T cell responses and viral variability in blood donation candidates with occult hepatitis B infection

Altered gut microbiota is associated with the formation of occult hepatitis B virus infection

Hepatitis B virus (HBV), a common blood transmission pathogen worldwide, can lead to viral hepatitis, cirrhosis, liver cancer, and other liver diseases. In particular, occult hepatitis B virus infection (OBI) may be caused by an immune response leading to suppressed virus replication. Gut microbiota can change the immunity status of the human body and, therefore, affect the replication of HBV. Thus, to identify whether there are differences in gut microbiota between HBV carriers and OBI carriers, we collected fecal samples from 18 HBV carriers, 24 OBI blood donors, and also 20 healthy blood donors as negative control. After 16S sequencing, we found that the abundance of Faecalibacterium was significantly reduced in samples from OBI blood donors compared with those from healthy blood donors. Compared with samples from HBV carriers, the samples from OBI blood donors had a significantly increased abundance of Subdoligranulum, which might stimulate immune activation, thus inhibiting HBV replication and contributing to the formation of occult infection. Our findings revealed the potential role of gut microbiota in the formation of OBI and further provided a novel strategy for the treatment of HBV infection.IMPORTANCEOccult hepatitis B virus infection (OBI) is a special form of hepatitis B virus infection with hepatitis B surface antigen (HBsAg) positive and hepatitis B virus (HBV) DNA negative. Gut microbiota may contribute to the immune response leading to suppressed virus replication and, thus, participates in the development of OBI. The study on gut microbiota of OBI blood donors provides novel data considerably advancing our understanding of the immune mechanism for the determination of occult hepatitis B virus infection, which is helpful for improving the strategy of the treatment of HBV infection.

Biomarkers of transfusion transmitted occult hepatitis B virus infection: Where are we and what next?

Blood transfusion is a vital procedure, where transfusion-transmitted infection of hepatitis B virus (HBV) remains an important issue, especially from blood donors with occult hepatitis B virus infection (OBI). Occult hepatitis B virus infection is a complex entity to detect using surrogate blood biomarkers for intrahepatic viral transcriptional activity, requiring a continually refined battery of tests utilised for screening. This review aims to critically evaluate the latest advances in the current blood biomarkers to guide the identification of OBI donors and discuss novel HBV markers that could be introduced in future diagnostic practice. Challenges in detecting low HBV surface antigen levels, mutants, and complexes necessitate ultrasensitive multivalent dissociation assays, whilst HBV DNA testing requires improved sensitivity but worsens inaccessibility. Anti-core antibody assays defer almost all potentially infectious donations but have low specificity, and titres of anti-surface antibodies that prevent infectivity are poorly defined with suboptimal sensitivity. The challenges associated with these traditional blood HBV markers create an urgent need for alternative biomarkers that would help us better understand the OBI. Emerging viral biomarkers, such as pre-genomic RNA and HBV core-related antigen, immunological HBV biomarkers of T-cell reactivity and cytokine levels, and host biomarkers of microRNA and human leucocyte antigen molecules, present potential advances to gauge intrahepatic activity more accurately. Further studies on these markers may uncover an optimal diagnostic algorithm for OBI using quantification of various novel and traditional blood HBV markers. Addressing critical knowledge gaps identified in this review would decrease the residual risk of transfusion-transmitted HBV infection without compromising the sustainability of blood supplies.

Clinical performance of a new multiplex assay for the detection of HIV-1, HIV-2, HCV, HBV, and HEV in blood donations in Catalonia (Spain)

BACKGROUND

Commercial multiplex nucleic acid tests (NATs) for HIV-1/HIV-2/HCV/HBV are widely used in developed countries to screen blood donations. HEV NAT screening has been implemented in some blood banks but is tested with a different assay.

STUDY DESIGN AND METHODS

This study describes the clinical sensitivity and specificity of the Procleix® UltrioPlex E (UPxE) assay on the automated Procleix Panther® system for the simultaneous detection of HIV-1/HIV-2/HCV/HBV/HEV. To evaluate routine performance, 10,138 donations were tested in parallel with UPxE (in ID-NAT) and current assays (Procleix Ultrio Elite [UE] assay in ID-NAT and Procleix HEV assay in pool of 16). To assess clinical sensitivity, archived donations positive for HCV, HIV-1, HBV, HEV, or occult HBV infection (OBI) were tested (n = 104-186).

RESULTS

Five donations were initially reactive (IR) with UPxE; none of them were reactive with current assays. Two of the three samples IR for HIV-1/HIV-2/HCV/HBV were confirmed positive for HBV (HBV NAT and/or anti-HBV core positive) and classified as OBI. The two samples IR for HEV were confirmed positive (Procleix HEV assay in ID-NAT and in-house RT-PCR HEV assay). One sample IR for HIV-1/HIV-2/HCV/HBV with UPxE and another with UE were not confirmed. UPxE showed a specificity of 99.99% for HIV-1/HIV-2/HCV/HBV and 100% for HEV. Comparable sensitivities were observed for HIV-1, HCV, HBV, OBI, and HEV samples tested in the UPxE, UE, and Procleix HEV assays.

DISCUSSION

UPxE may provide an efficient solution for the simultaneous detection of HIV-1, HIV-2, HCV, HBV, and HEV in blood donations in a single test.

HBsAg protein composition and clinical outcomes in chronic hepatitis D and variations across HBeAg-negative chronic HBsAg carriers

Background & Aims

HBsAg proteins are useful to identify HBV inactive carriers (ICs), but data on chronic hepatitis D (CHD) are scarce. This study aimed to describe HBsAg composition in CHD, its changes during the evolution, and the potential association with clinical outcomes. In addition, we assess the composition of HBsAg across different HBV genotypes and validate previous results on HBsAg proteins in an independent HBV cohort.

