Antiviral Treatment Strategies Research Articles

Simplified Antiviral Treatment Strategy for Hepatitis C in Ukraine

Simplified Antiviral Treatment Strategy for Hepatitis C in Ukraine

Antiviral treatment for chronic hepatitis B: Safety, effectiveness, and prognosis.

The goal of chronic hepatitis B (CHB) therapy is to improve the patient prognosis through the sustained inhibition of viral replication. However, due to the uncertainty and potentially unlimited duration of the treatment course, nucleus(t)ide analogue (NA) resistance and safety, financial costs and patient compliance, different endpoints of antiviral treatment have been proposed in CHB prevention and treatment guidelines. Different treatment endpoints are closely associated with the safety of drug withdrawal and improvements in prognosis. Antiviral treatment suppresses HBV DNA replication, drug withdrawal leads to relapse, and long-term treatment causes drug safety and resistance issues. Although hepatitis B e antigen seroconversion based on HBV DNA inhibition is considered as “a satisfactory endpoint”, drug withdrawal still leads to high relapse rates. Hepatitis B surface antigen (HBsAg) clearance is the “ideal endpoint” in terms of the safety of drug withdrawal and improvements in prognosis. However, the HBsAg clearance rate is low using the conventional single drug treatment and fixed course regimens. Recently, the application of an “optimized antiviral treatment strategy” has improved the HBsAg clearance rate, and make an “ideal endpoint” possible. This article reviews the different antiviral treatment endpoints in terms of the safety of drug withdrawal, improvements in prognosis and relevant advances.

Simian-Human Immunodeficiency Virus SHIV.CH505-Infected Infant and Adult Rhesus Macaques Exhibit Similar Env-Specific Antibody Kinetics, despite Distinct T-Follicular Helper and Germinal Center B Cell Landscapes.

Global elimination of pediatric human immunodeficiency virus (HIV) infections will require the development of novel immune-based approaches, and understanding infant immunity to HIV is critical to guide the rational design of these intervention strategies. Despite their immunological immaturity, chronically HIV-infected children develop broadly neutralizing antibodies (bnAbs) more frequently and earlier than adults do. However, the ontogeny of humoral responses during acute HIV infection is poorly defined in infants and challenging to study in human cohorts due to the presence of maternal antibodies. To further our understanding of age-related differences in the development of HIV-specific immunity during acute infection, we evaluated the generation of virus-specific humoral immune responses in infant (n = 6) and adult (n = 12) rhesus macaques (RMs) infected with a transmitted/founder (T/F) simian-human immunodeficiency virus (SHIV) (SHIV.C.CH505 [CH505]). The plasma HIV envelope-specific IgG antibody kinetics were similar in SHIV-infected infant and adult RMs, with no significant differences in the magnitude or breadth of these responses. Interestingly, autologous tier 2 virus neutralization responses also developed with similar frequencies and kinetics in infant and adult RMs, despite infants exhibiting significantly higher follicular T helper cell (Tfh) and germinal center B cell frequencies than adults. Finally, we show that plasma viral load was the strongest predictor of the development of autologous virus neutralization in both age groups. Our results indicate that the humoral immune response to SHIV infection develops with similar kinetics among infant and adult RMs, suggesting that the early-life immune system is equipped to respond to HIV-1 and promote the production of neutralizing HIV antibodies.IMPORTANCE There is a lack of understanding of how the maturation of the infant immune system influences immunity to HIV infection or how these responses differ from those of adults. Improving our knowledge of infant HIV immunity will help guide antiviral intervention strategies that take advantage of the unique infant immune environment to successfully elicit protective immune responses. We utilized a rhesus macaque model of SHIV infection as a tool to distinguish the differences in HIV humoral immunity in infants versus adults. Here, we demonstrate that the kinetics and quality of the infant humoral immune response to HIV are highly comparable to those of adults during the early phase of infection, despite distinct differences in their Tfh responses, indicating that slightly different mechanisms may drive infant and adult humoral immunity.

