Mutations of the core promoter and response to interferon treatment in chronic replicative hepatitis B

Effectiveness of antiviral treatment in HBeAg-negative chronic hepatitis B patients with normal or mildly elevated alanine aminotransferase: a retrospective study

Background

There are inadequate data and no histological evidence regarding the effects of antiviral treatment for hepatitis B e-antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with normal or mildly elevated alanine aminotransferase (ALT). This study investigated the effects of antiviral treatment on these patients.

Methods

We retrospectively analysed the outcomes of antiviral treatment for HBeAg-negative CHB patients with normal or mildly elevated ALT who were treated with nucleoside/nucleotide analogues (NAs) for up to 96 weeks.

Results

A total of 128 patients were enrolled; 74 patients had normal ALT and 54 patients had mildly elevated ALT. The total cumulative rates of viral suppression were 64.06%, 81.97%, and 96.39%, at weeks 24, 48, and 96, respectively. The cumulative rates of viral suppression for the normal and mildly elevated ALT groups were 67.85% and 58.97%, 86.39% and 76.31%, and 93.13% and 97.04% at weeks 24, 48, and 96, respectively. The serum HBV DNA levels at week 12 and hepatitis B surface antigen (HBsAg) levels at week 24 were significant predictors of the 96-week virological response. Of the 128 patients, 54 with normal ALT and 33 with mildly elevated ALT underwent FibroScan at baseline. Significant fibrosis (F ≥ 2) was found in 44.4% (n = 24) and 51.5% (n = 17) of the patients in the normal ALT group and mildly elevated ALT group, respectively. Compared with the values at baseline, liver stiffness values significantly decreased at week 48 (8.12 kPa vs. 6.57 kPa; p < 0.001) and week 96 (8.87 kPa vs. 6.43 kPa; p < 0.001), respectively.

Conclusions

HBeAg-negative CHB patients with normal ALT could benefit from antiviral therapy with NAs, similar to patients with mildly elevated ALT. Antiviral treatment is strongly recommended for HBeAg-negative CHB patients with normal ALT. Additionally, significant liver fibrosis is not rare in HBeAg-negative CHB patients with ALT less than two-times the upper limit of normal, and FibroScan should be performed regularly for these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02471-y.

Kinetics of hepatitis B surface antigen quasispecies during REP 2139-Ca therapy in HBeAg-positive chronic HBV infection

Chronic HBV infection results in various clinical manifestations due to different levels of immune response. In recent years, hepatitis B treatment has improved by long-term administration of nucleos(t)ide analogues (NUCs) and peg-interferon. Nucleic acid polymers (NAPs; REP 2139-Ca and REP 2139-Mg) are new antiviral drugs that block the assembly of subviral particles, thus preventing the release of HBsAg and allowing its clearance and restoration of functional control of infection when combined with various immunotherapies. In the REP 102 study (NCT02646189), 9 of 12 patients showed substantial reduction of HBsAg and seroconversion to anti-HBs in response to REP 2139-Ca, whereas 3 of 12 patients did not show responses (>1 log reduction of HBsAg and HBV DNA from baseline). We characterized the dynamic changes of HBV quasispecies (QS) within the major hydrophilic region (MHR) of the 'pre-S/S' open reading frame including the 'a' determinant in responders and nonresponders of the REP 102 study and four untreated matched controls. HBV QS complexity at baseline varied slightly between responders and nonresponders (P = .28). However, these responders showed significant decline in viral complexity (P = .001) as REP 2139-Ca therapy progressed but no significant change in complexity was observed among the nonresponders (P = .99). The MHR mutations were more frequently observed in responders than in nonresponders and matched controls. No mutations were observed in 'a' determinant of major QS population which may interfere with the detection of HBsAg by diagnostic assays. No specific mutations were found within the MHR which could explain patients' poor HBsAg response during REP 2139-Ca therapy.

The response of hepatitis B virus genotype to interferon is associated with a mutation in the interferon-stimulated response element

Genetic variation and genotype of Hepatitis B virus (HBV) are related to the efficiency of interferon alpha (IFN-α)-based antiviral therapy. However, the correlation of variation in interferon-stimulated response element (ISRE) and HBV genotype response to IFN-α therapy remains elusive.Differences of ISRE between genotype B and C HBV were explored using the HBV sequences retrieved from GenBank, and further investigated by ISRE region cloning and sequencing from 60 clinical samples post-IFN-α therapy. Additionally, ISRE mutants were constructed and their relation to responsiveness of IFN-α was evaluated by real-time PCR and Southern blot analysis.ISRE pattern between genotype B and C were found based on both clinical sample sequencing and full-length sequence alignment. The primary difference is the fourth base within the ISRE region, with T and C for genotype B and C, respectively. HBV with genotype C-type ISRE had a higher replicative capability as compared to HBV with genotype B-type ISRE after IFN-α treatment in huh7 cells. CONCLUSION:: Preference of ISRE between genotype B and C HBV are distinct. Single nucleotide difference (C to T) within the HBV ISRE region may link to the efficacy of IFN-α therapy to genotype B and C HBV. Therefore, this study provides a clue for the determination of IFN-α therapy response to HBV treatment.

Next generation sequencing identifies baseline viral mutants associated with treatment response to pegylated interferon in HBeAg-positive chronic hepatitis B

Current data of hepatitis B virus (HBV) variants associated with treatment outcome identified by next generation sequencing (NGS) are limited. This study was aimed at determining the role of baseline sequence variations in the enhancer II (EnhII), basal core promotor (BCP) and pre-core (PC) regions of HBV genotype C in patients treated with pegylated interferon (PEG-IFN). Patients with HBeAg-positive chronic hepatitis B (CHB) treated with 48-week PEG-IFN were enrolled. Combined response (CR) at week 96 was defined by HBeAg seroconversion plus HBV DNA < 2000 IU/mL and HBsAg < 1000 IU/mL. Pre-treatment viral mutations were characterized by Sanger sequencing and NGS (Miseq Illumina platform). Among 47 patients (32 male, mean age 32.4 years), CR was achieved in 12 (25.5%) individuals. Overall, NGS was superior to Sanger sequencing in detecting mutations (61.7% vs. 38.3%, P < 0.001). Based on NGS, the prevalence of T1753V (T1753C/A/G) and A1762T/G1764A variants were significantly lower in responders compared to non-responders (8.3% vs. 51.4%, P = 0.009 and 33.3% vs. 68.6%, P = 0.032, respectively). No significant difference between groups was found regarding C1653T and G1896A mutants. The absence of T1753V and A1762T/G1764A mutations were factors associated with CR (OR 11.65, 95%CI 1.36-100.16, P = 0.025, and OR 4.36, 95%CI 1.08-17.63, P = 0.039, respectively). The existence of pre-treatment T1753V, A1762T/G1764A mutations and their combination yielded negative predictive values of 94.7%, 85.7% and 93.8%, respectively. The presence of HBV mutants in the BCP region determined by NGS at baseline was associated with poor treatment outcome in patients with HBeAg-positive CHB receiving PEG-IFN.

Deep sequencing identifies hepatitis B virus core protein signatures in chronic hepatitis B patients

BACKGROUND

We aimed to identify HBc amino acid differences between subgroups of chronic hepatitis B (CHB) patients.

METHODS

Deep sequencing of HBc was performed in samples of 89 CHB patients (42 HBeAg positive, 47 HBeAg negative). Amino acid types were compared using Sequence Harmony to identify subgroup specific sites between HBeAg-positive and -negative patients, and between patients with combined response and non-response to peginterferon/adefovir combination therapy.

RESULTS

We identified 54 positions in HBc where the frequency of appearing amino acids was significantly different between HBeAg-positive and -negative patients. In HBeAg negative patients, 22 positions in HBc were identified which differed between patients with treatment response and those with non-response. The fraction non-consensus sequence on selected positions was significantly higher in HBeAg-negative patients, and was negatively correlated with HBV DNA and HBsAg levels.

CONCLUSIONS

Sequence Harmony identified a number of amino acid changes associated with HBeAg-status and response to peginterferon/adefovir combination therapy.

