HBV mutations in untreated HIV-HBV co-infection using genomic length sequencing

HIV-HBV Coinfection-Current Challenges for Virologic Monitoring

HIV-HBV coinfected patients have higher rates of liver-related morbidity, hospitalizations, and mortality compared to HBV or HIV mono-infected ones. Clinical studies have shown an accelerated progression of liver fibrosis and an increased incidence of HCC, resulting from the combined action of HBV replication, immune-mediated hepatocytolysis, and HIV-induced immunosuppression and immunosenescence. Antiviral therapy based on dually active antiretrovirals is highly efficient, but late initiation, global disparities in accessibility, suboptimal regimens, and adherence issues may limit its impact on the development of end-stage liver disease. In this paper, we review the mechanisms of liver injuries in HIV-HBV coinfected patients and the novel biomarkers that can be used for treatment monitoring in HIV-HBV coinfected persons: markers that assess viral suppression, markers for liver fibrosis evaluation, and predictors of oncogenesis.

Hepatocellular carcinoma in Hepatitis B and Human Immunodeficiency Virus coinfection in Africa: a focus on surveillance

Human immunodeficiency virus (HIV) and hepatitis-B virus (HBV) infections are weighty public health challenges, especially in the African continent. The direct carcinogenic effect of HBV means that it remains a potent cause of early-onset hepatocellular carcinoma (HCC) in Sub-Saharan Africa (SSA), where it causes significant morbidity and mortality. The presence of HIV infection in HBV-infected patients poses a complicating factor, as coinfection has been shown to hasten the progression of liver disease to cirrhosis and HCC, and often resulting in early-age hepatocarcinogenesis with consequent late diagnosis and lower survival. In this review, we discuss this unique conundrum, the epidemiology of HIV-HBV coinfection in SSA, its effect on liver disease and development of HCC, as well as practices and barriers to HCC surveillance in this distinct population. We propose a way forward to curb this considerable health burden focusing on reduction of disease stigma, the need for easy-to-measure biomarkers, and implementation of large prospective studies in this population.

Comparison and Correlation of Genetic Variability of the HBV Pre-S Region in HIV/HBV Co-Infected Patients: Quasispecies Perspective

Background

Human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infection can accelerate HBV-induced liver disease. A previous study showed that variation in the HBV pre-S region and quasispecies heterogeneity (Sn, mean genetic distance, dS, dN, and dS/dN) are both related to HBV-induced terminal liver disease in HBV mono-infection. Currently, data are lacking on quasispecies variation of the HBV pre-S region in HIV/HBV co-infection. Investigating the quasispecies variation of the HBV pre-S region and its related factors in HIV/HBV co-infection will help to better explore the pathogenic mechanism of HIV/HBV co-infection.

Methods

According to the HIV antibody results obtained before treatment, chronic HBV-infected patients were divided into HIV/HBV co-infected and HBV mono-infected groups. The clinical characteristics of all patients were collected, and DNA was extracted from the serum. The HBV pre-S region was amplified by nested PCR and was further TA cloned. BioEdit software 7.0 was used for sequence alignment with reference to the standard sequence of the matched HBV genotype. We used 1:1 propensity score matching (PSM) to control for baseline confounding factors between the two groups.

Results

After 1:1 PSM, we identified 100 patients with similar propensities: 50 HIV/HBV co-infected patients and 50 HBV mono-infected patients. HBV quasispecies indices were lower in the HIV/HBV co-infected group than those in the HBV mono-infected group. A significant correlation was observed between all quasispecies indices and soluble cluster of differentiation 163 (sCD163) and interleukin-18 (IL-18) in the HIV/HBV co-infected group; however, this phenomenon was not found in the HBV mono-infected group.

Conclusion

Combined HIV infection reduces quasispecies heterogeneity in the HBV pre-S region, and the quasispecies heterogeneity is related to the sCD163 and IL-18 levels.

Pre-S Deletions are Predominant Quasispecies in HIV/HBV Infection: Quasispecies Perspective

Background

Combined HIV infection can accelerate HBV-induced liver disease. It is known that HBV Pre-S deletion is closely related to HBV-associated terminal liver disease in HBV mono-infection. Currently, data on HBV Pre-S quasispecies feature deletion in HIV/HBV co-infected patients are lacking.

