Correlation between the promoter basal core and precore mutations and HBsAg quantification in French blood donors infected with hepatitis B virus

HBV PreC interacts with SUV39H1 to induce viral replication by blocking the proteasomal degradation of viral polymerase

Hepatitis B e antigen (HBeAg) seropositivity during the natural history of chronic hepatitis B (CHB) is known to coincide with significant increases in serum and intrahepatic HBV DNA levels. However, the precise underlying mechanism remains unclear. In this study, we found that PreC (HBeAg precursor) genetic ablation leads to reduced viral replication both in vitro and in vivo. Furthermore, PreC impedes the proteasomal degradation of HBV polymerase, promoting viral replication. We discovered that PreC interacts with SUV39H1, a histone methyltransferase, resulting in a reduction in the expression of Cdt2, an adaptor protein of CRL4 E3 ligase targeting HBV polymerase. SUV39H1 induces H3K9 trimethylation of the Cdt2 promoter in a PreC-induced manner. CRISPR-mediated knockout of endogenous SUV39H1 or pharmaceutical inhibition of SUV39H1 decreases HBV loads in the mouse liver. Additionally, genetic depletion of Cdt2 in the mouse liver abrogates PreC-related HBV replication. Interestingly, a negative correlation of intrahepatic Cdt2 with serum HBeAg and HBV DNA load was observed in CHB patient samples. Our study thus sheds light on the mechanistic role of PreC in inducing HBV replication and identifies potential therapeutic targets for HBV treatment.

Precore mutation enhances viral replication to facilitate persistent infection especially in HBeAg-negative patients

Naturally occurred precore (PC, G1896A) and/or basal core promoter (BCP, A1762T/G1764A) mutations are prevalent in chronic HBV-infected patients, especially those under HBeAg-negative status. However, the replicative capacity of HBV with PC/BCP mutations remains ambiguous. Herein, meta-analysis showed that, only under HBeAg-negative status, the serum HBV DNA load in patients with PC mutation was 7.41-fold higher than those without the mutation. Both PC mutation alone and BCP ​+ ​PC mutations promoted HBV replication in cell and hydrodynamic injection mouse models. In human hepatocyte chimeric mouse model, BCP ​+ ​PC mutations led to elevated replicative capacity and intrahepatic core protein accumulation. Mechanistically, preC RNA harboring PC mutation could serve as mRNA to express core and P proteins, and such pgRNA-like function favored the maintenance of cccDNA pool under HBeAg-negative status. Additionally, BCP ​+ ​PC mutations induced more extensive and severe human hepatocyte damage as well as activated endoplasmic reticulum stress and TNF signaling pathway in livers of chimeric mice. This study indicates that HBeAg-negative patients should be monitored on HBV mutations regularly and are expected to receive early antiviral treatment to prevent disease progression.

Evaluation of the Diagnostic Performances of the SD-Bioline®HBeAg Rapid Test Used Routinely for the Management of HBV-Infected Individuals in Burkina Faso

Hepatitis B e antigen (HBeAg) is a marker of wild-type hepatitis B virus replication. In resource-limited countries where access to enzyme-linked immunosorbent assay (ELISA) remains a challenge, rapid diagnostic tests (RDT) constitute a good alternative. The HBeAg status is employed to evaluate eligibility for antiviral therapy and to prevent the transmission of hepatitis B from mother to child (PMTCT). The objective of this study was to assess the diagnostic performance of the SD-Bioline®HBeAg RDT commonly used for detecting HBeAg in laboratories in Burkina Faso. The sample panel used was collected from HBsAg-positive patients received in the laboratory for the detection of HBeAg with the rapid test. The samples were retested for HBeAg using the VIDAS HBe/Anti-HBe enzyme-linked fluorescent assay (ELFA) (Gold standard). Then, the viral load (VL) of HBV DNA was determined using the GENERIC HBV CHARGE VIRLAE kit (GHBV-CV). The diagnostic performances of the SD-Bioline®HBeAg and its agreement with the gold standard were calculated with their 95% confidence intervals. Overall, 340 sera obtained from HBsAg-positive patients were included in this evaluation Compared to the VIDAS HBe/Anti-HBe ELFA test, the sensitivity (Se) and specificity (Sp) of the SD-Bioline®HBeAg test were 33.3% and 97.9%, respectively. The concordance between the two tests was 0.42. Depending on the viral load, the Se and Sp varied from 8.8% and 98.3% for a VL < 2000 IU/mL to 35.5% and 98.4% for a VL > 2,000,000 IU/mL. The results showed a low sensibility of the SD-Bioline®HBeAg RDT test, indicating that its use is inappropriate for the clinical management of HBV-infected patients. They also highlight the urgent need to develop HBeAg rapid tests with better sensitivities.

