Long-term outcome of primary non-responders to tenofovir therapy in HIV/HBV-co-infected patients: impact of HBV genotype G

Hepatitis B Virus Genotype G: The Odd Cousin of the Family

With a widespread distribution but low prevalence worldwide, the hepatitis B virus (HBV) genotype G (HBV/G) is a recently described genotype for which the origin and biology are poorly understood. Some unique features make HBV/G the most peculiar of all genotypes. In this review, we reflect on the major milestones in HBV/G research, highlighting the main aspects of its discovery, molecular epidemiology, and virological and clinical characteristics. We also illustrate common pitfalls in the routine detection, which may lead to underestimated rates of HBV/G infection. Large-scale analysis of data from dozens of articles was further performed, with the aim of gaining comprehensive insights into the epidemiological aspects of HBV/G. Finally, we point out recent findings on HBV/G origins and discuss new perspectives regarding the evolutionary history of HBV/G and the plausibility of an African geographic re-emergence of this genotype.

Epidemiology, Natural History, and Treatment of Hepatitis Delta Virus Infection in HIV/Hepatitis B Virus Coinfection

PURPOSE OF REVIEW

Limited data exist on the prevalence, determinants, and outcomes of hepatitis delta virus (HDV) infection among HIV/hepatitis B virus (HBV)-coinfected persons. This review provides current evidence on the epidemiology, natural history, and treatment of HDV infection in patients with HIV/HBV coinfection and highlights future research needs.

RECENT FINDINGS

Cross-sectional studies in Europe, Africa, South America, and Asia show that the prevalence of HDV among HIV/HBV-coinfected patients ranges from 1.2 to 25%. No studies have evaluated the prevalence of HDV infection among HIV/HBV-coinfected patients in the USA. HDV infection increases the risk of hepatic decompensation and hepatocellular carcinoma among HIV/HBV-coinfected patients. HDV treatment remains limited to pegylated interferon-alpha, which results in sustained virologic response in fewer than 25%. Data on the epidemiology, natural history, and treatment of HDV among HIV/HBV-coinfected persons remain limited. More research is needed to address these knowledge gaps in order to better manage HDV coinfection in HIV/HBV-coinfected patients.

Complex genetic encoding of the hepatitis B virus on-drug persistence

Tenofovir disoproxil fumarate (TDF) is one of the nucleotide analogs capable of inhibiting the reverse transcriptase (RT) activity of HIV and hepatitis B virus (HBV). There is no known HBV resistance to TDF. However, detectable variation in duration of HBV persistence in patients on TDF therapy suggests the existence of genetic mechanisms of on-drug persistence that reduce TDF efficacy for some HBV strains without affording actual resistance. Here, the whole genome of intra-host HBV variants (N = 1,288) was sequenced from patients with rapid (RR, N = 5) and slow response (SR, N = 5) to TDF. Association of HBV genomic and protein polymorphic sites to RR and SR was assessed using phylogenetic analysis and Bayesian network methods. We show that, in difference to resistance to nucleotide analogs, which is mainly associated with few specific mutations in RT, the HBV on-TDF persistence is defined by genetic variations across the entire HBV genome. Analysis of the inferred 3D-structures indicates no difference in affinity of TDF binding by RT encoded by intra-host HBV variants that rapidly decline or persist in presence of TDF. This finding suggests that effectiveness of TDF recognition and binding does not contribute significantly to on-drug persistence. Differences in patterns of genetic associations to TDF response between HBV genotypes B and C and lack of a single pattern of mutations among intra-host variants sensitive to TDF indicate a complex genetic encoding of the trait. We hypothesize that there are many genetic mechanisms of on-drug persistence, which are differentially available to HBV strains. These pervasive mechanisms are insufficient to prevent viral inhibition completely but may contribute significantly to robustness of actual resistance. On-drug persistence may reduce the overall effectiveness of therapy and should be considered for development of more potent drugs.

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.

Human immunodeficiency virus and hepatitis B genotype G/A2 recombinant co-infection: a case study

Background

Hepatitis B virus (HBV) genotypes have distinct geographical distributions and are associated with different clinical courses. HBV genotype G (HBV/G) is extremely rare among Human immunodeficiency virus (HIV) infected populations in Japan. Genetic analysis and clinical course of recombinant forms with HBV/G infection are seldom reported in the literature.