Methods

The characteristics and blood samples of patients with chronic HBV infection were collected and classified into an HIV/HBV co-infection group and an HBV mono-infection group according to HIV antibody results before treatment. HBV DNA in serum was extracted. The HBV Pre-S region was amplified by nested-PCR and was further T-A cloned. Using the standard sequence of the matched genotype HBV as a reference, BioEdit 7.0 software was employed for sequence alignment.

Results

HBV Pre-S regions were successfully amplified from 147 patients, including 71 cases in the HIV/HBV co-infected group and 76 cases in the HBV mono-infected group. The proportion of the HIV/HBV co-infected group with Pre-S quasispecies deletion was lower than that of the HBV mono-infected group. By analyzing the frequency of Pre-S quasispecies in the two groups, the frequency of Pre-S quasispecies in HIV/HBV co-infected patients with Pre-S quasispecies was higher than HBV mono-infected patients. The frequency of Pre-S quasispecies deletion of the S protein promoter region in the HIV/HBV co-infected group was significantly higher than that in the HBV mono-infected group.

Conclusion

High-frequency Pre-S quasispecies deletions are predominant in HIV/HBV co-infected patients; however, low-frequency Pre-S deletions are predominant in HBV mono-infected patients, providing a reference for the pathogenesis of the accelerated progression of liver disease in HIV/HBV co-infection.

Spectrum of Liver Disease in Hepatitis B Virus (HBV) Patients Co-infected with Human Immunodeficiency Virus (HIV): Results of the HBV-HIV Cohort Study

BACKGROUND

Because most HBV/HIV co-infected patients on combination antiretroviral therapy (cART) have suppressed HBV DNA and normal liver enzymes, the histologic spectrum of liver disease in HBV/HIV coinfection is poorly defined. To address this gap in knowledge, we conducted a prospective study to comprehensively characterize liver disease severity assessed by liver biopsy in a well-defined cohort of HBV/HIV patients in North America receiving cART.

METHODS

Adult HIV/HBsAg positive patients on stable cART were recruited. Demographic, clinical, serological, and virological data were collected. Liver histology was assessed by a central pathology committee. The association of demographic, clinical, serologic, and virologic characteristics with liver histology was assessed using logistic regression.

RESULTS

In this cross-sectional analysis, the mean age of the cohort (N = 139) was 49 years; 92% were male, 51% were non-Hispanic black, 7% had at-risk alcohol use with a median duration of infections of 14 years. The median ALT was 28 IU/L and CD4 count was 568 cells/mm. Almost all (99%) were on cART. Three-fourths (75%) had undetectable HIV RNA (<20 copies/mL). HBeAg was positive in 62%, HBV DNA was below the limit of quantification (<20 IU/mL) in 57% and <1000 IU/ mL in 80%; 7% had incomplete viral suppression (HBV DNA ≥1000 IU/mL and HIV RNA <20 copies/mL). Liver histology (available in n = 114) showed significant periportal, lobular, and portal inflammation (scores ≥2) in 14%, 31%, and 22% respectively. Over a third (37%) had significant fibrosis (Ishak stage ≥2); 24% had advanced fibrosis (Ishak stage ≥3). Higher ALT (adjusted OR 1.19 per 10 IU/L; 95% CI [1.01, 1.41]; p = 0.03) and lower platelet count (adjusted OR 0.81 per 20,000 mm; 95% CI [0.67-0.97]; p = 0.02) but not HBV DNA were independently associated with advanced fibrosis.

CONCLUSIONS

In this cohort of patients with HBV/HIV coinfection receiving long-term cART with viral suppression, we observed significant fibrosis in more than one-third of patients.

Effect of hepatitis B virus (HBV) surface-gene variability on markers of replication during treated human immunodeficiency virus-HBV infection in Western Africa

BACKGROUND & AIMS

Replication markers exhibit substantial variation during chronic hepatitis B virus (HBV) infection, part of which can be explained by mutations on the surface (S) gene. We aimed to identify S-gene mutations possibly influencing the quantification of HBV replication markers (MUPIQH) in HBV genotype E infection, common to Western Africa.