Methods

Quantitative HBsAg, medium HBsAg proteins (MHBs), and large HBsAg proteins (LHBs) were measured in two cohorts. The first cohort consisted of patients with CHD. A cross-sectional study of samples from two European institutions (N = 46) was conducted. Outcomes were assessed in a retrospective-prospective study of those patients with a follow-up of >1 year (n = 36), and the longitudinal evolution of HBsAg proteins in those with samples >5 years apart (n = 12) was analysed. The second cohort consisted of patients with HBeAg-negative HBV, and a cross-sectional study was performed (N = 141).

Results

Forty-one (89%) patients with CHD had detectable HDV-RNA, and the presence of HDV-RNA was associated with higher LHBs proportion (p = 0.010). Baseline MHBs (p = 0.051) and MHBs proportion (p = 0.086) tended to be higher in those developing clinical outcomes (9/36, 25%) after a median follow-up of 5.9 years. Patients in which HDV-RNA became spontaneously undetectable during follow-up (5/31, 16.1%) tended to present lower MHBs proportion (p = 0.085). In the longitudinal study, changes in LHBs proportion were observed (p = 0.041), whereas MHBs proportion remained stable (p = 0.209). Regarding HBV, ICs showed lower LHBs proportion (p = 0.027). LHBs and MHBs differed significantly according to HBV genotype, regardless of the HBV phase.

Conclusions

Patients with CHD with detectable HDV-RNA presented higher LHBs proportion than those with undetectable HDV-RNA. A trend toward having higher baseline MHBs proportion was observed in patients who developed clinical outcomes or remained with detectable HDV-RNA. This study validates the different HBsAg composition in HBV ICs and reveals the HBV-genotype influence in HBsAg composition.

Impact and implications

The composition of HBsAg in chronic hepatitis D differs in patients with detectable and undetectable HDV viral load and may help predict the likelihood of achieving undetectable HDV viraemia and the development of clinical events such as decompensation. The composition of the surface antigen is also useful to distinguish inactive carriers of HBV, and it varies according to HBV genotype.

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

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

Plasma cytokine profile in occult HBV-infected blood donors

Aim: Cytokine profile in occult HBV infection (OBI) was systematically investigated to identify the immunopathogenesis of OBI. Materials & methods: A total of 46 OBI, ten asymptomatic hepatitis B surface antigen carriers, ten chronic hepatitis B and 12 healthy blood donors were recruited. A total of 21 plasma cytokines were detected. Results: Compared with healthy blood donors, elevated plasma Th1, Th2, Th17 and immune regulatory associated cytokines were observed in OBI. Almost no significant difference was found for these cytokines among OBI, asymptomatic hepatitis B surface antigen carriers and chronic hepatitis B. OBI displayed the predominance of type 2 and regulatory immunity. Conclusion: OBI displayed the general cytokine profile of chronic HBV infection, which might contribute to virus persistence and the presence of the liver microinflammatory environment. The clinical implications of OBI deserve more attention.

Occult Hepatitis B Virus Infection: An Update

Occult hepatitis B virus (HBV) infection (OBI) refers to a condition in which replication-competent viral DNA is present in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for the HBV surface antigen (HBsAg). In this peculiar phase of HBV infection, the covalently closed circular DNA (cccDNA) is in a low state of replication. Many advances have been made in clarifying the mechanisms involved in such a suppression of viral activity, which seems to be mainly related to the host's immune control and epigenetic factors. OBI is diffused worldwide, but its prevalence is highly variable among patient populations. This depends on different geographic areas, risk factors for parenteral infections, and assays used for HBsAg and HBV DNA detection. OBI has an impact in several clinical contexts: (a) it can be transmitted, causing a classic form of hepatitis B, through blood transfusion or liver transplantation; (b) it may reactivate in the case of immunosuppression, leading to the possible development of even fulminant hepatitis; (c) it may accelerate the progression of chronic liver disease due to different causes toward cirrhosis; (d) it maintains the pro-oncogenic properties of the "overt" infection, favoring the development of hepatocellular carcinoma.

Occult hepatitis B — the result of the host immune response interaction with different genomic expressions of the virus

With over 40 years of history, occult hepatitis B infection (OBI) continues to remain an important and challenging public health problem. Defined as the presence of replication-competent hepatitis B virus (HBV) DNA (i.e., episomal HBV covalently closed circular DNA) in the liver and/or HBV DNA in the blood of people who test negative for hepatitis B surface antigen (HBsAg) in currently available assays, OBI is currently diagnosed using polymerase chain reaction (PCR) and real-time PCR assays. However, all efforts should be made to exclude a false negative HBsAg in order to completely follow the definition of OBI. In recent years, significant advances have been made in understanding the HBV lifecycle and the molecular mechanisms that lead to the persistence of the virus in the occult form. These factors are mainly related to the host immune system and, to a smaller proportion, to the virus. Both innate and adaptive immune responses are important in HBV infection management, and epigenetic changes driven by host mechanisms (acetylation, methylation, and microRNA implication) are added to such actions. Although greater genetic variability in the S gene of HBV isolated from OBIs was found compared with overt infection, the mechanisms of OBI are not mainly viral mutations.

Molecular characteristics of the full-length genome of occult hepatitis B virus from blood donors in China

The characteristics of a large sample size of the full-length genome of occult hepatitis B virus (HBV) infection (OBI) have not been extensively explored in China. Voluntary blood donors who were HBsAg-negative/HBV NAT-positive (HBsAg−/HBV NAT+) were identified by blood screening and recruited. Blood samples were tested for HBV serologic markers, viral loads, and PCR to identify OBI. HBV full-length genomes were obtained by amplifying two fragments using nested PCR. The characterization of OBI strains was based on sequence analyses compared with HBsAg+ strains obtained from the same donor population. Of the 50 full-length genomes of 172 identified OBI strains, 33 were classified as genotype B (OBI_B) and 17 strains as genotype C (OBI_C). Significantly higher nucleotide variabilities were observed in the Pre-S2/S promoter region (SP2) and core upstream regulatory sequence (CURS) in OBI_B than in their HBsAg+ controls (P < 0.05). Both OBI_B and OBI_C showed higher amino acid (aa) variabilities in Pol and Pre-S/S regions than their controls (P < 0.05). In addition, 19 novel OBI-related mutations were found spanning the four open reading frames (ORFs) of the HBV genome. Four novel deletions and one novel insertion were also found in OBI_C strains. Several novel OBI-related mutations spanning the four ORFs of the virus were identified by characterizing a large sample size of the full-length OBI genome, which may affect the production of HBsAg and contribute to the occult infection of HBV.