Case presentation

A 36-year old homosexual man with HIV infection was referred to a general hospital for assessment of chronic HBV infection. We cloned full-length HBV isolates and determined the complete genome sequences of 2 obtained clones, although mixture of multiple variant with different length is detected by HBV-DNA genotyping. The Bootscaning analysis using a full-length HBV genome revealed the clones represented as the HBV/A2 and the HBV/G/A2 recombinant strain. The HBV-DNA decreased from >9.1 to 2.5 log copies/mL after 24 months of antiretroviral therapy.

Conclusions

This patient was co-infected with HBV/A2 and HBV/G/A2 recombinant strain. This recombinant strain was not identical to HBV/G/A2 strains previously reported from Japan. Recombination with other genotypes could alter the clinical manifestations of chronic hepatitis B in people living with HIV.

Effects of long-term tenofovir-based combination antiretroviral therapy in HIV-hepatitis B virus coinfection on persistent hepatitis B virus viremia and the role of hepatitis B virus quasispecies diversity

OBJECTIVE

Hepatitis B virus (HBV) can persist in some HIV-HBV coinfected individuals on tenofovir disoproxil fumarate (TDF)-containing combination antiretroviral therapy (cART) but HBV resistance to TDF has not been reported and the source of persistent HBV DNA on TDF is poorly understood. The aims of this study were to assess long-term HBV suppression in HIV-HBV coinfected individuals receiving TDF and investigate quasispecies variation using ultradeep pyrosequencing (UDPS).

METHODS

Ninety-two HIV-HBV coinfected participants on, or about to commence, TDF-containing cART were enrolled [Australia (n = 40), Thailand (n = 52)] and followed for 2 years with study visits every 6 months. HBV reverse transcriptase sequencing was performed on samples with HBV DNA more than 400 IU/ml by population-based methods and UDPS. Quasispecies diversity was assessed using Shannon entropy.

RESULTS

Over 24 months, viremia was detected at least once in 17% (n = 16) of the cohort. Novel mutations were not identified in on TDF samples tested by population-based sequencing (n = 19). Using UDPS, the median Shannon entropy value in samples prior to TDF in patients aviremic on TDF was not statistically different from those who were viremic on TDF (n = 50; 8.4 and 9.1, respectively, P = 0.9). Longitudinal Shannon entropy analysis of on TDF samples from five participants showed three individuals with significant changes in viral diversity over time.

CONCLUSION

Persistent viremia on TDF-containing cART is common but TDF-resistance was not detected. In some individuals, changes in viral diversity over time were observed on TDF which could potentially be active viral replication. Further follow-up will be needed to determine the clinical significance of detectable HBV DNA on TDF-containing cART.

HBV genotypes and response to tenofovir disoproxil fumarate in HIV/HBV-coinfected persons

Background

Hepatitis B virus (HBV) genotypes can influence treatment outcome in HBV-monoinfected and human immunodeficiency virus (HIV)/HBV-coinfected patients. Tenofovir disoproxil fumarate (TDF) plays a pivotal role in antiretroviral therapy (ART) of HIV/HBV-coinfected patients. The influence of HBV genotypes on the response to antiviral drugs, particularly TDF, is poorly understood.

Methods

HIV/HBV-co-infected participants with detectable HBV DNA prior to TDF therapy were selected from the Swiss HIV Cohort Study. HBV genotypes were identified and resistance testing was performed prior to antiviral therapy, and in patients with delayed treatment response (>6 months). The efficacy of TDF to suppress HBV (HBV DNA <20 IU/mL) and the influence of HBV genotypes were determined.

Results

143 HIV/HBV-coinfected participants with detectable HBV DNA were identified. The predominant HBV genotypes were A (82 patients, 57 %); and D (35 patients, 24 %); 20 patients (14 %) were infected with multiple genotypes (3 % A + D and 11 % A + G); and genotypes B, C and E were each present in two patients (1 %). TDF completely suppressed HBV DNA in 131 patients (92 %) within 6 months; and in 12 patients (8 %), HBV DNA suppression was delayed. No HBV resistance mutations to TDF were found in patients with delayed response, but all were infected with HBV genotype A (among these, 5 patients with genotype A + G), and all had previously been exposed to lamivudine.

Conclusion

In HIV/HBV-coinfected patients, infection with multiple HBV genotypes was more frequent than previously reported. The large majority of patients had an undetectable HBV viral load at six months of TDF-containing ART. In patients without viral suppression, no TDF-related resistance mutations were found. The role of specific genotypes and prior lamivudine treatment in the delayed response to TDF warrant further investigation.

