia.

METHODS

A community-based cross-sectional study was conducted from September 2020 to January 2021. Serum samples were collected and assayed for HBsAg and HBV core antibody (anti-HBc) seromarkers using enzyme-linked immunosorbent assay (ELISA). In anti-HBc positive samples, HBV DNA was detected using real-time polymerase chain reaction (RT-PCR). Data were entered into Epi-Data version 3.1, cleaned, and analyzed using SPSS version 21.0. Descriptive and logistic regression analyses were employed. Statistical significance was decided at p < 0.05.

RESULTS

A total of 346 were individuals included in this study; 34 (9.8%) were tested positive for HBsAg. The rest 312 (90.2%) negatively tested were further assayed for anti-HBc, and 115 (36.7%) were found positive implying previous exposure to HBV, and 21 (18.3%) out of 115 anti-HBc positives had HBV DNA signifying OBI. The HBV DNA concentration below 200 IU/mL was 85.7%. A high rate of OBI was observed among individuals who had multiple sexual contacts, a family history of hepatitis, and tattooing.

CONCLUSION

In this study, the prevalence of OBI is high. This indicates the burden of HBV is considerable since screening is exclusively dependent on HBsAg which will not eliminate the possibility of residual cryptic transmission through blood donation, organ transplantation, perinatal transmission, and other contacts. Our results demonstrate that nucleic acid-based testing (NAT) should be an essential part of screening to prevent missing OBI.

Occult HCV and occult HBV coinfection in Iranian human immunodeficiency virus-infected individuals

The presence of hepatitis C virus (HCV) genome in liver biopsy or peripheral blood mononuclear cell (PBMC) specimens in the absence of detectable HCV-RNA in plasma of the people with or without anti-HCV antibodies has defined as occult HCV infection (OCI), whereas occult hepatitis B virus infection (OBI) is detection of hepatitis B virus (HBV) genome in the absence of traceable hepatitis B surface antigen in the plasma samples of patients. The purpose of this study is to determine the presence of OBI and OCI in human immunodeficiency virus (HIV)-infected individuals. In this cross-sectional research, 190 Iranian HIV-infected individuals were enrolled from September 2015 to February 2019. All participants were tested regarding various serological markers for HCV and HBV infections. Viral RNA and DNA were extracted from plasma and PBMC specimens, and the presence of HCV-RNA in plasma and PBMC samples was tested using reverse transcriptase-nested polymerase chain reaction (PCR), HBV viral load was determined in plasma samples using COBAS TaqMan 48 Kit, and also the presence of the HBV-DNA in PBMC samples was tested by real-time PCR. In this study, the prevalence of OBI and OCI in HIV-infected individuals was 3.1% and 11.4%, respectively. The genotypes of HCV in the patients with OCI were as follows: 57.1% were infected with subtype 3a, 35.7% were infected with subtype 1a, and 7.1% was infected with subtype 1b. It is noteworthy that in this study, two patients (1.1%) had OCI/OBI coinfections. The present study revealed that 1.1% of Iranian HIV-infected individuals had OBI and OCI at the same time. Therefore, it seems that designing prospective surveys to determine the presence of this coinfection in HIV-infected individuals is informative.

Evaluation of clinical sensitivity and specificity of hepatitis B virus (HBV), hepatitis C virus, and human immunodeficiency Virus-1 by cobas MPX: Detection of occult HBV infection in an HBV-endemic area

BACKGROUND

Transfusion-transmitted infectious diseases remain a major concern for blood safety, particularly with hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Nucleic acid testing (NAT) in donor screening shortens the serologically negative window period and reduces virus transmission. The cobas MPX (Roche Molecular Systems, Inc., Branchburg, New Jersey) is a recently developed multiplex qualitative PCR system that enables the simultaneous detection of HBV, HCV, and HIV with improved sensitivity and throughput using cobas 6800 and 8800 instruments.

OBJECTIVES

The aim of this study was to conduct an evaluation of the clinical sensitivity and specificity of cobas MPX detection of HBV, HCV, and HIV in clinical specimens.

STUDY DESIGN

Among samples referred for HBV, HCV, and HIV-1 quantification at Severance Hospital, Yonsei University College of Medicine, positive samples were selected to evaluate sensitivity. A total of 843 samples was tested using both cobas MPX and COBAS AmpliPrep/COBAS TaqMan Tests for HBV, HCV, and HIV-1 using the cobas 8800 system and a COBAS TaqMan 96 analyzer, respectively. Samples that showed discrepancies were confirmed by nested PCR.