High resolution HLA-DRB1 analysis and shared molecular amino acid signature of DRβ1 molecules in Occult hepatitis B infection

AIM

To investigate the association of human leukocyte antigen (HLA)-DRB1 alleles and the variations of polymorphic amino acid changes in DRβ1 chain in Shaanxi Han population with Occult hepatitis B infection (OBI).

METHODS

High-resolution HLA-DRB1 genotyping was performed in 107 OBI carriers and 280 normal controls. Sequence information was used to assign which amino acids were encoded at all polymorphic positions. Three-dimensional modeling was performed to explore the effect of the key residues on the HLA-DRB1 molecule.

RESULTS

Strong susceptible association for allele DRB1*07:01 was observed in OBI carriers. The amino acid variation at HLA-DRβ1 molecule revealed susceptible associations for residues Gln^4β, Val^57β(P9), Ser^60β(P9) and Val^78β(P4), the amino acids Arg^4β, Asp^57β(P9), Tyr^60β(P9) and Tyr^78β(P4) showed protective associations.

CONCLUSION

Alleles DRB1*07:01 showed strong susceptible associations in OBI carriers. The amino acid variations in DRβ molecules revealed significant molecular markers for susceptibility and protection from OBI in Shaanxi Han population.

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

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

[Prevalence of viral hepatitis B markers among blood donors in the Republic of Guinea]

INTRODUCTION

The problem of transfusion safety in relation to parenteral viral hepatitis still remains relevant. Viral hepatitis B (HB) remains the most common viral infection transmitted through transfusion procedures. One of the natural phases of chronic hepatitis B (CHB) is occult hepatitis B infection (OBI), characterized by an undetectable HBsAg (regardless of the other serological markers content) in the presence of hepatitis B virus (HBV) DNA in the liver tissue and an extremely low, up to undetectable, level of viral load in the blood. In the Republic of Guinea, as in most countries on the continent, the prevention of HBV transmission through transfusion is still based on HBsAg serological testing of donors only. In this connection, OBI remains as a potential threat to blood transfusion safety. Detection of HBV DNA is a reliable preventive measure against transmission of the virus from donors with HBsAg-negative HBV infection, especially in highly endemic regions. In this regard, the study was conducted to substantiate recommendations for improving blood safety against the background of significant HBV prevalence in the Republic of Guinea.The aim of the work was the evaluation of serological and molecular markers of HBV infection in blood donors in the Republic of Guinea.

MATERIAL AND METHODS

We examined 250 blood samples obtained from donors living in Conakry, Republic of Guinea. Samples were tested for the presence of serological (surface antigen, HBsAg; antibodies (ABs) to surface (anti-HBs IgG) and core (anti-HBc IgG) antigens) and molecular (DNA) markers of HBV infection.

RESULTS AND DISCUSSION

The overall detection rate of hepatitis B markers was 83.2%; HBsAg was detected in 16.4% of all individuals. The high incidence of HBsAg in men (19.55%) compared to women (8.45%) was shown, the relative risk of HBV infection with the formation of HBsAg-positive chronic hepatitis B in males was also significantly higher. The prevalence of the HBV DNA in the study group was 30.4%, the OBI cases accounted for 15.6%. The prevalence of this form of the disease was shown in donors aged 30-49 years (24.78%), in the group of people younger than 30 years, the incidence was lower (8.73%), and at the age of over 50 years, OBI was not detected. Based on the phylogenetic analysis of 76 virus isolates, it was shown that genotype E prevails in the examined group (85.53%).Cases of pathogen DNA detection occurred in HBsAg-negative blood donors in the presence of anti-HBs IgG (n = 4), as well as in the simultaneous presence of ABs anti-HBs IgG and anti-HBc IgG (n = 7). The viral load exceeded 200 IU/ml in OBI samples. Escape mutations were detected by sequencing in each OBI sample, contributing to the virus escaping from diagnostic based on screening for HBsAg.

CONCLUSION

Assessment of the prevalence viral hepatitis B markers in blood donors, determination of genotypes and clinically significant mutations of virus variants are necessary to ensure safe medical manipulations, control and prevention of the spread of this infectious agent.

Molecular and Serological Characterization of Hepatitis B Virus (HBV)-Positive Samples with Very Low or Undetectable Levels of HBV Surface Antigen

BACKGROUND

Gaps remain in the detection of nucleic acid test (NAT) yield and occult hepatitis B virus (HBV) infection (OBI) by current HBV surface antigen (HBsAg) assays. The lack of detection may be due to HBsAg levels below current assay detection limits, mutations affecting HBsAg assays or HBsAg levels, or the masking of HBsAg by antibody to HBsAg (anti-HBs). In this study, we evaluate the incremental detection of NAT yield and OBI from five diverse geographic areas by an improved sensitivity HBsAg assay and characterize the samples relative to the viral load, anti-HBs status, and PreS1-S2-S mutations. Included is a comparison population with HBV DNA levels comparable to OBI, but with readily detectable HBsAg (High Surface-Low DNA, HSLD).