Dynamic profile of the HBeAg-anti-HBe system in acute and chronic hepatitis B virus infection: A clinical-laboratory approach

Wild-type HBV infection is followed by the blood expression of its widely known serological markers of infection, and designated as, hepatitis B virus surface antigen (HBsAg) and its antibody (anti-HBs), anti-HBc antibodies (IgM/IgG), and hepatitis B virus 'e' antigen (HBeAg) and its antibody (anti-HBe). These markers are detected as the infection develops and its kinetic behavior serves as a basis for monitoring the disorder and for diagnosing the clinical form or infection phase. Among these, the HBeAg-anti-HBe system markers demonstrate a dynamic profile whose interpretation, both in the acute or chronic HBV infection context, can offer greater difficulty to the health professionals, due to its particularities. This review offers a revisit to the markers dynamics of this system in the acute and chronic HBV infection and to the clinical and laboratory significance of its expression in these two clinical contexts.

A Highly Prevalent Polymorphism in the Core Region Impairs Quantification of Hepatitis B Virus (HBV) by the cobas TaqMan HBV Assay

The high genetic variability of hepatitis B virus (HBV) can impair DNA quantification. Here, we investigate a major underquantification of HBV by the cobas TaqMan HBV assay (CTM; Roche). In France, between 2005 and 2017, HBV DNA was detected in 3,102 blood donations by use of the CTM (95% limit of detection [LOD₉₅], 4.8 IU/ml). HBV strains were sequenced in the S region (LOD₉₅, ∼30 IU/ml). Concordant (n = 120) and discordant (n = 45) samples were identified according to the agreement between the plasma viral load (pVL) determined by the CTM and sequencing; all samples were also quantified using the RealTime HBV assay (RTH; Abbott). The viral signature, cloning, and mutagenesis were used to characterize the polymorphism responsible for CTM misquantification. A CTM-RTH discordance (>1 log IU/ml) was found in 14/45 samples that had low pVLs and were successfully genotyped (pVL^low genoS⁺). PreC/C clones of concordant (C1, C2) and discordant (D1, D2) strains were used to challenge the CTM. Strains D1 and D2 were highly underquantified (42- and 368-fold). In clones, mutating the region corresponding to the CTM reverse primer from a discordant sequence to a concordant sequence restored the levels of quantification to 24% (D1→C1) and 59% (D2→C1) of theoretical levels, while mutating the sequence of a concordant strain to that of a discordant strain led to 78-fold (C1→D1) and 146-fold (C1→D2) decreases in quantification. Moreover, mutating positions 1961 and 1962 was enough to induce a 5-fold underquantification. We conclude that the CTM underestimates pVLs for HBV strains with mutations in the reverse primer target. Specifically, the polymorphism at nucleotides 1961 and 1962 is naturally present in 4.79 and 4.22% of genotype A and D strains, which are highly frequent in Europe, leading to a 5-fold decrease in quantification. Quantification using the new-generation Roche C4800 assay is not affected by this polymorphism.

Higher rates of HBsAg clearance with tenofovir-containing therapy in HBV/HIV co-infection

INTRODUCTION

Achieving functional cure of chronic HBV infection (Hepatitis B surface antigen [HBsAg] clearance, eventually followed by acquisition of anti-hepatitis B surface antigen [Anti-HBs]) in individuals with HIV and HBV infections is a rare event. In this setting, factors related to HBV cure have not yet been fully characterized.