CONCLUSIONS

The cobas MPX achieved excellent sensitivity and specificity for the detection of HBV, HCV, and HIV-1 in clinical samples. We found that the lower limit of detection (LOD) of blood screening by NAT actually improves clinical sensitivity, and occult HBV infection prevalence among healthy employees of the hospital was rather high.

Occult hepatitis B virus infection among hepatitis C virus seropositive and seronegative blood donors in Alexandria, Egypt

BACKGROUND AND AIMS

Occult hepatitis B virus infection (OBI, serum hepatitis B surface antigen negative but hepatitis B virus DNA positive) is an emerging problem in the safety of blood transfusion. The introduction of hepatitis B surface antigen in the screening panel for blood bank donors has substantially reduced, but not entirely eliminated, the risk of hepatitis B virus infection. It has been suggested that infection with hepatitis C virus may inhibit hepatitis B virus replication. Therefore, this study aimed at estimating the prevalence and risk factors for OBI among blood donors and determining its relationship with hepatitis C virus infection.

SUBJECTS AND METHODS

Presence of hepatitis B virus DNA and hepatitis C virus RNA was investigated for among 508 hepatitis B surface antigen-negative blood donors in Alexandria, Egypt. Half of the donors were identified as hepatitis C virus antibody reactive.

RESULTS

OBI was detected in 21 donors (4.1%) from the studied population: eight were among hepatitis C virus antibody positive donors (3.2%), among whom seven (33.3%) had hepatitis C virus RNA in their serum, and 13 (5.1%) were among hepatitis C virus antibody negative donors, with no statistically significant difference. The only significant risk factor for OBI among the studied blood donors was visiting local barbers.

CONCLUSION AND RECOMMENDATIONS

OBI is a considerable risk in blood banks, making screening for hepatitis B virus infection only on the basis of surface antigenemia insufficient.

[Clinical features of non-alcoholic fatty liver disease in cryptogenic hepatocellular carcinoma]

BACKGROUND/AIMS

Nonalcoholic fatty liver disease (NAFLD) may be one of the important causes of cryptogenic hepatocellular carcinoma (HCC). The aim of this study was to evaluate whether patients with cryptogenic HCC share clinical features similar to that of NAFLD.

METHODS

Cryptogenic HCC was defined as HCC that occurs in patients with the following conditions: HBsAg(-), anti-HCV(-), and alcohol ingestion of less than 20 g/day. All patients diagnosed with cryptogenic HCC from 2005 to 2012 (cryptogenic HCC group), and all patients diagnosed with HBV associated HCC between 2008 and 2012 (HBV-HCC group) were enrolled in the present study. Clinical features, BMI, lipid profiles, presence of diabetes mellitus, hypertension, and metabolic syndrome were compared between the two groups.

RESULTS

Cryptogenic HCC group was composed of 35 patients (19 males and 16 females) with a mean age of 70 ± 11 years. HBV-HCC group was composed of 406 patients (318 males and 88 females) with a mean age of 56 ± 7 years. Patients in the cryptogenic HCC group were older (p=0.001) and female dominant (p=0.042) than those in the HBV-HCC group. There were no differences in the laboratory test results including lipid profiles and Child-Turcotte-Pugh class between the two groups. Patients in the cryptogenic HCC group had higher prevalence of diabetes (37% vs. 17%, p=0.015), hypertension (49% vs.27%, p=0.051), metabolic syndrome (37% vs. 16%, p=0.001), and higher BMI (25.3 kg/m(2) vs. 24.1 kg/m(2), p=0.042) than those in the HBV- HCC group. The tumor stage was more advanced (stage III and IV) at diagnosis in the cryptogenic HCC group than in the HBV-HCC group (60% vs. 37%, p=0.007).

CONCLUSIONS

Cryptogenic HCC has clinical features similar to that of NAFLD and is diagnosed at a more advanced tumor stage.

