A 2010 update on occult hepatitis B infection

Mathematical model analysis of effective intervention strategies on transmission dynamics of hepatitis B virus

Hepatitis B is one of the world's most common and severe infectious diseases. Worldwide, over 350 million people are currently estimated to be persistent carriers of the hepatitis B virus (HBV), with the death of 1 million people from the chronic stage of HBV infection. In this work, developed a nonlinear mathematical model for the transmission dynamics of HBV. We constructed the mathematical model by considering vaccination, treatment, migration, and screening effects. We calculated both disease-free and endemic equilibrium points for our model. Using the next-generation matrix, an effective reproduction number for the model is calculated. We also proved the asymptotic stability of both local and global asymptotically stability of disease-free and endemic equilibrium points. By calculating the sensitivity indices, the most sensitive parameters that are most likely to affect the disease's endemicity are identified. From the findings of this work, we recommend vaccination of the entire population and screening all the exposed and migrants. Additionally, early treatment of both the exposed class after screening and the chronically infected class is vital to decreasing the transmission of HBV in the community.

Haplotype-dependent HLA-DRB1-DQB1 susceptibility to occult HBV infection in Xi'an Han population

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is primarily characterized by the persistence of HBV-DNA in the liver tissues and/or in the serum without detectable HBsAg. Human leukocyte antigen (HLA) polymorphisms have been found to be strongly associated with HBV in different ethnic backgrounds. The association of HLA-DRB1-DQB1 haplotypes with OBI has not been previously reported in China. The aim of this study was to identify the potential association of HLA-DRB1-DQB1 haplotypes that may be involved in OBI genetic susceptibility.

METHODS

A case-control study was conducted between 107 OBI subjects and 280 healthy controls from the blood donors in the Shaanxi Province Blood Center. The HLA-DRB1, DQB1 loci were genotyped using polymerase chain reaction-sequence based typing (PCR-SBT). Based on the genotype data of the two loci, haplotype estimation was performed.

RESULTS

HLA-DRB1*07:01-DQB1*02:02 (pc = 0.344 × 10^-3 , OR = 3.489, 95%CI = 2.000-6.088) and HLA-DRB1*09:01-DQB1*03:03 (pc = 0.02, OR = 2.370, 95%CI = 1.450-3.873) serve as the possible risk and susceptibility haplotypes for OBI in Xi'an Han after Bonferroni correction.

CONCLUSIONS

This study demonstrated that HLA II haplotypes were significantly associated with OBI in the Xi'an Han population. To the best of our knowledge, this is the first study to associate HLA-DRB1-DQB1 haplotypes with OBI, which can provide valuable insights into the relationship between the various genetic factors and immune responses in the Xi'an population. The findings can also form the basis for future studies about the role of HLA in OBI.

MicroRNA let-7 and viral infections: focus on mechanisms of action

MicroRNAs (miRNAs) are fundamental post-transcriptional modulators of several critical cellular processes, a number of which are involved in host defense mechanisms. In particular, miRNA let-7 functions as an essential regulator of the function and differentiation of both innate and adaptive immune cells. Let-7 is involved in several human diseases, including cancer and viral infections. Several viral infections have found ways to dysregulate the expression of miRNAs. Extracellular vesicles (EV) are membrane-bound lipid structures released from many types of human cells that can transport proteins, lipids, mRNAs, and miRNAs, including let-7. After their release, EVs are taken up by the recipient cells and their contents released into the cytoplasm. Let-7-loaded EVs have been suggested to affect cellular pathways and biological targets in the recipient cells, and can modulate viral replication, the host antiviral response, and the action of cancer-related viruses. In the present review, we summarize the available knowledge concerning the expression of let-7 family members, functions, target genes, and mechanistic involvement in viral pathogenesis and host defense. This may provide insight into the development of new therapeutic strategies to manage viral infections.

E2 Site Mutations in S Protein Strongly Affect Hepatitis B Surface Antigen Detection in the Occult Hepatitis B Virus

The mechanism of occult hepatitis B infection (OBI) has not yet been fully clarified. Our previous research found that novel OBI-related mutation within S protein, E2G, could cause the hepatitis B surface antigen (HBsAg) secretion impairment, which resulted in intracellular accumulation in OBI of genotype B. Here, to further explore the role of E2 site mutations in the occurrence of OBI, we analyzed these site mutations among 119 OBI strains identified from blood donors. Meanwhile, 109 wild-type HBV strains (HBsAg positive/HBV DNA positive) were used as control group. Furthermore, to verify the E2 site mutations, two conservative 1.3-fold full-gene expression vectors of HBV genotype B and C (pHBV1.3B and pHBV1.3C) were constructed. Then, the E2 mutant plasmids on the basis of pHBV1.3B or pHBV1.3C were constructed and transfected into HepG2 cells, respectively. The extracellular and intracellular HBsAg were analyzed by electrochemical luminescence and cellular immunohistochemistry. The structural characteristics of S proteins with or without E2 mutations were analyzed using relevant bioinformatics software. E2 mutations (E2G/A/V/D) existed in 21.8% (26/119) of OBIs, while no E2 mutations were found in the control group. E2G/A/V/D mutations could strongly affect extracellular and intracellular level of HBsAg (p < 0.05). Notably, unlike E2G in genotype B that could cause HBsAg intracellular accumulation and secretion decrease (p < 0.05), E2G in genotype C could lead to a very significant HBsAg decrease both extracellularly (0.46% vs. pHBV1.3C) and intracellularly (11.2% vs. pHBV1.3C) (p < 0.05). Meanwhile, for E2G/A mutations, the relative intracellular HBsAg (110.7-338.3% vs. extracellular) and its fluorescence intensity (1.5-2.4-fold vs. with genotype-matched pHBV1.3B/C) were significantly higher (p < 0.05). Furthermore, N-terminal signal peptides, with a typical cleavage site for peptidase at positions 27 and 28, were exclusively detected in S proteins with secretion-defective mutants (E2G/A). Our findings suggest that: (1) E2G/A/V/D mutations were confirmed to significantly influence the detection of HBsAg, (2) the underlying mechanism of OBI caused by E2G mutation is quite different between genotype B and genotype C, and (3) E2G/A could produce a N-terminal truncated S protein, which might attribute to the HBsAg secretion impairment in the OBIs.

Controversies in Treating Chronic Hepatitis B Virus Infection: Discordant Serologic Results

Despite effective vaccines and approved therapeutic agents, hepatitis B virus (HBV) remains a prevalent global health problem. Current guidelines rely on a combination of serologic, virological, and biochemical markers to identify the phase in the natural history of chronic HBV infection. Discordant serologic results can occur, which may lead to misclassification. Commonly encountered results that differ from the typical profiles seen in chronic HBV infection are described. For each scenario, the frequency of occurrence, possible explanations, and recommendations for clinical management are discussed. Recognition of discordant serologic findings is crucial for optimal clinical decision.