Toll-like receptor-mediated immune responses are attenuated in the presence of high levels of hepatitis B virus surface antigen

It has been recently shown that Toll-like receptor (TLR) signalling in murine nonparenchymal liver cells (NPCs) is suppressed in the presence of Hepatitis B virus surface antigen (HBsAg). It is not clear, however, whether this is also relevant for the adaptive immune responses and how this effect is mediated. Peripheral blood mononuclear cells (PBMCs) from Hepatitis B virus (HBV) patients and controls were stimulated by TLR ligands in the absence or presence of autologous serum. Interestingly, TLR-mediated cytokine expression (Interleukin-6 and -10) as well as TLR3-induced interferon (IFN) expression in PBMCs of HBV patients was significantly higher than in the healthy volunteers, showing a negative correlation with the levels of HBsAg. In addition, TLR3-mediated IFN-γ production was inhibited in the presence of HBV-containing serum. To mechanistically analyse this observation, murine Kupffer cells (KCs) and sinusoidal endothelial cells (LSECs) were stimulated with TLR3 ligands in the presence or absence of HBsAg. Mixed lymphocyte reactions were performed to study T-cell activation induced by TLR-stimulated NPCs. Gene expression of cytokines and TLR3 was analysed by quantitative rt-PCR, and activation of transcription factors was assessed by Western blot or reporter gene assays. TLR-induced expression of interferon γ, interferon sensitive genes and proinflammatory cytokines in murine KCs and LSECs was efficiently suppressed in the presence of HBsAg, whereas the expression of anti-inflammatory cytokines was enhanced. Activation of NFκB, IRF-3 and MAPKs in these liver cells was potently suppressed by HBsAg. T-cell activation mediated through TLR3-stimulated KCs or LSECs was suppressed by HBsAg which could be reverted by anti-IL-10 antibodies. These findings may, at least in part, explain how HBV evades innate and adaptive immune responses to maintain a persistent infection.

Computational vaccinology and epitope vaccine design by immunoinformatics

Human immune system includes variety of different cells and molecules correlating with other body systems. These instances complicate the analysis of the system; particularly in postgenomic era by introducing more amount of data, the complexity is increased and necessity of using computational approaches to process and interpret them is more tangible.Immunoinformatics as a subset of bioinformatics is a new approach with variety of tools and databases that facilitate analysis of enormous amount of immunologic data obtained from experimental researches. In addition to directing the insight regarding experiment selections, it helps new thesis design which was not feasible with conventional methods due to the complexity of data. Considering this features immunoinformatics appears to be one of the fields that accelerate the immunological research progression.In this study we discuss advances in genomics and vaccine design and their relevance to the development of effective vaccines furthermore several division of this field and available tools in each item are introduced.

Effect of antiretroviral HIV therapy on hepatitis B virus replication and pathogenicity

Coinfections with hepatitis B virus (HBV) and HIV are very frequent. Although HBV is a DNA virus, it replicates via reverse transcription like HIV. Structural similarities between the enzymatic pocket of the HBV DNA polymerase and HIV-1 reverse transcriptase are the basis that certain drugs inhibit both enzymes and thus the replication of both viruses. HBV components increase the pathogenic action of HIV and vice versa directly by certain proteins like HBsAg in the case of HBV and HIV-encoded Tat and Vpr and by disturbing the cytokine balance in affected cells. Antiretroviral therapy is highly beneficial for HIV/HBV-coinfected patients, but carries the risk of drug-induced resistance development and hepatotoxicity. Even with restoration of the immune capacity, signs of hepatic inflammation may develop even after 10 years of treatment.

Virologic and serologic outcomes of mono versus dual HBV therapy and characterization of HIV/HBV coinfection in a US cohort

OBJECTIVES

To characterize HIV/hepatitis B virus (HBV) coinfection in the AIDS Clinical Trials Group Longitudinal Linked Randomized Trials cohort and compare long-term HBV outcomes between regimens with 1 (MONO) or 2 (DUAL) anti-HBV agents.

DESIGN

A retrospective study of coinfected AIDS Clinical Trials Group Longitudinal Linked Randomized Trials subjects who received regimens containing anti-HBV agent(s).

METHODS

Stored samples at baseline and weeks 16, 32, 48, 144, and 240 were tested for HBV DNA, HBV e antigen (HBeAg), HBV e antibody (HBeAb), and hepatitis D virus (HDV) antibody. Resistance and genotype were tested in samples with HBV DNA >600 IU/mL. MONO versus DUAL analyses were limited to HBV treatment-naive subjects (Naive-MONO, Naive-DUAL).

