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We report the first published case of Prototheca wickerhamii breast implant infection. This occurred after mastectomy, chemotherapy, radiotherapy, breast reconstruction, implant revisions and breast seroma aspirations and was preceded by polymicrobial infection. Definitive treatment required implant removal and intravenous liposomal amphotericin B. The management of breast prosthesis infections is discussed., Highlights • Clinical update on breast implant infections. • Algae can cause chronic infections that persist despite broad-spectrum therapy. • Consider removal of prostheses to assist with source control. • Biofilm-active agents are useful adjuncts in prosthetic infections. • Adherence to principles of surgical site infection prevention is recommended.

Angiotensin converting enzyme 2 (ACE2) which breaks down profibrotic peptide angiotensin II to antifibrotic peptide angiotensin-(1–7) is a potential therapeutic target in liver fibrosis. We therefore investigated the long-term therapeutic effect of recombinant ACE2 using a liver-specific adeno-associated viral genome 2 serotype 8 vector (rAAV2/8-ACE2) with a liver-specific promoter in three murine models of chronic liver disease, including carbon tetrachloride-induced toxic injury, bile duct ligation-induced cholestatic injury, and methionine- and choline-deficient diet-induced steatotic injury. A single injection of rAAV2/8-ACE2 was administered after liver disease has established. Hepatic fibrosis, gene and protein expression, and the mechanisms that rAAV2/8-ACE2 therapy associated reduction in liver fibrosis were analyzed. Compared with control group, rAAV2/8-ACE2 therapy produced rapid and sustained upregulation of hepatic ACE2, resulting in a profound reduction in fibrosis and profibrotic markers in all diseased models. These changes were accompanied by reduction in hepatic angiotensin II levels with concomitant increases in hepatic angiotensin-(1–7) levels, resulting in significant reductions of NADPH oxidase assembly, oxidative stress and ERK1/2 and p38 phosphorylation. Moreover, rAAV2/8-ACE2 therapy normalized increased intrahepatic vascular tone in fibrotic livers. We conclude that rAAV2/8-ACE2 is an effective liver-targeted, long-term therapy for liver fibrosis and its complications without producing unwanted systemic effects.

Hepatitis B virus (HBV) infection can result in a spectrum of outcomes from immune-mediated control to disease progression, cirrhosis, and liver cancer. The host molecular pathways that influence and contribute to these outcomes need to be defined. Using an immunocompetent mouse model of chronic HBV infection, we identified some of the host cellular and molecular factors that impact on infection outcomes. Here, we show that cellular inhibitor of apoptosis proteins (cIAPs) attenuate TNF signaling during hepatitis B infection, and they restrict the death of infected hepatocytes, thus allowing viral persistence. Animals with a liver-specific cIAP1 and total cIAP2 deficiency efficiently control HBV infection compared with WT mice. This phenotype was partly recapitulated in mice that were deficient in cIAP2 alone. These results indicate that antagonizing the function of cIAPs may promote the clearance of HBV infection.

