Mutation at codon 130 in hepatitis B virus (HBV) core region increases markedly during acute exacerbation of hepatitis in chronic HBV carriers

The dynamic variation position and predominant quasispecies of hepatitis B virus: Novel predictors of early hepatocarcinoma

To find the predictors of early HCC based on the dynamic changes of HBV quasispecies, this study utilizing the second-generation sequencing (NGS) and high-order multiplex droplet digital PCR (ddPCR) technology to examine the HBV quasispecies in serum of total 247 subjects recruited from high-incidence area of HCC. In the discovery stage, 15 non-synonymous Single Nucleotide Polymorphisms (SNPs) with higher variant proportion in HCC case group were founded (all P<0.05). Furthermore, the variant proportions in some of these SNPs were observed changing regularly within 5 years before the onset of HCC, and 5 of them located in HBX, 2 in HBS and 2 in HBC. The HBV predominant quasispecies and their consensus sequences were identified by genetic evolution analysis, in which the high HBS and HBC quasispecies heterogeneity were found associated with the forming of multifarious quasispecies clones, and the HBX gene had the highest proportion of predominant quasispecies (46.7 % in HBX vs 12.7 % and 13.8 % in HBS and HBC respectively) with the key variations (G1512A, A1630G, T1753C/G/A, A1762T and G1764A) determined. In the validation stage, we confirmed that the combined double mutations of G1512A+A1630G, A1762T+G1764A, and the combined triple mutations of T1753C/G/A + A1762T+G1764A, all expressed higher in early HCC cases when comparing with control group (all P<0.05). We also demonstrated the advantages of ddPCR using in multi-variations detection in large-sample for early HCC surveillance and screening. So we think that the dynamic of key HBV variation positions and their different combinations determined by quasispecies anlysis in this study can act as the novel predictors of early hepatocarcinoma and suitable to popularize and apply in HCC screening.

Progressive accumulation of mutations in the hepatitis B virus genome and its impact on time to diagnosis of hepatocellular carcinoma

To evaluate how hepatitis B virus (HBV) genetic variation affected progression from chronic carrier state to hepatocellular carcinoma (HCC), we analyzed HBV full-length sequences in blood obtained <1-20 years before diagnosis from 117 HCC cases and 118 controls nested in a cohort of 4,841 HBV carriers, for whom HBV genotypes B and C are predominant. The relationship between each viral single-nucleotide polymorphism (SNP) and HCC development was assessed using ordinal logistic models according to five periods of time to diagnosis (TTD). Thirty-one HBV-SNPs showed significant association with TTD after adjustment for HBV genotype, 24 of which could also be analyzed with an extended analysis on the full-length data in conjunction with 512 partial sequences (nucleotides 2,436-1,623) from the cohort. The obtained 10 robust candidate HBV-SNPs (P ≤ 0.0304), which showed odds ratios ranging from 1.89 to 8.68, were further confirmed in 163 GenBank HBV-HCC sequences from nine Asia regions, assayed after HCC diagnosis, representing the end stage of progressive hepatic diseases. The prevalence of these HBV-SNPs and their cumulative number, presented in terms of mutation score, increased with time approaching HCC diagnosis, with an odds ratio of 2.17, 4.21, 8.15, and 19.15, respectively, for the mutation score of 1, 2, 3, and ≥4 versus 0. The mutation score for predicting short-term HCC risk outperformed other factors, including HBV-DNA levels, viral genotype, and various combinations of risk factors, and revealed increasing accuracy with shorter TTD (<4.5 years before diagnosis: area under the curve = 0.83-0.89; sensitivity = 72.7%-94.1%; specificity = 58.3%-70.5%; conditioned on optimized cutoff for genotype B and C, respectively).

CONCLUSIONS

Identifying and tracking viral mutations is important for monitoring hepatitis B progression and early detection of HCC. (Hepatology 2016;64:720-731).