Hepatitis B virus reactivation associated with antirheumatic therapy: Risk and prophylaxis recommendations

Accompanying the increased use of biological and non-biological antirheumatic drugs, a greater number of cases of hepatitis B virus (HBV) reactivation have been reported in inactive hepatitis B surface antigen (HBsAg) carriers and also in HBsAg-negative patients who have resolved HBV infection. The prevalence of resolved infection varies in rheumatic disease patients, ranging from 7.3% to 66%. Through an electronic search of the PubMed database, we found that among 712 patients with resolved infection in 17 observational cohort studies, 12 experienced HBV reactivation (1.7%) during biological antirheumatic therapy. Reactivation rates were 2.4% for etanercept therapy, 0.6% for adalimumab, 0% for infliximab, 8.6% for tocilizumab, and 3.3% for rituximab. Regarding non-biological antirheumatic drugs, HBV reactivation was observed in 10 out of 327 patients with resolved infection from five cohort studies (3.2%). Most of these patients received steroids concomitantly. Outcomes were favorable in rheumatic disease patients. A number of recommendations have been established, but most of the supporting evidence was derived from the oncology and transplantation fields. Compared with patients in these fields, rheumatic disease patients continue treatment with multiple immunosuppressants for longer periods. Optimal frequency and duration of HBV-DNA monitoring and reliable markers for discontinuation of nucleoside analogues should be clarified for rheumatic disease patients with resolved HBV infection.

Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants

Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult infections caused by HBV genotype C2; the variants of preS and S related to severe liver diseases among chronically infected patients were also responsible for the majority of HBV occult infections. We also reported that HBsAg variants from occult-infected Korean individuals exhibit lower HBsAg secretion capacity but not reduced HBV DNA levels. In addition, these variants exhibit increased ROS-inducing capacity compared with the wild-type strain, linking HBV occult infections to liver cell damage. Taken together, our previous reports suggest the transmission potential of distinct HBV occult infection-related variants in South Korea.

Investigation of occult hepatitis B virus infection in anti-hbc positive patients from a liver clinic

Occult hepatitis B infection (OBI) is manifested by presence of very low levels (<200IU/mL) of Hepatitis B viral DNA (HBV DNA) in the blood and the liver while exhibiting undetectable HBV surface antigen (HBsAg). The molecular mechanisms underlying this occurrence are still not completely understood. This study investigated the prevalence of OBI in a high-risk Australian population and compared the HBV S gene sequences of our cohort with reference sequences. Serum from HBV DNA positive, HBsAg negative, and hepatitis B core antibody (anti-HBc) positive patients (study cohort) were obtained from samples tested at SEALS Serology Laboratory using the Abbott Architect, as part of screening and diagnostic testing. From a total of 228,108 samples reviewed, 1,451 patients were tested for all three OBI markers. Only 10 patients (0.69%) out of the 1,451 patients were found to fit the selection criteria for OBI. Sequence analysis of the HBV S gene from 5 suspected OBI infected patients showed increased sequence variability in the ‘a’ epitope of the major hydrophilic region compared to reference sequences. In addition, a total of eight consistent nucleotide substitutions resulting in seven amino acid changes were observed, and three patients had truncated S gene sequence. These mutations appeared to be stable and may result in alterations in HBsAg conformation. These may negatively impact the affinity of hepatitis B surface antibody (anti-HBs) and may explain the false negative results in serological HBV diagnosis. These changes may also enable the virus to persist in the liver by evading immune surveillance. Further studies on a bigger cohort are required to determine whether these amino acid variations have been acquired in the process of immune escape and serve as markers of OBI.

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.

Rare detection of occult hepatitis B virus infection in children of mothers with positive hepatitis B surface antigen

The prevalence of occult Hepatitis B virus (HBV) infection in children was considerably varied from 0.1-64% in different reports. In this study we aimed to investigate the prevalence of occult HBV infection among the children born to mothers with positive hepatitis B surface antigen (HBsAg) in Jiangsu, China. Serum samples were collected from 210 children of 207 mothers with positive HBsAg. HBV serological markers were detected by ELISA and HBV DNA was detected by nested PCR. Homology comparison of HBV sequences recovered from the child and mother was used to define the infection. Three children (1.43%) were positive for HBsAg, in whom the HBV pre S and S gene sequence in each child was identical to that in her mother. Of the 207 HBsAg-negative children, nine displayed HBV DNA positive by two nested PCR assays using primers derived from S and C genes. However, the sequence alignment showed that the sequences in each child were considerably different from those in his/her mother. Therefore, the sequences amplified from the children were very likely resultant from the cross-contaminations. Furthermore, the nine children with 'positive HBV DNA' were all negative for anti-HBc, and one had anti-HBs 3.42 mIU/ml and eight others had anti-HBs from 72 to >1000 mIU/ml, indicating that the nine children were less likely infected with HBV. Therefore, none of the 207 HBsAg-negative children of HBV-infected mothers was found to have occult HBV infection. We conclude that the prevalence of occult HBV infection in vaccinated children born to HBsAg positive mothers should be extremely low. We recommend that homology comparison of sequences recovered from the child and mother be used to define the occult HBV infection in children born to HBV infected mothers.