RESULTS

Of 150 study subjects, median age was 40 years, 96% were male; 57% white, 26% black, 13% Hispanic. Baseline median CD4 was 224 cells per cubic millimeter, HIV RNA 4.48 log10 copies/mL, HBV DNA 6.30 log10 IU/mL; 59% HBeAg positive and 65% HBeAb negative; HBV genotypes A = 69%, G = 18%, D = 7%, <2% for A/G, B, C, F, H. Coinfection with HDV was 2%. There were 49 Naive-MONO (lamivudine) and 22 Naive-DUAL (11 lamivudine + tenofovir, 11 emtricitabine + tenofovir) with detectable HBV DNA. In the 240-week follow-up, HBV DNA suppression was not significantly higher in Naive-DUAL (P = 0.14); lower baseline HBV DNA (P < 0.01) was associated with suppression. Among 32 Naive-MONO subjects with detectable HBV DNA at baseline and results at week 48, 41% suppressed; among such 15 Naive-DUAL subjects, 53% suppressed. HBeAg and HBeAb analyses showed similar trends.

CONCLUSIONS

While consistent trends toward increased HBV DNA suppression, HBeAg loss and HBeAb seroconversion were observed in Naive-DUAL compared with Naive-MONO, they were not statistically significant. Overall, HDV coinfection was low.

Incidence and risk factors for incomplete HBV DNA suppression in HIV/HBV-co-infected patients initiating tenofovir-based therapy

Suppression of hepatitis B virus (HBV)-DNA to undetectable levels is an important goal for HIV/HBV-co-infected patients receiving anti-HBV-active antiretroviral therapy (ART), and current guidelines recommend that this outcome should be reached by 1 year of treatment. However, the proportion of patients that fail to achieve an undetectable HBV DNA at this time point and its determinants remain unknown in clinical practice. The objective of this study was to determine the incidence and risk factors for incomplete HBV suppression following 1 year of tenofovir-based ART. We performed a cohort study among tenofovir-treated HIV/HBV-co-infected patients. Patients had HBV viraemia, initiated tenofovir-based ART and had HBV DNA measured at 1 year of therapy. The primary outcome was incomplete HBV suppression (HBV DNA ≥2.6 log IU/mL) at 1 year. Logistic regression determined odds ratio (ORs) of incomplete HBV suppression for risk factors of interest. Among 133 patients, 54% (95% CI, 46-63%) had incomplete HBV suppression at 1 year. Incomplete suppression was associated with higher baseline HBV DNA (OR, 1.46 per log IU/mL increase; 95% CI, 1.1-1.94) and detectable HIV viraemia at 1 year (OR, 2.52; 95% CI, 1.19-5.32). Among 66 patients with suppressed HIV RNA at 1 year, 28 (42%) failed to achieve an undetectable HBV DNA. Failure to suppress HBV DNA by 1 year occurred in a sizeable proportion of tenofovir-treated HIV/HBV-co-infected patients. Higher HBV DNA and detectable HIV viraemia were risk factors for incomplete HBV suppression.

Tenofovir-based combination therapy for HIV/HBV co-infection: factors associated with a partial HBV virological response in patients with undetectable HIV viraemia

OBJECTIVE

The aim of this study was to identify and describe patients with detectable hepatitis B virus (HBV) DNA in the presence of undetectable HIV RNA after 48 weeks of tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) or lamivudine (3TC) treatment.

DESIGN

Case-control study. Cases or delayed responders were defined as detectable HBV DNA (>20 IU/ml) with undetectable HIV RNA (<40 c/ml) after 48 weeks TDF/3(F)TC combination therapy. Controls or virological responders were defined as both undetectable HIV and HBV after 48 weeks TDF/3(F)TC therapy.

RESULTS

Twenty-three cases were identified and matched to 24 controls. 87% cases and 46% controls were eAg-positive (P=0.005). Nine of 23 (39%) cases and seven of 24 (29%) controls had 3TC monotherapy prior to TDF. Similar proportions had 3TC/FTC resistance pre-TDF (30% cases, 24% controls). The cases had significantly higher baseline HBV DNA pre-3TC (median 1.2×10(8) vs. 3.1×10(6) IU/ml; P=0.009) and pre-TDF (1.1×10(8) vs. 2.6×10(4) IU/ml; P=0.012). Sixteen of 23 cases eventually achieved undetectable HBV DNA after 42.2 (27.2, 54.9) months. Six of 23 still have detectable HBV DNA after 46.2 (28.2, 65.6) months. Only one delayed responder patient developed a new 3(F)TC mutation and they received intensification with entecavir and achieved undetectable HBV DNA. No patient developed TDF resistance.