Subversion of Immune Response by Human Cytomegalovirus.

Human cytomegalovirus (HCMV) is the most common cause of congenital infections and is an important pathogen in immunocompromised individuals. Despite a robust host immune system, HCMV able to replicate, evade host defenses, establish latency for life. A significant portion of HCMV genome dedicated to encode gene products for modulation of host immune response. Growing number of HCMV gene products are being recognized to play role in immune evasion. Information on viral immune evasion mechanisms by which HCMV persists in host will be useful in devising antiviral intervention strategies and development of new vaccines. This minireview provides a brief overview of immune evasion strategy adapted by HCMV by utilizing its gene products in modulation of host immune response.

Zika virus: Molecular responses and tissue tropism in the mammalian host.

Zika virus (ZIKV) outbreaks have raised alarm because of reports of congenital Zika virus syndrome in infants. The virus is also known to cause the debilitating Guillain-Barré syndrome in adults. As a result, extensive research has been carried out on the virus over the past few years. To study the molecular responses of viral infectivity in mammals, in vitro two-dimensional and three-dimensional cellular models have been employed. The in vivo models of mouse, pig, chicken, and nonhuman primates are primarily used to investigate the teratogenicity of the virus, to study effects of the virus on specific tissues, and to study the systemic effects of a proposed antiviral agent. The virus exhibits wide tissue tropism in the mammalian host. The major host tissues of viral persistence and propagation are neural tissue, ocular tissue, testicular tissue and placental tissue. An understanding of the function of viral components, viral replication cycle, and the molecular responses elicited in the host tissues is imperative for designing antiviral treatment strategies and for development of vaccines. This review provides an update on ZIKV research models and mammalian host responses with respect to ZIKV tissue infection.

Increasing the Capping Efficiency of the Sindbis Virus nsP1 Protein Negatively Affects Viral Infection.

Alphaviruses are arthropod-borne RNA viruses that are capable of causing severe disease and are a significant burden to public health. Alphaviral replication results in the production of both capped and noncapped viral genomic RNAs (ncgRNAs), which are packaged into virions during infections of vertebrate and invertebrate cells. However, the roles that the ncgRNAs play during alphaviral infection have yet to be exhaustively characterized. Here, the importance of the ncgRNAs to alphaviral infection was assessed by using mutations of the nsP1 protein of Sindbis virus (SINV), which altered the synthesis of the ncgRNAs during infection by modulating the protein's capping efficiency. Specifically, point mutations at residues Y286A and N376A decreased capping efficiency whereas a point mutation at D355A increased the capping efficiency of the SINV genomic RNA during genuine viral infection. Viral growth kinetics levels were significantly reduced for the D355A mutant relative to wild-type infection, whereas the Y286A and N376A mutants showed modest decreases in growth kinetics. Overall genomic translation and nonstructural protein accumulation were found to correlate with increases and decreases in capping efficiency. However, genomic, minus-strand, and subgenomic viral RNA synthesis were largely unaffected by the modulation of alphaviral capping activity. In addition, translation of the subgenomic alphaviral RNA (vRNA) was found not to be impacted by changes in capping efficiency. The mechanism by which the decreased presence of ncgRNAs reduced viral growth kinetics levels operated through the impaired production of viral particles. Collectively, these data illustrate the importance of ncgRNAs to viral infection and suggest that they play an integral role in the production of viral progeny.IMPORTANCE Alphaviruses have been the cause of both localized outbreaks and large epidemics of severe disease. Currently, there are no strategies or vaccines which are either safe or effective for preventing alphaviral infection or treating alphaviral disease. This deficit of viable therapeutics highlights the need to better understand the mechanisms behind alphaviral infection in order to develop novel antiviral strategies for treatment of alphaviral disease. In particular, this report details a previously uncharacterized aspect of the alphaviral life cycle: the importance of noncapped genomic viral RNAs for alphaviral infection. This offers new insights into the mechanisms of alphaviral replication and the impact of the noncapped genomic RNAs on viral packaging.