METHODS

Seventy-three antiretroviral treatment (ART)-naïve human immunodeficiency virus (HIV)-HBV co-infected patients from Côte d'Ivoire, initiating anti-HBV-containing ART, had available HBV S-gene sequences. S-gene MUPIQHs were screened at ART initiation based on lower HBV-DNA or HBsAg quantification (qHBsAg) compared to wildtype. Their association with HBV virological response and qHBsAg slope during treatment was evaluated.

RESULTS

Genotype E was predominant (95.9%). At ART initiation, median HBV-DNA was 7.27 log₁₀ copies/mL (IQR = 5.26-8.33) and qHBsAg 4.08 log₁₀ IU/mL (IQR = 3.49-4.61). Twelve S-gene MUPIQHs were identified among 21 patients (28.8%): sS140L (n = 4), sD144A (n = 1), sS167L (n = 2), sS174N (n = 6), sP178Q (n = 2), sG185L (n = 2), sW191L (n = 2), sP203Q/R (n = 2), sS204N/I/R/K/T/G (n = 7), sN207T (n = 2), sF212C (n = 1) and sV224A/Y (n = 7). MUPIQHs at positions s185+s191+s224 and s178+s204 were within highly covarying networks of S-gene mutations. Older age (P = 0.02), elevated transaminases (P = 0.03) and anti-hepatitis B "e" antibody-positive serology (P = 0.009) were significantly associated with prevalent MUPIQHs at ART initiation. During treatment, baseline MUPIQHs were not associated with time-to-undetectable HBV-DNA (P = 0.7) and qHBsAg levels decreased at similar rates between those with vs without MUPIQHs (P = 0.5).

CONCLUSION

Several novel S-gene mutations were associated with reductions in replication markers among West African co-infected patients. These mutations, however, do not affect response during antiviral treatment. Their diagnostic and clinical consequences need clarification.

Precore G1896A mutation is associated with reduced rates of HBsAg seroclearance in treated HIV hepatitis B virus co-infected patients from Western Africa

The nucleotide substitution G1896A on the precore (pc) region has been implicated in virological and serological responses during treatment in hepatitis B virus (HBV)-infected patients. Whether this mutation affects the therapeutic course of HIV-HBV co-infected patients, especially from Western Africa, is unknown. In this prospective cohort study, 86 antiretroviral (ARV)-naïve HIV-HBV co-infected patients from Côte d'Ivoire, initiating ARV-treatment containing lamivudine (n = 53) or tenofovir (n = 33), had available baseline pc sequences. Association of the pcG1896A mutation with time to undetectable HBV-DNA, hepatitis B "e" antigen (HBeAg) seroclearance (in HBeAg-positive patients), and hepatitis B surface antigen (HBsAg) seroclearance was evaluated using Cox proportional hazards regression. At ARV-initiation, median HBV-DNA was 6.04 log₁₀ copies/mL (IQR = 3.70-7.93) with 97.7% harbouring HBV genotype E. Baseline pcG1896A mutation was identified in 51 (59.3%) patients, who were more commonly HBeAg-negative (P < .001) and had basal core promotor A1762T/G1764A mutations (P < .001). Patients were followed for a median 36 months (IQR = 24-36). Cumulative proportion of undetectable HBV-DNA was significantly higher in patients with baseline mutation (pcG1896A = 86.6% vs no pcG1896A = 66.9%, P = .04), but not after adjusting for baseline HBV-DNA levels and anti-HBV agent (P = .2). No difference in cumulative proportion of HBeAg seroclearance was observed between mutation groups (pcG1896A = 57.1% vs no pcG1896A = 54.3%, P = .7). Significantly higher cumulative proportion of HBsAg seroclearance was observed in patients without this mutation (pcG1896A = 0% vs no pcG1896A = 36.9%, P < .001), even after adjusting for baseline HBsAg quantification and anti-HBV agent (P < .001). In conclusion, lacking the pcG1896A mutation before ARV initiation appeared to increase HBsAg seroclearance rates during treatment. The therapeutic implications of this mutation need further exploration in this setting.