Chronic hepatitis C virus (HCV) infection results in progressive liver fibrosis leading to cirrhosis and liver cancer. The mechanism for this remains unclear but hepatocyte apoptosis is thought to play a major role. Hepatocyte apoptosis in human liver tissue was determined by immunohistochemistry for cytokeratin 18 (M30 CytoDEATH) and cleaved poly(ADP-ribose) polymerase (PARP). In vitro studies were performed with replication-defective recombinant adenoviruses expressing HCV proteins (rAdHCV) to study the effects of HCV on cell death in Huh7 cells, primary mouse hepatocytes (PMoHs) and primary human hepatocytes (PHHs). Cell viability and apoptosis were studied using crystal violet assays and Western blots probed for cleaved caspase-3 and cleaved PARP, with and without treatment with the pan-caspase inhibitor Q-VD-OPh and necrostatin-1. Liver tissue of HCV-infected patients expressed elevated levels of apoptotic markers compared with HCV-negative patients. rAdHCV infection reduced cell viability compared with uninfected controls and cells infected with control virus (rAdGFP). Huh7, PMoHs and PHHs infected with rAdHCV showed significantly increased levels of apoptotic markers compared with uninfected controls and rAdGFP-infected cells. In rAdHCV-infected Huh7, treatment with Q-VD-OPh and necrostatin-1 both improved cell viability. Q-VD-Oph also reduced cleaved PARP in rAdHCV-infected Huh7 and PMoHs. Hepatocyte apoptosis is known to be increased in the livers of HCV-infected patients. HCV promoted cell death in primary and immortalized hepatocytes, and this was inhibited by Q-VD-OPh and necrostatin-1. These findings indicate that HCV-induced cell death occurs by both apoptosis and necroptosis, and provide new insights into the mechanisms of HCV-induced liver injury.

The Japanese encephalitis virus (JEV) is endemic in many countries in southern Asia and the western Pacific Rim, with new spread to previously unrecognized countries. It is an important cause of childhood neurological disease associated with permanent neurological sequelae and death. Fortunately, JE is a vaccine-preventable disease. The ChimeriVax™-JE (Sanofi Pasteur, Lyon, France) is a live-attenuated chimeric vaccine derived from the live-attenuated yellow fever virus, YF17D, which expresses the envelope proteins of the attenuated JEV vaccine strain, SA14-14-2. It is a safe, well-tolerated vaccine that is highly immunogenic in adults and children. The average geometric mean neutralizing antibody titer (GMT) in adults is 1,392 and over 90% of adults remain seroprotected 5 years after vaccination. In children and toddlers, more than 80% remain seroprotected 2 years after primary vaccination and demonstrate a robust and durable anamnestic response (>500-fold rise in GMT) with 99.1% seroprotection rates 1 year after a booster vaccine dose. The ChimeriVax™-JE is effective in children living in endemic regions where the vaccine could possibly be integrated into existing childhood vaccination programs. ChimeriVax™-JE is also indicated for travelers at risk of JE infection.

Background Infection with pandemic A/H1N1/2009 influenza virus led to hospitalisation of patients not expected to be at risk of severe disease from seasonal influenza infection. Objectives We sought to establish whether (i) DC maturation was compromised in patients experiencing severe pandemic influenza infection, (ii) the pandemic virus differed from seasonal influenza virus in its ability to induce DC maturation and (iii) there was an associated inability to activate memory B cells or induce antibody. Study design Peripheral blood mononuclear (PBMCs) cells were sampled from individuals with confirmed acute pandemic A/H1N1/2009 influenza infection or from healthy vaccinated controls. DCs were differentiated from the PBMC and tested for their ability to mature following stimulation with pandemic virus, seasonal H3N2 influenza virus or LPS. Serum samples from the patients were used to assess seroconversion to influenza and the levels of influenza specific memory B cells in PBMC were also determined. Results DCs obtained from all individuals exhibited negligible maturation marker upregulation when exposed to pandemic A/H1N1/2009 virus but showed a strong response to the seasonal H3N2 virus and LPS. Robust levels of memory B cell were obtained in both groups and patients seroconverted to the virus. Conclusions Overall, the ability of patient's DC to mature in response to different stimuli was no different to that of control subjects DCs. Importantly, panH1N109 virus failed to induce substantial DC maturation in any individual, contrasting with seasonal virus, but this did not result in failure to mount memory B cell and antibody responses to the virus.