Novel HBV recombinants between genotypes B and C in 3'-terminal reverse transcriptase (RT) sequences are associated with enhanced viral DNA load, higher RT point mutation rates and place of birth among Chinese patients

As one of the major global public health concerns, hepatitis B virus (HBV) can be divided into at least eight genotypes, which may be related to disease severity and treatment response. We previously demonstrated that genotypes B and C HBV, with distinct geographical distribution in China, had divergent genotype-dependent amino acid polymorphisms and variations in reverse transcriptase (RT) gene region, a target of antiviral therapy using nucleos(t)ide analogues. Recently recombination between HBV genotypes B and C was reported to occur in the RT region. However, their frequency and clinical significance is poorly understood. Here full-length HBV RT sequences from 201 Chinese chronic hepatitis B (CHB) patients were amplified and sequenced, among which 31.34% (63/201) were genotype B whereas 68.66% (138/201) genotype C. Although no intergenotypic recombination was detected among C-genotype HBV, 38.10% (24/63) of B-genotype HBV had recombination with genotype C in the 3'-terminal RT sequences. The patients with B/C intergenotypic recombinants had significantly (P<0.05) higher serum HBV DNA level than the "pure" B-genotype cohort did. Moreover, the B/C intergenotypic recombinants were prone to more substitutions at several specific residues in the RT region than genotype B or C. Besides, unlike their parental genotypes, the recombinant HBV appeared to display an altered geographic distribution feature in China. Our findings provide novel insight into the virological, clinical and epidemiological features of new HBV B/C intergenotypic recombinants at the 3' end of RT sequences among Chinese CHB patients. The highly complex genetic background of the novel recombinant HBV carrying new mutations affecting RT protein may contribute to an enhanced heterogeneity in treatment response or prognosis among CHB patients.

Contribution of C1485T mutation in the HBx gene to human and murine hepatocarcinogenesis

Although Hepatitis B virus (HBV) X gene mutations are frequently detected in HBV-related human hepatocellular carcinoma (HCC) patients, causative HBx mutations in the development of HCC have not yet been determined. We herein identified C1485T and C1653T mutations in the HBx gene as independent risk of HCC for HBV through the analysis using serum from chronic hepatitis B patients. We generated transgenic mice expressing wild-type (WT-HBxTg) and mutant (C1485T-HBxTg) HBx to assess the carcinogenic potential of mutated HBx. C1485T-HBxTg mice were more susceptible to diethylnitrosamine-induced hepatocarcinogenesis than WT-HBxTg mice and control non-Tg mice. The promotion of hepatocarcinogenesis in C1485T-HBxTg mice was accompanied by the activation of β-catenin and Jun N-terminal kinase (JNK) signaling pathways as well as the production of reactive oxygen species, whereas the activation of nuclear factor-kappa B in the livers of C1485T-HBxTg mice was attenuated. These results demonstrate that the HBx C1485T mutation contributes to human and murine hepatocarcinogenesis.

Viral minority variants in the core promoter and precore region identified by deep sequencing are associated with response to peginterferon and adefovir in HBeAg negative chronic hepatitis B patients

BACKGROUND AND AIM

Precore (PC) and basal core promoter (BCP) mutations are associated with responses to interferon-based treatment in HBeAg-positive chronic hepatitis B (CHB) patients. Here, we identify viral minority variants in these regions and assess association with response to peginterferon-alfa (Peg-IFN) and adefovir combination therapy.

PATIENTS AND METHODS

Ultra-deep pyrosequencing analysis of the BCP and PC region was performed for 89 CHB patients (42 HBeAg-positive; 47 HBeAg-negative), at baseline and during treatment. Specifically, associations of individual positions with the HBeAg-negative phenotype were studied, as well as the association of the most prevalent mutations with combined response in HBeAg-positive and -negative patients at week 72 (HBeAg negativity, HBV-DNA <2000 IU/mL and ALT normalization at 24 weeks of treatment-free follow-up).

RESULTS

The mutations most strongly correlated with the HBeAg-negative phenotype were at positions 1762/1764 and 1896/1899 in the BCP and PC region, respectively. No major changes in nucleotide composition of these positions were observed during treatment. In HBeAg-negative patients, a combined presence of 1764A and 1896A was correlated with lower ALT levels (p = 0.004), whereas the presence of 1899A was correlated with higher age (p = 0.030), lower HBV-DNA level (p = 0.036), and previous IFN therapy (p = 0.032). The presence of 1764A/1896A or the absence of 1899A at baseline, was associated with lower response rates, after adjustment for HBV genotype (p = 0.031 and p = 0.017) and HBsAg level (p = 0.035 and p = 0.022).

CONCLUSION

We identified novel correlations between common BCP and PC variants with response to Peg-IFN and adefovir in HBeAg-negative patients. Ultimately, this may guide the selection of those patients most likely to benefit from Peg-IFN-based treatment.

Studies of nosocomial outbreaks of hepatitis B in nursing homes in Germany suggest a major role of hepatitis B e antigen expression in disease severity and progression

Hepatitis B virus (HBV) causes acute or chronic hepatitis B. Local outbreaks of HBV infections in skilled nursing facilities is a matter of growing concern in developed countries. Here, we investigated two outbreaks of hepatitis B that recently occurred in nursing homes in Germany. The outbreak at location A was associated with acute fulminant hepatitis with fatal outcome in several cases, while individuals infected at location B developed asymptomatic or mild hepatitis B. Sequence analysis of viruses involved in these outbreaks revealed different, but unique HBV strains for each location. Each of the strains produced high viremia of more than 10(9) virions/mL serum. We found that the mild course of hepatitis B at location B was caused by a circulating wild-type HBV genotype A2 strain, which is commonly found in Central Europe. Complete genome sequences of isolates obtained from infected patients revealed nearly 100% sequence identity at the nucleotide level as well as expression of HBV e protein (HBeAg), a known T cell tolerogen in the incubation or chronic phases of HBV infection. By contrast, the outbreak at location A was associated with an HBV genotype D2 variant that lacked HBeAg expression, suggesting that immunopathology and selection of specific HBV variants played a major role in the severe (or even fulminant) acute hepatitis observed at location A. Importantly, all patients were diagnosed with type 2 diabetes mellitus, a known risk factor for healthcare-associated transmission of HBV. The study leads us to suggest that, besides strict adherence to hygiene standards, additional efforts are required to reduce the risk of HBV transmission and fulminant disease progression in healthcare settings and nursing homes. In this context, a general screening for HBsAg and active hepatitis B vaccination should be considered for people living in nursing homes, especially for those with diagnosed diabetes or other predisposing factors for HBV transmission.

Retrospective study of the prevalence and clinical significance of hepatitis B virus precore and basal core promoter variants

BACKGROUND

Hepatitis B virus (HBV) precore (PC) and basal core promoter (BCP) variants are well known; however, their prevalence in North America is unclear, especially among hepatitis B e antigen-negative patients.

OBJECTIVE

To investigate the prevalence of PC⁄BCP mutations and their clinical significance.

METHODS

One hundred twenty-eight patients positive for both hepatitis B surface antigen and hepatitis B e antibody were selected, and PC⁄BCP mutations were identified using a line probe assay. The subjects' charts were reviewed for race⁄ethnicity, HBV genotype, HBV viral load, sex, liver enzyme levels, imaging and biopsy results up to 10 years before the study.

RESULTS

The prevalence of PC and BCP variants were 47.6% and 62.5%, respectively. Older age was associated with aspartate aminotransferase-to-platelet index ratio (APRI) ≥0.7 (P=0.011) and abnormal imaging⁄biopsy results (P=0.0008). Although the presence of BCP variant(s) was associated with APRI ≥0.7 (P=0.029), it was not associated with abnormal imaging⁄biopsy results. The combination of age ≥50 years and the presence of BCP variant(s) was associated with abnormal imaging⁄biopsy results, suggestive of either cirrhosis or hepatocellular carcinoma (not observed with PC mutation). Neither sex or genotype, or median HBV viral load showed significant influence on any of these outcomes.