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

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

HIV-hepatitis B virus coinfection: epidemiology, pathogenesis, and treatment

: HIV infection has a significant impact on the natural history of chronic hepatitis B virus (HBV) infection, with increased levels of HBV DNA, accelerated progression of liver disease and increased liver-associated mortality compared with HBV monoinfection. Widespread uptake and early initiation of HBV-active antiretroviral therapy has substantially improved the natural history of HIV-HBV coinfection but the prevalence of liver disease remains elevated in this population. In this paper, we review recent studies examining the natural history and pathogenesis of liver disease and seroconversion in HIV-HBV coinfection in the era of HBV-active antiretroviral therapy and the effects of HIV directly on liver disease. We also review novel therapeutics for the management of HBV with a particular emphasis on clinical strategies being developed for an HBV cure and an HIV cure and their impact on HIV-HBV coinfected individuals.

Hepatitis B virus sequencing and liver fibrosis evaluation in HIV/HBV co-infected Nigerians

OBJECTIVES

Molecular characteristics of hepatitis B virus (HBV), such as genotype and genomic mutations, may contribute to liver-related morbidity and mortality. The association of these characteristics with liver fibrosis severity in sub-Saharan Africa is uncertain. We aimed to characterise molecular HBV features in human immunodeficiency virus (HIV)/HBV co-infected Nigerians and evaluate associations between these characteristics and liver fibrosis severity before and after antiretroviral therapy (ART) initiation.

METHODS

HIV/HBV co-infected Nigerians underwent liver fibrosis estimation by transient elastography (TE) prior to and 36 months after ART initiation. Basal core promoter/precore (BCP/PC) and preS1/preS2/S regions of HBV were sequenced from baseline plasma samples. We evaluated associations between HBV mutations and liver fibrosis severity by univariate and multivariable regression.

RESULTS

At baseline, 94 patients underwent TE with median liver stiffness of 6.4 (IQR 4.7-8.7) kPa. Patients were predominantly infected with HBV genotype E (45/46) and HBe-antigen negative (75/94, 79.8%). We identified BCP A1762T/G1764A in 15/35 (43%), PC G1896A in 20/35 (57%), 'a' determinant mutations in 12/45 (26.7%) and preS2 deletions in 6/16 (37.5%). PreS2 mutations were associated with advanced fibrosis in multivariable analysis. At follow-up, median liver stiffness was 5.2 (IQR 4.1-6.6) kPa. No HBV molecular characteristics were associated with lack of fibrosis regression, although HIV virologic control, body mass index (BMI) and baseline CD4+ T-cell count were associated with a decline in fibrosis stage.

CONCLUSION

Frequent BCP/PC and preS1/preS2/S mutations were found in ART-naïve HIV/HBV co-infected Nigerians. Median liver stiffness declined after initiation of ART, regardless of pre-ART HBV mutational pattern or virologic characteristics.

Higher prevalence of cancer related mutations 1762T/1764A and PreS deletions in hepatitis B virus (HBV) isolated from HBV/HIV co-infected compared to HBV-mono-infected Chinese adults