Background/aims Dysregulation of the cell cycle is frequently associated with tumor development. Hepatitis B virus (HBV) is associated with a significant risk of developing hepatocellular carcinoma but the effects of HBV on cell cycle regulation are not completely understood. Methods We have used a recombinant adeno-HBV model system to investigate the effect of infection with HBV and the replication defective lamivudine resistant mutant rtM204I mutant on hepatocyte cell cycle and cell viability. Results Huh7 cells synchronised at the G1/S phase of the cell cycle were arrested at the G2/M following infection with rAdHBV-wt and rAdHBV-M204I. This was accompanied by increased levels of p21 cip1 , p-cdc2, cyclins D, A and B. Cell viability was reduced and cleaved caspase 3 levels were increased in HBV- and rtM204I-infected cells. rAdHBV-M204I-infected Huh7 cells also demonstrated significant up-regulation of phospho-ERK, phospho-Akt, p53 and phospho-Mdm2 compared to mock-infected cells. These changes were comparable to those following infection of Huh7 cells with rAdHBV-wt. Conclusion Our results suggest that HBV, regardless of phenotype, produces cell cycle arrest and reduced hepatocyte viability. Perturbations in these cellular processes are likely to underlie HBV-associated liver oncogenic transformation and may help explain the ongoing risk of developing hepatocellular carcinoma in individuals in whom the lamivudine resistant rtM204I mutant emerges.

An effective immune response against hepatitis C virus (HCV) requires the early development of multi-specific class 1 CD8(+) and class II CD4(+) T-cells together with broad neutralizing antibody responses. We have produced mammalian-cell-derived HCV virus-like particles (VLPs) incorporating core, E1 and E2 of HCV genotype 1a to produce such immune responses. Here we describe the biochemical and morphological characterization of the HCV VLPs and study HCV core-specific T-cell responses to the particles. The E1 and E2 glycoproteins in HCV VLPs formed non-covalent heterodimers and together with core protein assembled into VLPs with a buoyant density of 1.22 to 1.28 g cm(-3). The HCV VLPs could be immunoprecipited with anti-ApoE and anti-ApoC. On electron microscopy, the VLPs had a heterogeneous morphology and ranged in size from 40 to 80 nm. The HCV VLPs demonstrated dose-dependent binding to murine-derived dendritic cells and the entry of HCV VLPs into Huh7 cells was blocked by anti-CD81 antibody. Vaccination of BALB/c mice with HCV VLPs purified from iodixanol gradients resulted in the production of neutralizing antibody responses while vaccination of humanized MHC class I transgenic mice resulted in the prodution of HCV core-specific CD8(+) T-cell responses. Furthermore, IgG purified from the sera of patients chronically infected with HCV genotypes 1a and 3a blocked the binding and entry of the HCV VLPs into Huh7 cells. These results show that our mammalian-cell-derived HCV VLPs induce humoral and HCV-specific CD8(+) T-cell responses and will have important implications for the development of a preventative vaccine for HCV.

Background/Aims Chronic infection with the hepatitis B virus (HBV) is strongly associated with the development of hepatocellular carcinoma but the mechanism by which this occurs is unknown. Numerous studies have focused on the HBV X protein showing that it activates signal transduction pathways while few have investigated these changes in HBV-replicating hepatocytes. Methods We utilized the recombinant adenovirus system to deliver a replication competent HBV genome into Huh7 and primary marmoset hepatocytes (PMH) to examine the effects of active viral replication on the regulation of Ras-ERK signal transduction and related pathways. Results Huh7 cells and PMHs replicating HBV demonstrated significant upregulation in phosphorylated ERK, Akt, c-myc together with increased p53, cyclin B1 and p21 cip1 expression and cell cycle progression to G2 phase in the absence of increased cell proliferation. Phosphorylation of the key cell survival kinase, Akt, was significantly increased, resulting in increased serine phosphorylation of the downstream target, GSK3-β. Conclusions These results demonstrated simultaneous activation of the MAP Kinase and Akt pathways in HBV-replicating hepatocytes that resulted in dysregulation in the control of cell cycle progression and which help explain the early pathogenic mechanisms that underlie malignant transformation associated with chronic hepatitis B infection.