Case-Control Study of the Immune Status of Humans Infected With Zoonotic Gorilla Simian Foamy Viruses

BACKGROUND

Zoonotic simian foamy viruses (SFVs) establish persistent infections in humans, for whom the long-term consequences for health are poorly described. In this study, we aimed to characterize blood-cell phenotypes and plasma biomarkers associated with gorilla SFV infection in humans.

METHODS

We used a case-control design to compare 15 Cameroonian hunters infected with gorilla SFV (cases) to 15 controls matched for age and ethnicity. A flow cytometry-based phenotypic study and quantification of plasma immune biomarkers were carried out on blood samples from all participants. Wilcoxon signed-rank tests were used to compare cases and controls.

RESULTS

Cases had a significantly higher percentage of CD8 T lymphocytes than controls (median, 17.6% vs 13.7%; P = .03) but similar levels of B, natural killer, and CD4 T lymphocytes. Cases also had a lower proportion of recent CD4 thymic emigrants (10.9% vs 18.6%, P = .05), a higher proportion of programmed death receptor 1 (PD-1) expressing memory CD4 T lymphocytes (31.7% vs 24.7%, P = .01), and higher plasma levels of the soluble CD163 scavenger receptor (0.84 vs .59 µg/mL, P = .003) than controls.

CONCLUSIONS

We show, for the first time, that chronic infection with SFV is associated with T lymphocyte differentiation and monocyte activation.

Occult Hepatitis B virus infection among HIV negative and positive isolated anti-HBc individuals in eastern Ethiopia

The absence of hepatitis B surface antigen (HBsAg) and the presence of antibody to hepatitis B core antigen (anti-HBc) in the blood of apparently healthy individuals may not indicate the absence of circulating hepatitis B virus (HBV) and might be infectious. Despite the risk of HBV transmission, there has been no report from Ethiopia examining this issue; therefore, this study determined occult HBV infection (OBI) among isolated anti-HBc (IAHBc) HIV negative and HIV positive individuals on ART in eastern Ethiopia. A total of 306 IAHBc individuals were included in this study. DNA was extracted, amplified, and detected from plasma using a commercially available RealTime PCR platform (Abbott m2000rt) following the manufacturer's instructions. Data were entered into EPI Data version 3.1, cleaned, and analyzed using Stata version 13. Descriptive analysis was used to calculate prevalence, summarize sociodemographic data and other factors. From the 306 IAHBc individuals (184 HIV positive and 122 HIV negative) included in the study, 183 (59.8%) were female of which 142 (77.6%) were within the reproductive age group. DNA extraction, amplified and detection was conducted in 224 individuals. The overall OBI prevalence was 5.8% (5.6% in HIV negative and 6% in HIV positive) among the IAHBc individuals. The HBV DNA concentration among the occult hepatitis B individuals was < 200 IU/mL, indicating a true occult. This study reported the burden of OBI, which pauses a significant public health problem due to the high burden of HBV infection in the country. OBI may cause substantial risk of HBV transmission from blood transfusion, organ transplantation as well as vertical transmission as screening is solely dependent on HBsAg testing.

Novel hepatitis B virus surface antigen mutations associated with occult genotype B hepatitis B virus infection affect HBsAg detection

The causative factors of occult hepatitis B infection are complicated and not yet been fully elucidated. Mutations in hepatitis B virus (HBV) S gene are one of the factors may contributing to occult infection. In this study, 89 blood donors with genotype B occult HBV infection were investigated. Fifty-seven hepatitis B surface antigen (HBsAg)-positive/HBV DNA-positive blood donors served as control group for comparison. Occult HBV-related mutations with a high incidence (P < .05) in the S gene were identified. To further verify these occult infection-related mutations, a conservative full-gene expression vector of HBV B genotype (pHBV1.3B) was constructed. Then, the mutant plasmids on the basis of pHBV1.3B were constructed and transfected into HepG2 cells. Extracellular as well as intracellular HBsAg was analysed by electrochemical luminescence and cellular immunohistochemistry. Ten occult infection-related mutations (E2G, Q101R, K122R, M133T, D144E, G145R, V168A, S174N, L175S and I226S) were significantly more frequent in the occult infection group (P < .05). Five of the ten mutations (E2G, D144E, G145R, V168A and S174N) strongly decreased extracellular HBsAg level (P < .05) in the transfection system. Notably, the E2G mutation had the most significant impact on the ratio of extracellular HBsAg (3.8% vs pHBV1.3B) and intracellular HBsAg (239.3% vs pHBV1.3B) (P < .05), and the fluorescence density of E2G mutant HBsAg was significantly higher than that of pHBV1.3B (P < .0001). Hence, ten mutations were associated with genotype B occult HBV infection; E2G and V168A were novel mutations which we confirmed significantly affect HBsAg detection. E2G might cause HBsAg secretion impairment that results in intracellular accumulation and a decrease in HBsAg secretion.

Hepatitis B and Pregnancy: Virologic and Immunologic Characteristics

The hepatitis B virus (HBV) is an important human pathogen. Unvaccinated infants infected through mother-to-child transmission (MTCT) are at >95% risk of developing serum hepatitis B surface antigen-positive chronic hepatitis B (CHB). Despite complete passive-active HBV immunoprophylaxis, approximately 10% of infants born to mothers who are highly viremic develop CHB, and thus maternal treatment with nucleos(t)ide analogs (tenofovir disoproxil fumarate, lamivudine, or telbivudine) is recommended in the third trimester of pregnancy to reduce MTCT risk. Viral rebound usually occurs after stopping treatment and, in the context of maternal immunologic reconstitution postpartum, can also precipitate host immune-mediated hepatic (biochemical) flares. In this article, we review the epidemiology of HBV MTCT, discuss management and potential mechanisms of HBV vertical transmission, and highlight recent studies on virologic and immunologic aspects of hepatitis B in pregnancy and postpartum.

Low prevalence of occult hepatitis B virus infection in chronic haemodialysis and kidney transplant patients

BACKGROUND

Occult hepatitis B virus infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in serum and/or liver in HBsAg-negative patients. We investigated the prevalence of OBI in large chronic haemodialysis (CHD) and kidney transplant recipients (KTxR) cohorts, including determination of HBV DNA in peripheral blood mononuclear cells (PBMCs).

METHODS

HBV DNA was determined in both serum and PBMCs in 417 CHD patients, 417 KTxR, 20 HBsAg-positive non-CHD non-KTx patients (positive controls) and 40 HBsAg-negative healthy subjects (negative controls).