What is the meaning of a nonresolved viral nucleic acid test-reactive minipool?

BACKGROUND

This study aimed at analyzing the prevalence of hepatitis B virus (HBV) DNA among hepatitis B surface antigen (HBsAg)-negative donations by cobas TaqScreen MPX test (Roche Molecular Systems) and discussing the meaning of a reactive minipool (MP) that does not resolve to an individual donation (ID)-reactive result.

STUDY DESIGN AND METHODS

Nucleic acid amplification testing (NAT) was performed in 12 Chinese blood centers on 826,044 serologic negative donations in MPs of six. MP-reactive pools that were resolved to ID-reactive donations were confirmed by Roche TaqMan viral load assays. Antibody to hepatitis B surface antigen and antibody to hepatitis B core antigen (anti-HBc) results were also analyzed. Cycle threshold (Ct) values of reactive MPs were analyzed in relation to the probability of pool resolution.

RESULTS

A total of 1267 of 137,674 pools were reactive, of which 839 donations were reactive by ID-NAT. The MP6 HBV NAT-yield rate lay between 1 in 1600 and 1 in 1000. At MP Ct values equal or below 37, the probability of pool resolution was approximately 80%. The prevalence of anti-HBc in ID-reactive donations was 81%. The proportion of reactive pools that could not be resolved was 36%. The prevalence of anti-HBc in donations implicated in nonresolved MPs was significantly higher than those in nonreactive MPs (48% vs. 37%, p = 0.016).

CONCLUSION

The anti-HBc data suggest that approximately 10% of nonresolved MPs contain HBV DNA from a low-viral-load occult carrier. We consider ID-NAT resolution testing in duplicate to minimize HBV transmission risk associated with transfusing nonreactive donations implicated in reactive MPs.

[Occult hepatitis B virus infection and hepatocellular carcinoma]

Many studies have suggested that occult HBV infection has a substantial clinical relevance to hepatocellular carcinoma (HCC). Occult HBV infection is an important risk factor for the development of cirrhosis and HCC in patients without HBsAg. As a matter of fact, occult HBV infection is one of the most common causes of crytogenic HCC in endemic areas of HBV. However, there still are controversial issues about the association between occult HBV infection and HCC according to the underlying liver disease. In alcoholic cirrhosis, occult HBV infection may exert synergistic effect on the development of HCC. However, there is insufficient evidence to relate occult HBV infection to hepatocarcinogenesis in non-alcoholic fatty liver disease. In cryptogenic HCC, occult HBV infection may play a direct role in the development of HCC. In order to elucidate the assocciation between occult HBV infection and HCC, underlying liver disease must be specified and larger number of cases must be included in future studies.

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

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

Occult hepatitis B virus infection 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.

Prevalence of occult hepatitis B virus infection in hemodialysis patients

BACKGROUND/AIMS

The prevalence of occult HBV infection depends on the prevalence of HBV infection in the general population. Hemodialysis patients are at increased risk for HBV infection. The aim of this study was to determine the prevalence of occult HBV infection in hemodialysis patients.

METHODS

Total of 98 patients undergoing hemodialysis in CHA Bundang Medical Center (Seongnam, Korea) were included. Liver function tests and analysis of HBsAg, anti-HBs, anti-HBc and anti-HCV were performed. HBV DNA testing was conducted by using two specific quantitative methods.

RESULTS

HBsAg was detected in 4 of 98 patients (4.1%), and they were excluded. Among 94 patients with HBsAg negative and anti-HCV negative, one (1.1%) patient with the TaqMan PCR test and 3 (3.2%) patients with the COBAS Amplicor HBV test were positive for HBV DNA. One patient was positive in both methods. Two patients were positive for both anti-HBs and anti-HBc and one patient was negative for both anti-HBs and anti-HBc.