Influenza A/H3N2 virus infection in immunocompromised ferrets and emergence of antiviral resistance.

Influenza viruses can cause severe life threatening infections in high-risk patients, including young children, the elderly and patients with compromised immunity due to underlying medical conditions or immunosuppressive treatment. The impaired immunity of these patients causes prolonged virus infection and combined with antiviral treatment facilitates the emergence of viruses with resistance mutations. The diverse nature of their immune status makes them a challenging group to study the impact of influenza virus infection and the efficacy of antiviral therapy. Immunocompromised ferrets may represent a suitable animal model to assess influenza virus infection and antiviral treatment strategies in immunocompromised hosts. Here, ferrets were given a daily oral solution of mycophenolate mofetil, tacrolimus and prednisolone sodium phosphate to suppress their immune system. Groups of immunocompromised and immunocompetent ferrets were inoculated with an A/H3N2 influenza virus and were subsequently treated with Oseltamivir or left untreated. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was performed on the throat and nose specimens to study virus replication during the course of infection. All immunocompromised ferrets had prolonged presence of viral RNA and a higher total amount of virus shedding compared to the immunocompetent ferrets. Although Oseltamivir reduced the total amount of virus shedding from the nose and throat of treated ferrets, it also resulted in the emergence of the neuraminidase R292K resistance substitution in all these animals, as determined by mutation specific RT-PCR and next-generation sequencing. No additional mutations that could be associated with the emergence of the R292K resistance mutation were detected. The immunocompromised ferret model can be used to study A/H3N2 virus shedding and is a promising model to study new antiviral strategies and the emergence of antiviral resistance in immunocompromised hosts.

An easy, rapid, and sensitive method for detection of drug-resistant influenza virus by using a sialidase fluorescent imaging probe, BTP3-Neu5Ac.

Immunochromatographic kits and RT-PCR are widely used as diagnostic tools for influenza detection in clinical and hygiene fields. Immunochromatographic kits are useful for differential typing of influenza A and influenza B but cannot show if the detected virus strains have acquired drug resistance against neuraminidase inhibitors that target sialidase activity of viral neuraminidase. Although RT-PCR enables determination of drug-resistant mutants, its efficacy is limited to viruses carrying a known substitution in their neuraminidase genome sequence. In the present study, an easy, rapid and sensitive method for detection of drug-resistant influenza viruses regardless of major antigenic changes or genomic mutations was developed. By using the method in combination with virus-concentrated membranes in centrifugal filter units and a sialidase imaging probe, 2-(benzothiazol-2-yl)-4-bromophenyl-N-acetylneuraminic acid (BTP3-Neu5Ac), sialidase activity of influenza neuraminidase was visualized on membranes by the green fluorescence of produced hydrophobic BTP3 under UV irradiation with a handheld UV flashlight. Fluorescence images in the presence or absence of neuraminidase inhibitors clearly discriminated drug-resistant influenza viruses from drug-sensitive ones. The assay can be done within 15 min. The detection sensitivity was shown to be equal to or higher than the sensitivities of commercial immunochromatographic kits. The assay will be a powerful tool for screening and monitoring of emerging drug-resistant influenza viruses and would help clinicians decide effective antiviral treatment strategies when such mutants have become prevalent.

Mathematical Analysis of Viral Replication Dynamics and Antiviral Treatment Strategies: From Basic Models to Age-Based Multi-Scale Modeling.