METHODS

A total of 347 samples collected from the USA, South Africa, Spain, Cameroon, Vietnam, and Cote D'Ivoire representing NAT yield (HBsAg(-), antibody to HBV core antigen (anti-HBc)(-), HBV DNA(+), N = 131), OBI (HBsAg(-), anti-HBc(+), HBV DNA(+), N = 188), and HSLD (HBsAg(+), anti-HBc(+), HBV DNA(+), N = 28) were tested with ARCHITECT HBsAg NEXT (HBsAgNx) (sensitivity 0.005 IU/mL). The sequencing of the PreS1-S2-S genes from a subset of 177 samples was performed to determine the genotype and assess amino acid variability, particularly in anti-HBs(+) samples.

RESULTS

HBsAgNx detected 44/131 (33.6%) NAT yield and 42/188 (22.3%) OBI samples. Mean HBV DNA levels for NAT yield and OBI samples were lower in HBsAgNx(-) (50.3 and 25.9 IU/mL) than in HBsAgNx(+) samples (384.1 and 139.5 IU/mL). Anti-HBs ≥ 10 mIU/mL was present in 28.6% HBsAgNx(+) and 45.2% HBsAgNx(-) OBI, and in 3.6% HSLD samples. The genotypes were A1, A2, B, C, D, E, F, and H. There was no significant difference between HBsAgNx(-) and HBsAgNx(+) in the proportion of samples harboring substitutions or in the mean number of substitutions per sample in PreS1, PreS2, or S for the NAT yield or OBI (p range: 0.1231 to >0.9999). A total of 21/27 (77.8%) of HBsAgNx(+) OBI carried S escape mutations, insertions, or stop codons. HSLD had more PreS1 and fewer S substitutions compared to both HBsAgNx(-) and HBsAgNx(+) OBI. Mutations/deletions associated with impaired HBsAg secretion were observed in the OBI group.

CONCLUSIONS

HBsAgNx provides the improved detection of NAT yield and OBI samples. Samples that remain undetected by HBsAgNx have exceptionally low HBsAg levels below the assay detection limit, likely due to low viremia or the suppression of HBsAg expression by host and viral factors.

Partial restoration of immune response in Hepatitis C patients after viral clearance by direct-acting antiviral therapy

BACKGROUND & AIMS

HCV CD4+ and CD8+ specific T cells responses are functionally impaired during chronic hepatitis C infection. DAAs therapies eradicate HCV infection in more than 95% of treated patients. However, the impact of HCV elimination on immune responses remain controversial. Here, we aimed to investigate whether HCV cure by DAAs could reverse the impaired immune response to HCV.

METHODS

We analyzed 27 chronic HCV infected patients undergoing DAA treatment in tertiary care hospital, and we determined the phenotypical and functional changes in both HCV CD8+ and CD4+ specific T-cells before and after viral clearance. PD-1, TIM-3 and LAG-3 cell-surface expression was assessed by flow cytometry to determine CD4+ T cell exhaustion. Functional responses to HCV were analyzed by IFN-Ɣ ELISPOT, intracellular cytokine staining (IL-2 and IFN-Ɣ) and CFSE-based proliferation assays.

RESULTS

We observed a significant decrease in the expression of PD-1 in CD4+ T-cells after 12 weeks of viral clearance in non-cirrhotic patients (p = 0.033) and in treatment-naive patients (p = 0.010), indicating a partial CD4 phenotype restoration. IFN-Ɣ and IL-2 cytokines production by HCV-specific CD4+ and CD8+ T cells remained impaired upon HCV eradication. Finally, a significant increase of the proliferation capacity of both HCV CD4+ and CD8+ specific T-cells was observed after HCV elimination by DAAs therapies.

CONCLUSIONS

Our results show that in chronically infected patients HCV elimination by DAA treatment lead to partial reversion of CD4+ T cell exhaustion. Moreover, proliferative capacity of HCV-specific CD4+ and CD8+ T cells is recovered after DAA's therapies.

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

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

Overt and occult hepatitis B among immigrants and native blood donors in Madrid, Spain

Background:

The risk of transfusion-transmitted viral infections is very low in developed countries. Recent massive migration flows from highly hepatitis B virus (HBV), hepatitis C virus (HCV) and/or HIV endemic regions to Europe may have changed this scenario.

Methods:

During 2017 and 2018, a total of 491,753 blood donations (291,762 donors) were evaluated at the Madrid Regional Transfusion Center. All were tested for hepatitis B surface antigen (HBsAg), anti-HCV and anti-HIV, as well as for HBV-DNA, HCV-RNA and HIV-RNA.

Results:

Overall, 35 donors were positive for HIV-RNA and 26 for HCV-RNA. HBV markers were found in 111 (0.022%) donors, split out into three categories: HBsAg+ (n = 93; 0.019%), occult B infection (OBI) (n = 17; 0.003%), and acute HBV window period (n = 1; 0.0002%). All 17 OBI donors were positive for anti-HBc and confirmed as viremic in repeated testing. Viral load amounts were uniformly below 100 IU/mL. Ten OBI donors were repeated donors and look-back studies could be completed for eight of them. Fortunately, none of all prior recipients experienced transfusion transmitted hepatitis B. Compared with HBsAg+ donors, OBI donors were more frequently native Spaniards (76% versus 40%) and older (median age 52 versus 42 years old).

Conclusion:

Active HBV infection is currently found in 0.022% of blood donations (0.038% of donors) in Madrid. This rate is 3-fold greater than for HIV and/or HCV. On the other hand, HBsAg+ donors are 3-fold more frequent than OBI donors and more often immigrants than native Spaniards. No transfusion-transmitted HBV infections were identified during the study period, including retrospective checking of former recipients of OBI donors.

Cytokine profile during occult hepatitis B virus infection in chronic hepatitis C patients

Background

The hepatitis B virus (HBV) is one of the leading causes of acute, chronic and occult hepatitis (OBI) representing a serious public health threat. Cytokines are known to be important chemical mediators that regulate the differentiation, proliferation and function of immune cells. Accumulating evidence indicate that the inadequate immune responses are responsible for HBV persistency. The aim of this study were to investigate the cytokines IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10 and IL-17A in patients with OBI and verify if there is an association between the levels of these cytokines with the determination of clinical courses during HBV occult infection.