CONCLUSIONS

The present study suggests that the prevalence of PC and BCP mutations are higher than what has been previously reported. One potential explanation would be increased immigration in the past decade. Considering the potential public health and clinical implications of these variants, long-term multicentre and prospective studies could further unravel the uncertainty around these variants.

Short- and long-term outcome of interferon therapy for chronic hepatitis B infection

Hepatitis B virus (HBV) infection is a serious clinical problem worldwide. Conventional interferon (IFN)-α has been approved for the treatment of chronic hepatitis B (CHB). Short-term studies have demonstrated that IFN-based therapy is moderately effective in inducing the loss of hepatitis e antigen (HBeAg) or seroconversion (30%-40%) in HBeAg-positive patients and also produces sustained HBV DNA suppression (20%-30%) in HBeAg-negative patients. Many studies have reported a correlation between the HBV genotype and response to IFN treatment. The highest response rate to IFN treatment was found in patients infected with HBV genotype A, followed by HBV genotypes B, C, and D. The long-term effect of IFN-α on CHB has not yet been elucidated. The ability of IFN-α treatment to prevent new cirrhosis, complications associated with cirrhosis, and development of hepatocellular carcinoma (HCC) is controversial. The beneficial effect of IFN-α treatment in reducing the development of HCC has mainly been observed in treatment responders who already have cirrhosis. These inconsistent findings may be attributed to the inevitable limitations of comparisons across studies, including differences in the baseline characteristics of the study and the moderate suppression of HBV replication by IFN-α relative to nucleoside/nucleos(t)ide analogs.

Peginterferon α in the treatment of chronic hepatitis B

INTRODUCTION

Hepatitis B virus (HBV) infection is a global health problem. Peginterferon α (PEG-IFN), which includes PEG-IFN α-2a (Pegasys) and PEG-IFN α-2b (Peg-Intron), can be used to treat patients with chronic hepatitis B (CHB) infection. A finite duration of PEG-IFN therapy may lead to long-term viral suppression. Clinically, it is important to identify super-responders and null-responders to PEG-IFN due to its substantial side effects.

AREAS COVERED

From the literature review, it is known that PEG-IFN is more effective for hepatitis B e antigen (HBeAg)-positive patients who have high pre-treatment alanine aminotransferase level, lower HBV DNA level and genotype A (vs genotype D), as well as those with more favourable viral predictors, such as precore stop codon or basal core promoter mutants infections in Asian patients and wild-type virus in Caucasian patients. For HBeAg-positive patients and HBeAg-negative patients with genotype D infection, PEG-IFN therapy could be terminated early at week 12 or 24 in primary non-responders defined by the Hepatitis B surface antigen stopping rules. With regard to host factors, single nucleotide polymorphisms of IL28B do not seem to affect the treatment outcomes in Asian patients, but its role in Caucasian patients remains disputed.

EXPERT OPINION

Most of the known predictors need validation by large prospective trials. In addition, we need to identify more baseline predictors for super-responders in order to achieve personalised PEG-IFN treatment for CHB.

Susceptibility of different hepatitis B virus isolates to interferon-alpha in a mouse model based on hydrodynamic injection

Interferon alpha (IFN-α) is commonly used for the treatment of chronic hepatitis B (CHB) patients. Many factors including viral genetics may determine the outcome of IFN-α therapy. In this study, we tested whether the expression of IFN-α directly in the liver inhibits HBV gene expression and replication using a HBV hydrodynamic injection (HI) mouse model. Two replication-competent clones from different HBV isolates that belonging to HBV genotype A and B based on a pAAV vector (pAAV-HBV-A and pAAV-HBV-B) were compared for their susceptibility to IFN-α. HBV clones were injected into mice either alone or in combination with a murine (m) IFN-α expression plasmid (pmIFN-α). HBsAg and HBeAg concentrations and HBV DNA levels in mice differed after injection of these two HBV clones. Co-application of pmIFN-α together with the two distinct isolates resulted in markedly different kinetics of decline of HBsAg, HBeAg, and HBV DNA levels in the mice. Immunohistochemical staining of liver sections with anti-HBc showed that mIFN-α application completely inhibited the expression of HBcAg in mice inoculated with pAAV-HBV-B, whereas the expression of HBcAg was only reduced in mice with pAAV-HBV-A. Consistently, mice injected with pAAV-HBV-B and pmIFN-α showed higher expression levels of the IFN-stimulated genes (ISGs) ISG15, OAS, PKR as well as proinflammatory cytokine IL-6 in the liver. In addition, expression levels of anti-inflammatory cytokine IL-10 was down-regulated significantly in liver of the mice injected with pAAV-HBV-B and pmIFN-α. Our data demonstrate that IFN-α exerts antiviral activity in HBV mouse model, but different HBV isolates may have diverse susceptibility to IFN-α.

An HBV-HIV co-infected patient treated with tenofovir-based therapy who achieved HBs antigen/antibody seroconversion

The present report describes a case of a patient with hepatitis B virus (HBV)-human immunodeficiency virus (HIV) co-infection who was treated with tenofovir disoproxil (TDF)-based highly active antiretroviral therapy (HAART) and who achieved HBs antigen (Ag)/antibody (Ab) seroconversion. An 18-year-old Japanese man with HIV and HBV co-infection presented to our hospital. His CD4 count was decreased, and TDF-based HARRT was started. At 30 months after initiation of therapy, HBsAg was not detected. At 36 months after initiation of therapy, HBsAb was detected. We conclude that TDF-based therapy is useful for the management of patients with HBV and HIV co-infection.

Distinct evolution and predictive value of hepatitis B virus precore and basal core promoter mutations in interferon-induced hepatitis B e antigen seroconversion

Precore (PC) (G1896A) and basal core promoter (BCP) (A1762T/G1764A) mutations of the hepatitis B virus (HBV) genome often emerge in chronic hepatitis B (CHB) patients. Their roles in hepatitis B e antigen (HBeAg) seroconversion induced by interferon (IFN) therapy remain controversial, partly because quantitative analysis for these mutants is lacking. This study aimed to develop a new assay to accurately quantify the PC and BCP mutant percentages and correlate their dynamic changes with IFN-induced HBeAg seroconversion in HBeAg-positive CHB patients. The PC and BCP mutant percentages were analyzed by polymerase chain reaction (PCR)-pyrosequencing. Our results showed that this quantitative assay for PC and BCP mutants achieved high accuracy (R(2) > 0.99) within a range between 10% and 90% mutants. We examined dynamic changes of the PC and BCP mutant percentages following IFN treatment in 203 HBeAg-positive CHB patients. By multiple logistic regression analysis, we found that the chance of HBeAg seroconversion increased by 2.2% (odds ratio [OR] = 1.022, 95% confidence interval [CI]: 1.009-1.034, P = 0.001) and 2.3% (OR = 1.023, 95% CI: 1.010-1.037, P = 0.001) per 1% increase of the pretreatment PC and BCP mutant percentages, respectively, after adjustment for other predictors. However, only the pretreatment PC mutation percentage was significantly associated with HBeAg seroconversion with HBV DNA < 2,000 IU/mL (OR = 1.030, 95% CI: 1.014-1.047, P < 0.001). Furthermore, the mutant percentage of PC, but not BCP, in patients achieving HBeAg seroclearance with HBV DNA < 20,000 IU/mL increased significantly during IFN treatment (P = 0.039). Interestingly, patients with HBeAg seroconversion who had a high PC mutant percentage at the end of IFN treatment tended to exhibit high viremia after seroconversion.

CONCLUSION

Quantitative analysis of PC and BCP mutants can predict IFN-induced HBeAg seroconversion and demonstrate their distinct evolution patterns during HBeAg seroconversion. (HEPATOLOGY 2013).

Binding sensitivity of adefovir to the polymerase from different genotypes of HBV: molecular modeling, docking and dynamics simulation studies

AIM

To investigate the molecular mechanisms underlying the influence of DNA polymerase from different genotypes of hepatitis B virus (HBV) on the binding affinity of adefovir (ADV).

METHODS

Computational approaches, including homology modeling, docking, MD simulation and MM/PBSA free energy analyses were used.