Viral infectious diseases are a global health concern, as is evident by recent outbreaks of the middle east respiratory syndrome, Ebola virus disease, and re-emerging zika, dengue, and chikungunya fevers. Viral epidemics are a socio-economic burden that causes short- and long-term costs for disease diagnosis and treatment as well as a loss in productivity by absenteeism. These outbreaks and their socio-economic costs underline the necessity for a precise analysis of virus-host interactions, which would help to understand disease mechanisms and to develop therapeutic interventions. The combination of quantitative measurements and dynamic mathematical modeling has increased our understanding of the within-host infection dynamics and has led to important insights into viral pathogenesis, transmission, and disease progression. Furthermore, virus-host models helped to identify drug targets, to predict the treatment duration to achieve cure, and to reduce treatment costs. In this article, we review important achievements made by mathematical modeling of viral kinetics on the extracellular, intracellular, and multi-scale level for Human Immunodeficiency Virus, Hepatitis C Virus, Influenza A Virus, Ebola Virus, Dengue Virus, and Zika Virus. Herein, we focus on basic mathematical models on the population scale (so-called target cell-limited models), detailed models regarding the most important steps in the viral life cycle, and the combination of both. For this purpose, we review how mathematical modeling of viral dynamics helped to understand the virus-host interactions and disease progression or clearance. Additionally, we review different types and effects of therapeutic strategies and how mathematical modeling has been used to predict new treatment regimens.

E1B-55K-Mediated Regulation of RNF4 SUMO-Targeted Ubiquitin Ligase Promotes Human Adenovirus Gene Expression.

Human adenovirus (HAdV) E1B-55K is a multifunctional regulator of productive viral replication and oncogenic transformation in nonpermissive mammalian cells. These functions depend on E1B-55K's posttranslational modification with the SUMO protein and its binding to HAdV E4orf6. Both early viral proteins recruit specific host factors to form an E3 ubiquitin ligase complex that targets antiviral host substrates for proteasomal degradation. Recently, we reported that the PML-NB-associated factor Daxx represses efficient HAdV productive infection and is proteasomally degraded via a SUMO-E1B-55K-dependent, E4orf6-independent pathway, the details of which remained to be established. RNF4, a cellular SUMO-targeted ubiquitin ligase (STUbL), induces ubiquitinylation of specific SUMOylated proteins and plays an essential role during DNA repair. Here, we show that E1B-55K recruits RNF4 to the insoluble nuclear matrix fraction of the infected cell to support RNF4/Daxx association, promoting Daxx PTM and thus inhibiting this antiviral factor. Removing RNF4 from infected cells using RNA interference resulted in blocking the proper establishment of viral replication centers and significantly diminished viral gene expression. These results provide a model for how HAdV antagonize the antiviral host responses by exploiting the functional capacity of cellular STUbLs. Thus, RNF4 and its STUbL function represent a positive factor during lytic infection and a novel candidate for future therapeutic antiviral intervention strategies.IMPORTANCE Daxx is a PML-NB-associated transcription factor that was recently shown to repress efficient HAdV productive infection. To counteract this antiviral measurement during infection, Daxx is degraded via a novel pathway including viral E1B-55K and host proteasomes. This virus-mediated degradation is independent of the classical HAdV E3 ubiquitin ligase complex, which is essential during viral infection to target other host antiviral substrates. To maintain a productive viral life cycle, HAdV E1B-55K early viral protein inhibits the chromatin-remodeling factor Daxx in a SUMO-dependent manner. In addition, viral E1B-55K protein recruits the STUbL RNF4 and sequesters it into the insoluble fraction of the infected cell. E1B-55K promotes complex formation between RNF4- and E1B-55K-targeted Daxx protein, supporting Daxx posttranslational modification prior to functional inhibition. Hence, RNF4 represents a novel host factor that is beneficial for HAdV gene expression by supporting Daxx counteraction. In this regard, RNF4 and other STUbL proteins might represent novel targets for therapeutic intervention.