Methods

114 patients with chronic hepatitis C were investigated through serological and molecular tests, the OBI coinfected patients were subjected to the test for cytokines using the commercial human CBA kit. As controls, ten healthy donors with no history of liver disease and 10 chronic HBV monoinfected patients of similar age to OBI patients were selected.

Results

Among 114 HCV patients investigated, 11 individuals had occult hepatitis B. The levels of cytokines were heterogeneous between the groups, most of the cytokines showed higher levels of production detection among OBI/HCV individuals when compared to control group and HBV monoinfected pacients. We found a high level of IL-17A in the HBV monoinfected group, high levels of TNF-α, IL-10, IL-6, IL-4 and IL-2 in OBI/HCV patients.

Conclusion

These cytokines could be involved in the persistence of HBV DNA in hepatocytes triggers a constant immune response, inducing continuous liver inflammation, which can accelerate liver damage and favor the development of liver cirrhosis in other chronic liver diseases.

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

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

Hepatitis B virus persistence and reactivation

Hepatitis B virus (HBV) infection causes chronic hepatitis and has long term complications. Individuals ever infected with HBV are at risk of viral reactivation under certain circumstances. This review summarizes studies on HBV persistence and reactivation with a focus on the definitions and mechanisms. Emphasis is placed on the interplay between HBV replication and host immunity as this interplay determines the patterns of persistence following viral acquisition. Chronic infections exhibit as overt persistence when a defective immune response fails to control the viral replication. The HBV genome persists despite an immune response in the form of covalently closed circular DNA (cccDNA) and integrated DNA, rendering an occult state of viral persistence in individuals whose infection appears to have been resolved. We have described HBV reactivation that occurs because of changes in the virus or the immune system. This review aims to raise the awareness of HBV reactivation and to understand how HBV persists, and discusses the risks of HBV reactivation in a variety of clinical settings.

Existence of hepatitis B virus surface protein mutations and other variants: demand for hepatitis B infection control in Cambodia

Background

This study aimed to detect Hepatitis B virus (HBV) genome sequences and their variants as of nationwide scale using dried blood spot (DBS) samples and to provide up-to-date reference data for infection control and surveillance in Cambodia.

Method

Among 2518 children age 5–7 years and their 2023 mothers participated in 2017 Cambodia nationwide sero-survey on hepatitis B surface antigen (HBsAg) prevalence using multistage random sampling strategy, 95 mothers and 13 children positive to HBsAg were included in this study. HBV DNA was extracted from DBS, then performed polymerase chain reaction. HBV genotypes and potential variants were examined by partial and full length genomic analysis.

Results

HBsAg positive rate was 4.7% (95/2023) in mothers and 0.52% (13/2518) in their children. Genotype C (80.49%) was abundantly found throughout the whole Cambodia whilst genotype B (19.51%) was exclusively found in regions bordering Vietnam. S gene mutants of HBV were found in 24.29% of mothers and 16.67% of children with HBV DNA positive sera. Full-length genome analysis revealed the homology of 99.62–100% in each mother-child pair. Genotype B was clarified to recombinant genotype B4/C2 and B2/C2. Double (48.39%) and combination mutation (32.26%) were observed in core promoter region of HBV C1 strains.

Conclusions

This study showed the capable of DBS for large-scale molecular epidemiological study of HBV in resource limited countries. Full-genome sequences yield the better understanding of sub-genotypes, their variants and the degree of homology between strains isolated from mother-child pairs calls for effective strategies on prevention, control and surveillance of mother-to-child HBV transmission in Cambodia.

Evaluation of occult hepatitis B infection in tissue donors: a multicenter analysis in Spain

Traditionally, when antibody to the Hepatitis B core antigen (anti-HBc) and antibody to the Hepatitis B surface antigen (anti-HBs) are positive, the donor is considered suitable. However, the literature contains cases with this profile and circulating hepatitis B virus DNA. The aim of the study is to analyze the incidence of occult hepatitis B virus infection (OBI). Retrospective data were evaluated for deceased tissue donors in ten Tissue Establishments (Spain) during 2017. The data included demographic data and the serological markers for hepatitis B that each tissue establishment performed. A total number of 1933 tissue donors were evaluated. A total of 180 donors were excluded: 6 (0.3%) with Hepatitis B surface antigen (HBs positive), and 174 in which DNA testing was not performed. Anti-HBc was positive in 175 donors (10%), in which anti-HBs was negative in 30 (17.1%) and positive in 145 (82.9%). In total, 27 donors with DNA positive (1.5%) were found, of which 3 of 117 donors (1.7%) showed anti-HBc negative and anti-HBs positive (> 10 IU/ml), 4 of 30 donors (13.3%) showed anti-HBc positive and anti-HBs negative and 20 of 145 donors (13.8%) showed both anti-HBc and anti-HBs positive. The highest probability of finding DNA occurs when anti-HBc is positive, regardless of the presence of anti-HBs. In our study, the probability of OBI was 1.5%. The classic concept that when anti-HBc and anti-HBs are positive (even with a titer of over 100 IU/ml) the donor can be accepted should, therefore, be reconsidered, and DNA testing should be mandatory.

Update of the statements on biology and clinical impact of occult hepatitis B virus infection

In October 2018 a large number of international experts with complementary expertise came together in Taormina to participate in a workshop on occult hepatitis B virus infection (OBI). The objectives of the workshop were to review the existing knowledge on OBI, to identify issues that require further investigation, to highlight both existing controversies and newly emerging perspectives, and ultimately to update the statements previously agreed in 2008. This paper represents the output from the workshop.