RESULTS

Sequence analyses revealed that residue 238 near the binding pocket was not only a polymorphic site but also a genotype-specific site (His238 in genotype B; Asn238 in genotype C). The calculated binding free-energy supported the hypothesis that the polymerase from HBV genotype C was more sensitive to ADV than that from genotype B. By using MD simulation trajectory analysis, binding free energy decomposition and alanine scanning, some energy variation in the residues around the binding pocket was observed. Both the alanine mutations at residues 236 and 238 led to an increase of the energy difference between genotypes C and B (ΔΔG(C-B)), suggesting that these residues contributed to the genotype-associated antiviral variability with regard to the interaction with ADV.

CONCLUSION

The results support the hypothesis that the HBV genotype C polymerase is more sensitive to ADV than that from genotype B. Moreover, residue N236 and the polymorphic site 238 play important roles in contributing to the higher sensitivity of genotype C over B in the interaction with ADV.

High frequency of genotype D and spontaneous hepatitis B virus genomic mutations among Haitians in a multiethnic North American population

GOALS/BACKGROUND

The importance of hepatitis B virus (HBV) genotype and mutations has been increasingly recognized. We aimed to determine HBV genotype, precore (PC), and basal core promoter region (BCP) mutations in a HBV multiethnic South Florida population.

STUDY

Samples from 213 patients were tested for HBV-DNA using Abbott RealTime HBV IUO assay, and for mutations using INNO-LiPA assay.

RESULTS

Patients were predominantly male (67%); 61 (31%) were African American, 60 (28%) Hispanic, 37 (17%) Haitian, 27 (19%) white non-Hispanic, and 14 (6.6%) Asian. Genotype A was found in 101 (69%), D in 25 (17%), F in 9 (6%), G in 7 (5%), C and E in 6 (4%) each, B in 4 (3%), and H in 2 (1%) patients. Mixed genotypes were detected in 11 patients. Genotype A was more prevalent in all ethnicities except for Asian. Among hepatitis B e antigen (HBeAg)-negative patients (59%), BCP, PC, and combined BCP/PC mutations were found in 30 (37.5%), 13 (16.3%), and 14 (17.5%), respectively. Genotype D was associated with higher frequency of HBeAg-negative status [18/24 (75%) vs. 62/121 (51%) P=0.03] and mutations [16/19 (84%) vs. 40/67 (60%) P=0.04] compared with others. Genotype A was negatively associated with mutations [26/31 (84%) vs. 30/55 (55%), P=0.009]. PC mutations were more common in genotype D (14/19, 73%) compared with genotype A (7/54, 13%, P<0.0001). One-hundred percent and 79% of Asians and Haitians had spontaneous mutations, respectively. All Haitians with genotype D had PC mutations and 3 (50%) had BCP/PC.

CONCLUSIONS

The present study shows that HBeAg-negative status and spontaneous mutations were more common with genotype D; the presence of genotype D in Haitians was always associated with spontaneous mutations.

Presence of precore and core promoter mutants limits the probability of response to peginterferon in hepatitis B e antigen-positive chronic hepatitis B

Peginterferon (PEG-IFN) treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) results in HBeAg loss in 30% of patients, but clearance of hepatitis B virus (HBV) DNA and hepatitis B surface antigen (HBsAg) from serum is less often achieved. We investigated whether the presence of precore (PC) and basal core promoter (BCP) mutants before PEG-IFN treatment affects serological and virological response. A total of 214 HBeAg-positive CHB patients treated with PEG-IFN ± lamivudine for 52 weeks in a global randomized trial were classified at baseline as wildtype (WT) or non-WT (detectable mutants at PC/BCP) by line-probe assay. Response was assessed at 6 months posttreatment and through long-term follow-up (LTFU). Mutants were detected in 64% of patients, in varying frequencies across HBV genotypes A through D. Patients with WT had higher baseline HBV DNA, HBeAg, and HBsAg levels than patients with non-WT. Patients with WT were more likely to achieve HBeAg loss with HBV DNA <10,000 copies/mL (response, 34 versus 11%, P < 0.001) and HBsAg clearance (18 versus 2%, P < 0.001) at week 78 than non-WT patients. Among WT patients who achieved HBeAg clearance at week 78, 78% had undetectable HBV DNA and 61% achieved HBsAg clearance at LTFU (versus 26% and 15% in non-WT patients, P < 0.001 for both). The presence of WT virus at baseline was an independent predictor of response (odds ratio [OR] 2.90, 95% confidence interval [CI]: 1.15-7.31, P = 0.023) and HBsAg clearance (OR 5.58, 95% CI: 1.26-24.63, P = 0.013) and patients with non-A genotypes with detectable mutants had a low probability of response.

CONCLUSION

The presence of only WT virus at baseline is a strong predictor of response (HBeAg loss with HBV DNA <10,000 copies/mL) to PEG-IFN for HBeAg-positive CHB. Patients with detectable PC and/or BCP mutants have a lower probability of response and are less optimal candidates for PEG-IFN therapy.

Antiviral therapies: focus on hepatitis B reverse transcriptase

Hepatitis B virus (HBV) is the etiologic agent of mankind's most serious liver disease. While the availability of a vaccine has reduced the number of new HBV infections, the vaccine does not benefit the approximately 350 million people already chronically infected by the virus. Most of the drugs approved by the FDA for the treatment of hepatitis B target the reverse transcriptase (RT or P gene product) and are nucleoside RT inhibitors (NRTIs) that suppress viral replication. However, prolonged monotherapies directed against a single target result in the emergence of viral resistance. HBV genotypic differences affect NRTI resistance, and because the reading frames of the S (surface antigen) and P genes partially overlap, genomic differences that affect the surface of the virus may also alter the viral polymerase sequence, function and drug susceptibility. The scope of this review is to assess the effects of HBV genotypic variation on the development of drug resistance to NRTIs. Some RT residues that vary among different genotypes are in the vicinity of residues that mutate and give rise to NRTI resistance. Interactions between these amino acids can help explain the effect of HBV genotype on the development of NRTI resistance during antiviral therapies, and might help in the design of improved therapeutic strategies.

Effect of host and viral factors on hepatitis B e antigen-positive chronic hepatitis B patients receiving pegylated interferon-α-2a therapy

BACKGROUND

Pegylated interferon (PEG-IFN)-α-2a improves the hepatitis B e antigen (HBeAg) seroconversion rate in HBeAg-positive chronic hepatitis B patients. However, baseline factors predicting favourable responses to PEG-IFN-α-2a remain largely unknown.

METHODS

A total of 115 HBeAg-positive chronic hepatitis B patients who had a pre-therapy serum alanine aminotransferase (ALT) level over two times the upper limit of normal and received PEG-IFN-α-2a for 6-12 months were consecutively enrolled according to the local reimbursed guidelines. HBeAg seroconversion and combined response defined as HBeAg seroconversion, HBV-DNA level <20,000 IU/ml as well as ALT normalization at 6 months off therapy were primary and secondary therapeutic end points, respectively. Baseline viral factors, including viral load, genotype and major sequences of precore stop codon/basal core promoter (BCP), and host factors, including three single nucleotide polymorphisms among the HLA-DPA1, HLA-DPB1 and IL28B regions, were determined to correlate with therapeutic end points.

RESULTS

HBeAg seroconversion and combined response rates were 26.1% and 18.3%, respectively. By multivariate analysis, BCP mutation (OR 8.04, 95% CI 2.00-32.28) and rs3077 G/G genotype (OR 3.49, 95% CI 1.12-10.84) were associated with a higher HBeAg seroconversion rate; BCP mutation (OR 9.28, 95% CI 1.92-44.99) and baseline viral load <2 × 10(6) IU/ml (OR 4.78, 95% CI 1.37-16.69) were associated with a higher combined response rate.

CONCLUSIONS

BCP mutation is associated with higher HBeAg seroconversion and combined response rates at 6 months off therapy in HBeAg-positive chronic hepatitis B patients treated with PEG-IFN-α-2a. Genetic variants in the HLA-DPA1 region may also affect treatment-induced HBeAg seroconversion.