Henipavirus Infection: Natural History and the Virus-Host Interplay

The review summarizes the history of the emergence of the Henipviruses, provides a general introduction of their molecular biology and the efforts to develop antiviral treatment strategies, including the successful development of a veterinary vaccine. Paramyxoviridae, genus Henipavirus comprises emerging pathogens detected in Southeast Asia, Australia and Africa. Henipaviruses are enveloped with non-segmented, negative-sense, single-stranded RNA molecules and are distinguished from other Paramyxoviruses by a substantially larger RNA genome. Hendra virus (HeV) and Nipah virus (NiV) are the causative agents of zoonotic disease outbreaks in Australia and Asia, respectively, and are indigenous to fruit bats. HeV and NiV can cause severe diseases with neurological and respiratory manifestations in humans and intermediate hosts but do not cause a disease in the natural bat host. The primary spill-over reservoir for humans to come into contact with HeV in Australia and NiV in Malaysia are horses and pigs, respectively. Direct bat-to-human transmissions are reported from NiV infections in Bangladesh. The life cycle of the Henipaviruses includes replication of the RNA genome in the cytoplasm, a nuclear phase of the viral matrix protein, and assembly and budding of infectious virions at the cell membrane. To prevent the establishment of an antiviral cellular state, Henipaviruses encode structural and non-structural viral proteins able to antagonize the interferon type I response. For the development of antiviral treatments, strategies are under investigation to interfere with viral replication and entry, and finally to generate antibodies suitable for passive immunotherapy. A veterinary vaccine against HeV has been in use since 2012 to protect horses, and hence interrupts the transmission pathway to humans. The successful development of a veterinary vaccine based on a soluble HeV envelope protein may set the path for the development of an optimal vaccine against the medically relevant NiV. Henipaviruses are widely distributed, predominantly using fruit bats as their natural hosts. Their broad species tropism, the capacity to exploit different transmission pathways, and the ability to cause severe diseases in humans and intermediate hosts highlight the need for potent antiviral strategies or vaccines. The characterization of the viral gene products, interacting host factors and immune targets is essential for the development of antiviral strategies to be able to overcome the threat of these emerging pathogens.

The role of host DNA ligases in hepadnavirus covalently closed circular DNA formation.

Hepadnavirus covalently closed circular (ccc) DNA is the bona fide viral transcription template, which plays a pivotal role in viral infection and persistence. Upon infection, the non-replicative cccDNA is converted from the incoming and de novo synthesized viral genomic relaxed circular (rc) DNA, presumably through employment of the host cell’s DNA repair mechanisms in the nucleus. The conversion of rcDNA into cccDNA requires preparation of the extremities at the nick/gap regions of rcDNA for strand ligation. After screening 107 cellular DNA repair genes, we herein report that the cellular DNA ligase (LIG) 1 and 3 play a critical role in cccDNA formation. Ligase inhibitors or functional knock down/out of LIG1/3 significantly reduced cccDNA production in an in vitro cccDNA formation assay, and in cccDNA-producing cells without direct effect on viral core DNA replication. In addition, transcomplementation of LIG1/3 in the corresponding knock-out or knock-down cells was able to restore cccDNA formation. Furthermore, LIG4, a component in non-homologous end joining DNA repair apparatus, was found to be responsible for cccDNA formation from the viral double stranded linear (dsl) DNA, but not rcDNA. In conclusion, we demonstrate that hepadnaviruses utilize the whole spectrum of host DNA ligases for cccDNA formation, which sheds light on a coherent molecular pathway of cccDNA biosynthesis, as well as the development of novel antiviral strategies for treatment of hepatitis B.