In the era of combination therapy for human immunodeficiency virus (HIV), liver disease including hepatocellular carcinoma (HCC), are the major causes of death for patients co-infected with hepatitis B virus (HBV) and HIV. However, the mechanisms remain obscure. We aimed to determine whether HCC-related HBV mutations including 1762T/1764A double mutation and pre-S deletions occur more frequently in HBV/HIV co-infected individuals compared to HBV mono-infected individuals. In this study, the basic core promoter (BCP) and the preS/S regions of HBV isolated from 61 pairs of HBV/HIV co-infected and HBV mono-infected participants were analyzed. We found that the prevalence of HBV isolates with 1762T/1764A and/or preS deletion mutations was 37.7% (95% CI: 29.1-46.3). The prevalence of these mutations in HBV/HIV co-infected group (52.5%, 95% CI: 40.0-65.0) was significantly higher than in the HBV mono-infected group (23.0%, 95% CI: 12.4-33.6) (X²=11.307, P<0.05). HBV/HIV co-infection was associated with higher viral loads but these higher viral loads were not associated with the higher prevalence of HCC-related HBV mutations. Individually 1762T1764A (44.3%) or preS deletions (23%) occurred more frequently in isolates from co-infected compared to mono-infected individuals (21.3%, 4.9%, respectively) (X²=7.290, P<0.05; X²=8.270, P<0.05). Moreover, 1762T/1764A and preS deletions occurred more frequently in genotypes C and I compared to genotype B (p<0.05). Multivariate analysis revealed that co-infection with HIV was associated with the development of both 1762T/1764A ((RR: 2.932(1.325-6.488)) and preS deletions ((RR: 5.759(1.562-21.235)). These results demonstrate that co-infection with HIV was associated with increased prevalence of HCC-related mutations in HBV isolates from Chinese patients.

Recent advances in inferring viral diversity from high-throughput sequencing data

Rapidly evolving RNA viruses prevail within a host as a collection of closely related variants, referred to as viral quasispecies. Advances in high-throughput sequencing (HTS) technologies have facilitated the assessment of the genetic diversity of such virus populations at an unprecedented level of detail. However, analysis of HTS data from virus populations is challenging due to short, error-prone reads. In order to account for uncertainties originating from these limitations, several computational and statistical methods have been developed for studying the genetic heterogeneity of virus population. Here, we review methods for the analysis of HTS reads, including approaches to local diversity estimation and global haplotype reconstruction. Challenges posed by aligning reads, as well as the impact of reference biases on diversity estimates are also discussed. In addition, we address some of the experimental approaches designed to improve the biological signal-to-noise ratio. In the future, computational methods for the analysis of heterogeneous virus populations are likely to continue being complemented by technological developments.

Evidence of susceptibility to lamivudine-based HAART and genetic stability of hepatitis B virus (HBV) in HIV co-infected patients: A South African longitudinal HBV whole genome study

BACKGROUND

Reports on the concomitant impact of HIV co-infection and long term highly active anti-retroviral therapy (HAART) on the genetic stability and molecular evolution of HBV are limited in sub-Saharan Africa.

MATERIALS AND METHODS

This retrospective study investigated the molecular evolution of chronic HBV in HIV co-infected patients on lamivudine (3TC)-based HAART over a 5year period. Four HIV co-infected patients, consecutively recruited and followed-up, were screened for hepatitis B serological markers, and their viral loads determined. The HBV genome was amplified from longitudinal samples and characterized by Bayesian inference, mutational analysis, and identification of immune selection pressure.

RESULTS

All patients exhibited persistent chronic HBV infection at baseline, as well as over the course of follow-up despite exposure to 3TC-based HAART. The polymerase gene in all isolates was relatively variable prior to HAART initiation at baseline and during the course of follow-up, although primary drug resistance mutations were not detected. All but one patient were infected with HBV subgenotype A1. The divergence rates between baseline and the last follow-up sequences ranged from 0 to 2.0×10(-3) substitutions per site per year (s/s/y). Positive selection pressure was evident within the surface and core genes.

CONCLUSION

Despite persistent HBV infection in the HIV co-infected patients exposed to long term 3TC-based HAART, the molecular evolution of HBV over a 5year period was unremarkable. In addition, HBV exhibited minimal genetic variability overtime.

Insights into human immunodeficiency virus-hepatitis B virus co-infection in India

Shared routes of transmission lead to frequent human immunodeficiency virus (HIV)-hepatitis B virus (HBV) co-infection in a host which results in about 10% of HIV positive individuals to have chronic hepatitis B infection worldwide. In post-antiretroviral therapy era, liver diseases have emerged as the leading cause of morbidity and mortality in HIV-infected individuals and HBV co-infection have become the major health issue among this population particularly from the regions with endemic HBV infection. In setting of HIV-HBV co-infection, HIV significantly impacts the natural history of HBV infection, its disease profile and the treatment outcome in negative manner. Moreover, the epidemiological pattern of HBV infection and the diversity in HBV genome (genotypic and phenotypic) are also varied in HIV co-infected subjects as compared to HBV mono-infected individuals. Several reports on the abovementioned issues are available from developed parts of the world as well as from sub-Saharan African countries. In contrast, most of these research areas remained unexplored in India despite having considerable burden of HIV and HBV infections. This review discusses present knowledge from the studies on HIV-HBV co-infection in India and relevant reports from different parts of the world. Issues needed for the future research relevant to HIV-HBV co-infection in India are also highlighted here, including a call for further investigations on this field of study.