In recurrent hepatitis C (HCV) post-liver transplantation (OLT), the combination of immunosuppressants and HCV is postulated to increase hepatocyte apoptosis and liver fibrosis. We evaluated hepatocyte apoptosis within the liver tissue of patients with postOLT HCV recurrence compared to HCV-negative individuals and correlated these findings with the effects of immunosuppressants on HCV-induced cell death and its inhibition in primary mouse hepatocytes (PMoH). Liver biopsies from patients with and without HCV were evaluated by immunohistochemistry for markers of apoptosis M30 CytoDEATH (M30) and cleaved PARP (clPARP). PMoH from C57BL/6 mice were infected with recombinant adenoviruses (rAdHCV) that expressed HCV proteins in hepatocytes. Infected cells were treated with cyclosporine, tacrolimus, sirolimus and/or MMF with or without pan-caspase inhibitor Q-VD-Oph. Cell viability and apoptosis were evaluated using crystal violet assays and Western immunoblots probed for cleaved caspase-3 (clCas3) and clPARP. Both M30 and clPARP were increased in the liver biopsies of patients with postOLT HCV recurrence compared to HCV-negative individuals. Treatment of rAdHCV-infected PMoH with cyclosporine, tacrolimus or sirolimus reduced cell viability and increased clCas3 and clPARP compared to rAdHCV infection alone. Addition of MMF to cyclosporine, tacrolimus or sirolimus further reduced cell viability and increased clCas3 and clPARP. Q-VD-Oph improved cell viability in HCV-infected PMoH treated with immunosuppressants alone and in combination and reduced clCas3 and clPARP by approximately 90%. Immunosuppressive agents, especially in combination, enhanced apoptosis in HCV-infected hepatocytes. The finding that Q-VD-Oph reversed hepatocyte death suggests that treatments utilizing apoptosis inhibition might reduce liver injury in postOLT HCV recurrence.

Prolonged treatment of chronic hepatitis B virus (HBV) infection with lamivudine ([−]-β- l -2′,3′-dideoxy-3′ thiacytidine) or famciclovir may select for viral mutants that are drug resistant due to point mutations in the polymerase gene. Determining whether such HBV mutants are sensitive to new antiviral agents is therefore important. We used a transient transfection system to compare the sensitivities of wild-type HBV and four lamivudine- and/or famciclovir-resistant HBV mutants to adefovir [9-(2-phosphonyl-methoxyethyl)-adenine; PMEA] and the nucleoside analogues (−)-β- d -2, 6-diaminopurine dioxolane (DAPD) and 2′-fluoro-5-methyl-β- l -arabinofuranosyluracil ( l -FMAU). The drug-resistant mutants contained amino acid substitutions in the polymerase protein. We found that the M550I and M550V plus L526M substitutions, which confer lamivudine resistance, did not confer cross-resistance to adefovir or DAPD, but conferred cross-resistance to l -FMAU. The M550V substitution in isolation conferred a similar phenotype to M550I, except that it did not confer significant resistance to l -FMAU. The L526M substitution, which is associated with famciclovir resistance, conferred cross-resistance to l -FMAU but not to adefovir or DAPD. Inhibition of HBV secretion by DAPD, l -FMAU, and adefovir did not always correlate with inhibition of the generation of intracellular HBV replicative intermediates, suggesting that these analogs may preferentially inhibit specific stages of the viral replication cycle.

Persistent hepatitis B virus infection can lead to the development of chronic liver disease, cirrhosis and primary hepatocellular carcinoma. The only therapy of confirmed benefit in chronic hepatitis B is interferon alpha, which can lead to long-term benefit in only a third of highly selected patients. A number of new therapeutic approaches are being actively developed for treating chronic hepatitis B, including the use of nucleoside analogues, cytokines, antisense oligonucleotides, ribozymes, dominant negative mutants and DNA-based vaccines. Recent clinical trials with the nucleoside analogues have identified several important challenges for future drug development, in which the gene therapy-based approach may prove useful either alone or most probably in various combinations. Future clinical trials should aim to address these challenges using the new therapies so that the goal of substantial and sustained inhibition of viral replication with the accompanying improvement in the underlying liver disease can be achieved.