Intracellular immunization against HIV infection with an intracellular antibody that mimics HIV integrase binding to the cellular LEDGF protein

Preventing the protein-protein interaction of the cellular chromatin binding protein Lens Epithelium-Derived Growth Factor (LEDGF) and human immunodeficiency virus (HIV) integrase is an important possible strategy for anti-viral treatment for AIDS. We have used Intracellular Antibody Capture technology to isolate a single VH antibody domain that binds to LEDGF. The crystal structure of the LEDGF-VH complex reveals that the single domain antibody mimics the effect of binding of HIV integrase to LEDGF which is crucial for HIV propagation. CD4-expressing T cell lines were constructed to constitutively express the LEDGF-binding VH and these cells showed interference with HIV viral replication, assayed by virus capsid protein p24 production. Therefore, pre-conditioning cells to express antibody fragments confers effective intracellular immunization for preventing chronic viral replication and can be a way to prevent HIV spread in infected patients. This raises the prospect that intracellular immunization strategies that focus on cellular components of viral integrase protein interactions can be used to combat the problems associated with latent HIV virus re-emergence in patients. New genome editing development, such as using CRISPR/cas9, offer the prospect intracellularly immunized T cells in HIV+ patients.

Astragalus polysaccharides inhibit avian infectious bronchitis virus infection by regulating viral replication

The avian coronavirus causes infectious bronchitis (IB), which is one of the most serious diseases affecting the avian industry worldwide. However, there are no effective strategies for controlling the IB virus (IBV) at present. Therefore, development of novel antiviral treatment strategies is urgently required. As reported, astragalus polysaccharides (APS) have potential antiviral effects against several viruses; however, the antiviral effect of APS against IBV remains unclear. In this study, we explored whether APS had the potential to inhibit IBV infectionby utilizing several in vitro experimental approaches. To this end, the effect of APS on the replication of IBV was examined in chicken embryo kidney (CEK) cells. Viral titers were calculated by using the plaque formation assay, and the cytotoxicity of APS was tested by utilizing a Cell Counting Kit-8 assay. The expression of viral mRNA and cytokine (IL-1β, IL-6, IL-8 and TNF-α) mRNA transcripts was determined by real-time quantitative RT-PCR(qRT-PCR). IBV titers in infected CEK cells treated with APS were significantly reduced in a dose-dependent manner, indicating that APS inhibited IBV replication in vitro. We also found that the decreased viral replication after APS treatment was associated with reduced mRNA levels of the cytokines IL-1B, IL-6, IL-8 and TNF-α. In conclusion, these results suggest that APS exhibit antiviral activities against IBV and it may represent a potential therapeutic agent for inhibiting the replication of IBV.

Cost-effectiveness of community-based treatment of chronic hepatitis B in China

Objective: Since eliminating hepatitis B in China would need considerable public health resources, the economics problem of the strategy of community-based antiviral treatment for chronic hepatitis B (CHB) has become an important issue. The cost-effectiveness and affordability of the strategy were evaluated in this study. Methods: According to the advocacy on eliminating hepatitis B by WHO and the comprehensive protocol of community based prevention of major infectious diseases and the guideline for CHB prevention and treatment in China, the decision analytic Markov model was constructed with the parameters from national surveys or Meta-analysis. A cohort population aged 20-59 years was used as study subjects. The strategy of CHB antiviral treatment was compared with the strategies of hepatitis B vaccination and non-intervention, respectively. The costs and disability-adjusted life years (QALYs) of the strategies were calculated from the societal and payer perspectives. The incremental cost-effectiveness ratio (ICER) and the cost-effectiveness ratio (CER) were calculated for the comparison of the strategies. One-way and probability sensitivity analysis were performed for uncertainty of the results. And the cost-effectiveness and affordability curves were introduced to estimate the budget impact on the strategies. Results: In the Chinese aged 20-59 years, the ICER of CHB antiviral treatment was 37 598.6 yuan (RMB) per QALYs and the ICERs were smaller in the low age groups, indicating that the antiviral treatment strategy is cost-effective and low age groups should be the priority population. The ICER of hepatitis B vaccination was -64 000.0 yuan (RMB) per QALYs, indicating that hepatitis B vaccination is cost saving. The CER of CHB antiviral treatment ranged from 731.8 to 1 813.3 yuan (RMB) per QALYs compared with hepatitis B vaccination, and the CER of CHB antiviral treatment was higher than that of hepatitis B vaccination in all age groups, indicating that hepatitis B vaccination would be more cost-effective than CHB antiviral treatment. The price of antiviral drug, entercavir, can influence the cost effectiveness of CHB antiviral treatment. If the price of entercavir declined half, CHB antiviral treatment would be cost-saving. The probability sensitivity analysis showed that people's willing to pay for CHB antiviral treatment should not be ignored, although the results of economics evaluation of CHB antiviral treatment were reliable. The results of affordability analysis indicated that the antiviral treatment strategy could not be implemented with the budget lower than 30 million yuan (RMB), the probability of implementing the strategy was 42.6% if the budget reaches 127 million yuan (RMB), and only when the budget reaches 269 million yuan (RMB), the goal of CHB antiviral treatment strategy can be fully realized. Conclusions: Although the strategy of CHB antiviral treatment as prevention in Chinese aged 20-59 years is cost-effective, it is not an appropriate public health measure due to the high cost. The cost effectiveness would be higher by conducting hepatitis B vaccination and then antiviral treatment in susceptible population.