Comparison of two immunoassays for determining hepatitis B virus serum markers

BACKGROUND

To evaluate and compare the detection efficacy of serum hepatitis B virus (HBV) markers by two immunoassays: electrochemiluminescence immunoassay (ECLIA) and enzyme-linked immunosorbent assay (ELISA).

METHODS

ECLIA and ELISA were used to analyze 359 serum samples, including 64 HBsAg/anti-HBs coexistence serological pattern samples (samples positive for both HBsAg and anti-HBs), 24 HBeAg/anti-HBe coexistence serological pattern samples (samples positive for both HBeAg and anti-HBe), and 271 normal serological pattern samples (negative for either of the combinations).

RESULTS

In the normal serological pattern samples, the concordance rates of the two methods in detecting serum HBV markers were as follows: 97.05% for HBsAg, 92.62% for anti-HBs, 100% for HBeAg, 76.75% for anti-HBe, and 58.67% for anti-HBc. The differences in the qualitative criteria for anti-HBc and anti-HBe were primarily responsible for the discrepancy between the two methods (κ-values of 0.657 and 0.253, respectively). Most weak positive results, determined by ECLIA, were negative determined by ELISA, whereas the results of HBsAg, anti-HBs, and HBeAg detection were generally consistent. In the HBsAg/anti-HBs coexistence serological pattern samples, the concordance rates of HBsAg and anti-HBs detection were 98.44% and 34.38%, respectively. The positive rate of ELISA does not vary as the COI (cut-off index) varies which was determined by ECLIA; in the HBeAg/anti-HBe coexistence serological pattern samples, the concordance rates of HBeAg and anti-HBe detection were 45.83% and 79.17%, respectively. Most weak positive results, determined by ECLIA, were negative when determined by ELISA.

CONCLUSION

The discrepancies between the two assays in normal serological patterns samples and HBeAg/anti-HBe coexistence serological pattern samples were mostly due to the different sensitivity of the two assays, but for the HBsAg/anti-HBs coexistence serological pattern samples, the discrepancy was not caused by the different sensitivity. It is the difference in determining anti-HBs which led to the discrepancy.

Hepatitis B virus genotype B results in better immediate, late and sustained responses to peginterferon-alfa in hepatitis-B-e-antigen-positive patients

BACKGROUND AND AIMS

This study investigated outcome predictors in hepatitis-B-e-antigen (HBeAg)-positive chronic hepatitis B patients treated with peginterferon alfa-2a.

METHODS

A total of 88 HBeAg-positive patients receiving peginterferon alfa-2a for 6 months and followed up for at least 24 weeks were prospectively analyzed. Precore and core promoter genes of hepatitis B virus (HBV) were sequenced from the serial serum samples of 88 patients.

RESULTS

After 24 weeks of follow up, 38.6% and 28.4% of patients achieved HBeAg clearance and combined response, respectively. Multivariate analysis disclosed that pretreatment HBeAg sample to cut-off (S/Co) ratio ≤ 200, alanine aminotransferase > 200 IU/mL, HBV genotype B and T1846 were independent factors for HBeAg clearance, and HBeAg S/Co ratio ≤ 200 and HBV genotype B were major determinants for combined response. HBeAg S/Co ratio ≤ 10 at week 12 of therapy was the useful factor for treatment response and had a greater power (P = 0.012) to predict HBeAg clearance than HBV DNA. Patients with HBeAg clearance had a higher frequency of A1896 mutation at baseline and during therapy than those without HBeAg clearance, and the frequency of A1896 decreased during treatment. During follow up, delayed HBeAg seroconversion and reactivation of HBV after HBeAg clearance were observed in eight non-responders and 20 patients with HBeAg clearance, respectively. HBV genotype B was a significant factor to predict both responses.

CONCLUSIONS

Pretreatment HBeAg S/Co ratio ≤ 200 and HBV genotype B were major determinants for treatment response to peginterferon. Genotype-B-infected patients had higher probability of delayed HBeAg clearance and sustained response. Rapid decrease of HBeAg titer was useful on treatment predictor.

Prevalence of HBV genotypes among Egyptian hepatitis patients

Phylogenetic analysis has led to the classification of hepatitis B virus into eight genotypes, designated A to H. The genotypes have differences in biological properties and show heterogeneity in their global distribution. These attributes of the genotypes may account not only for differences in the prevalence of hepatitis B virus mutants in various geographic regions, but also makes them responsible for differences in the clinical outcome and response to antiviral treatment in different population groups. Africa is one of the highly endemic regions of HBV with five genotypes (A-E) identified. Almost all patients in the Mediterranean area are infected with genotype D. However, there is little information of genotype distribution in Egypt. A total of 140 Egyptian patients with hepatitis B surface antigen (HBsAg) positive were enrolled in this study. Of the 140 patients, only 100 patients were HBV DNA positive and only these were included in the study. They were classified into 20 patients with acute hepatitis (AH), 75 patients with chronic active hepatitis (CAH) and 5 patients with hepatocellular carcinoma (HCC). HBV genotypes were determined using INNO-LiPA methodology which is based on the reversed hybridization principle. This study showed that genotype D constituted 87% of the total infections (75 CAH cases, 7 AH cases and 5 HCC cases). The other 13% showed mixed infections of D/F. These findings show that the most prevalent genotype in Egypt is genotype D especially in CAH and HCC patients while the mixed type D/F is only encountered in AH.

[Direct cytopathic effects of particular hepatitis B virus genotypes in immunosuppressive condition]

Little is known about the direct cytopathic effect of hepatitis B virus (HBV) and its association with particular viral genotype or genetic mutation. In some immunosuppressed chronic HBV patients who had liver transplantation or HIV-coinfection, high viremia and liver fibrosis may occur. These findings suggest that hepatic injuries could arise in the absence of a mature immune system and the difference of genotype and/or specific mutation would affect cytopathic potential of the virus. We investigate HBV genotype-related differences in viral replication, antigens expression and histopathology using in vitro replication model or uPA/SCID mice harboring human hepatocytes, demonstrating that different HBV genotypes and even particular mutation are associated with different virological and histopathological characteristics. Infection with HBV/C2 as well as PC mutant of the HBV/B1 in immunosuppressive conditions can induce direct cytopathic effect in "humanized" part of the murine liver.

Retrospective characterization of the S open reading frame of HBV isolated from children with membranous nephropathy treated with interferon-alpha2b

BACKGROUND

A causal relationship exists between HBV infection and membranous nephropathy. The association is especially close in Black children in sub-Saharan Africa. Interferon-alpha2b is commonly used to treat this condition, but is effective in only 30-40% of patients. The reason for the poor response is unknown. The objective of this study was to determine if mutations in the surface gene of HBV isolated from Black children with HBV-associated membranous nephropathy before, during and after interferon treatment, have any effect on treatment response and vice versa.

METHODS

HBV DNA was extracted from a responder, a reverter and a non-responder before and after initiation of 16 weeks of interferon-alpha2b treatment. The preS1/preS2/S region was amplified, cloned and sequenced.

RESULTS

The preS2 region was the most variable in the reverter and the non-responder, and the S region was the most variable in the non-responder. Phylogenetic analysis showed that the viral population dynamics between the responder and the reverter/non-responder strains differed as a result of mutations in the surface gene.

CONCLUSIONS

The presence of mutations in the S region of HBV could be used as predictive markers to differentiate interferon-alpha2b responders from non-responders provided that detailed analysis of further genomes confirms our findings.

Effect of nucleoside analog-interferon sequential therapy on patients with acute exacerbation of chronic hepatitis B

AIM

Nucleoside analog (NA)-interferon (IFN) sequential therapy may enable the long-term control of chronic hepatitis B (CHB) and the withdrawal of the nucleoside analog. We evaluated the efficacy of NA-IFN sequential therapy for acute exacerbation of CHB.

METHODS

A total of 12 patients with acute exacerbation of CHB, nine of whom were positive for hepatitis B e antigen (HBeAg), were enrolled in this study. All the patients were treated with lamivudine 100 mg/day alone for 20 weeks, then with both IFN-alpha 6 megaunits three times per week and lamivudine for 4 weeks, and lastly, with IFN-alpha alone for 20 weeks. Patients whose serum alanine aminotransferase (ALT) level was normalized, whose serum hepatitis B virus (HBV) DNA level decreased to less than 5 log copies/mL, and HBeAg level was absent 24 weeks after the end of treatment were defined as having sustained virological response (SVR). The other patients were defined as having no response (NR).