Occult hepatitis B virus and surface antigen mutant infection in healthy vaccinated cohorts and children with various forms of hepatitis and multiple transfusions

BACKGROUND AND AIMS

Despite the success of universal infant immunization initiated in Taiwan in 1984, occult hepatitis B virus infection (OBI) and circulating surface antigen mutants remain potential obstacles for eventual eradication of HBV infection.

METHODS

From 3299 apparently healthy, neonatally-vaccinated subjects (<30 years of age ) enrolled during 2014 serosurvey, we recruited all HBsAg-positive (n = 17), all HBsAg-negative but anti-HBc-positive (n = 132) and randomly selected HBsAg-negative and anti-HBc-negative subjects (n = 411). These recruited subjects and 81 HBsAg-negative children with various forms of hepatitis and multiple transfusions were analysed for serum HBV DNA.

RESULTS

In healthy, HBsAg-negative subjects, OBI frequency was higher in anti-HBc-positive than anti-HBc-negative individuals (8/90[8.9%] vs 8/301[2.7%], P = 0.0192) aged <18-years, but was not different between anti-HBc-positive and anti-HBc-negative individuals (0/11[0%] vs 3/110[2.7%], P > 0.05) aged 18 to 30 years. OBI occurred more frequently in children of HBsAg-positive mothers than in children of HBsAg-negative mothers (10/101 [9.9%] vs 1/75 [1.3%], P = 0.025). The prevalence of surface 'a' determinant (aa110-160) mutants was 13.3% (2/15) in OBI subjects compared to 36.4% (4/11) in HBsAg-positive subjects (P > 0.05). OBI was found in 30% (3/10) of serologic 'non-A to E' viral hepatitis, 14.3% (3/21) of chronic hepatitis C and 2.0% (1/50) of multitransfused, thalassemic children.

CONCLUSIONS

In this highly immunized population, surface antigen mutant infection is uncommon and has low contribution to OBI development. HBsAg screening plus highly sensitive HBV DNA assays are needed for assurance of blood supply safety. Multiple transfusions from HBsAg-negative blood donors rarely result in persistent HBV infection. HBV might be related to some of serologic 'non-A to E' viral hepatitis.

Genetic polymorphisms of HLA-DP and isolated anti-HBc are important subsets of occult hepatitis B infection in Indonesian blood donors: a case-control study

BACKGROUND

Occult hepatitis B infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in the serum and/or liver in HBsAg-negative individuals. OBI is associated with the risk of viral transmission, especially in developing countries, and with progressive liver disease and reactivation in immunosuppressive patients. The objective of this study was to evaluate the relation of OBI to HLA-DP single nucleotide polymorphisms (SNPs) encoding antigen-binding sites for the immune response to HBV infection. As HLA-DP variants affect the mRNA expression of HLA-DPA1 and HLA-DPB1 in the liver, we hypothesised that high levels of HLA-DPA1 and HLA-DPB1 expression favour OBI development.

METHODS

The study enrolled 456 Indonesian healthy blood donors (HBsAg negative). OBI was defined as the presence of HBV-DNA in at least two of four open reading frames (ORFs) of the HBV genome detected by nested PCR. SNPs in HLA-DPA1 (rs3077) and HLA-DPB1 (rs3135021, rs9277535, and rs2281388) were genotyped using real-time Taqman® genotyping assays.

RESULTS

Of 122 samples positive for anti-HBs and/or anti-HBc, 17 were determined as OBI. The minor allele in rs3077 was significantly correlated with OBI [odds ratio (OR) = 3.87, 95% confidence interval (CI) = 1.58-9.49, p = 0.0015]. The prevalence of the minor allele (T) was significantly higher in subjects with OBI than in those without (59% and 33%, respectively). The combination of haplotype markers (TGA for rs3077-rs3135021-rs9277535) was associated with increased risk of OBI (OR = 4.90, 95%CI = 1.12-21.52 p = 0.038). The prevalence of OBI was highest in the isolated anti-HBc group among the three seropositive categories: anti-HBs <500 mIU/ml, anti-HBs ≥500 mIU/ml, and isolated anti-HBc (29.41%, p = 0.014).

CONCLUSION

Genetic variants of HLA-DP and the presence of anti-HBc are important predictors of OBI in Indonesian blood donors.

TRIAL REGISTRATION

Ref: KE/FK/194/EC; registered 01 March 2013. Continuing approval Ref: KE/FK/536/EC; registered 12 May 2014.

Serum hepatitis B core-related antigen is more accurate than hepatitis B surface antigen to identify inactive carriers, regardless of hepatitis B virus genotype

OBJECTIVES

To investigate whether hepatitis B surface antigen (HBsAg) and hepatitis B core-related antigen (HBcrAg) levels are useful to identify inactive carriers among HBeAg-negative patients infected by different hepatitis B virus (HBV) genotypes.

METHODS

In all, 202 consecutive HBeAg-negative patients with chronic hepatitis B, 135 inactive carriers and 67 with HBV activity, were prospectively followed for 1 year.

RESULTS

In HBeAg-negative patients, HBsAg levels differed across the different genotypes (p <0.001). The highest levels were observed in genotypes F or H (4.2 ± 0.6 logIU/mL), followed by genotype E (3.4 ± 1.1 logIU/mL), genotype A (3.4 ± 0.8 logIU/mL), and the lowest in genotype D (2.7 ± 1.1 logIU/mL). Variations in HBsAg levels were similar in inactive carriers and patients with HBV activity. HBsAg <3 logIU/mL showed good performance for identifying genotype D inactive carriers: 76% of genotype D inactive carriers met this cut-off versus ≤31% for genotypes A, E, F or H. However, in patients with genotype A, HBsAg levels ≤3.7 logIU/mL better classified inactive carriers. The combination of a single measurement of HBcrAg ≤3 logU/mL plus HBV DNA ≤2000 IU/mL yielded a positive predictive value and diagnostic accuracy >85% in all HBV genotypes, except genotype H or F, with values of 62.5% and 72.7%, respectively, for the two parameters.