CONCLUSION

We report the largest series of HIV/HBV co-infected patients failing to achieve undetectable HBV after 48 weeks TDF/3(F)TC despite undetectable HIV viraemia. This outcome was associated with positive eAg and higher baseline HBV DNA. Our data suggest that clinicians should not intensify therapy with entecavir unless there is evidence of new 3TC/FTC mutations as the majority of patients go on to suppress HBV. TDF resistance was not seen.

Prevalence of hepatitis B virus and hepatitis C virus in patients with human immunodeficiency virus infection in Central China

Co-infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) with human immunodeficiency virus (HIV) has an adverse effect on liver disease progression. This study investigated the prevalence of HBV and/or HCV co-infection in HIV-infected patients in Central China. A total of 978 HIV-infected patients from Hunan Province were enrolled. HBV serum markers, anti-hepatitis-C-virus antibody (anti-HCV), HBV DNA, and HBV genotypes were analyzed. The prevalence of hepatitis B surface antigen (HBsAg) and anti-HCV in HIV-infected patients was 19.4 % and 62.4 %, respectively. The prevalence of anti-HCV in HIV-positive intravenous drug users was 93.6 %. Among HBsAg-positive patients, 88.1 % were found to have at least one HBV serum marker. The rates of HIV mono-infection, HBV/HIV dual infection, HCV/HIV dual infection, and HBV/HCV/HIV triple infection were 30.4 %, 7.2 %, 50.2 %, and 12.2 %, respectively. Antibody to HBsAg (Anti-HBs) was more common in anti-HCV-positive than anti-HCV-negative patients (53.3 % vs 40.2 %, P = 0.000), but isolated hepatitis B core antibody (anti-HBc) was more common in anti-HCV-negative than anti-HCV-positive patients (24.2 % vs 12.3 %, P = 0.000). Hepatitis B e antigen (HBeAg) and sexual transmission were independent risk factors for active HBV replication. Intravenous drug use and male sex were independent risk factors, but old age and presence of HBeAg were independent protective factors for anti-HCV. Co-infection of HBV and/or HCV with HIV infection is common in central China. HCV status is associated with anti-HBs and isolated anti-HBc in co-infected patients.

Virology and clinical sequelae of long-term antiviral therapy in a North American cohort of hepatitis B virus (HBV)/human immunodeficiency virus type 1 (HIV-1) co-infected patients

There are limited recent data worldwide on clinical and virological outcomes in hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfected patients on dual active antiretroviral therapy (ART).

METHODS

We completed a retrospective review of 53 coinfected patients. HBV DNA in plasma was tested by PCR (sensitivity <20-<55 IU/ml or ∼100-300 copies/ml, Roche Diagnostics). Quantitative hepatitis B surface antigen (qHBsAg) was measured by an in-house assay (calibration range 0.24-62.5 IU/ml). HBV genotyping was done by line probe assay, and HBV variants determined by sequencing the HBV polymerase (P)/overlapping surface (S) gene.

RESULTS

There were 7% (4/53) non-liver related deaths, ∼11% (6/53) had >F2 fibrosis, including 3 with cirrhosis. The median CD4+ T cell count was 415 cells/mm(3) (range 60-1310). 54% (28/51) were HBeAg-positive, and 81% (43/53) on ART had undetectable HBV DNA but only 5% (3/51) lost HBeAg. In 11/53 with HBV sequencing, 90% (10/11) were found to have HBV genotype A (HBV-A) and/or 27% (3/11) had a mixed A/G infection. Anti-HBV drug resistant mutations were detected in 54% (6/11) (i.e., any combination of rtV173L, rtL180M, M204V) and 45% (5/11) had an immune escape mutation (sP120S). In 12 with qHBsAg testing, the majority (9/12) had low-level qHBsAg ∼1-3 log(10) IU/ml.

SUMMARY

Liver disease occurs in ∼10% of coinfected patients on ART and many have low-level HBV DNA and qHBsAg. In those sequenced most were HBV-A or mixed A/G genotype, and several carry P and S mutants highlighting the complex molecular virology of HBV during HIV coinfection.