RESULTS

Four out of nine (44.4%) HBeAg-positive and all three HBeAg-negative patients achieved SVR. The levels of serum alanine aminotransferase (ALT), HBV DNA and HBV core-related antigen were similar between SVR and NR patients at baseline. Three of four patients (75.0%) whose serum HBeAg became negative at the end of treatment achieved SVR, while one of five (20.0%) whose serum HBeAg remained positive achieved SVR.

CONCLUSION

NA-IFN sequential therapy for patients with acute exacerbation of CHB enables the withdrawal of treatment and is particularly effective for patients whose serum HBeAg has become undetectable by the end of the IFN treatment.

Drug delivery systems and liver targeting for the improved pharmacotherapy of the hepatitis B virus (HBV) infection

In spite of the progress made in vaccine and antiviral therapy development, hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma, with more than 400 million people chronically infected worldwide. Antiviral therapy with nucleos(t)ide analogues and/or immunomodulating peptides is the only option to control and prevent the progression of the disease in chronic hepatitis B (CHB)-infected patients. So far, the current antiviral monotherapy remains unsatisfactory because of the low efficacy and the development of drug resistance mutants. Moreover, viral rebound is frequently observed following therapy cessation, since covalent closed circular DNA (cccDNA) is not removed from hepatocytes by antiviral therapy. First, this review describes the current pharmacotherapy for the management of CHB and the new drug candidates being investigated. Then, the challenges in the development of drug delivery systems for the targeting of antiviral drugs to the liver parenchyma are discussed. Finally, perspectives in the design of a more efficient pharmacotherapy to eradicate the virus from the host are addressed.

Antigenic and physicochemical characterization of the 2nd International Standard for hepatitis B virus surface antigen (HBsAg)

BACKGROUND

Standard preparations for HBsAg are required for quality control of test kits and clinical studies on HBsAg quantitation. WHO provides purified heat inactivated HBsAg diluted in negative defribinated plasma as 2nd International Standard (IS) for quality control of tests.

OBJECTIVE

Study of possible alterations of antigenicity, protein composition, size and density of the heat inactivated source material (SM) for the 2nd IS.

STUDY DESIGN

Native HBsAg and SM were examined by quantitative immune electrophoresis (QIE), SDS-PAGE, ultracentrifugation and gel chromatography. HBV DNA was sequenced and the HBsAg geno/subtype derived.

RESULTS

The SM contained 97,600 International Units HBsAg/ml in QIE which agreed very well with the previous evaluations by WHO using 10 different assays. In SDS-PAGE, SM showed on a strong background the small HBs proteins but no preS proteins. SM had a more heterogeneous density than native HBsAg and contained particle aggregates. The HBsAg geno/subtype of SM was A2/adw2.

CONCLUSIONS

The IS has very good HBs antigenicity, but it lacks the preS domains, has modified HBs proteins and is partially aggregated. While it has been proven very useful for quality control of tests, certain inconsistencies due to the altered structure of its HBsAg cannot be excluded.

Prediction of response to treatment of chronic hepatitis B with pegylated interferon in the Philippines

The response marker for interferon has not been investigated fully for hepatitis B viruses (HBVs) in the Philippines where novel subtypes B5 and C5 were recognized recently. The prediction parameters for interferon treatment were assessed, with emphasis on the mutation patterns in the basal core promoter and precore regions in patients with chronic hepatitis B. Seventeen HBeAg-positive patients were stratified according to response to treatment with pegylated interferon based on HBe seroconversion and HBV load. Intra-patient distributions of wild-type strains (A1762, G1764) and variants (T1762, A1764) were analyzed using HBV-DNA amplification and subsequent molecular cloning. The rate of variants (T1762, A1764) harbored by a patient was higher among responders (41.2% and 31% per person on average) than among non-responders (2.4% and 2.4%) to treatment with pegylated interferon at the baseline, respectively (P < 0.05). The rate of variants (T1762, A1764) harbored by responders (41.2% and 31%) decreased to 1.7% and 1.7%, and wild-type strains (A1762, G1764) conversely became majority (98.3% and 98.3%) after treatment with pegylated interferon, respectively. HBV strains harbored by two of six responders and a patient with lower baseline load (1.0 x 10(4) copies/ml) showed genotype shift from A to other genotypes, where genotype A disappeared preferentially after the loss of HBeAg and genotypes B and C formed a major population. These results suggest that the HBV variants (T1762, A1764) and HBV genotype A in the Philippines have an advantage in the response to pegylated interferon. These results warrant a large-scale examination for further precise prediction of the response to treatment with interferon.

Low pretreatment serum HBsAg level and viral mutations as predictors of response to PEG-interferon alpha-2b therapy in chronic hepatitis B

BACKGROUND

Viral genomic mutations have become increasingly recognized as being associated with the outcome of chronic HBV infection. However, the role of viral mutations as a predictor of response to pegylated-interferon (PEG-IFN) therapy has so far remained unclear.

STUDY DESIGN

Viral mutations in the enhancer II/basal core promoter (BCP)/precore and the pre-S regions were characterized by direct sequencing in pretreatment serum samples of 50 patients with chronic hepatitis B (33 HBeAg-positive and 17 HBeAg-negative), who were treated for 48 weeks with PEG-IFN alpha-2b.

RESULTS

Sustained virological response at 48 weeks post treatment, defined as HBeAg seroconversion and HBV DNA<2000IU/mL for HBeAg-positive patients, and HBV DNA<200IU/mL for HBeAg-negative patients, was achieved in 12 (36.4%) and 6 (35.3%) of HBeAg-positive and HBeAg-negative patients, respectively. Response to PEG-IFN therapy correlated to low pretreatment HBsAg level but did not correlate with HBV genotype, pretreatment alanine transaminase and HBV DNA levels. In HBeAg-positive hepatitis, PEG-IFN response correlated with the appearance of double BCP mutations (A1762T/G1764A) at baseline (P=0.041). In the HBeAg-negative group, response to PEG-IFN therapy was associated with the presence of pre-S mutation/deletions (P=0.028). Multivariate analysis identified low pretreatment HBsAg level as an independent factor associated with SVR in both groups.

CONCLUSIONS

Pretreatment quantitative HBsAg determination is useful for predicting response to PEG-IFN therapy. The presence of double BCP and pre-S mutation/deletions at entry may be associated with a high rate of antiviral response in HBeAg-positive and HBeAg-negative hepatitis, respectively.

Prevalence of hepatitis B virus genotype B in Vietnamese patients with chronic hepatitis B

PURPOSE

Hepatitis B virus (HBV) genotypes can affect treatment response to interferon-based therapy and disease outcomes in patients with chronic hepatitis B (CHB). Little data exist to characterize HBV genotypes in Vietnamese, one of the largest minority groups in the United States and also one with one of the highest CHB and liver cancer disease burdens. The goal of this study was to compare the distribution of HBV genotypes in Vietnamese and Chinese patients.

METHODS

We performed a cross-sectional study of 567 consecutive patients of Vietnamese (n = 478) or Chinese (n = 89) descent, with HBV genotype mutation analysis performed between 7/2,005 and 6/2,008 at a community gastroenterology clinic and a university-affiliated liver clinic in the United States.

RESULTS

There were no significant differences between the Vietnamese and Chinese groups in mean age (45 and 44 years), gender (58% and 61% male), HBeAg status (64% and 65% negative), median alanine aminotransferase (33 and 41 U/L), and log(10) HBV DNA (4.9 and 5.0 log(10) IU/ml), or the prevalence of precore/basic core promoter mutations (72% and 71%), respectively. Vietnamese patients had a much higher prevalence of HBV genotype B and a lower prevalence of genotype C than Chinese patients: 74% and 25% vs. 55% and 43% (P = 0.001).