Predominance of precore mutations and clinical significance of basal core promoter mutations in chronic hepatitis B virus infection in Indonesia

Chronic hepatitis B virus (HBV) infection is a major health problem worldwide, with a particularly high prevalence in the Asian-Pacific region. During chronic hepatitis B virus (HBV) infection, mutations commonly occur in the basal core promoter (BCP) and precore (PC) regions of HBV, affecting HBeAg expression, particularly following HBeAg serocon-version. Mutations in the B- and T-cell epitopes of the HBV core have also been observed during disease progression. The clinical significance of HBV genome variability has been demonstrated, however the results are a subject of controversy. Considering the characteristics of the virus associated with geographical location, the profiles of BCP, PC and core mutations and their clinical implications in patients with chronic HBV infection in Surabaya, Indonesia, were investigated. The BCP, PC and core mutations and HBV genotypes were detected by direct sequencing. The HBeAg/anti-HBe status and HBV DNA levels were also assessed. This study enrolled 10 patients with chronic HBV infection (UC) from Dr Soetomo General Hospital and Indonesian Red Cross, Surabaya, East Java, Indonesia, 10 patients with chronic hepatitis B and liver cirrhosis (LC) and 4 patients with chronic hepatitis B and hepatocellular carcinoma (HCC) from Dr Soetomo General Hospital. The PC mutation A1896 was predominant in all the groups (60-100%), together with the PC variant T1858, which was associated with HBV genotype B. The number of detected core mutations (Thr/Ser130) was higher in HCC patients (50%). However, the BCP mutations T1762/A1764 were predominant in LC patients (50-60%). The LC and HCC patients carried HBV isolates with additional mutations, at least at BCP or PC, mainly following HBeAg seroconversion. In the majority of anti-HBe-positive samples, the BCP T1762/A1764 mutations were associated with a high viral load, regardless of the PC 1896 status. In conclusion, the PC mutations were found to be predominant in all the groups. However, the BCP mutations were mainly detected in the LC group and may be considered as a critical indicator of a poor clinical outcome.

Naturally occurring core immune-escape and carboxy-terminal mutations\truncations in patients with e antigen negative chronic hepatitis B

INTRODUCTION

Hepatocellular injury is often progressive in patients with hepatitis B e antigen negative chronic hepatitis B (HBeAg -ve CHB). There is scant data on association of core mutations occurring in patients with HBeAg -ve CHB with severity of liver disease.

MATERIALS AND METHODS

Hundred and eighteen patients with chronic infection who were HBeAg negative, anti-HBe, and HBV DNA positive were enrolled. Precore and core regions were amplified, sequenced, and analyzed for precore, T helper, cytotoxic T lymphocytes (CTLs), B-cell epitope, and core carboxy-terminal region mutations.

RESULTS

Majority of patients were infected with HBV genotype D: 96 (81%) [D1: 16, D2: 55 and D5: 25] followed by genotype A1: 15 (13%) and genotype C: 7 (6%) [C1: 5 and unidentified subgenotype C: 2]. Classical (A1896) as well as nonclassical precore region mutations were detected in 30 (25%) and in 9 (7.6%) patients, respectively. Core immune escape, core carboxy-terminal mutations and truncations were detected in 61 (52%), 11 (9.3%), and 14 (12%) patients, respectively. Three core immune escape mutations were significantly higher in patients with coexisting precore stop codon compared with patients without precore stop codon mutation, cT12S (43 vs. 8%, p < 0.001), cS21T (16 vs. 3.4%, p < 0.026), and cE77D (30 vs. 4.5%, p < 0.002). When frequency of core immune escape mutations was compared among CHB and decompensated patients, and cT12S: (27 vs. 10%, p < 0.05), cS21T (16 vs. 1.35%, p < 0.01), cT67P/N: (20 vs. 4%, p < 0.001), cE113D (11.37 vs. 1.35%, p < 0.05), and cP130T/Q (7 vs. 0%, p < 0.001) mutations were found to be significantly higher in decompensated patients.

CONCLUSION

Core immune-escape mutations cT12S, cS21T, cT67P, cE113D, and cP130T/Q are significantly higher in decompensated liver disease patients and could influence the severity of liver disease in HBeAg -ve CHB patients.

Clinical usefulness of measuring red blood cell distribution width in patients with hepatitis B

Background

Red blood cell distribution width (RDW), an automated measure of red blood cell size heterogeneity (e.g., anisocytosis) that is largely overlooked, is a newly recognized risk marker in patients with cardiovascular diseases, but its role in persistent viral infection has not been well-defined. The present study was designed to investigate the association between RDW values and different disease states in hepatitis B virus (HBV)-infected patients. In addition, we analyzed whether RDW is associated with mortality in the HBV-infected patients.