Hepatitis B Virus-HIV Coinfection: Forgotten but Not Gone

Owing to shared routes of transmission and common risk factors, coinfection with hepatitis B virus (HBV) and HIV is common. As AIDS-related opportunistic infections have declined with successful antiretroviral therapy (ART), liver-related mortality has emerged as the second leading cause of death among patients infected with HIV HIV infection negatively impacts the natural history of HBV, increasing the risks for cirrhosis, hepatocellular carcinoma, and liver-related mortality. With the availability of effective antiviral therapy active against both HIV and HBV and simplified treatment algorithms, it has become easier than ever to treat coinfected patients. However, the issues of suboptimal response, incomplete viral suppression, adverse effects of long-term antiviral treatment, and potential hepatotoxicity of ART remain major challenges.

Genotyping and virological characteristics of hepatitis B virus in HIV-infected individuals in Sudan

OBJECTIVES

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) share common routes of blood-borne transmission. In HBV mono-infected Sudanese individuals, genotypes D, E, and A circulate. The objective of this study was to molecularly characterize HBV from HBV/HIV co-infected individuals.

METHODS

The polymerase overlapping the S region and the basic core promoter (BCP/PC) of HBV from 32 hepatitis B surface antigen (HBsAg)-positive and 18 HBsAg-negative serum samples were amplified and sequenced.

RESULTS

HBV from 37 samples was successfully genotyped and the genotype distribution was 46.0% D, 21.6% E, 18.9% A, and 13.5% D/E recombinant. Compared to mono-infected individuals, the frequencies of the D/E recombinant and genotype A were higher in HBV/HIV co-infected patients, as was the intra-group divergence of genotype E. BCP/PC mutations affecting hepatitis B e antigen (HBeAg) expression at the transcriptional and translational levels were detected. Two HBsAg-positive individuals had pre-S deletion mutants. The following mutations in the S region could account for the HBsAg negativity: sM133T, sE164G, sV168G, and sS174N. No primary drug resistance mutations were found.

CONCLUSIONS

In HBV/HIV co-infected Sudanese patients, the ratio of genotype A to non-A was higher than that in mono-infected patients. The genotype E intra-group divergence in HBV/HIV co-infected individuals was significantly higher than that in HBV mono-infected patients.

HBV whole-genome mutation profile in HIV-1/HBV coinfected patients in a long-term follow-up study

PURPOSE

Human immunodeficiency virus (HIV-1)-infected patients frequently harbour hepatitis B and C viruses (HBV and HCV, respectively). Possible modifications of the natural history of hepatitis B may occur. The aim of this study was to characterise HBV diversity and evolutionary and mutational viral genome profiles in HIV-1/HBV coinfections.

METHODS

HIV-1 and HBV markers determinations (Roche, FRG; Abbott, USA) and HBV genome-length retrospective analysis were performed in follow-up isolates from patients who were either stably HBsAg-negative with a low level of HBV DNA (occult hepatitis B infection, OBI) or HBsAg-positive with a high level of HBV DNA. Phylogenetic analysis (maximum likelihood method, MEGA5), statistical analysis and evolutionary rates calculation (d S/d N) were applied.

RESULTS

Positive selection pressures in the PreS/S region and a significantly higher number of mutations in this region including the major hydrophilic region (MHR) and the "a" determinant were shown in HBsAg-negative (possibly OBI) compared to stably HBsAg-positive HIV-1/HBV subgenotypes D3/A2 coinfected patients. Mutants previously described in HIV-1/HBV coinfected patients were found. Known mutants Y100C, P127T and P120A associated to Y134H and S143T and new S mutants, which may potentially affect HBsAg expression and secretion and anti-HBs binding, were detected in baseline sera persisting up to the end of 9 years follow-up. Known mutations of BCP, Pre-C, C and X regions were also characterised. Natural mutants strictly known as being involved in diagnostic failure were not detected; however, numerous corresponding sites showed amino acid variations.