METHODS

HIV-infected individuals with chronic HBV infection enrolled in the French Dat'AIDS cohort (NCT02898987), who started combined antiretroviral (cART)-anti-HBV treatment were retrospectively analyzed for HBsAg loss and Anti-HBs seroconversion.

RESULTS

Overall, 1419 naïve-subjects received three different cART-anti-HBV treatment schedule: (1) 3TC or FTC only (n = 150), (2) TDF with or without 3TC or FTC (n = 489) and (3) 3TC or FTC as first line followed by adding/switching to TDF as second line (n = 780). Individuals were followed-up for a median of 89 months (IQR, 56-118). HBV-DNA was < 15 IU/mL in 91% of individuals at the end of the follow-up. Overall, 97 individuals cleared HBsAg (0.7/100 patient-years), of whom, 67 seroconverted for Anti-HBs (0.5/100 patient-years). A high CD4 nadir, a short delay between HBV diagnosis and treatment, a longer time on HBV therapy, an African origin and TDF-based therapy were independent predictors of HBsAg clearance (Probability of odds ratio [OR]>1, >95%) suggested by Bayesian analysis. Also, TDF-based regimen as first line (OR, 3.03) or second line (OR, 2.95) increased rates of HBsAg clearance compared to 3TC or FTC alone, with a 99% probability.

CONCLUSIONS

HBsAg clearance rate was low in HIV-HBV co-infected cART-anti-HBV treated individuals, but was slightly improved on TDF-based regimen.

Clinical implication and viral mutation in basal core promoter/pre-core of hepatitis B virus C/D recombinant

BACKGROUND AND AIM

Hepatitis B virus (HBV) C/D recombinant is predominant in Tibet in Western China. Although the geographical and ethnic distributions of the C/D recombinant have been described, the clinical implication and the characteristics of viral mutation in the basal core promoter (BCP)/pre-core (PC) region remain unclear.

METHODS

A total of 174 chronic HBV carriers, including 115 with chronic hepatitis B, 45 with liver cirrhosis, and 14 with hepatocellular carcinoma, were enrolled. Using next-generation sequencing, the S and BCP/PC genes were determined and analyzed.

RESULTS

Genotypes B, C2, D, and C/D recombinant were detected in 1.1% (2/174), 19.5% (34/174), 0.6% (1/174) and 78.7% (137/174) of the patients, respectively. The clinical parameters and viral mutation frequency in the BCP/PC region were compared between C2- and C/D recombinant-infected patients. The distribution of C2 and C/D did not differ by disease status or liver function. Significantly higher levels of HBV DNA (6.7 ± 1.6 vs. 5.9 ± 1.5, p = 0.014), HBeAg (263.5 vs. 20.0, p = 0.013) and A1762T/G1764A double-mutations (81.0 vs. 61.8%, p = 0.018), but a lower frequency of G1896A stop mutation (33.6 vs. 76.5%, p < 0.001) was observed in patients with the C/D recombinant than in patients with genotype C2. The clonal frequencies of A1762T, G1764A, G1896A and A1846T were lower in patients with C/D than C2.

CONCLUSION

The C/D recombinant has different mutation pattern in the BCP/PC region compared with genotype C2. The lower clonal frequencies of BCP/PC mutations may explain the higher levels of HBV DNA and HBeAg in C/D-infected patients.

Low incidence of precore W28* mutant variants in treated hepatitis B virus and human immunodeficiency virus co-infected patients