CONCLUSIONS

HBsAg levels varied across genotypes in HBeAg-negative patients. HBsAg levels <3 logIU/mL were only useful for identifying genotype D inactive carriers. A single HBcrAg measurement ≤3 logU/mL plus HBV DNA ≤2000 IU/mL was highly accurate for identifying inactive carriers, regardless of their HBV genotype.

Characterization of Novel Hepatitis B Virus PreS/S-Gene Mutations in a Patient with Occult Hepatitis B Virus Infection

Objective

The impact of hepatitis B virus (HBV) preS/S-gene mutations on occult HBV infection (OBI) is not fully understood. This study characterized multiple novel HBV preS/S-gene mutants obtained from an OBI patient.

Methods

PreS/S-gene mutants were analyzed by clonal sequencing. Viral replication and expression were analyzed by transfecting HBV genomic recombinants into HepG2 cells.

Results

Twenty-one preS/S-gene mutants were cloned from four sequential serum samples, including 13 mutants that were not previously documented: (1) sI/T126V+sG145R; (2) preS1 nt 3014−3198 deletion; (3) preS1 nt 3046−3177 deletion; (4) preS1 nt 3046−3177 deletion+s115−116 “INGTST” insertion; (5) preS1 nt 3046−3177 deletion+s115−116 “INGTST” insertion+sG145R; (6) preS1 nt 3115−3123 deletion+sQ129N; (7) preS1 nt 3115−3123 deletion+s126−127 “RPCMNCTI” insertion; (8) s115−116 “INGTST” insertion; (9) s115−116 “INGTST” insertion+sG145R; (10) s126−127 “RPCMNCTI” insertion; (11) preS1 nt 2848−2862 deletion+preS2 initiation codon M→I; (12) s122−123 “KSTGLCK” insertion+sQ129N; and (13) preS2 initiation codon M→I+s131−133TSM→NST. The proportion of preS1 nt 3046−3177 deletion and preS2 initiation codon M→I+s131−133TSM→NST mutants increased in the viral pool with prolonged disease. The 13 novel OBI-related mutants showed a 51.2−99.9% decrease in HBsAg levels compared with that of the wild type. Additional N-glycosylation-associated mutations, sQ129N and s131−133TSM→NST, but not s126−127 “RPCMNCTI,” greatly attenuated anti-HBs binding to HBsAg. Compared with the wild type, replication and surface antigen promoter II activity of the preS1 nt 3046−3177 deletion mutant decreased by 43.3% and 97.0%, respectively.

Conclusion

PreS/S-gene mutations may play coordinated roles in the presentation of OBI and might be associated with disease progression. This has implications for HBV diagnosis and vaccine improvement.

Genetic variation of occult hepatitis B virus infection

Occult hepatitis B virus infection (OBI), characterized as the persistence of hepatitis B virus (HBV) surface antigen (HBsAg) seronegativity and low viral load in blood or liver, is a special form of HBV infection. OBI may be related mainly to mutations in the HBV genome, although the underlying mechanism of it remains to be clarified. Mutations especially within the immunodominant “α” determinant of S protein are “hot spots” that could contribute to the occurrence of OBI via affecting antigenicity and immunogenicity of HBsAg or replication and secretion of virion. Clinical reports account for a large proportion of previous studies on OBI, while functional analyses, especially those based on full-length HBV genome, are rare.

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

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

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

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

Doubtful Role of IL28B Polymorphism in Occult Hepatitis B Infection

AIMS

To investigate the influence of IL28B polymorphism in occult hepatitis B infection (OBI) and whether IL28B genetic variants are associated with hepatitis B virus (HBV)-specific T-cell responses.

PATIENTS AND METHODS

The rs12979860 IL28B genotype was determined in 34 OBI blood donors, 22 spontaneous HBV resolvers, 36 inactive HBV carriers and 25 seronegative donors. T-cell responses to HBV recombinant proteins were assessed by interferon-γ enzyme-linked immunospot assay.

RESULTS

The frequency of the IL28B CC genotype among OBI patients was similar to that of inactive carriers [41 vs. 39%, respectively, p = 0.961; odds ratio (OR) = 1.10; 95% confidence interval (CI) = 0.42-2.86; p = 0.845]. The IL28B CC genotype was found more frequently in spontaneous resolvers, although the differences were not significant (45 vs. 39%, spontaneous resolvers and inactive carriers, respectively; p = 0.828; OR = 1.31; 95% CI = 0.45-3.83; p = 0.622). HBV-specific T-cell responses were detected in OBIs, and significantly stronger T-cell responses towards hepatitis B envelope antigen were observed in those with the IL28B CC genotype. In spontaneous resolvers and inactive carriers, IL28B CC did not correlate with the magnitude of T-cell responses.

CONCLUSIONS

In OBI donors, IL28B CC correlates with the intensity of HBV-specific T-cell responses. In this study, IL28B CC is not statistically associated with OBI or with HBV clearance, but a larger number of cases is needed before completely ruling out its role in HBV infection.

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 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.

Mutations associated with occult hepatitis B in HIV-positive South Africans

Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, although viral mutations are likely a significant factor. In this study, sera from 394 HIV-positive South Africans were tested for HBV DNA and HBsAg. For patients with detectable HBV DNA, the overlapping surface and polymerase open reading frames (ORFs) were sequenced. Occult-associated mutations-those mutations found exclusively in individuals with occult HBV infection but not in individuals with chronic HBV infection from the same cohort or GenBank references-were identified. Ninety patients (22.8%) had detectable HBV DNA. Of these, 37 had detectable HBsAg, while 53 lacked detectable surface antigen. The surface and polymerase ORFs were cloned successfully for 19 patients with chronic HBV and 30 patients with occult HBV. In total, 235 occult-associated mutations were identified. Ten occult-associated mutations were identified in more than one patient. Additionally, 15 amino acid positions had two distinct occult-associated mutations at the same residue. Occult-associated mutations were common and present in all regions of the surface and polymerase ORFs. Further study is underway to determine the effects of these mutations on viral replication and surface antigen expression in vitro.