Methodology/Principal Findings

One hundred and twenty-three patients, including 16 with acute hepatitis B (AHB), 61 with chronic hepatitis B (CHB), and 46 with chronic severe hepatitis B (CSHB), and 48 healthy controls were enrolled. In all subjects, a blood sample was collected at admission to examine liver function, renal function, international normalized ratio and routine hematological testing. All patients were followed up for at least 4 months. A total of 10 clinical chemistry, hematology, and biochemical variables were analyzed for possible association with outcomes by using Cox proportional hazards and multiple regression models. RDW values at admission in patients with CSHB (18.30±3.11%, P<0.001), CHB (16.37±2.43%, P<0.001) and AHB (14.38±1.72%, P<0.05) were significantly higher than those in healthy controls (13.03±1.33%). Increased RDW values were clinically associated with severe liver disease and increased 3-month mortality rate. Multivariate analysis demonstrated that RDW values and the model for end-stage liver disease score were independent predictors for mortality (both P<0.001).

Conclusion

RDW values are significantly increased in patients with hepatitis B and associated with its severity. Moreover, RDW values are an independent predicting factor for the 3-month mortality rate in patients with hepatitis B.

Hepatitis B virus DNA is more powerful than HBeAg in predicting peripheral T-lymphocyte subpopulations in chronic HBV-infected individuals with normal liver function tests

AIM: To investigate the peripheral T-lymphocyte subpopulation profile, and its correlations with hepatitis B virus (HBV) replication level in chronic HBV-infected (CHI) individuals with normal liver function tests (LFTs).

METHODS: Frequencies of T-lymphocyte subpopu-lations in peripheral blood were measured by flow cytometry in 216 CHI individuals. HBV markers were detected with ELISA. Serum HBV DNA load was assessed with quantitative real-time PCR. Information of age at HBV infection, and maternal HBV infection status was collected. ANOVA linear trend test and linear regression were used in statistical analysis.

RESULTS: CHI individuals had significantly decreased relative frequencies of CD3⁺, CD4⁺ subpopulations and CD4⁺/CD8⁺ ratio, and increased CD8⁺ subset percentage compared with uninfected individuals (all P < 0.001). There was a significant linear relationship between the load of HBV DNA and the parameters of T-lymphocyte subpopulations (ANOVA linear trend test P < 0.01). The parameters were also significantly worse among individuals whose mothers were known to be HBV carriers, and those having gained infection before the age of 8 years. In multiple regressions, after adjustment for age at HBV infection and status of maternal HBV infection, log copies of HBV DNA maintained its highly significant predictive coefficient on T-lymphocyte subpopulations, whereas the effect of HBeAg was not significant.

CONCLUSION: HBV DNA correlates with modification in the relative T-lymphocyte subpopulation frequencies. High viral load is more powerful than HBeAg in predicting the impaired balance of T-cell subsets.

Effect of viral load on T-lymphocyte failure in patients with chronic hepatitis B

AIM

To investigate peripheral T-lymphocyte sub-population profile and its correlation with hepatitis B virus (HBV) replication in patients with chronic hepatitis B (CHB).

METHODS

Distribution of T-lymphocyte subpopulations in peripheral blood was measured by flow cytometry in 206 CHB patients. HBV markers were detected with ELISA. Serum HBV DNA load was assessed with quantitative real-time polymerase chain reaction (PCR). The relationship between HBV replication and variation in peripheral T-cell subsets was analyzed.

RESULTS

CHB patients had significantly decreased CD3+ and CD4+ cells and CD4+/CD8+ ratio, and increased CD8+ cells compared with uninfected controls (55.44 +/- 12.39 vs 71.07 +/- 4.76, 30.92 +/- 7.48 vs 38.94 +/- 3.39, 1.01 +/- 0.49 vs 1.67 +/- 0.33, and 34.39 +/- 9.22 vs 24.02 +/- 4.35; P < 0.001, respectively). Univariate analysis showed a similar pattern of these parameters was significantly associated with high viral load, presence of serum hepatitis B e antigen (HBeAg) expression, liver disease severity, history of maternal HBV infection, and young age at HBV infection, all with P < 0.01. There was a significant linear relationship between viral load and these parameters of T-lymphocyte subpopulations (linear trend test P < 0.001). There was a negative correlation between the levels of CD3+ and CD4+ cells and CD4+/CD8+ ratio and serum level of viral load in CHB patients (r = -0.68, -0.65 and -0.75, all P < 0.0001), and a positive correlation between CD8+ cells and viral load (r = 0.70, P < 0.0001). There was a significant decreasing trend in CD3+ and CD4+ cells and CD4+/CD8+ ratio with increasing severity of hepatocyte damage and decreasing age at HBV infection (linear trend test P < 0.01). In multiple regression (after adjustment for age at HBV infection, maternal HBV infection status and hepatocyte damage severity) log copies of HBV DNA maintained a highly significant predictive coefficient on T-lymphocyte subpopulations, and was the strongest predictor of variation in CD3+, CD4+, CD8+ cells and CD4+/CD8+ ratio. However, the effect of HBeAg was not significant.