The precore (pc) W28* mutation arises from immune-selective pressures during the hepatitis B "e" antigen (HBeAg)-positive phase of chronic hepatitis B virus (HBV) infection and has been linked to severe liver-related morbidity. Here, we examined the determinants of harboring this mutation and its rate of emergence in treated patients co-infected with human immunodeficiency virus (HIV) and HBV. In a three-year prospective cohort of 165 HIV-HBV co-infected patients, pcW28* mutation was determined via DNA-chip during yearly sampling. In a subgroup with liver biopsies, HBV covalently-closed circular (ccc)-DNA and total intrahepatic (IH)-DNA were quantified by real-time PCR. From respective inclusion to year-3 visits, median HBV-DNA levels decreased (5.88 log₁₀ IU/mL to <1.78 log₁₀ IU/mL, p < 0.001) and tenofovir-use increased (15.8%-71.4%, p < 0.001). At baseline, 47 of 162 (29.0%) patients had the pcW28* mutation and were more frequently HBeAg-negative (adjusted-OR = 4.37, 95%CI = 1.76-10.86) and had non-A HBV genotypes (adjusted-OR = 9.14, 95%CI = 4.05-20.66). No association with HIV-related factors was observed. In 114 patients without baseline mutation and available data, four developed incident pcW28* mutation by the end of follow-up (cumulative 3.5%, 95%CI = 1.3-9.1%). In the 32 patients with liver biopsies, 10 (31.3%) patients harboring the pcW28* mutation had significantly lower adjusted mean cccDNA (0.05 versus without = 0.43 copies/cell, p < 0.001) and total IH-DNA levels (2.31 versus without = 18.59 copies/cell, p = 0.006). In conclusion, the pcW28* mutation infrequently appeared in this co-infected study population with increased use of potent antivirals and suppressed levels of circulating virus.

Prevalence and Characteristics of Precore Mutation in Iran and Its Correlation with Genotypes of Hepatitis B

Introduction

Mutation of the HBV precore gene prevents the production of HBeAg, which is an important target for immune responses. Distribution of this mutation varies along with frequency of HBV genotypes in accordance with geographic and ethnic variations. The general objective of this study was to evaluate the prevalence and characteristics of precore mutation in Iran and its correlation with genotypes of hepatitis B.

Methods

In this cross-sectional study, viral DNA of 182 Iranian hepatitis B surface antigen positive patients who were admitted to Bandar Abbas Blood Transfusion Organization in 2012 and 2013 was retrieved from their serum samples. HBeAg, anti-HBe, and anti-HBc IgM diagnostic tests were performed using ELISA kits. Precore and Pre-S regions were amplified using specific primers and PCR thereafter to determine the genotypes; precore mutation, PCR, and restriction fragment length polymorphism (RFLP) methods also were applied. SPSS version 12 was used for data analysis by Mann–Whitney U test, Fisher’s exact probability test, and t-test.

Results

A total of 62 patients (34.1%) had precore mutation (A1896G), and genotype D was the predominant genotype in these patients, which was followed by an unknown genotype that was suspected for genotype B. Interestingly, the relationships between precore mutation and HBeAg (p=0.037) and genotype D (p=0.005) were significant; however, no correlation was observed between this mutation and acute or chronic hepatitis and sex of patients.

Conclusion

This study found high prevalence of precore mutations in southern Iran, which was significantly associated with HBeAg and genotype D.

Prevalence and Characteristics of Basal Core Promoter Mutations in Iran and its Correlation with Acute and Chronic Hepatitis B Infection

Introduction

Manifestations of HBV infection differ in chronic and acute phases. Therefore, identifying the determinants such as mutations has a vital role in the treatment of the disease. A dual transversion in the basal core promoter (BCP) region is common among HBV patients. Thus, the present study was conducted with the objective of determining the prevalence of basal core promoter (BCP) mutations and its correlation with the outcome of HBV infection.

Method

In this cross-sectional study, samples were obtained from 182 Iranian HBsAg positive patients who were admitted to the Bandar Abbas Blood Transfusion Organization in 2012 and 2013. They were screened by ELISA test using commercial kits to detect serological marker anti-HBc IgM for distinct chronic hepatitis from acute infection. Thereafter, the extracted DNA was used for determination of the BCP mutations by PCR-RFLP technique. Data analyses were performed with SPSS 12 by Mann–Whitney U test, Fisher’s exact probability test, and t-test.

Results

BCP mutations were observed in 15 samples (8.24%) of the study population, and serological tests determined that, among the BCP mutants, one sample (6.67%) was HBeAg positive, 14 samples (93.33%) were HBeAg negative, and four samples (2.2%) were positive for anti-HBc IgM test. Data analysis indicated a statistically significant association between BCP mutations and acute hepatitis (p=0.002). However, no relationship was detected between the prevalences of the BCP mutations and gender of subjects (p>0.567).