Although many studies provide strong evidence supporting the development of HCV virus-like particle (VLP)-based vaccines, the fact that heterologous viral vectors and/or multiple dosing regimes are required to induce protective immunity indicates that it is necessary to improve their immunogenicity. In this study, we have evaluated the use of an anionic self-adjuvanting lipopeptide containing the TLR2 agonist Pam(2)Cys (E(8)Pam(2)Cys) to enhance the immunogenicity of VLPs containing the HCV structural proteins (core, E1 and E2) of genotype 1a. While co-formulation of this lipopeptide with VLPs only resulted in marginal improvements in dendritic cell (DC) uptake, its ability to concomitantly induce DC maturation at very small doses is a feature not observed using VLPs alone or in the presence of an aluminium hydroxide-based adjuvant (Alum). Dramatically improved VLP and E2-specific antibody responses were observed in VLP+E(8)Pam(2)Cys vaccinated mice where up to 3 doses of non-adjuvanted or traditionally alum-adjuvanted VLPs was required to match the antibody titres obtained with a single dose of VLPs formulated with this lipopeptide. This result also correlated with significantly higher numbers of specific antibody secreting cells that was detected in the spleens of VLP+E(8)Pam(2)Cys vaccinated mice and greater ability of sera from these mice to neutralise the binding and uptake of VLPs by Huh7 cells. Moreover, vaccination of HLA-A2 transgenic mice with this formulation also induced better VLP-specific IFN-γ-mediated responses compared to non-adjuvanted VLPs but comparable levels to that achieved when coadministered with complete freund's adjuvant. These results suggest overall that the immunogenicity of HCV VLPs can be significantly improved by the addition of this novel adjuvant by targeting their delivery to DCs and could therefore constitute a viable vaccine strategy for the treatment of HCV.

Hepatitis C (HCV)-infected patients have a poorer survival post-liver transplantation compared to patients transplanted for other indications, since HCV recurrence post-transplant is universal and commonly follows an aggressive course. There is increasing evidence that in the non-transplant setting, induction of hepatocyte apoptosis is one of the main mechanisms by which HCV drives liver inflammation and fibrosis, and that HCV proteins directly promote apoptosis. Recent studies have shown that post-liver transplant, there is a link between high levels of HCV replication, enhanced hepatocyte apoptosis and the subsequent development of rapidly progressive liver fibrosis. Although the responsible mechanisms remain unclear, it is likely that immunosuppressive drugs play an important role. It is well known that immunosuppressants impair immune control of HCV, thereby allowing increased viral replication. However there is also evidence that immunosuppressants may directly induce apoptosis and this may be facilitated by the presence of high levels of HCV replication. Thus HCV and immunosuppressants may synergistically interact to further enhance apoptosis and drive more rapid fibrosis. These findings suggest that modulation of apoptosis within the liver either by changing immunosuppressive therapy or the use of apoptosis inhibitors may help prevent fibrosis progression in patients with post-transplant HCV disease.