RESULTS

Chronic haemodialysis group: two of 376 patients were HBsAg-positive. The 374 HBsAg-negative patients tested negative for HBV DNA in both serum and PBMCs. KTxR group: 14 of 417 patients were HBsAg-positive. One of 403 HBsAg-negative patients tested positive for HBV DNA in serum but not in PBMCs. Positive controls: six of 20 patients were under antiviral therapy and had negative HBV DNA in both serum and PBMCs. In 11 of 14 remaining patients, HBV DNA was detected in serum and in both serum and PBMCs in 3 patients. Negative controls: All 34 patients were anti-HBc-negative and HBV DNA-negative in both serum and PBMCs. In the long term, the only case of anti-HBc-negative OBI lost anti-HBs 5 years after inclusion in the study and showed HBV reactivation with HBsAg re-seroconversion.

CONCLUSIONS

We found nil prevalence of OBI in CHD patients and a very low prevalence (<1%) in KTxR suggesting that routine screening for HBV DNA is not required in CHD population in our region. However, in KTxR, pretransplant screening with HBV DNA should be considered. Testing for HBV DNA in PBMCs does not seem to be of additional value.

Effectiveness of PCR primers for the detection of occult hepatitis B virus infection in Mexican patients

BACKGROUND

Occult hepatitis B infection (OBI) is defined as the presence of hepatitis B virus (HVB) DNA in the liver of HBsAg negative individuals with or without detectable viral DNA in serum. OBI is a diagnostic challenge as it is characterized by a very low viral load, intermittently detectable through time. Individuals with OBI can develop chronic hepatic disease, including liver cirrhosis and hepatocellular carcinoma. The aim of this work was to produce tools to improve OBI detection of the HVB genotypes prevalent in Mexico.

METHODS

We designed and tested primers to detect OBI in serum samples by nested and real-time PCR. Conserved sites in the viral genome were determined by alignment of the most frequent HBV genotypes in Mexico (H, G/H, F and D) and primers spanning the entire viral genome were designed for first round and nested PCR. Primers were tested in serum samples of 45 patients not co-infected with hepatitis C virus or with HIV, out of a group of 116 HBsAg (-)/anti-HBc (+) individuals. Primers were also tested in a control group with chronic HBV. Nested PCR products obtained from HBsAg (-)/anti-HBc (+) were sequenced and used to design primers for real-time PCR (SYBR Green).

RESULTS

The most effective primer pairs to detect HBV products by nested PCR targeted ORF regions: PreS2/P, S/P, X/PreC, and C; while by real-time PCR they targeted ORF regions PreS2/P, S/P, X, and C. Out of the 45 HBsAg (-)/anti-HBc (+) patients tested, the viral genome was detected in 28 (62.2%) and 34 (75.5%), with nPCR and real-time PCR respectively.

CONCLUSION

Primers designed for real-time PCR detected up to 75.5% of suspected OBI Mexican patients, with or without liver disease, which represents an improvement from previous PCR strategies.

Ideal Cure for Hepatitis B Infection: The Target is in Sight

Hepatitis B virus (HBV) is one of the most common causes of liver cirrhosis and hepatocellular carcinoma. Despite recent strides in pharmacotherapy, complete cure of HBV infection still remains an enigma. The biggest obstacle in HBV therapy is clearance of covalently closed circular deoxyribonucleic acid (cccDNA). We discuss about the role of cccDNA in HBV life cycle, efficacy and shortcomings of currently available antivirals as well as promising novel targets to achieve ideal HBV cure.

Prevalence and natural course of occult hepatitis B virus infection in residents of 2 communities of Wuwei City, Gansu Province, China

Occult hepatitis B infection (OBI) is characterized by serum hepatitis B surface antigen (HBsAg) negative and hepatitis B virus (HBV) DNA positive (HBsAg-/HBV DNA+). Occult hepatitis B infection in community-based populations has been scarcely investigated, and OBI outcomes remain unclear, especially in Wuwei, a region located in Northwest China. This region is one of the areas in China that has the highest prevalence of chronic HBV infection. A prospective study was performed in the general population of 2 towns of Wuwei from June 2011 to May 2014. A questionnaire was used to collect demographic and medical data, and serum samples were collected from the participants and stored until analysis. DNA was detected using quantitative PCR (qPCR) or nested PCR, the HBV DNA from HBV DNA-positive or possible positive (below the detection limit) subjects was extracted and amplified by nested PCR, and the PCR products were sequenced. Sequence analysis was performed using the Mega 6.0 program and CLC sequence viewer software. Hepatitis B virus DNA was detected in 90 of 3,080 HBsAg-negative subjects, and the prevalence of OBI in the study population was 2.92% (90/3,080, 95% CI: 2.33%-3.51%). Hepatitis B virus genomes in 51 of 80 objects (63.75%) contained mutations in the "a" determinant of HBsAg. After 2 years follow-up, 42 of 90 HBV DNA of OBI subjects remained positive, and the natural clearance rate of OBI subjects was 53.3%. Occult hepatitis B infection prevalence in this cohort was much lower than chronic HBV infection in the same region. HBV DNA was cleared in most OBI subjects during the 2 year period. Our data suggest that some OBI may represent a late stage of resolving the HBV infection process.

Current concepts on immunopathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) infection is a leading cause of liver damage and hepatic inflammation. Upon infection, effective antiviral responses by CD8+ T cells, CD4+ T cells, Natural killer (NK) cells, and monocytes can lead to partial or complete eradication of the viral infection. To date, many studies have shown that the production of inhibitory cytokines such as Interleukin 10 (IL-10), Transforming growth factor beta (TGF-β), along with dysfunction of the dendritic cells (DCs), and the absence of efficient innate immune responses could lead to T cell exhaustion, development of persistent infection, and inability to eradicate the viral infection from liver. Understanding the immunopathogenesis of the virus could be useful in providing further insights toward novel strategies in the eradication of HBV infection.

Association of human leukocyte antigen polymorphisms with occult hepatitis B virus infection in a Shaanxi Han population

BACKGROUND

Occult hepatitis B virus (HBV) infection (OBI) is defined as HBV DNA detection in serum or in the liver by sensitive diagnostic tests in HBV surface antigen (HBsAg) negative patients with or without serologic markers of previous HBV exposure. Because the human leukocyte antigen (HLA) system is an integral component of the immune response, we hypothesized that the highly polymorphic HLA genes were the key determinants of HBV persistence and clearance. The present study aimed to calculate the allelic frequency of HLA loci and investigate the association between HLA alleles and the outcome of OBI in Shaanxi Han population in the northwest of China.

METHODS

We conducted a case-control study between 107 OBI subjects and 280 healthy control individuals from blood donors of Shaanxi Blood Center. Five HLA loci, including HLA-A,-B,-C,-DRB1 and -DQB1, were selected and further genotyped using a polymerase chain reaction sequence-based typing (SBT) method.