CONCLUSIONS

Evolutionary and genotypic differences observed, particularly in the PreS/S region, between HBsAg-negative (OBI) and HBsAg-positive HIV-1/HBV coinfected patients, may contribute, in association with mutations of other genomic regions, to the HBsAg-negative phenotype.

Molecular characterization of HBV strains circulating among the treatment-naive HIV/HBV co-infected patients of eastern India

Previously we reported that the exposure to hepatitis B virus (HBV) infection serves as a major threat among the treatment naive HIV infected population of eastern India. Hence, molecular characterization of these strains is of utmost importance in order to identify clinically significant HBV mutations. A total of 85 treatment naive HIV/HBV co-infected participants were included of whom the complete basal core promoter/precore region, the core and the whole envelope gene could be successfully sequenced for 59, 57 and 39 isolates respectively. Following phylogenetic analysis, it was found that HBV/D was the predominant genotype with HBV/D2 (38.5%) being the most prevalent subgenotype followed by HBV/A1. The major mutations affecting HBeAg expression includes the A1762T/G1764A (13.6%), G1896A (22%) and G1862T mutation (33.9%) which was predominantly associated with HBV/A1. Moreover, the prevalence of G1896A was considerably high among the HBeAg negative HIV/HBV co-infected subjects compared to HBV mono-infection. The main amino acid substitutions within the MHC class II restricted T-cell epitope of HBcAg includes the T12S (15.8%) and T67N (12.3%) mutation and the V27I (10.5%) mutation in the MHC class I restricted T-cell epitope. PreS1/S2 deletion was detected in 3 isolates with all harboring the BCP double mutation. Furthermore, the frequently occurring mutations in the major hydrophilic loop of the S gene include the T125M, A128V and M133I/L. Therefore, this study is the first from India to report useful information on the molecular heterogeneity of the HBV strains circulating among the treatment naive HIV/HBV co-infected population and is thus clinically relevant.

New insights into how HBV manipulates the innate immune response to establish acute and persistent infection

The mechanisms by which HBV establishes and maintains chronic infection are poorly understood. Although adult acquired HBV is generally cleared by a robust immune response, most individuals infected at childbirth or in very early childhood develop lifelong chronic infection. In addition, acute infections are unresolved in approximately 5% of individuals infected in adulthood. The host cell mechanisms that ensure establishment and resolution of acute infection and persistent infection remain unclear. Currently, two schools of thought suggest that either HBV is a 'stealth' virus, which initially establishes infection by avoiding host innate immune responses, or that HBV facilitates initial infection and progression to persistence by actively manipulating the host innate immune response to its advantage. There is increasing evidence that activation of innate host cell signalling pathways plays a major role in limiting adult acquired HBV infection and that, in turn, HBV has evolved numerous strategies to counteract these defence mechanisms. In this review, we summarize current knowledge regarding innate immune responses to HBV infection and discuss how HBV regulates cell signalling pathways to its advantage, particularly in the setting of chronic HBV infection. In turn, we show how an intimate knowledge of innate immune responses is driving development of novel therapeutic agents to treat chronic HBV infection.

Influence of HIV-associated degree of immune suppression on molecular heterogeneity of hepatitis B virus among HIV co-infected patients

We have investigated the molecular diversity of Hepatitis B virus (HBV) among the HIV co-infected patients from eastern-India. HBsAg/HBV-DNA positive subjects (n=73) from 874 HIV-infected patients were analyzed by sequencing followed by genetic diversity quantification. HBV/genotype-D and HBV/sugenotype-D2 were predominant. HBV/D2 isolates from patients with low CD4 count manifested significantly lower non-synonymous substitutions (p<0.0001) and Shannon entropy (p=0.0006) in their surface and polymerase gene in comparison to those from moderately increased CD4 count. ART-induced immune-reconstitution therefore might raise non-synonymous immune/therapy escape substitutions among these HBV/D2 isolates. Decreased genetic diversity and increased viral load in the HBV/D2 isolates might facilitate the maintenance of their wild type characteristics in the low CD4 count, leading to its increased prevalence in this group. Interestingly, genetic diversity in HBV/A1, the next common subgenotype, was modified in the opposite manner. Together our results underscore the need for proper HBV molecular monitoring in HIV co-infection.