Background & Aims HCV patients who fail conventional interferon-based therapy have limited treatment options. Dendritic cells are central to the priming and development of antigen-specific CD4 + and CD8 + T cell immunity, necessary to elicit effective viral clearance. The aim of the study was to investigate the safety and efficacy of vaccination with autologous dendritic cells loaded with HCV-specific cytotoxic T cell epitopes. Methods We examined the potential of autologous monocyte-derived dendritic cells (MoDC), presenting HCV-specific HLA A2.1-restricted cytotoxic T cell epitopes, to influence the course of infection in six patients who failed conventional therapy. Dendritic cells were loaded and activated ex vivo with lipopeptides. In this phase 1 dose escalation study, all patients received a standard dose of cells by the intradermal route while sequential patients received an increased dose by the intravenous route. Results No patient showed a severe adverse reaction although all experienced transient minor side effects. HCV-specific CD8 + T cell responses were enumerated in PBMC by ELIspot for interferon-γ. Patients generated de novo responses, not only to peptides presented by the cellular vaccine but also to additional viral epitopes not represented in the lipopeptides, suggestive of epitope spreading. Despite this, no increases in ALT levels were observed. However, the responses were not sustained and failed to influence the viral load, the anti-HCV core antibody response and the level of circulating cytokines. Conclusions Immunotherapy using autologous MoDC pulsed with lipopeptides was safe, but was unable to generate sustained responses or alter the outcome of the infection. Alternative dosing regimens or vaccination routes may need to be considered to achieve therapeutic benefit.

The mechanism by which hepatitis B virus (HBV) infection causes severe inflammatory liver diseases is multifactorial and related to interactions with cell signaling pathways and the ensuing inflammatory response. Activation of JAK/STAT/SOCS signaling is essential for the induction of cellular antiviral responses, contributes to apoptosis and is negatively regulated by SOCS proteins. Recent reports have shown that SOCS3 activation interferes with viral protein expression and treatment response and thereby plays a major role in hepatitis virus infections. We analyzed the expression of SOCS3 in liver specimens from HBV-infected patients using immunohistochemistry (IHC) and determined the effect of HBV on STAT/SOCS signaling in functional cell culture experiments (HuH-7) using HBV-expressing adenoviral constructs (AdHBV). Increased expression of SOCS3 protein was identified in liver specimens from patients with chronic HBV-infection and this correlated with the severity of liver inflammation. In accordance with the IHC-findings, in vitro analyses demonstrated that HBV infection of HuH7 cells was associated with increased expression of SOCS3 protein. In spite of the over expression of its negative regulator SOCS3 we observed a constitutive activation of STAT3. SOCS1 levels were not increased while pSTAT1 was suppressed in HBV-infected HuH7 cells. Our results demonstrate that STAT/SOCS-signaling is dysregulated in HBV-infected hepatocytes both in vivo and in vitro and this correlated with the severity of liver inflammatory changes. This interference of STAT/SOCS signaling by HBV may result in an ineffective immune response against HBV and potentially contributes to viral pathogenesis, malignant transformation and may represent an important mechanism of viral persistence.

Objective: The hepatitis B virus X (HBx) protein plays an important role in the pathogenesis of hepatocellular carcinoma (HCC). One potential mechanism by which HBx can cause liver cancer may involve intracellular distribution and consecutively modulation of the proliferative important STAT/SOCS signaling with upregulation of STAT3. Methods: 153 Vietnamese HBV-infected patients, including 48 patients with HCC, were analyzed. HBx sequences were determined by sequencing and subcloned for functional experiments. Intracellular localization of HBx mutants was determined by immunofluorescence assays. The impact of HBx mutants on JAK/STAT/SOCS signaling was investigated using Western blot and PCR analyses. Results: In 4/48 HCC patients, truncated HBx together with full-length mutated HBx proteins were observed. Expression of HBx mutant proteins demonstrated an atypical nuclear and perinuclear localization. Functional experiments to determine the effect of HBx mutants on STAT/SOCS signaling demonstrated a significantly increased upregulation of STAT3 activation (p > 0.001) in comparison to wild-type (wt)-HBx. STAT1 was not activated either by wt-HBx or HBx mutants. Interestingly, SOCS1 and SOCS3 expression was not activated by wt-HBx and HBx mutants. Conclusions: Our results suggest that atypical nuclear/perinuclear localization of HBx mutants might be responsible for an enhanced activation of STAT3, inhibition of STAT1 and silencing of SOCS1/SOCS3 expression. This observation points to an active role of HBx mutants in hepatocarcinogenesis that involves dysregulation of STAT/SOCS signaling.