RESULTS

Using the chi-squared test, we found that the allele frequencies of HLA-B*44:03 [odds ratios (OR) = 2.146, 95% confidence interval (CI) = 1.070-4.306, p = 0.028]; C*07:01 (OR = 4.693, CI = 1.822-12.086, p = 0.000); DQB1*02:02 (OR = 1.919, CI = 1.188-3.101, p = 0.007); and DRB1*07:01 (OR = 2.012, CI = 1.303-3.107, p = 0.001) were markedly higher in the OBI group compared to the healthy control group. The allele frequencies of HLA-DRB1*08:03 (OR = 0.395, CI = 0.152-1.027, p = 0.049); DRB1*15:01 (OR = 0.495, CI = 0.261-0.940, p = 0.029); and DQB1*06:02 (OR = 0.500, CI = 0.249-1.005, p = 0.048) were obviously lower in the OBI group compared to the healthy control group. These data indicated that HLA-B*44:03, C*07:01, DQB1*02:02 and DRB1*07:01 were related to OBI infection, whereas HLA-DRB1*08:03, DRB1*15:01 and DQB1*06:02 alleles were associated with HBV DNA clearance in a Shaanxi Han population.

CONCLUSIONS

The results of the present study suggest that host HLA gene is an important influencing factor for OBI pathogenesis.

Identification and characterization of interferon signaling-related microRNAs in occult hepatitis B virus infection

Background

Occult hepatitis B virus infection (OBI) is an important risk factor of liver cirrhosis and hepatocellular carcinoma. Type 1 interferon (IFN) signaling-related miRNAs were significantly associated with hepatitis B virus (HBV) infection. However, the characteristics of serum IFN signaling-related miRNAs in OBI remain unclear. Therefore, this study aimed to analyze the expression levels of serum IFN signaling-related miRNAs in OBI and to evaluate their potential values for OBI diagnosis.

Methods

Twenty serum samples for training test (10 healthy controls and 10 OBI patients) and 438 validation serum samples from healthy controls, asymptomatic HBsAg carriers (ASC), and chronic hepatitis B (CHB) and OBI patients were collected. Expression levels of 32 IFN signaling-related miRNAs were analyzed in training and validation sets of samples using RT-qPCR.

Results

Among 32 IFN signaling-related miRNAs, decreased miR-122 levels and increased miR-130a levels were detected in training OBI samples. Furthermore, the results from validation test showed that the mean serum miR-122 and miR-130a level was 2.28 ± 0.96 and 3.11 ± 0.93 in OBI subjects, respectively. Compared to the healthy controls, ASC and CHB patients, miR-122 levels were significantly downregulated, while miR-130a levels were significantly upregulated in OBI patients. ROC analysis indicated that miR-122 + miR-130a could differentiate OBI from healthy controls, ASC, and CHB (≥ 0.87 of AUC).

Conclusions

Our study suggested that decreased serum miR-122 level and increased miR-130a level were significantly associated with OBI. Moreover, a combination of miR-122 and miR-130a could be served as a potential marker for OBI diagnosis.

Electronic supplementary material

The online version of this article (10.1186/s13148-017-0404-9) contains supplementary material, which is available to authorized users.

Temporal trend of hepatitis B surface mutations in the post-immunization period: 9 years of surveillance (2005-2013) in eastern China

Limited information is available about the temporal trend in the prevalence and evolution of hepatitis B virus (HBV) S-gene mutations in the post-immunization era in China. From 2005 to 2013, 1077 hepatitis B cases under 15 years of age reported through Chinese National Notifiable Disease Reporting System (NNDRS) were successfully sequenced of S-gene in Shandong province, China. A total of 97 (9.01%) cases had amino acid (aa) substitution in the “α” determinant of HBsAg. The yearly prevalence from 2005 to 2013 maintained at a relatively stable level, and showed no significant change (P > 0.05). Multivariate logistic regression analysis demonstrated that the prevalence of “α” mutations was independently associated with the maternal HBsAg status (P < 0.05), and not with surveillance year and hepatitis B vaccination (P > 0.05). The hottest mutation position was aa126 (I126S/N and T126A, 29.63%), and aa 145 (G145R/A, 25.93%). Mutated residue 126 tended to occur less frequent, while that of residue 145 was more frequent with increasing year. Our data showed that there was no increase in the frequency of HBV “α” mutations over time during the post-immunization period. However, long-term vaccination might enhance the change of HBV mutational pattern, and G145 mutation was becoming dominant.

Occult hepatitis B virus infection in HIV positive patients at a tertiary healthcare unit in eastern India

Occult HBV infection (OBI), defined by the presence of HBV DNA in absence of hepatitis B surface antigen (HBsAg), is a significant concern in the HIV-infected population. Of 441 HIV+/HBsAg- patients analyzed, the overall prevalence of OBI was 6.3% (28/441). OBI was identified in 21 anti-HBc positives (17.8%), as well as among those who lacked any HBV-specific serological markers (2.2%). Comparison with HIV/HBV co-infection revealed that the levels of CD4, ALT, and HBV DNA were significantly lower during occult infection. Discrete differences were also observed with respect to quasispecies divergence. Additionally, subgenotype D1 was most frequent in occult infection, while D2 was widespread during chronic infection. The majority (~90%) of occult D1 sequences had the sQ129R mutation in the surface gene. This study highlights several distinct features of OBI in India and underscores the need for additional HBV DNA screening in HIV-positive individuals.

Prevalence and characterization of occult hepatitis B infection among blood donors in central Saudi Arabia

OBJECTIVES

To evaluate the prevalence of occult hepatitis B viral infections (OBIs)  among blood donors considering the clinical and epidemiological importance of identifying OBIs.

METHODS

A cross-sectional study conducted at King Khalid University Hospital, Riyadh, Saudi Arabia between January 2011 and January 2012. Blood donors (n=8501) were screened for Hepatitis B virus surface antigen (HBsAg) and hepatitis B core antibodies (HBcAb). All HBsAg-negative and HBcAb-positive samples were tested further for hepatitis B surface antibodies (HBsAb), hepatitis B virus (HBV)-DNA, and HBV genotyping.  

RESULTS

Of the 8501 serum samples tested, 56 (0.7%) were positive and 8445 (99.3%) were negative for HBsAg. Among the HBsAg-negative samples, 198 (2.3%) were positive for HBcAb and these patients were suspected to have OBIs. Among the HBcAb-positive samples, 119 (60.1%) were positive while 79 (39.9%) were negative for HBsAb. Analysis of HBV-DNA for the suspected OBIs showed that 17 out of 198 samples (8.6%) yielded positive results, and all of them were HBsAb-negative. The viral load was low (less than 20-186 IU/mL) in all OBIs. Hepatitis B virus genotyping showed that 15 out of 17 samples (88.2%) were genotype D, and the other 2 samples (11.8%) were genotype E. 

CONCLUSION

The prevalence of OBIs among blood donors in Riyadh was 0.2%. Therefore, it is recommended that HBV molecular testing should be incorporated with serological assays for screening of blood donors.