CONCLUSIONS

The present study showed the prevalence of occult HBV infection in HBsAg negative and anti-HCV negative patients on hemodialysis at our center was 3.2%. Because there is possibility of HBV transmission in HBsAg negative patients on hemodialysis, more attention should be given to prevent HBV transmission.

Occult hepatitis B virus infection as a cause of posttransfusion hepatitis in patients with cancers

BACKGROUND

Prevalence of hepatitis B virus (HBV) infection is increased in patients of cancer with increased mortality. Multiple transfusions of blood and blood-related products are a potential source.

AIMS

This study aims to assess the incidence of hepatitis B surface antigen (HBsAg) seroconversion in cancer patients receiving transfusion of blood or blood-related products and identify possible reasons for infection in these patients.

MATERIAL AND METHODS

Patients of cancer receiving blood products, who were HBsAg-, anti-hepatitis B core (HBc)-, and HBV DNA-negative prior to transfusion, were tested for HBsAg by ELISA at 6, 12, and 24 weeks after the last transfusion. Blood donors were screened for HBsAg by ELISA.

RESULTS

Twenty of 3,600 (0.56 %) blood donors tested positive for HBsAg and were rejected. Nine of 150 (6 %) cancer patients became HBsAg-positive posttransfusion which included seven patients who presented with acute hepatitis B and other two patients who remained HBsAg-positive without hepatitis. In 6/9 (66.6 %) patients, HBsAg positivity was related to blood transfusion as their corresponding blood donors on retesting the stored samples were positive for anti-HBc antibody and HBV DNA. In other three patients, the cause of their HBsAg positivity could not be ascertained.

CONCLUSION

Occult HBV infection in blood donors is a potential source of posttransfusion HBV infection in recipients. Anti-HBc antibody and HBV DNA should be tested in blood donors especially when blood is given to cancer patients receiving chemotherapy.

Hepatitis B in immunosuppressed cancer patients: pathogenesis, incidence and prophylaxis

BACKGROUND

Hepatitis B virus (HBV) reactivation in immunosuppressed cancer patients is a serious clinical problem for HBV carriers undergoing chemotherapy, because it may result in severe liver injury and prevent completion of life-saving treatment of the underlying malignant disease.

DESIGN

We reviewed the literature on the incidence, pathogenesis and management of hepatitis B in immunosuppressed cancer patients. The role of primary prophylaxis has also been reviewed.

RESULTS

Patients with a previous HBV infection (negative for hepatitis B surface antigen [HBsAg], and positive for both hepatitis B core antibody [anti-HBc] and/or hepatitis B surface antibody [HBsAb]) can experience HBV reactivation. All guidelines support screening of patients with cancer who are about to undergo potentially immunosuppressive therapy, even if the ASCO provisional clinical opinion considers the screening for patients at heightened risk for chronic HBV infection or if undergoing highly immunosuppressive therapy, as hematopoietic cell transplantation and regimens including rituximab. Several meta-analyses support the prophylactic role of lamivudine in preventing HBV reactivation. Most of studies evaluated retrospectively or, if prospectively designed, compared the effect of prophylactic antiviral therapy against historical controls.

CONCLUSION

Screening for HBV should be considered before chemotherapy. Prophylaxis with lamivudine can reduce the incidence of HBV reactivation as well as HBV-related morbidity and mortality. Unsolved issues include the role of antiviral agent with higher potency and less resistance, how to monitor patients for reactivation and when to stop prophylaxis.

Occult HBV infection

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

Non-bacterial infections in Asian patients treated with alemtuzumab: a retrospective study of the Asian Lymphoma Study Group