Conclusions

The prevalence of BCP variants was low in the south of Iran, and this mutation can lead to acute phase of viral hepatitis.

Investigation of a Novel Hepatitis B Virus Surface Antigen (HBsAg) Escape Mutant Affecting Immunogenicity

Mutation in the hepatitis B virus surface antigen (HBsAg) may affect the efficiency of diagnostic immunoassays or success of vaccinations using HBsAg. Thus, antigenicity and immunogenicity analyses of the mutated HBsAg are necessary to develop novel diagnostic tools and efficient vaccinations. Here, the in vitro antigenicity of three wild-type HBsAg open reading frames (ORFs) (adr4, W1S [subtype adr] and W3S [subtype adr]) isolated from clinically infected patients and nineteen synthesized single/double/multiple amino acid-substituted mutants were tested with commercial ELISA kits. Immunofluorescence staining of transfected cells and Western blot analysis confirmed that these ORFs were expressed at comparable levels in HEK-293 cells. W1S and adr4 were clearly detected, whereas W3S could not be detected. Using the same commercial immunoassay kit, we found that the single mutants, K120P and D123T, were marginally reactive, whereas W3S-aW1S and the double mutant, K120P/D123T, exhibited antigenicity roughly equivalent to the wild-type wako1S. On the other hand, the single mutants of W1S, P120K and T123D, significantly impaired the reactivity, while W1S-aW3S and the double mutant of W1S, P120K/T123D, resulted in a complete loss of antigenicity. In addition, ELISA revealed reduced HBs antigenicity of two mutants, W1S N146G and W1S Q129R/G145R. These commercial ELISA-based antigenic reactivities of HBsAg were also strongly correlated with the predicted Ai alterations of affected amino acids due to the specific mutation. In conclusion, this study showed for the first time that lysine (K120) and aspartate (D123) simultaneously affected HBsAg antigenicity, leading to diagnostic failure. These findings will improve diagnostic assays and vaccine development.

Different precore/core mutations of hepatitis B interact with, limit, or favor liver fibrosis severity

BACKGROUND AND AIM

The impact of basal core promoter (BCP) and precore (PC) mutants of the hepatitis B virus (HBV) on liver disease severity remains controversial. The aim of the present study was to screen BCP and PC mutations in 252 HBV surface antigen (HBsAg) positive carriers in France and to assess relationships between these mutations and severe fibrosis.

METHODS

Direct sequencing of the precore/core gene was used to detect A1762T/G1764A and G1757A mutations in the BCP and G1896A and G1899A mutations in the PC region.

RESULTS

The prevalences of A1762T/G1764A, G1757A, G1896A, and G1899A mutations were 34.1%, 38.7%, 54.9%, and 29.3% (P < 0.001), respectively. The independent predictors of severe fibrosis (≥F3 Metavir) were older age (P < 0.001), male gender (P = 0.012), elevated alanine aminotransferase (P < 0.001), and the double A1762T/G1764A mutant with no other mutations (P = 0.011). Interestingly, the association of the G1899A mutation with the double A1762T/G1764A mutant significantly counteracted the deleterious effect of the sole double A1762T/G1764A mutant (odds ratio [OR] = 0.28 vs. OR = 3.55, respectively, P = 0.028).

CONCLUSIONS

Patients with the A1762T/G1764A mutation have a higher risk of severe fibrosis. The G1899A mutation is a protective factor against severe fibrosis that counteracted the deleterious effect of the A1762T/G1764A mutation. Finally, host phenotypic and HBV genotypic markers independently predict fibrosis severity.