Infections due to alphaherpesviruses in early post-transplant period after allogeneic haematopoietic stem cell transplantation: Results of a 5-year survey

BackgroundInfections caused by human α-herpesviruses usually have a benign course with recurrencies. However, they may become dangerous in immunocompromised hosts. In this case, molecular methods constitute a reliable diagnostic tool enabling rapid assessment of the efficacy of antiviral treatment strategies. ObjectivesWe estimated the frequency of alphaherpesviral DNAemia and the viral load during early post-transplantation period after alloHSCT; we also analyzed association of the DNAemia and chosen parameters of the patients. Study designA cohort of 190 alloHSCT recipients from two hospitals in Warsaw, Poland, was examined weekly during 100-day early post-transplantation period using quantitative real time PCR assays. A total of 2475 sera samples were evaluated for the presence of α-herpesviral DNA in patients, of whom 117 (62%) received unrelated grafts, while the remaining 73 (38%) received grafts from sibling donors. All patients received standard antiviral prophylaxis with acyclovir. In the examined group, anti-HSV-1, anti-HSV-2 and anti-VZV IgGs were examined prior to transplantation, ResultsWithin the study period, DNA of α-herpesviruses was detected in 44 patients (23.2%). Most patients tested positive for HSV-1 DNA (43 patients, 22.6%), single patient for HSV-2, and no patient positive for VZV. Clinical symptoms such as pneumonia, skin changes, elevated levels of aminotransferases were observed in five patients, four of these patients presented symptoms of GvHD at the same time. (2,6%). Statistics shows that GvHD (P<0.001) and matched unrelated donor as a source of HSCT (P=0.048) are associated with the development of HSV-1 DNAemia. ConclusionsAlthough our data demonstrate frequent reactivation of HSV-1 in the early post-transplant period, the rate of symptomatic infections was low. We did not find association between HSV-1 viremia and mortality, but significant association with GvHD and donor source was observed.

Hepatitis C virus infection in maintenance hemodialysis patients: recommendations for diagnostics and treatment.

Hepatitis C virus (HCV) infection is highly prevalent among patients treated with maintenance hemodialysis and is an important cause of morbidity and mortality. It is necessary to determine the HCV genotype and the viral load to monitor the clinical and laboratory features and to establish an optimal antiviral treatment strategy. Antiviral treatments are presented with a standard interferon-based regimen and new direct-acting antiviral agents. The advent of direct-acting antivirals has improved the efficacy and safety of HCV treatment for most patients, even in difficult-to-treat populations such as patients on hemodialysis. HCV treatment with direct-acting antivirals in hemodialysis patients is highly effective, with viral eradication rates similar to those seen in patients without chronic kidney disease and with acceptable adverse event profiles.