Occult HBV among Anti-HBc Alone: Mutation Analysis of an HBV Surface Gene and Pre-S Gene

PURPOSE

The aim of this study is to investigate the molecular characteristics of occult hepatitis B virus (HBV) infection in 'anti-HBc alone' subjects.

MATERIALS AND METHODS

Twenty-four patients with 'anti-HBc alone' and 20 control patients diagnosed with HBV were analyzed regarding S and pre-S gene mutations. All specimens were analyzed for HBs Ag, anti-HBc, and anti-HBs. For specimens with an anti-HBc alone, quantitative analysis of HBV DNA, as well as sequencing and mutation analysis of S and pre-S genes, were performed.

RESULTS

A total 24 were analyzed for the S gene, and 14 were analyzed for the pre-S gene through sequencing. A total of 20 control patients were analyzed for S and pre-S gene simultaneously. Nineteen point mutations of the major hydrophilic region were found in six of 24 patients. Among them, three mutations, S114T, P127S/T, M133T, were detected in common. Only one mutation was found in five subjects of the control group; this mutation was not found in the occult HBV infection group, however. Pre-S mutations were detected in 10 patients, and mutations of site aa58-aa100 were detected in 9 patients. A mutation on D114E was simultaneously detected. Although five mutations from the control group were found at the same location (aa58-aa100), no mutations of occult HBV infection were detected.

CONCLUSION

The prevalence of occult HBV infection is not low among 'anti-HBc alone' subjects. Variable mutations in the S gene and pre-S gene were associated with the occurrence of occult HBV infection. Further larger scale studies are required to determine the significance of newly detected mutations.

Quantification of intrahepatic total HBV DNA in liver biopsies of HBV-infected patients by a modified version of COBAS® Ampliprep/COBAS®TaqMan HBV test v2.0

Intrahepatic total HBV DNA (it-HBV DNA) level might reflect the size of virus reservoir and correlate with the histological status of the liver. To quantitate it-HBV DNA in a series of 70 liver biopsies obtained from hepatitis B chronic patients, a modified version of the COBAS^®Ampliprep/COBAS^®TaqMan HBV test v2.0 was used for this purpose. The linearity and reproducibility of the modified protocol was tested by quantifying serial dilutions of a full-length HBV containing plasmid and it-HBV DNA from a reference patient. A good linear trend between the expected values and those generated by the assay was observed at different concentrations of both plasmid and reference patient (R ² = 0.994 and 0.962, respectively). Differences between the values obtained in two independent runs were ≤0.3 log IU for the plasmid and ≤0.6 log IU/mg for the reference patient, showing a high inter-run reproducibility. In the 70 liver biopsies, it-HBV DNA level ranged from 1.4 to 5.4 log IU/mg, with a good linearity and reproducibility between the values obtained in two runs [R ² = 0.981; median (IQR) difference of it-HBV DNA 0.05 (0.02-0.09) IU/mg]. The modified COBAS^®Ampliprep/COBAS^®TaqMan HBV test v2.0 allows an accurate quantitation of it-HBV DNA. Its determination may have prognostic value and may be a useful tool for the new therapeutic strategies aimed at eradicating the HBV infection.

High Prevalence of Hepatitis B Virus Infection in the Age Range of 20-39 Years Old Individuals in Lome

BACKGROUND

Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). It affects all women and men irrespective of age. Although sub-Saharan Africa is an area of high prevalence of this disease, data on the prevalence of acute and chronic HBV infections in this region remain to be widely documented.

OBJECTIVE

This study aimed to investigate the prevalence of HBV in relation to age in Centre Hospitalier Universitaire Campus (CHU-C), one of the two teaching hospitals of Lome, Togo.

METHOD

The present study is a cross-sectional study about the prevalence of hepatitis B surface antigen (HBsAg) carriage from 2009 to 2011. All study participants were screened for HBsAg at the Immunology laboratory of CHU Campus of Lome.

RESULTS

One thousand two hundred individuals were screened for HBsAg from 2009-2011. The overall prevalence of HBV infection was 19.08%. This prevalence was significantly higher in men (25.00%) than women (14.80%). The highest prevalence of HBV was observed in age range of 20-29 years and 30-39 years with respectively 26.33% and 21.67%. The lowest prevalence was 6.08%, found in people over 50 years. Concerning the clinical indication of the test, the prevalence during the clinical abnormalities related to liver (CARL) was the highest (26.21%), followed by the systematic screening (SS) with 20.25% while the pre-operative assessment (POA) showed the lowest prevalence with 5.56%.

CONCLUSION

The study shows the high prevalence of HBsAg carriage in young people. This could be used to enhance prevention and treatment of HBV infection in Togo.

[Clinical and morphological correlations in occult hepatitis B]

Occult hepatitis B (ОHB) characterized by the absence of blood HBsAg attracts the attention of specialists of different profiles; however, its clinical morphological aspects have not been practically studied.

AIM

to estimate the proportion of OHB in the structure of fatal outcomes in chronic viral hepatitis (CVH) and to characterize its clinical course and structural changes on autopsy materials.

MATERIAL AND METHODS

A total of 455 autopsy cases of CVH were examined for its etiology in the S.P. Botkin Clinical Hospital of Infectious Diseases in 2014-2016. An in-depth prospective clinical analysis was made to investigate 28 cases of OHB in the stage of decompensated liver cirrhosis, which had subsequently culminated in death. The criteria of inclusion were history data and clinical symptoms of CVH in the detection of markers for hepatitis A, C, and D and HIV in serum HBcAb in the absence of HBsAg. HBsAbs were also determined. Along with the traditional morphological examination, immunohistochemistry (IHC) for HBsAg and HBcAg was carried out.

RESULTS

There were 108 CVHB cases (23.7% of the total cases of CVH), including 77 OHB cases (71.3% of those of CVHB) while HBsAg was not determined. HBsAb-negative patients were more often observed to have clinical signs of jaundice (p<0.05) and skin itching (p<0.05). Dyspepsia and hemorrhagic manifestations prevailed in patients with HBsAb (more than 10 IU/l) (p<0.05). All the cases were found to have characteristic morphological signs of CVH, including intranuclear inclusions and nuclear polymorphism in 10.7% of deaths. There was an IHC-positive reaction to VHB antigens in 28.6% of the patients and a doubtful reaction in 25.0%.

CONCLUSION

Serum НВсAb may serve as a diagnostic marker for HBV infection. Clinical and morphological correlations enabled the authors to state that CVHB was present in all cases in the absence of serum HBsAg in the patients.

Evolution in Our Understanding of Hepatitis B Virus Virology and Immunology

Hepatitis B virus (HBV) infection is a major global health challenge. HBV can cause significant morbidity and mortality by establishing acute and chronic hepatitis. Approximately 250 million people worldwide are chronically infected, and more than 2 billion people have been exposed to HBV. Since the discovery of HBV, the advances in our understanding of HBV virology and immunology have translated into effective vaccines and therapies for HBV infection. Although current therapies successfully suppress viral replication but rarely succeed in viral eradication, recent discoveries in HBV virology and immunology provide exciting rationales for novel treatment strategies aiming at HBV cure.