BackgroundChronic infection with hepatitis B virus (HBV) is a major factor associated with the development of hepatocellular carcinoma, but the mechanism by which this occurs is unknown. Treatment of chronic hepatitis B with lamivudine results in virological suppression and histological improvement; however, the role of lamivudine in preventing the development of hepatocellular carcinoma is less well defined. We recently reported that replication of HBV in a cell-culture system was associated with the upregulation of pERK, pAkt, pc-Myc, nuclear cyclin B1, p21cip1and p53 together with G2 cell cycle arrest.MethodsIn order to determine whether lamivudine is able to reverse the HBV-induced changes on signal transduction and cell cycle, we infected Huh7 cells with a recombinant adeno-HBV virus in the presence of 0–50 μM of lamivudine. Signal transduction and cell cycle regulatory proteins were analysed by western immunoblot.ResultsAlthough lamivudine was able to inhibit HBV replication, it failed to reverse the changes on ERK and Akt phosphorylation. Correspondingly, levels of phospho-GSK3β and p21cip1/waf1were increased, as were cyclin D1, cyclin B1, p53 and pc-Myc.ConclusionsLamivudine was ineffective in reversing the HBV-induced changes in signal transduction pathways and cell cycle regulatory proteins, indicating that the HBV-infected cells remained primed for oncogenic transformation despite viral suppression.

Background The role of neutralizing antibody (NAb) in determining response to antiviral therapy has not been established. Objective In this study we have analysed the kinetic's of the NAb response in patients with chronic hepatitis C who received antiviral therapy. Study design Seventeen patients infected with genotype 1, 2a/c or 3a hepatitis C virus (HCV) were enrolled, eight with a sustained virological response (SVR), five non-responders and four relapsers. Results The mean NAb titre required to neutralize 50% of the E1E2-pp in patients who achieved an SVR (294 ± S.D. 51), in relapsers (246 ± S.D. 61.7) and non-responders (286 ± S.D. 80.95) did not differ significantly between the patient groups and did not alter during the course of treatment ( P > 0.01). Genetic variation present before antiviral therapy was analysed by single strand conformation polymorphism (SSCP) and failed to demonstrate a significant difference in the mean number of amplified E1E2 DNA fragments from the serum of patients who achieved an SVR (3.15 ± S.D. 1.53), relapsers (2.8 ± S.D. 1.32) or non-responders (3.69 ± S.D. 1.75). The baseline serum HCV viral loads were also not significantly different between patients who achieved an SVR (1.4 × 10 6 copies/ml; ±S.D. 2.4 × 10 6 ), relapsers (1.3 × 10 7 copies/ml; ±S.D. 2.4 × 10 7 ) and non-responders (1.5 × 10 6 copies/ml; ±S.D. 1.1 × 10 6 ). Conclusion We have shown that neutralizing anti-HCVpp antibody is not associated with response to antiviral therapy. In addition, there was no correlation between baseline virological load, circulating viral quasispecies, NAb titres and final response to treatment.

The clinical management of chronic hepatitis B infection has entered a new era with the introduction and widespread use of oral nucleoside analogues such as lamivudine and nucleotides such as adefovir dipivoxil. From this, new challenges have now emerged in terms of preventing antiviral drug resistance, promoting viral clearance and improving long-term survival. For example, the natural history of nucleoside or nucleotide analogue-associated hepatitis B virus resistant mutants has yet to be determined. Furthermore, the increasing prevalence of HBeAg negative disease with its reduced response to current therapies represents an ongoing challenge to attempts to improve standard of care. There is increasing recognition of the pivotal role that viral load and genotype, and their complex interactions with the host immune response, play in determining the outcome of these treatment interventions. The purpose of this paper is to highlight several key factors that should be considered in the context of future clinical research and management of chronic hepatitis B.