Genotyping and molecular characterization of hepatitis B virus from human immunodeficiency virus-infected individuals in southern Africa

Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) are hyperendemic in sub-Saharan Africa. The HBV genotypes prevailing in HIV-infected Africans are unknown. Our aim was to determine the HBV genotypes in HIV-infected participants and to identify clinically significant HBV mutations. From 71 HBV DNA^+ve HIV-infected participants, 49 basic core promoter/precore (BCP/PC) and 29 complete S regions were successfully sequenced. Following phylogenetic analysis of 29 specimens in the complete S region, 28 belonged to subgenotype A1 and one to D3. Mutations affecting HBeAg expression at the transcriptional (1762T1764A), translational (Kozak 1809–1812, initiation 1814–1816, G1896A with C1858T), or post translational levels (G1862T), were responsible for the high HBeAg-negativity observed. The G1862T mutation occurred only in subgenotype A1 isolates, which were found in one third (7/21) of HBsAg^−ve participants, but in none of the 18 HBsAg^+ve participants (p<0.05). Pre-S deletion mutants were detected in four HBsAg^+ve and one HBsAg^−ve participant/s. The following mutations occurred significantly more frequently in HBV isolated in this study than in strains of the same cluster of the phylogenetic tree: ps1F25L, ps1V88L/A; ps2Q10R, ps2 R48K/T, ps2A53V and sQ129R/H, sQ164A/V/G/D, sV168A and sS174N (p<0.05). ps1I48V/T occurred more frequently in females than males (p<0.05). Isolates with sV168A occurred more frequently in participants with viral loads >200 IU per ml (p<0.05) and only sS174N occurred more frequently in HBsAg^−ve than in HBsAg^+ve individuals (p<0.05). Prior to initiation of ART, ten percent, 3 of 29 isolates sequenced, had drug resistance mutations rtV173L, rtL180M+rtM204V and rtV214A, respectively. This study has provided important information on the molecular characteristics of HBV in HIV-infected southern Africans prior to ART initiation, which has important clinical relevance in the management of HBV/HIV co-infection in our unique setting.

Comparative analysis of hepatitis B virus genotype a molecular evolution in patients infected with HBV and in patients co-infected with HBV and HIV

HIV infection has a significant impact on the natural progression of liver disease caused by infection with hepatitis B virus (HBV), but its role in the molecular evolution of HBV is unknown. It is difficult to study the molecular evolution of HBV longitudinally considering its genomic complexity, which implies the analysis of paired samples. This study aimed to analyze the difference in the evolutionary dynamics of HBV among patients with HIV and uninfected individuals. In this study, 17 patients infected chronically with HBV were recruited, 9 of them were co-infected with HIV. Patients were HBe antigen-positive and infected with HBV genotype A. Paired plasma samples were collected from each patient 3 years apart, and they were compared subsequently to each other. The HBV phylogenetic inference among isolates from patients infected with HBV and co-infected with HBV and HIV tends to cluster separately. Likewise, when comparing the HBV evolutionary rate and genetic distances, values were higher in the former in both preC/C and S genomic regions. Intra-host analyses of HBV isolates revealed high diversity and complexity of quasispecies among patients infected with HBV exhibiting high numbers of viral variants and genetic distance. In summary, after studying the HBV molecular evolution among isolates ascribed to genotype A at inter- and intra-host levels, HBV exhibited low quasispecies complexity and diversity as well as low evolutionary rates in the presence of HIV co-infection, suggesting that the co-infection may have an impact on the HBV molecular evolution most likely from the weakened cellular immune response.