Detection of occult hepatitis B and window period infection among blood donors by individual donation nucleic acid testing in a tertiary care center in South India

With the introduction of highly sensitive hepatitis B surface antigen immunoassay, transfusion associated HBV infection have reduced drastically but they still tend to occur due to blood donors with occult hepatitis B infection (OBI) and window period (WP) infection. Sera from, 24338 healthy voluntary blood donors were screened for HBsAg, HIV and HCV antibody using Vitros Enhanced Chemiluminescent Immunoassay. The median age of the donor population was 30 (range 18-54) with male preponderance (98%). All serologically negative samples were screened by nucleic acid testing (NAT) for viral DNA and RNA. NAT-positive samples were subjected to discriminatory NAT for HBV, HCV, and HIV and all samples positive for HBV DNA were tested for anti-HBc, anti-HBs, HBeAg. Viral load was determined using artus HBV RG PCR Kit. Of the 24,338 donors screened, 99.81% (24292/24338) were HBsAg negative of which NAT was positive for HBV DNA in 0.0205% (5/24292) donors. Four NAT positive donors had viral load of <200 IU/ml making them true cases of OBI. One NAT positive donor was negative for all antibodies making it a case of WP infection. Among OBI donors, 75% (3/4) were immune and all were negative for HBeAg. Precise HBV viral load could not be determined in all (5/5) NAT positive donors due to viral loads below the detection limit of the artus HBV RG PCR Kit. The overall incidence of OBI and WP infections was found to be low at 1 in 6503 and 1 in 24214 donations, respectively. More studies are needed to determine the actual burden of WP infections in Indian blood donors.

Update on occult hepatitis B virus infection

The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

Hepatitis B virus infection in blood donors in Argentina: prevalence of infection, genotype distribution and frequency of occult HBV infection

This study describes the prevalence of HBV infection based on detection of HBsAg and HBV-DNA by NAT in 70,102 blood donors in Argentina (Córdoba province) and shows the viral genotype distribution and frequency of occult HBV infection (OBI) in this population. Forty-two donors were confirmed positive for HBV infection (0.06 %), and four had OBI. Genotype F was the most prevalent (71.4 %), followed by A (14.3 %), C (7.1 %) and D (7.1 %). This is the first report of the prevalence of confirmed HBV infection and the high frequency of occult HBV infection in a blood bank in Argentina.

Hepatitis B Virus Infection in the General Population of Iran: An Updated Systematic Review and Meta-Analysis

CONTEXT

The hepatitis B virus (HBV) is a major global public health problem, affecting more than 2 billion people worldwide. Accurate and updated data on HBV prevalence is important for further planning to control the infection. The aim of this study was to update the prevalence estimate of HBV infection in the general population of Iran.

EVIDENCE ACQUISITION

A systematic review was done for data on the prevalence of HBV infection in the general Iranian population published between Jan. 1, 1990, and Jan. 1, 2016, in both international and national databases, including PubMed, Scopus, Web of Science, Scientific Information Database, IranMedex, and Magiran. All papers with clearly described time and location of the study, proper sampling strategies, and proper analysis methods were included in the present study. Data were extracted by two independent reviewers. Prevalence of HBV infection with a 95% confidence interval (CI) was calculated using Stata software, version 13.

RESULTS

The polled estimated prevalence of HBV infection in the general population of Iran was 2.2 % (95% CI: 1.9% - 2.6%). The highest prevalence of HBV infection (8.9%, 95% CI: 7.6% - 10.2%) was reported from Golestan province, and the lowest prevalence (0.7%, 95% CI: 0.4% - 1.1%) was seen in Kermanshah province. The prevalence of HBV infection was estimated at 3% (95% CI: 2.2% - 3.8%) for Iranian males and 1.7% (95% CI: 1.2% - 2.3%) for Iranian females. The prevalence of HBV infection in the general population of Iran was 2.9% (95% CI: 2.5% - 3.4%) before 2010 and 1.3% (95% CI: 0.9% - 1.7%) after 2010.

CONCLUSIONS

In total, Iran was classified within the low-intermediate HBV prevalence areas (2% - 4%), while according to recent data (after 2010), Iran was classified within the low HBV prevalence areas (< 2%), indicating that preventive measures conducted in Iran have been effective.

Clinical course of 161 untreated and tenofovir-treated chronic hepatitis B pregnant patients in a low hepatitis B virus endemic region

Hepatitis B immunoprophylaxis failure is linked to high maternal viraemia. There is limited North American data on hepatitis B outcomes in pregnancy. Pregnant hepatitis B carriers were enrolled January 2011-December 2014 and offered tenofovir in the 3rd trimester if hepatitis B virus (HBV)-DNA was >7-log IU/mL. Outcomes were determined in treated vs untreated patients. In total, 161 women with 169 pregnancies (one twin, 170 infants; median age 32 years), 18% (29/161) HBeAg+ and median HBV-DNA 2.51 log IU/mL (IQR 1.66-3.65; range 0.8-8.1) were studied. 14.3% (23/161) received tenofovir due to high viral load (16/23, median 74 days, IQR 59-110) or due to liver disease (7/23). In 10/16 treated due to high viraemia, with confirmed adherence, follow-up HBV-DNA showed a 5.49 log decline (P = 0.003). In treatment naïve mothers, median alanine aminotransferase (ALT) increased from 17 IU/L (IQR 12-24) to 29 (IQR 18-36) post-partum (P = 1.5e-7). In seven highly viraemic mothers who declined therapy (HBV-DNA >8-log IU/mL); median ALT increased ~3X from baseline (P < 0.01). 26% (44/169) had Caesarean section with no difference in treated vs untreated subjects. No tenofovir-treated mothers had renal dysfunction. Data were available on 167/170 infants; in 50.8% (85/167) who completed immunoprophylaxis, 98.8% (84/85, including 12 exposed to tenofovir in utero) were HBV immune. One infant born to an HBeAg+ mother with HBV-DNA >8-log IU/mL failed immunoprophylaxis. In this prospective Canadian cohort study, most untreated mothers experienced mild HBV flares. Tenofovir in pregnancy is well tolerated and reduces viral load prior to parturition.

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.