CONCLUSIONS

Chinese patients with CHB often carry either B or C genotype. Vietnamese patients with CHB mostly have HBV genotype B. Additional studies are needed to further characterize the clinical significance of HBV genotype in the natural history and treatment outcomes of CHB in Vietnamese patients.

Benefits and risks of interferon therapy for hepatitis B

Alpha interferon is the only licensed drug for hepatitis B with immunomodulatory as well as viral inhibitory properties. Potential advantages of interferon compared to nucleoside analogs include a lack of drug resistance, a finite and defined treatment course, and a higher likelihood for hepatitis B surface antigen (HBsAg) clearance. Approximately 30% of hepatitis B e antigen (HBeAg)-positive and 40% of HBeAg-negative cases have a sustained virological response (when defined as HBeAg seroconversion and/or hepatitis B virus (HBV) DNA levels below 20,000 copies/mL, respectively) 6 months after completion of a 48-week course of peginterferon alfa-2a These responses remain durable in 80% and 50% of cases, respectively, when evaluated several years later. Recent studies have shown that changes in HBsAg and HBeAg concentration during treatment predict sustained virological response and serial monitoring of HBsAg is helpful in predicting HBsAg clearance. HBeAg-positive patients with genotype A have higher rates of HBeAg and HBsAg clearance, whereas HBeAg-negative patients with genotype D have the lowest rate of response to interferon therapy. Long-term follow-up of virological responders to either standard alpha interferon or peginterferon has demonstrated a progressive increase in the rate of HBsAg clearance, particularly in patients who were initially HBeAg-positive. Future studies need to address if specific virological benchmarks during therapy can be used to tailor treatment duration.

CONCLUSION

Peginterferon alfa has a place as first-line therapy of hepatitis B in patients who are carefully selected on the basis of pretreatment serum HBV DNA and aminotransferase levels, safety considerations, and viral genotype.

Hepatitis B virus genotype-associated variability in antiviral response to adefovir dipivoxil therapy in Chinese Han population

It is well known that different genotypes of hepatitis B virus (HBV) have a different sensitivity to interferon-alpha or lamivudine (nucleoside analogue) antiviral therapy. However, for adefovir dipivoxil (ADV, a nucleotide analogue), the antiviral response of the different genotypes remains to be clarified. In order to evaluate the response of HBV genotypes to ADV therapy and to identify factors that might affect initial virological response, we performed a retrospective analysis on patients with chronic hepatitis B (CHB) in Chinese Han population. The study included 183 patients, who had been tested positive for hepatitis B e antigen (HBeAg) and had been treated with ADV (10 mg/day) for 48 weeks. The numbers of patients infected with HBV genotype B and genotype C were 98 and 75 cases, respectively, and the remaining 10 patients were mixture infection of genotypes B plus C or genotypes B plus D. The mean HBV-DNA reduction and HBV-DNA seroclearance of genotypes B and C at 48 weeks were 3.6 log(10) and 3.1 log(10) copies/ml (p < 0.05) and 41.8% and 34.6% (p < 0.05), respectively. There were no statistically significant differences between genotypes B and C in terms of HBeAg loss, anti-HBe seroconversion and normalization of serum alanine aminotransferase (ALT). Multivariate analysis showed that young age, low pretreatment HBV-DNA and/or elevated ALT level might be independent predictive factors associated with initial virological response. Thus, in Han CHB patients who are HBeAg-positive, HBV genotype B shows a better virological response to ADV therapy than does genotype C.

HBV genotypes in India: do they influence disease severity?

AIMS

Association of HBV genotypes (especially A and D) with severity of liver disease is controversial. We studied the influence of HBV genotypes on liver disease severity among Indian patients.

METHODS

We selected 247 HBV infected patients (42 acute hepatitis, 87 carriers, 44 chronic hepatitis B [CHB], 35 liver cirrhosis [LC] and 40 hepatocellular carcinoma [HCC]). Genotyping of stored sera was performed using genotype-specific enzyme-linked immunosorbent assay (ELISA) and restriction fragment length polymorphism (RFLP). The distribution of genotypes in disease states of differing clinical, histological and biochemical severity were compared.

RESULTS

The most common genotype was D (162/237, 68.3%), followed by A (61, 25.7%) and C (14, 5.9%). The distribution of HBV genotypes between patients with acute hepatitis and CHB (carriers + CHB + LC + HCC), or between carriers and disease states (CHB + LC + HCC), or between mild chronic infection (carriers + CHB) and complications of chronic HBV infection (LC + HCC) was similar. Eighty-seven patients had liver biopsy; the median histological activity index (HAI) and fibrosis stage at baseline were similar between genotype groups (four [1-9] genotype A [n = 28]), three (2-4) genotype C (n = 4) and four (1-10) genotype D (n = 55); P = 0.33 for HAI score; (0.5 [0-6] genotype A, 0.5 [0-4] genotype C and 1 [0-6] genotype D; P = 0.92 for fibrosis stage). The response to therapy was similar between the genotypes.

CONCLUSION

Clinical, histological severity and therapeutic responses are similar among patients with HBV genotypes A and D.

Advances in the diagnosis and treatment of hepatitis B

PURPOSE OF REVIEW

Hepatitis B virus is responsible for much morbidity and mortality worldwide. Although the armament of drugs licensed for its treatment grows, it is increasingly apparent that the efficacy of these drugs is dependent upon much more that their pharmacology.

RECENT FINDINGS

A better understanding of the natural history of chronic hepatitis B infection together with recent advances in the molecular biology of antiviral resistance have given added dimensions to physicians' decision-making thought processes.

SUMMARY

The present review outlines the recent advances in diagnostic testing that enable a better understanding of an individual patient's phase of illness and also how such information can update treatment choices better. In the second part of this review, the licensed therapies and their relative merits are discussed, as is their role in managing resistance to antiviral therapy.

Genetic Variability of Hepatitis B virus and Response to Antiviral Therapy

Hepatitis B virus (HBV) infection is a global health issue. Effective and individualized treatment of chronic hepatitis B to prevent progression to end-stage liver diseases and hepatocellular carcinoma is needed. HBV can be classified into eight genotypes (A–H) on the basis of genome sequence divergence. In addition, several naturally occurring HBV mutants have also been identified. The epidemiology of HBV genotypes and their implications for response to antiviral therapy have become increasingly recognized. Recent studies suggested that responses to standard interferon treatment in patients with genotype A or B are better than those with genotype C or D; however, conflicting results exist regarding the response to pegylated interferon. The influence of dose and duration on interferon-based therapy remains to be clarified. In addition to genotype, naturally occurring mutations such as precore and core promoter mutations have also attracted much attention, because they have been shown to affect the disease progression of HBV-related chronic liver disease and possibly the response to antiviral therapy. Here, we review the differences in antiviral theraputic response among HBV genotypes and discuss the role of precore or core promoter mutations in response to antiviral therapy.

Current antiviral therapies for chronic hepatitis B

Among current treatment options for chronic hepatitis B, nucleoside/nucleotide analog therapy has better tolerability and most patients respond to the therapy, while interferon (IFN) therapy has rather severe side-effects and a lower response rate. However, nucleoside/nucleotide analog therapies have problems of the emergence of drug resistance and poor sustainability of response after discontinuation. After the first nucleoside/nucleotide analog lamivudine, adefovir and entecavir are now utilized in many countries. Adefovir has efficacy for lamivudine resistant patients and current data suggests that adding adefovir to ongoing lamivudine is better than switching to adefovir in terms of viral suppression and the occurrence of resistance. Entecavir can be the first choice for naïve patients, although cross-resistance has been known for lamivudine resistant patients and mutational screening should take place before using entecavir with such patients. Many other new nucleoside/nucleotide analogs are being developed such as telbivudine, clevudine and tenofovir; the details of each drug will be disclosed in near future.