CONCLUSION

T-lymphocyte failure was significantly associated with viral replication level. The substantial linear dose-response relationship and strong independent predictive effect of viral load on T-lymphocyte subpopulations suggests the possibility of a causal relationship between them, and indicates the importance of viral load in the pathogenesis of T cell hyporesponsiveness in these patients.

Analysis of the core gene of hepatitis B virus in Korean patients

BACKGROUND/AIMS

As the core gene of hepatitis B virus (HBV) is a major immunological target, its mutation may evoke or evade immune clearance. We investigated the frequency and location of HBV core gene substitutions according to hepatitis B e antigen (HBeAg) status and viral replication status, and evaluated the association of these substitutions with the different stages of chronic HBV infection in Korean patients.

METHODS

The study population included 45 HBeAg-positive/DNA-positive patients (group I), 49 HBeAg-negative/DNA-positive patients (II) and 50 HBeAg-negative/DNA-negative patients (III). The HBV core gene was analysed by polymerase chain reaction (PCR) and sequencing.

RESULTS

The frequency of core gene substitutions increased from group I to group III. Substitutions were commonly detected at codons 87, 97, 112 and 130. The frequency of substitutions at codons 87 and 112 was higher in groups II/III than in group I. The frequency of the codon I97F substitutions was the highest in group III. However, the codon 130 substitution was more frequently found in groups I/II than in group III.

CONCLUSION

Core gene substitutions were more frequently detected in HBeAg-negative and/or HBV DNA-negative patients. The substitutional hot spots were codons 87, 97, 112 and 130; substitutions at these codons might play a role in immune-modulation during the course of chronic HBV infection.

An application of gene comparative image for predicting the effect on replication ratio by HBV virus gene missense mutation

Hepatitis B viruses (HBVs) show instantaneous and high-ratio mutations when they are replicated, some sorts of which significantly affect the efficiency of virus replication through enhancing or depressing the viral replication, while others have no influence at all. The mechanism of gene expression is closely correlated with its gene sequence. With the rapid increase in the number of newly found sequences entering into data banks, it is highly desirable to develop an automated method for simulating the gene regulating function. The establishment of such a predictor will no doubt expedite the process of prioritizing genes and proteins identified by genomics efforts as potential molecular targets for drug design. Based on the power of cellular automata (CA) in treating complex systems with simple rules, a novel method to present HBV gene image has been introduced. The results show that the images thus obtained can very efficiently simulate the effects of the gene missense mutation on the virus replication. It is anticipated that CA may also serve as a useful vehicle for many other studies on complicated biological systems.

Hepatitis B and C Virus Variants in Long-Term Immunosuppressed Renal Transplant Patients in Latvia

The incidence of genome variants of hepatitis B and hepatitis C viruses among 38 long-term (2-15 years) immunosuppressed patients after renal transplantation and 10 patients undergoing dialysis was investigated. Twelve patients had only HBV infection, 9 had only HCV infection and 14 were co-infected. Regions corresponding to the HBV X/EnII/BCP, preC/C, preS/S and to the HCV core were sequenced for molecular characterization of the HBV and HCV genomes. Fifty-seven percent of HBV DNA isolates belonged to genotype D and 42% to genotype A, whereas 77% of HCV RNA isolates belonged to genotype 1b and only 17% to genotype 3a. One sample (6%) was of genotype 2c. Detailed analysis of the above-mentioned HBV genome regions revealed the presence of nucleotide point mutations, which, in some cases, resulted in amino acid substitutions. The clinical significance of such mutations is discussed.

Detection of T lymphocyte subsets and mIL-2R on surface of PBMC in patients with hepatitis B

AIM: To study the levels of T lymphocyte subsets and membrane interleukin-2 receptor (mIL-2R) on surface of peripheral blood mononuclear cells (PBMCs) of patients with hepatitis B and its role in the pathogenesis of hepatitis B.

METHODS: The levels of T lymphocyte subsets and mIL-2R in PBMC before and after being stimulated with PHA were detected by biotin-streptavidin (BSA) technique in 196 cases of hepatitis B.