Functional analysis of 'a' determinant mutations associated with occult HBV in HIV-positive South Africans

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the absence of hepatitis B surface antigen (HBsAg). Occult HBV is associated with the development of hepatocellular carcinoma, reactivation during immune suppression, and virus transmission. Viral mutations contribute significantly to the occult HBV phenotype. Mutations in the 'a' determinant of HBsAg are of particular interest, as these mutations are associated with immune escape, vaccine escape and diagnostic failure. We examined the effects of selected occult HBV-associated mutations identified in a population of HIV-positive South Africans on HBsAg production in vitro. Mutations were inserted into two different chronic HBV backbones and transfected into a hepatocyte-derived cell line. HBsAg levels were quantified by enzyme-linked immunosorbent assay (ELISA), while the detectability of mutant HBsAg was determined using an HA-tagged HBsAg expression system. Of the seven mutations analysed, four (S132P, C138Y, N146D and C147Y) resulted in decreased HBsAg expression in one viral background but not in the second viral background. One mutation (N146D) led to a decrease in HBsAg detected as compared to HA-tag, indicating that this mutation compromises the ability of the ELISA to detect HBsAg. The contribution of occult-associated mutations to the HBsAg-negative phenotype of occult HBV cannot be determined adequately by testing the effect of the mutation in a single viral background, and rigorous analysis of these mutations is required.

Hepatitis Viruses B and D and Human Immunodeficiency Virus Infections in Hemodialysis Patients in the South of Iran: Prevalence and Genotypes

BACKGROUND

Hepatitis B virus (HBV), hepatitis D virus (HDV), and human immunodeficiency virus (HIV) are transmitted by blood transfusion. Thus, hemodialysis (HD) patients are more prone to become the carriers of these infections due to their treatment demands.

OBJECTIVES

The aim of this study was to assess the prevalence of HBV and HIV infections among HD patients in Bandar Abbas, Iran, 2015.

PATIENTS AND METHODS

A total of 153 patients with chronic renal failure undergoing HD at Shahid Mohammadi hospital in Bandar Abbas were examined for hepatitis B surface antigen (HBsAg), anti- hepatitis C virus, and anti-HIV over a period of 2 months. Thereafter, all of the specimens were evaluated for HBV-DNA, HDV-RNA and HIV-RNA using polymerase chain reaction (PCR) and further techniques. All statistical analyses were carried out using SPSS version 12 for Windows with the t-test and chi-square (χ(2)) test.

RESULTS

Both kinds of assay determined that nine (5.88%) patients were HBV positive (HBsAg-positive), whereas no HIV- and HDV-positive patients were diagnosed. All of the diagnosed HBV samples belonged to genotype D; the prevalence of HBV is associated with age, duration of HD, history of blood transfusion, and using shared HD devices.

CONCLUSIONS

In conclusion, the prevalence of HBV infection was low in the south of Iran, but genotype D represented the major HBV genotype in this population. Among the variables, age, duration of HD, history of blood transfusion, and using shared HD devices influenced the prevalence of HBV among HD patients.

Deep sequencing of hepatitis B virus basal core promoter and precore mutants in HBeAg-positive chronic hepatitis B patients

Mutants in the basal core promoter (BCP) and precore (PC) regions of hepatitis B virus (HBV) genome are associated with the progression of chronic hepatitis B (CHB) infection. However, quasispecies characteristics of naturally occurring mutants in those regions in HBeAg-positive CHB patients has not been well described, partly limited by quantitative assay. This study aimed to develop an Ion Torrent deep sequencing assay to determine BCP and PC mutant percentages in HBeAg-positive CHB patients who were treatment naïve and correlate them with different viral and host factors. Our results showed that Ion Torrent deep sequencing could achieve high accuracy (R²>0.99) within a dynamic range between 1% and 100%. Twelve hotspots with prevalence of greater than 20% were observed in EnhII/BCP/PC regions. G1719T, T1753V, A1762T and G1764A were genotype C related. BCP A1762T/G1764A double mutants were generally accompanied with PC 1896 wild type or lower PC G1896A mutant percentage. Lower serum HBeAg and HBsAg levels were associated with higher BCP A1762T/G1764A mutant percentages (≥50%). ALT levels were higher in patients with PC G1896A mutant percentage greater than 10%. In conclusion, deep sequencing such as Ion Torrent sequencing could accurately quantify HBV mutants for providing clinical relevant information during HBV infection.