This retrospective study concerns non-bacterial infections in Asian patients receiving alemtuzumab. The clinical data of 182 patients treated with alemtuzumab alone or alemtuzumab-containing chemotherapy between the years 2003 and 2009 was collected from six Asian countries. Alemtuzumab was used in the setting of frontline (n =48) or salvage (n =90) treatment, and as a part of the conditioning regimen for allogeneic stem cell transplant (n =44). Reactivation of cytomegalovirus (66/182) and varicella zoster virus (25/182), and fungal infection (31/182) including invasive pulmonary aspergillosis, were the most common infectious complications in this retrospective analysis. Thus, we recommend routine prophylaxis with valganciclovir and itraconazole, especially when alemtuzumab is used in the conditioning regimen for allogeneic stem cell transplant. Pneumocystis jirovecii pneumonia (PJP) was found in four patients (3%, 4/122) receiving alemtuzumab as conditioning for stem cell transplant or salvage treatment. Three cases of hepatitis B virus reactivation were found in antigen-negative patients, and 16 cases of tuberculosis were observed. Infection is the major complication of alemtuzumab therapy, and these infectious complications are potentially severe and life-threatening. Based on our retrospective analysis, we have constructed a guideline for antimicrobial prophylaxis in Asian patients receiving alemtuzumab therapy.

The characteristics of the synonymous codon usage in hepatitis B virus and the effects of host on the virus in codon usage pattern

BACKGROUND

Hepatitis B virus (HBV) infection is one of the main human health problem and causes a large-scale of patients chronic infection worldwide.. As the replication of HBV depends on its host cell system, codon usage pattern for the viral gene might be susceptible to two main selections, namely mutation pressure and translation selection. In this case, a deeper investigation between HBV evolution and host adaptive response might assist control this disease.

RESULT

Relative synonymous codon usage (RSCU) values for the whole HBV coding sequence were studied by Principal component analysis (PCA). The characteristics of the synonymous codon usage patterns, nucleotide contents and the comparison between ENC values of the whole HBV coding sequence indicated that the interaction between virus mutation pressure and host translation selection exists in the processes of HBV evolution. The synonymous codon usage pattern of HBV is a mixture of coincidence and antagonism to that of host cell. But the difference of genetic characteristic of HBV failed to be observed to its different epidemic areas or subtypes, suggesting that geographic factor is limited to influence the evolution of this virus, while genetic characteristic based on HBV genotypes could be divided into three groups, namely (i) genotyps A and E, (ii) genotype B, (iii) genotypes C, D and G.

CONCLUSION

Codon usage patterns from PCA for identification of evolutionary trends in HBV provide an alternative approach to understand the evolution of HBV. Further more, a combined selection of mutation pressure with translation selection on codon usage might shed a light on understanding the evolutionary trends of HBV genotypes.

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 seems to be higher among subjects at high risk for HBV infection and with liver disease than among individuals at low risk of infection and without liver disease.

Prevalence of antibodies to hepatitis B core antigen and occult hepatitis B virus infections in Korean blood donors

BACKGROUND

This study was performed to determine the prevalence of antibodies to hepatitis B core antigen (anti-HBc) among Korean blood donors and frequencies of hepatitis B virus (HBV) DNA and antibodies to hepatitis B surface antigen (anti-HBs) in anti-HBc-positive donors.

STUDY DESIGN AND METHODS

A total of 12,461 consenting blood donors were consecutively enrolled from Korean Red Cross Blood Services from April to October 2008. All of the donors were screened for anti-HBc with an electrochemiluminescence immunoassay. Repeat-reactive anti-HBc-positive donors were assayed for anti-HBs and for HBV DNA using a multiplex test (Cobas TaqScreen, Roche Molecular Systems) on individual donation.

RESULTS

Of the 12,461 donors, 1682 (13.5%) were reactive for anti-HBc. Among different age groups, there was a steady increase in the anti-HBc-positive rate, ranging from 2.0% in the age group of less than 20 years to 80.0% in the age group of 60 years and older (p<0.0001). Of the anti-HBc-positive donors, 1523 (90.5%) were anti-HBs positive. HBV DNA was detected in two donors who were anti-HBc positive and hepatitis B surface antigen negative. The prevalence of occult HBV infection was 0.016%, and the HBV nucleic acid test (NAT) yield was 1 in 838 (0.12%).

CONCLUSION

This study helps to determine the current status of hepatitis B infection and the prevalence of occult HBV infection in the blood donor population in Korea. We estimate that in Korea, up to 161 units per million donated units from blood donors may contain HBV DNA. Although the potential infectivity of these units has been debated upon, the HBV NAT assay could prevent certain transfusion-transmitted HBV infections.