RESULTS: In patients with hepatitis B, the levels of CD₃⁺, CD₄⁺ cells, and the ratio of CD₄⁺ cells/CD₈⁺ cells were lower, but the level of CD₈⁺ cells was higher than those in normal controls (42.20 ± 6.01 vs 65.96 ± 6.54, 38.17 ± 5.93 vs 41.73 ± 6.40, 0.91 ± 0.28 vs 1.44 ± 0.31, 39.86 ± 6.36 vs 30.02 ± 4.54, P < 0.01). The total expression level of mIL-2R in PBMC before and after being stimulated with PHA was also lower than those in normal controls (3.47 ± 1.55 vs 4.52 ± 1.49, 34.03 ± 2.94 vs 37.95 ± 3.00, P < 0.01). In all the patients with hepatitis B, the levels of T lymphocyte subsets and mIL-2R in PBMC with HBV-DNA (+) were lower than those with HBV-DNA (-), which were significantly different (39.57 ± 7.11 vs 44.36 ± 5.43, 34.36 ± 7.16 vs 40.75 ± 5.87, 37.82 ± 6.54 vs 41.72 ± 6.21, 0.88 ± 0.33 vs 0.99 ± 0.27, 2.82 ± 1.62 vs 3.85 ± 1.47, 31.56 ± 3.00 vs 35.84 ± 2.83, P < 0.01). In addition, the levels of CD₃⁺, CD₄⁺, CD₈⁺ cells, the ratio of CD₄⁺ cells/CD₈⁺ cells and mIL-2R among different courses of hepatitis B were all significantly different (F = 3723.18, P < 0.01. F = 130.43, P < 0.01. F = 54.01, P < 0.01. F = 2.99, P < 0.05. F = 7.16, P < 0.01).

CONCLUSION: Both cellular and humoral immune functions are obviously in disorder in patients with hepatitis B, which might be closely associated with the chronicity in patients.

Molecular epidemiology and immunology of hepatitis B virus infection - an update

Hepatitis B virus (HBV) continues to be one of the most important viral pathogens in humans. This review provides an update on the molecular epidemiology and immunology of HBV infection. DNA sequencing has allowed replacement of the initial serotypic classification of HBV strains by a more systematic genotype system that currently consists of 7 members (genotypes A-G). More recently, sequence analysis of virus isolates from many individual patients has revealed the occurrence of certain mutational hot spots in the genome, some of which appear to correlate with the patient's immunological and/or disease status; however, cause and effect are not always easily discernible. This holds particularly for the issue of whether virus variants exist that have, per se, an increased pathogenic potential; due to the scarcity of appropriate experimental in vivo models, such hypotheses are difficult to prove. Similarly, because of the compact organization of the HBV genome, almost every single mutation may have pleiotropic phenotypic effects. Nonetheless, there is accumulating evidence that at least some frequently observed mutations are causally related to viral escape from selective pressures, such as the presence of antibodies against dominant B cell epitopes, or drugs that inhibit the viral reverse transcriptase; possibly, this is also true for the cellular immune response. Therefore, despite the availability of an effective prophylactic vaccine, further extensive efforts are required to monitor the emergence of vaccination- and therapy-resistant HBV variants and to prevent their spread in the general population.

Rapid detection of hepatitis B virus mutations using real-time PCR and melting curve analysis

Current methods of detecting hepatitis B virus (HBV) mutations are time consuming, labor intensive, and not suitable for screening large numbers of samples. In the present study, we documented the advantages of a system that exploits differences in thermal stability between perfect match and mismatch hybrids, and thereby distinguishes between wild-type and mutants. Hybridization probes were designed complementary to specific wild-type HBV sequences in surface (S), precore, and basal core promoter (BCP) regions of the HBV genome (nt 587, 1896, and 1762/1764, respectively). Two probes were designed for each mutation: anchor probes were 3' labeled with fluorescein and sensor probes, 5' labeled with LC-Red 640, and 3' phosphorylated. Temperatures for each probe melted from amplification products were then determined in a melting program. Sera from 12 patients, each containing identified HBV mutants (6 S-escape, 1 precore, 1 BCP, and 4 mixed precore and BCP), and 5 control sera from patients with wild-type virus were analyzed. Genomic sequences of mutant and wild-type viruses were confirmed by direct sequencing. Real-time polymerase chain reaction (PCR) with fluorescent hybridization probes accurately identified each mutant and wild-type genome. Melting temperatures obtained from probe-product duplexes for the 3 mutants were distinguished from wild-type (>4.0 degrees C, minimal) within 45 minutes. The sensitivity of the system was 100 copies/mL and as few as 5% of mutant among wild-type virus were detected. In conclusion, real-time PCR with fluorescent hybridization probes is a specific, sensitive, quantitative, and rapid means of detecting clinically relevant HBV mutants.