Autophagy promoted infectious kidney and spleen necrosis virus replication and decreased infectious virus yields in CPB cell line

Autophagy plays important functions in viral replication and pathogenesis. In this study, we investigated the role of autophagy in the replication of infectious kidney and spleen necrosis virus (ISKNV), an agent that has caused devastating losses in Chinese perch (Siniperca chuatsi) industry. We found that ISKNV infection triggered the complete autophagic process, as demonstrated by microtubule-associated protein 1 light chain 3B II (LC3B-II) conversion, an increased accumulation of punctate GFP-LC3-expressing cells, a higher number of autophagosome-double-membrane vesicles in the cytoplasm, and increased levels of autophagic flux in CPB cells. Then, we investigated the role of autophagy in the process of ISKNV replication. Results showed that inducing autophagy by rapamycin promoted ISKNV replication and proteins synthesis but decreased extracellular virus yields. While, blocking autophagosome-lysosome fusion by chloroquine (CQ) promoted infectious virus yields in culture supernatant. These results offer insight into the complex interactions between ISKNV and host cell, providing new insights into viral pathogenesis and antiviral treatment strategies.

An experimental evaluation of drug-induced mutational meltdown as an antiviral treatment strategy.

The rapid evolution of drug resistance remains a critical public health concern. The treatment of influenza A virus (IAV) has proven particularly challenging, due to the ability of the virus to develop resistance against current antivirals and vaccines. Here, we evaluate a novel antiviral drug therapy, favipiravir, for which the mechanism of action in IAV involves an interaction with the viral RNA-dependent RNA polymerase resulting in an effective increase in the viral mutation rate. We used an experimental evolution framework, combined with novel population genetic method development for inference from time-sampled data, to evaluate the effectiveness of favipiravir against IAV. Evaluating whole genome polymorphism data across 15 time points under multiple drug concentrations and in controls, we present the first evidence for the ability of IAV populations to effectively adapt to low concentrations of favipiravir. In contrast, under high concentrations, we observe population extinction, indicative of mutational meltdown. We discuss the observed dynamics with respect to the evolutionary forces at play and emphasize the utility of evolutionary theory to inform drug development.

Clinical Significance of Quantitative HBsAg Titres and its Correlation With HBV DNA Levels in the Natural History of Hepatitis B Virus Infection

Quantification of serum hepatitis B antigen (HBsAg) is an important test that marks active infection with hepatitis B and helps in the prediction of the clinical outcome and management of hepatitis B virus (HBV) infection. Correlation with HBV DNA quantitative levels may help in developing strategies for antiviral treatment. This study is aimed to evaluate HBsAg titres in various phase of HBV infection in HBsAg positive patients, and its correlation with HBV DNA viral load levels. 976 HBV related patients were analysed in this retrospective cross-sectional study. Patients were categorised on the basis of the phase of HBV infection: immune tolerant phase (IT, n=123), immune clearance phase (IC, n=192), low-replicative phase (LR, n=476), and HBeAg-negative hepatitis (ENH, n=185). HBsAg titres were quantified and correlated with HBV-DNA levels and clinical parameters. Median HBsAg titres were different between each phases of HBV infection (P<0.001): (4.62log10IU/ml), IC (3.88log10IU/ml), LR (2.76log10IU/ml) and ENH (2.94log10IU/ml). HBsAg and HBV DNA levels showed significant correlation in the whole group (r=0.694, P<0.001), and this was also observed in different phases of HBV infection. Strong correlation in IT phase (r=0.603, P<0.001) and IC phase (r=0.523, P<0.001), moderate in LR phase (r=0.362, P<0.001) and weak in ENH (r=0.110, P=0.04). No correlation was observed between serum HBsAg levels and biochemical parameters. The study demonstrated significant difference in the median baseline values of serum HBsAg titres in different phases of HBV infection and provides additional information in understanding the natural history of HBV-infection.