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.

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.

Molecular analysis of the hepatitis B virus presurface and surface gene in patients from eastern China with occult hepatitis B

This study was designed to detect and analyze mutations that occur within the presurface and surface (pre-S/S) gene of HBV in patients with occult hepatitis B, and determine their relationship to that disorder. Among 254 HBsAg negative samples of blood collected in eastern China, 183 were positive for anti-HBc alone, 61 were positive for anti-HBe alone, and 10 samples were positive for HBeAg. Within this group, 15 samples were found to be HBV DNA positive by real-time PCR and were designated Group I. A control group of 28 HBsAg positive samples were chosen at random from patients with chronic hepatitis B and designated Group II. The HBV pre-S/S gene was amplified by PCR and subjected to sequencing analysis. Occult hepatitis B was found in 1.6% of the patients with anti-HBc alone and in 3.3% of those with anti-HBe alone. Occult hepatitis B also was found in all HBsAg negative but HBeAg positive samples. Sequencing analysis showed a significant correlation between point mutations within the "a" determinant and occult hepatitis B (P < 0.0001), and a close relationship between pre-S deletion mutations and occult hepatitis B (P = 0.06). There were unique amino acid mutations at the G145 position other than G145R. The HBV DNA levels in patients with occult hepatitis B were significantly lower than those found in the control group. The "a" determinant mutations and pre-S deletions may play important roles in occult hepatitis B by affecting the expression, synthesis and secretion of the S protein and by impeding viral release and replication.

Occult hepatitis B: clinical viewpoint and management

Occult HBV infection (OBI) is defined as HBV DNA detection in serum or in the liver by sensitive diagnostic tests in HBsAg-negative patients with or without serologic markers of previous viral exposure. OBI seems to be higher among subjects at high risk for HBV infection and with liver disease. OBI can be both a source of virus contamination in blood and organ donations and the reservoir for full blown hepatitis after reactivation. HBV reactivation depends on viral and host factors but these associations have not been analyzed thoroughly. In OBI, it would be best to prevent HBV reactivation which inhibits the development of hepatitis and subsequent mortality. In diverse cases with insufficient data to recommend routine prophylaxis, early identification of virologic reactivation is essential to start antiviral therapy. For retrieving articles regarding OBI, various databases, including OVID, PubMed, Scopus, and ScienceDirect, were used.

T-Cell Response to Hepatitis B Core Antigen: Identification of Prior Exposure to and Confirmatory Testing for Screening for Anti-HBc

Background. During routine donor screening in the blood bank, it is not uncommon to find isolated reactivity for anti-HBc in the absence of detectable HBV DNA in a first donation but absence of reactivity to anti-HBc in subsequent donations, suggesting a false-positive result for anti-HBc. Study Design and Methods. The blood donor population was screened between January 2010 and October 2011. We selected 2,126 donations positive only for anti-HBc from a total of 125,068 donations. During the process, OBI donors were identified, and their HBcAg-specific T-cell response was analyzed and compared to donors with chronic (HBsAg positive) and recovered (anti-HBc only) infection. We analyzed correlations between signal levels (Co/s) in the competitive assay for anti-HBc and HBV DNA detection. Results. In the 21-month study period, 21 blood donors with anti-HBc alone were identified as OBI (1 in each 5955 donors). The relevant finding was the observation that anti-HBc only subjects with Co/s ≥ 0.1 did not have either HBcAg-specific T-cells or detectable HBV DNA and OBI subjects presented with Co/s ≤ 0.1 and HBcAg T-cell response. In the subset of 21 OBI subjects, 9 donors remained positive for HBcAg T-cell response after four collections. In all 9 samples, we observed HBV DNA fluctuation. Conclusion. Our data suggest that HBcAg-specific T-cell response could be used to confirm anti-HBc serological status, distinguishing previous exposure to Hepatitis B virus from anti-HBc false-positive results.

Repeated exposure to trace amounts of woodchuck hepadnavirus induces molecularly evident infection and virus-specific T cell response in the absence of serological infection markers and hepatitis

Exposure to multiple small doses of hepatitis B virus (HBV) is a frequent occurrence in high-risk groups, including close relatives of infected individuals, primary care givers, and intravenous drug users. It remains uncertain whether such repeated contact may culminate in a symptomatic infection coinciding with hepatitis in individuals not immunoprotected. In this study, we evaluated consequences of multiple exposures to small, liver-nonpathogenic amounts of infectious hepadnavirus in the woodchuck model of hepatitis B. Virus-naïve animals were intravenously injected with 6 weekly doses of 110 DNase digestion-protected virions of woodchuck hepatitis virus (WHV), injected again with 6 weekly 110-virion doses after 7.5 months, and then challenged or not with a liver-pathogenic dose of 1.1 × 10(6) virions of the same inoculum. The data revealed that two rounds of such repeated exposure did not result in serologically evident infection or hepatitis. However, a low-level WHV DNA-positive infection accompanied by a WHV-specific T cell response in the absence of antiviral antibody reactivity was established. The kinetics of the virus-specific and mitogen-induced (generalized) T cell responses and the inability to induce immunoprotection against challenge with a large, liver-pathogenic virus dose were closely comparable to those previously reported for occult infection initiated by a single liver-nonpathogenic dose of WHV. Thus, repeated exposures to small quantities of hepadnavirus induce molecularly evident but serologically silent infection that does not culminate in hepatitis or generate immune protection. The findings imply that the HBV-specific T cell response encountered in the absence of serological markers of infection likely reflects ongoing occult infection.