Occult hepatitis B virus infection in Egypt

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

Clinical relevance of hepatitis B virus variants

The hepatitis B virus (HBV) is a global public health problem with more than 240 million people chronically infected worldwide, who are at risk for end-stage liver disease and hepatocellular carcinoma. There are an estimated 600000 deaths annually from complications of HBV-related liver disease. Antiviral therapy with nucleos/tide analogs (NA) targeting the HBV polymerase (P) can inhibit disease progression by long-term suppression of HBV replication. However, treatment may fail with first generation NA therapy due to the emergence of drug-resistant mutants, as well as incomplete medication adherence. The HBV replicates via an error-prone reverse transcriptase leading to quasispecies. Due to overlapping open reading frames mutations within the HBV P can cause concomitant changes in the HBV surface gene (S) and vice versa. HBV quasispecies diversity is associated with response to antiviral therapy, disease severity and long-term clinical outcomes. Specific mutants have been associated with antiviral drug resistance, immune escape, liver fibrosis development and tumorgenesis. An understanding of HBV variants and their clinical relevance may be important for monitoring chronic hepatitis B disease progression and treatment response. In this review, we will discuss HBV molecular virology, mechanism of variant development, and their potential clinical impact.

Occult hepatitis B virus infection

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

Reactivation of hepatitis B virus in hematopoietic stem cell transplant recipients in Japan: efficacy of nucleos(t)ide analogues for prevention and treatment

We retrospectively reviewed 413 recipients with hematologic malignancies who underwent hematopoietic stem cell transplantation (HSCT) between June 1986 and March 2013. Recipients with antibody to hepatitis B core antigen (anti-HBc) and/or to hepatitis B surface antigen (anti-HBs) were regarded as experiencing previous hepatitis B virus (HBV) infection. Clinical data of these recipients were reviewed from medical records. We defined ≥1 log IU/mL increase in serum HBV DNA from nadir as HBV reactivation in hepatitis B surface antigen (HBsAg)-positive recipients, and also defined ≥1 log IU/mL increase or re-appearance of HBV DNA and/or HBsAg as HBV reactivation in HBsAg-negative recipients. In 5 HBsAg-positive recipients, 2 recipients initially not administered with nucleos(t)ide analogues (NUCs) experienced HBV reactivation, but finally all 5 were successfully controlled with NUCs. HBV reactivation was observed in 11 (2.7%) of 408 HBsAg-negative recipients; 8 of these were treated with NUCs, and fortunately none developed acute liver failure. In 5 (6.0%) of 83 anti-HBc and/or anti-HBs-positive recipients, HBV reactivation occurred. None of 157 (0%) recipients without HBsAg, anti-HBs or anti-HBc experienced HBV reactivation. In HSCT recipients, HBV reactivation is a common event in HBsAg-positive recipients, or in HBsAg-negative recipients with anti-HBc and/or anti-HBs. Further attention should be paid to HSCT recipients with previous exposure to HBV.

Occult hepatitis B virus infection in Chinese cryptogenic intrahepatic cholangiocarcinoma patient population

BACKGROUND

There is no information available about occult hepatitis B virus (HBV) infection (OBI) in individuals with intrahepatic cholangiocarcinoma (ICC).

GOALS

To investigate the correlation between OBI and ICC.

STUDY

A retrospective case-control study was conducted. The cases were 183 cryptogenic ICC patients (group I), and the controls were 549 healthy individuals (group II). The cases and controls were matched for age, sex, and inhabitancy. Adjusted odds ratios and 95% confidence intervals were calculated. Intrahepatic total HBV DNA in 63 paraffin-embedded samples was collected from patients in group I (n=44), HBV-associated ICC patients (n=3), and hepatic cavernous hemangioma patients with seronegative HBsAg (hepatitis B S antigen) (group III; n=16). We determined the levels of serum and intrahepatic HBV DNA and compared the level of intrahepatic HBV DNA in 44 cryptogenic patients from group I with the level in the patients from group III.

RESULTS

Compared with group II, group I had a lower prevalence of anti-HBs (antibody against HBsAg) and a higher prevalence of anti-HBe (antibody against hepatitis B e antigen) and anti-HBc (antibody against hepatitis B c antigen). Multivariate analysis confirmed that anti-HBe and anti-HBc positivity were associated with ICC. The odds ratios and 95% confidence intervals for anti-HBe and anti-HBc were 2.482 and 1.482-4.158, 4.556 and 2.938-7.066, respectively. Compared with group III, cryptogenic ICC cases showed more frequent detection of intrahepatic total HBV DNA (63.64% vs. 18.75%, P=0.002).

CONCLUSIONS

OBI may represent an important risk factor for ICC. HBsAg seroclearance does not signify eradication of HBV and may not entirely prevent the development of ICC.

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

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

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

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

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

MicroRNAs associated with HBV infection and HBV-related HCC

Hepatitis B virus (HBV) infection is a global problem and a major risk factor for hepatocellular carcinoma (HCC). microRNAs (miRNAs) comprise a group of small noncoding RNAs regulating gene expression at the posttranslational level, thereby participating in fundamental biological processes, including cell proliferation, differentiation, and apoptosis. In this review, we summarize the roles of miRNAs in HBV infection, the recently identified mechanism underlying dysregulation of miRNAs in HBV-associated HCC, and their association with hepatocarcinogenesis. Moreover, we discuss the recent advances in the use of circulating miRNAs in the early diagnosis of HCC as well as therapies based on these aberrantly expressed miRNAs.

Persistence of hepatitis B virus covalently closed circular DNA in hepatocytes: molecular mechanisms and clinical significance

Covalently closed circular DNA (cccDNA) is the transcriptional template of hepatitis B virus (HBV). Extensive research over the past decades has unveiled the important role of cccDNA in the natural history and antiviral treatment of chronic HBV infection. cccDNA can persist in patients recovering from acute HBV infection for decades. This explains why HBV reactivation occasionally occurs in patients with resolved hepatitis B receiving intensive immunosuppressive agents. In addition, although advances in antiviral treatment dramatically improve the adverse outcomes of chronic hepatitis B (CHB), accumulating evidence demonstrates that current antiviral treatments alone, be they nucleos(t)ide analogs (NAs) or interferon (IFN), fail to cure most CHB patients because of the persistent cccDNA. NA suppresses HBV replication by directly inhibiting viral polymerase, while IFN enhances host immunity against HBV infection. Viral rebound often occurs after discontinuation of antiviral treatment. The loss of cccDNA can be induced by non-cytolytic destruction of cccDNA or immune-mediated killing of infected hepatocytes. It is known that NA has no direct effect on viral transcription or cccDNA stability. Therefore, the long half-life of hepatocytes leads to a very slow decline in cccDNA in patients under antiviral therapy. Novel antiviral agents targeting cccDNA or cccDNA-containing hepatocytes are thus required for curing chronic HBV infection.

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.

Occult hepatitis B virus among the patients with abnormal alanine transaminase

Background:

The occult hepatitis B infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in the sera or in the liver biopsy and the absence of hepatitis B surface antigen (HBsAg) by serological test.

Objectives:

The current study aimed to evaluate the occult HBV infection by polymerase chain reaction (PCR) and determine HBV genotyping among the patients with abnormal alanine transaminase (ALT) in Ahvaz city, Iran.