Molecular characterization of occult hepatitis B virus in genotype E-infected subjects

Occult hepatitis B virus (HBV) infection (OBI), defined as the presence of HBV DNA without detectable HBV surface antigen (HBsAg), is frequent in west Africa, where genotype E is prevalent. The prevalence of OBI in 804 blood donors and 1368 pregnant women was 1.7 and 1.5%, respectively. Nine of 32 OBI carriers were evaluated with HBV serology, viral load and complete HBV genome sequence of two to five clones. All samples except one were anti-HBV core antigen-positive and three contained antibodies against HBsAg (anti-HBs). All strains were of genotype E and formed quasispecies with 0.20-1.28% intra-sample sequence variation. Few uncommon mutations (absent in 23 genotype E reference sequences) were found across the entire genome. Two mutations in the core region encoded truncated or abnormal capsid protein, potentially affecting viral production, but were probably rescued by non-mutated variants, as found in one clone. No evidence of escape mutants was found in anti-HBs-carrying samples, as the 'a' region was consistently wild type. OBI carriers constitute approximately 10% of all HBV DNA-viraemic adult Ghanaians. OBI carriers appear as a disparate group, with a very low viral load in common, but multiple origins reflecting decades of natural evolution in an area essentially devoid of human intervention.

The association of complex liver disorders with HBV genotypes prevalent in Pakistan

Background

Genotyping of HBV is generally used for determining the epidemiological relationship between various virus strains and origin of infection mostly in research studies. The utility of genotyping for clinical applications is only beginning to gain importance. Whether HBV genotyping will constitute part of the clinical evaluation of Hepatitis B patients depends largely on the availability of the relevance of the evidence based information. Since Pakistan has a HBV genotype distribution which has been considered less virulent as investigated by earlier studies from south East Asian countries, a study on correlation between HBV genotypes and risk of progression to further complex hepatic infection was much needed

Methods

A total of 295 patients with HBsAg positive were selected from the Pakistan Medical Research Council's (PMRC) out patient clinics. Two hundred and twenty six (77%) were males, sixty nine (23%) were females (M to F ratio 3.3:1).

Results

Out of 295 patients, 156 (53.2%) had Acute(CAH), 71 (24.2%) were HBV Carriers, 54 (18.4%) had Chronic liver disease (CLD) Hepatitis. 14 (4.7%) were Cirrhosis and HCC patients. Genotype D was the most prevalent genotype in all categories of HBV patients, Acute (108), Chronic (39), and Carrier (53).

Cirrhosis/HCC (7) were HBV/D positive. Genotype A was the second most prevalent with 28 (13%) in acute cases, 12 (22.2%) in chronics, 14 (19.7%) in carriers and 5 (41.7) in Cirrhosis/HCC patients. Mixed genotype (A/D) was found in 20 (12.8%) of Acute patients, 3 (5.6%) of Chronic and 4 (5.6%) of carriers, none in case of severe liver conditions.

Conclusion

Mixed HBV genotypes A, D and A/D combination were present in all categories of patients except that no A/D combination was detected in severe conditions. Genotype D was the dominant genotype. However, genotype A was found to be more strongly associated with severe liver disease. Mixed genotype (A/D) did not significantly appear to influence the clinical outcome.

Deficiencies in the standardization and sensitivity of diagnostic tests for hepatitis B virus

The patterns of hepatitis B virus (HBV) markers described in textbooks apply to acute and chronic infection with wild-type HBV. Deviations from these patterns occur in the very early phase, in low-level (or occult) infection and under immunosuppression. Variability may originate from the virus, the host or the test kits. In order to obtain a reliable diagnosis under these conditions, tests for all three markers of HBV infection have to be applied: HBsAg, HBV DNA and anti-HBc. All tests should be as sensitive as feasible, but even then occult infection may be missed. Reliable detection of occult or mutated HBV is particularly important in blood and organ donors and in patients before or with immunosuppression.

Role of viral factors in the natural course and therapy of chronic hepatitis B

Hepatitis B virus (HBV) infection is a global health problem that causes a wide spectrum of liver disease, including acute or fulminant hepatitis, inactive carrier state, chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The pathogenesis of hepatocyte damage associated with HBV is mainly through immune-mediated mechanisms. On the basis of the virus and host interactions, the natural history of HBV carriers who are infected in early life can be divided into four dynamic phases. The frequency, extent, and severity of hepatitis flares or acute exacerbation in the second immune clearance and/or fourth reactivation phase predict liver disease progression in HBV carriers. In the past decade, hepatitis B viral factors including serum HBV DNA level, genotype, and naturally occurring mutants predictive of clinical outcomes have been identified. The higher the serum HBV DNA level after the immune clearance phase, the higher the incidence of adverse outcomes over time. In addition, high viral load, genotype C, basal core promoter mutation, and pre-S deletion correlate with increased risk of cirrhosis and HCC development. As to the treatment of chronic hepatitis B, patients with high HBV DNA level and genotype C or D infection are shown to have a worse response to interferon therapy. In conclusion, serum HBV DNA level, genotype, and naturally occurring mutants are identified to influence liver disease progression and therapy of chronic hepatitis B. More investigations are needed to clarify the molecular mechanisms of the viral factors involved in the pathogenesis of each stage of liver disease and the response to antiviral treatments.

Variations in the core promoter/pre-core region in HBV genotype C in Japanese and Northern Vietnamese patients

Hepatitis B virus (HBV) subgenotypes Cs (C1) and Ce (C2) are common in East Asia. To investigate the genomic difference of HBV genotype C between two separated regions, 50 subgenotype Cs-infected Vietnamese and 70 subgenotype Ce-infected Japanese patients were enrolled for analysis. The patients were categorized to either a hepatocellular carcinoma group (HCC) or a non-HCC group including liver cirrhosis, chronic hepatitis, and asymptomatic carriers. HBV serology, HBV-DNA level, and variations in core promoter/pre-core region were examined. Phylogenetic analysis based on the full genome sequences and nucleotide sequences partly in the S gene and in the P gene revealed that all Japanese strains (70/70) were subgenotype Ce, and nearly all of the Vietnamese strains (50/51) were subgenotype Cs, excluding one subgenotype C5. C1858 and G1775 were common in the Vietnamese (64% and 40%) but not in the Japanese (0%). The prevalence of C/A1753 in Vietnamese was higher than that in the Japanese (32% vs. 17.1%), however the frequency of A1896 in the Japanese was significantly higher (32.9% vs. 12%, P < 0.05). Most of the Vietnamese patients with HCC had a high level of HBV-DNA, the Japanese HCC had a relatively low level. In the Vietnamese, C/A1753 and C1858 were associated closely with T1762A1764, higher HBV-DNA levels and higher HCC incidence. The multivariate analysis revealed that male, T1653 and C/A1753 were independent risk factors for HCC. The subgenotypes and unique mutations of HBV genotype C in the Vietnamese and Japanese differed, and C/A1753 and C1858 variants might play a role in the pathogenesis of liver disease in Vietnamese patients.

Sequential treatment with lamivudine and alpha-interferon in anti-HBe-positive chronic hepatitis B patients: a pilot study

BACKGROUND

In chronic hepatitis B, long-term use of alpha interferon is hampered by side effects, and long-term treatment with nucleos(t)ide analogues is burdened by drug-resistant mutants. We hypothesized that alternate rounds of lamivudine and alpha interferon might circumvent previous shortcomings.

AIM

To evaluate efficacy of sequential lamivudine or IFN-alpha2b monotherapies in preventing occurrence of tyrosine-methionine-aspartate-aspartate (YMDD) mutants and achieving virological and biochemical response.

METHODS

Fifteen patients with hepatitis B surface antigen, anti-HBe-positive chronic hepatitis received four consecutive rounds of monotherapy with lamivudine (100 mg/day), IFN-alpha2b (5MU/tiw), lamivudine, IFN-alpha2b. Serum HBV-DNA levels were evaluated during and off treatment, HBV polymerase and pre-core/core regions sequenced.

RESULTS

End-of-treatment response was achieved in 10 patients (67%). One patient did not respond, a second developed genotypic resistance at week 24. A rebound in viremia occurred in three patients at week 48. Six patients (40%) remained sustained responders. Triple promoter mutations at nucleotides 1762-1764-1896 prevailed in non-responders (60%) as compared to responders (20%). L180M/M204V mutations were identified during virological breakthrough.

CONCLUSION

Sequential approach of alternate rounds of lamivudine or interferon may help patients to tolerate a prolonged schedule of therapy and protect them from emergence of viral strains.