Development of occult hepatitis B viral infection in pregnancy: implications for antenatal screening in women from endemic areas

Occult hepatitis B virus (HBV) infection, manifest clinically by the presence of HBV deoxyribonucleic acid (HBV DNA) in peripheral blood in individuals who test negative for the HBV surface antigen (HBsAg), may occur in various clinical contexts, including under the influence of pharmacological immunosuppression in patients from areas endemic for HBV and, hence, at risk of previous exposure. Pregnancy is a condition associated with immune suppression, but whether virus-specific immunity may be suppressed to an extent sufficient to allow occult HBV infection to develop is currently unknown. This is potentially relevant not only to the mother's health but also because vertical transmission has been reported in the occult HBV infection setting. We report a 30-year-old woman from a country endemic for HBV who, prior to pregnancy, was persistently HBsAg-negative with undetectable HBV DNA in peripheral blood, in whom HBV DNA became increasingly detectable during pregnancy, peaking in the third trimester, before returning to undetectable levels postpartum. HBsAg remained negative and liver function tests were normal throughout. Immunoglobulin M hepatitis B core antibody, a marker of the possibility of acquisition of a new HBV infection, was also negative. The baby received immunization against HBV infection from birth and has remained HBV negative at six months. This report documents for the first time that occult HBV infection may develop during pregnancy. Further data are required regarding the prevalence of this phenomenon, predisposing factors, impact on maternal health and risk of vertical transmission so that implications for current antenatal screening strategies that do not include measurement of HBV DNA in peripheral blood can be properly determined.

Detection of hepatitis B virus DNA among accepted blood donors in Nanjing, China

BACKGROUND

Posttransfusion hepatitis B virus (HBV) infection still occurs although its incidence has been substantially reduced since the introduction of screening of hepatitis B surface antigen (HBsAg) in blood donors. This study aimed to investigate the occult HBV infection in accepted blood donors in Nanjing, China.

RESULTS

The lower detection limit of the nested PCR in this study was estimated to be 20 copies/ml HBV DNA. The positive rate of occult HBV infection was 0.13% (5 of 2972) in the accepted blood donors. Sequencing data showed that the amplified HBV sequences were not identical each other and to the known sequences cloned in our laboratory, excluding the false-positive caused by cross-contamination. Phylogenetic analysis showed that the HBV in all five donors was genotype B; a single base deletion was detected in the S region of HBV DNA from one donor, and no mutation was observed in the "a" determinant of HBsAg from four other donors. All five donors were negative for anti-HBs and one was positive for anti-HBc.

CONCLUSIONS

The prevalence of occult HBV infection in the accepted blood donors in Nanjing, China is relatively high. The data would be meaningful in adapting strategy to eliminate posttransfusion HBV infection in China.

Occult hepatitis B virus infection: a covert operation

Detection of occult hepatitis B requires assays of the highest sensitivity and specificity with a lower limit of detection of less than 10 IU/mL for hepatitis B virus (HBV) DNA and <0.1 ng/mL for hepatitis B surface antigen (HBsAg). This covert condition is relatively common in patients with chronic hepatitis C virus (HCV) that seems to exert some influence on the replicative capacity and latency of HBV. Detection of virus-specific nucleic acid does not always translate into infectivity, and the occurrence of primer-generated HBV DNA that is of partial genomic length in immunocompetent individuals who have significant levels of hepatitis B surface antibody (anti-HBs) may not be biologically relevant. Acute flares of alanine aminotransferase (ALT) that occur during the early phase of therapy for HCV or ALT levels that remain elevated at the end of therapy in biochemical nonresponders should prompt an assessment for occult hepatitis B. Similarly, the plasma from patients with chronic hepatitis C that is hepatitis B core antibody (anti-HBc) positive (+/-anti-HBs at levels of <100 mIU/mL) should be examined for HBV DNA with the most sensitive assay available. If a liver biopsy is available, immunostaining for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) should be contemplated and a portion of the sample tested for HBV DNA. This is another reason for optimal collection of a specimen (e.g. two passes with a 16-guage needle under ultrasound guidance). Transmission of HBV to immunosuppressed orthotopic liver transplant recipients by donors with occult hepatitis B (OHB) will continue to occupy the interests of the transplant hepatologist. As patients with OHB may have detectable HBV DNA in serum, peripheral blood mononuclear cells (PBMC) and/or liver that can be reactivated following immunosuppression or intensive cytotoxic chemotherapy, the patient needs to be either monitored or treated depending on the pretreatment serological results such as an isolated anti-HBc reaction or a detectable HBV DNA.