Patients and Methods:

The sera of 120 patients, 54 (45%) females and 66 (55%) males, with abnormal ALT 40-152 IU were collected. All the patients were negative for HBsAg for more than one year. The patients` sera were tested by PCR using primers specified for the S region of HBV. Then the positive PCR products were sequenced to determine HBV genotyping and phylogenic tree.

Results:

Of these 120 subjects, 12 (10%) patients including 6 (5%) males and 6 (5%) females were found positive for HBV DNA by PCR, which indicated the presence of occult HBV infection among these patients. The sequencing results revealed that genotype D was predominant with sub-genotyping D1 among OBI patients.

Conclusions:

Occult hepatitis B infection is remarkably prevalent in Ahvaz, Iran, and should be considered as a potential risk factor for the transmission of Hepatitis B Virus throughout the community by the carriers.

Occult HBV infection in Morocco: from chronic hepatitis to hepatocellular carcinoma

BACKGROUND & AIMS

Morocco is one of low to intermediate endemic areas for hepatitis B virus (HBV) infection, but no reports have been published on Occult HBV infection (OBI). To determine the prevalence of OBI and its clinical impact among patients with cryptogenic and HCV-related chronic liver disease in Morocco.

METHODS

A total of 152 HBsAg-negative patients (60 patients with cryptogenic hepatitis and 92 HCV carriers) were enrolled in this study. Sera collected from all patients were tested for anti-HBc and anti-HBs antibodies. OBI was assessed in serum and liver tissue samples using highly sensitive PCR assays targeting Surface, X and core regions of the HBV genome and confirmed by Southern blot hybridization.

RESULTS

A high rate of anti-HBc positivity was found among patients with HCV infection (57/92, 61.95%) compared to those with cryptogenic hepatitis (24/60, 40%) (P = 0.034). A high prevalence of OBI was found among patients with HCV infection (42/92, 45.65%) compared to those with cryptogenic hepatitis (17/60, 28.3%) (P = 0.013). In both groups, the prevalence of OBI increased in parallel with advancing stage of liver disease (χ2 = 6.73; P = 0.0095). The highest proportion of OBI was reached among HCV-related HCC cases (62.5%). Multivariate Cox regression analysis revealed that older age (≥56 years), positivity for anti-HBc and presence of OBI were independent risk factors for the development of HCC in HCV-infected patients.

CONCLUSION

This study helps to understand the current status of OBI and its impact on the severity of liver disease in Moroccan patients.

[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 infection in the immigrant population of Sicily, Italy

In Italy, about 7 % of the resident population is represented by immigrants originating from geographic regions at high endemicity for hepatitis B virus infection. This study aims to assess the prevalence of occult HBV infection (OBI) including the identification of HBV-genotypes in a population of immigrants serologically negative for hepatitis B surface antigen (HBsAg). Between May 2006 and May 2010, 339 immigrants were tested for markers of HBV, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. HBV-DNA was tested by using nested-PCR assays on three different genetic region. HBV-DNA was detected in plasma samples of 11/339 (3.2 %) patients. Most of them had no serological markers of HBV infection, 3/58 (5.2 %) were anti-HBc-alone, and 4/13 (30.8 %) were anti-HIV positive. HIV positivity was the only factor independently associated with the higher probability of observing OBI (OR = 16.5, p < 0.001). No HCV co-infected patients were found. Genotype D was detected in 9/11 (81.8 %) OBI cases, while the remaining two (18.2 %) were classified as genotype E. Although OBI was found at lower rate than expected among immigrants from highly endemic countries, anti-HBc alone positivity was confirmed as a sentinel marker of occult HBV infection. Nevertheless, a marked heterogeneity of HBV markers was found among HBV-DNA positive subjects. Our finding evidenced the predominance of HBV-genotype D viral strains among OBI cases, also in those from geographical areas where overt HBV infections are mainly sustained by viral genotypes other than D.

Diagnostic characteristics and hepatic histopathology in 115 patients with liver injury of unknown reasons

AIM: To improve the awareness of liver injury of unknown causes by analyzing the diagnostic and pathological features of unexplained liver injury.

METHODS: A total of 115 patients with liver injury of unknown reasons were enrolled in this study. The biochemical and immunological features, as well as virus markers, abdominal imaging findings and hepatic histopathology were analyzed.

RESULTS: A definite diagnosis was achieved by liver biopsy in 109 patients. Among them, 38 were diagnosed with primary biliary cirrhosis (PBC), and the main pathological feature was non-suppurative inflammation in the bile duct; 31 with autoimmune hepatitis (AIH), which showed obvious interface inflammation in liver tissue; 27 with nonalcoholic fatty liver disease (NAFLD), which showed visible hepatic steatosis and ballooning degeneration; 4 with occult hepatitis B, which presented with portal inflammation and infiltration of lymphocytes and were positive for HBcAg and/or HBsAg as revealed by immunohistochemistry; 2 with hepatic amyloidosis, which showed a lot of eosin amyloid deposits reactive with Congo red in liver cells and blood sinus; 2 with hemochromatosis, which showed obvious iron pigment deposition in liver cells; 2 with glycogen storage disease, which showed extensive hyaline degeneration in hepatic cells and was positive for Dpas; 1 with schistosomiasis with schistosome eggs detected microscopically; 1 with toxoplasmosis, and electron microscopy revealed Toxoplasma gondii rhoptry; 1 with Dubin-Johnson syndrome, which showed thick, dark brown pigment particles in liver cells. There were still 6 cases in whom a definite diagnosis could not be achieved after liver biopsy.

CONCLUSION: Autoimmune liver diseases are main causes of liver injury of unknown causes, followed by NAFLD. Liver parasite, genetic diseases and metabolic diseases are rare. Liver biopsy should be emphasized in patients with liver injury of unknown reasons.

Occult HBV infection: a faceless enemy in liver cancer development

The hepatitis B virus (HBV) represents a worldwide public health problem; the virus is present in one third of the global population. However, this rate may in fact be higher due to occult hepatitis B virus infection (OBI). This condition is characterized by the presence of the viral genome in the liver of individuals sero-negative for the virus surface antigen (HBsAg). The causes of the absence of HBsAg in serum are unknown, however, mutations have been identified that produce variants not recognized by current immunoassays. Epigenetic and immunological host mechanisms also appear to be involved in HBsAg suppression. Current evidence suggests that OBI maintains its carcinogenic potential, favoring the progression of fibrosis and cirrhosis of the liver. In common with open HBV infection, OBI can contribute to the establishment of hepatocellular carcinoma. Epidemiological data regarding the global prevalence of OBI vary due to the use of detection methods of different sensitivity and specificity. In Latin America, which is considered an area of low prevalence for HBV, diagnostic screening methods using gene amplification tests for confirmation of OBI are not conducted. This prevents determination of the actual prevalence of OBI, highlighting the need for the implementation of cutting edge technology in epidemiological surveillance systems.