Quantitation of hepatitis B virus DNA in plasma using a sensitive cost-effective "in-house" real-time PCR assay

BACKGROUND

Sensitive nucleic acid testing for the detection and accurate quantitation of hepatitis B virus (HBV) is necessary to reduce transmission through blood and blood products and for monitoring patients on antiviral therapy. The aim of this study is to standardize an "in-house" real-time HBV polymerase chain reaction (PCR) for accurate quantitation and screening of HBV.

MATERIALS AND METHODS

The "in-house" real-time assay was compared with a commercial assay using 30 chronically infected individuals and 70 blood donors who are negative for hepatitis B surface antigen, hepatitis C virus (HCV) antibody and human immunodeficiency virus (HIV) antibody. Further, 30 HBV-genotyped samples were tested to evaluate the "in-house" assay's capacity to detect genotypes prevalent among individuals attending this tertiary care hospital.

RESULTS

The lower limit of detection of this "in-house" HBV real-time PCR was assessed against the WHO international standard and found to be 50 IU/mL. The interassay and intra-assay coefficient of variation (CV) of this "in-house" assay ranged from 1.4% to 9.4% and 0.0% to 2.3%, respectively. Virus loads as estimated with this "in-house" HBV real-time assay correlated well with the commercial artus HBV RG PCR assay ( r = 0.95, P < 0.0001).

CONCLUSION

This assay can be used for the detection and accurate quantitation of HBV viral loads in plasma samples. This assay can be employed for the screening of blood donations and can potentially be adapted to a multiplex format for simultaneous detection of HBV, HIV and HCV to reduce the cost of testing in blood banks.

Prevalence and virological features of occult hepatitis B virus infection in female sex workers who work uncontrolled in Turkey

BACKGROUND

There is little information about the prevalence of occult hepatitis B virus infection (OHBVI). We have investigated the prevalence and virological features of OHBVI among female sex workers (FSWs) in Istanbul.

METHODS

Hepatitis B surface antigen (HBsAg) was tested in FSWs who work uncontrolled and were admitted to Venereal Diseases Hospital. HBV DNA and anti-HBs were investigated in all the HBsAg-negative cases. Hepatitis B envelope (HBe) antigen, anti-HBe, anti-hepatitis B core (HBc) antigen, HBV genotype, S gene and precore (PC)/basic core promoter (BCP) mutations were determined in HBV DNA-positive sera.

RESULTS

Two hundred and eighty-six volunteers were enrolled and 32.5% (n=93) of them had anti-HBs positivity. HBV DNA (range 30-209 copy/ml) was positive in 11 anti-HBs-negative and two anti-HBs-positive cases. The prevalence of OHBVI was 4.5% (13/286). Anti-HBc was positive in 77% (10/13) of those with OHBVI and anti-HBe positivity was 53.8% (7/13). Only genotype D was present in all occult HBV-infected cases. One PC (G1896A) and one BCP (T1762/A1764) mutation was found, but S gene mutation was not detected in any of the samples.

CONCLUSION

In this population, OHBVI may have a negligible role in the horizontal transmission because of a very low viral load, and PC and core promoter mutations are very rare.

Hepatitis B virus reactivation in a surface antigen-negative and antibody-positive patient after rituximab plus CHOP chemotherapy

Rituximab is a monoclonal antibody that targets B-lymphocytes, and it is widely used to treat non-Hodgkin's lymphoma. However, its use has been implicated in HBV reactivation that's related with the immunosuppressive effects of rituximab. Although the majority of reactivations occur in hepatitis B carriers, a few cases of reactivation have been reported in HBsAg negative patients. However, reactivation in an HBsAg negative/HBsAb positive patient after rituximab treatment has never been reported in Korea. We present here an HBsAg-negative/HBsAb-positive 66-year-old female who displayed reactivation following rituximab plus CHOP chemotherapy for diffuse large B-cell lymphoma. While she was negative for HBsAg at diagnosis, her viral status was changed at the time of relapse as follows: HBsAg positive, HBsAb negative, HBeAg positive, HBeAb negative and an HBV DNA level of 1165 pg/ml. Our observation suggests that we should monitor for HBV reactivation during rituximab treatment when prior HBV infection or occult infection is suspected, and even in the HBsAg negative/HBsAb positive cases.