High Replication Rate Research Articles

Rapid response of benthic deep-sea microbes (viruses and prokaryotes) to an intense dense shelf water cascading event in a submarine canyon of the NW Mediterranean Sea

A major dense shelf water cascading (DSWC) event occurred in 2005 downward the Cap de Creus Canyon (Gulf of Lion, NW Mediterranean Sea), which caused a significant change in environmental parameters and biological components. Here we describe the effects of this DSWC event on benthic microbes and on virus-prokaryote interactions, and we explore their implications on the functioning of the canyon’s ecosystem. We collected sediment samples at increasing depths inside the canyon and in the adjacent deep continental margin over a period of five years, i.e. during and after the DSWC event, which led to the deposition of high amounts of fresh and labile organic matter that stimulated C production by benthic prokaryotes and increased their abundance and biomass. The enhanced prokaryotic metabolism, still evident 6 months after the DSWC event, was associated with high viral replication rates and prokaryotic mortality, which released 3.4–6.3 gC m−2 over such a 6 months period. Such values are up to 3-times higher than the yearly C-flux to the seafloor reported in this area in years without DSWC. We conclude that DSWC can significantly enhance benthic prokaryotic metabolism and C cycling through viral-induced prokaryotic mortality.

Recent advances in understanding DNA replication: cell type-specific adaptation of the DNA replication program.

DNA replication is an essential process occurring prior to cell division. Cell division coupled to proliferation ensures the growth and renewal of a large variety of specialized cell types generated during embryonic development. Changes in the DNA replication program occur during development. Embryonic undifferentiated cells show a high replication rate and fast proliferation, whereas more differentiated cells are characterized by reduced DNA synthesis and a low proliferation rate. Hence, the DNA replication program must adapt to the specific features of cells committed to different fates. Recent findings on DNA synthesis regulation in different cell types open new perspectives for developing efficient and more adapted therapies to treat various diseases such as genetic diseases and cancer. This review will put the emphasis on recent progress made in this field.

Computer analysis of resistance mutations to HCV NS5A antivirals

Background: Hepatitis C virus (HCV) is characterized by a high replication rate associated with a high rate of genetic errors because viral RNA polymerase lacks correction systems. It is therefore not surprising that mutations that occur naturally in the HCV genome in some cases coincide with positions involving amino acids responsible for resistance to direct-acting antivirals (DAAs). Thus, it is important to determine whether mutations produce conformational changes that interfere with drug-target binding to prevent potential therapeutic failures. To develop computational analysis of the mutations of resistance to DAAs in the NS5A gene to identify conformational change of the protein Methods & Materials: Resistance mutations to DAAs described in the literature were represented in the three-dimensional structure of domain I of the NS5A protein. We used the program PyMol (http://pymol.sourceforge.net). We also used the structure Con1 isolate of HCV-1b extracted from the database Protein DataBank (www.ebi.ac.uk/pdbsum), with code (3FQQ). Results: Resistance mutations have been described in the N-terminal region of domain I of NS5A at amino acid positions 23, 28, 30, 31, 32, 54, 58 and 93. The mutations associated with resistance to DAAs were found where the surfaces of the two monomers forming NS5A dimer I were contacted. Conclusion: The mutations associated with the analyzed resistance were located close to the binding site of daclatasvir (DCV), and ledipasvir (LDV), which would affect the drug-target binding and would have a possible impact on the treatment with DAAs.

Estimating the Reproducibility of Experimental Philosophy

Responding to recent concerns about the reliability of the published literature in psychology and other disciplines, we formed the X-Phi Replicability Project (XRP) to estimate the reproducibility of experimental philosophy (osf.io/dvkpr). Drawing on a representative sample of 40 x-phi studies published between 2003 and 2015, we enlisted 20 research teams across 8 countries to conduct a high-quality replication of each study in order to compare the results to the original published findings. We found that x-phi studies – as represented in our sample – successfully replicated about 70% of the time. We discuss possible reasons for this relatively high replication rate in the field of experimental philosophy and offer suggestions for best research practices going forward.

Systematic Mendelian randomization framework elucidates hundreds of CpG sites which may mediate the influence of genetic variants on disease.

We have undertaken a systematic Mendelian randomization (MR) study using methylation quantitative trait loci (meQTL) as genetic instruments to assess the relationship between genetic variation, DNA methylation and 139 complex traits. Using two-sample MR, we identified 1148 associations across 61 traits where genetic variants were associated with both proximal DNA methylation (i.e. cis-meQTL) and complex trait variation (P < 1.39 × 10−08). Joint likelihood mapping provided evidence that the genetic variant which influenced DNA methylation levels for 348 of these associations across 47 traits was also responsible for variation in complex traits. These associations showed a high rate of replication in the BIOS QTL and UK Biobank datasets for 14 selected traits, as 101 of the attempted 128 associations survived multiple testing corrections (P < 3.91 × 10−04). Integrating expression quantitative trait loci (eQTL) data suggested that genetic variants responsible for 306 of the 348 refined meQTL associations also influence gene expression, which indicates a coordinated system of effects that are consistent with causality. CpG sites were enriched for histone mark peaks in tissue types relevant to their associated trait and implicated genes were enriched across relevant biological pathways. Though we are unable to distinguish mediation from horizontal pleiotropy in these analyses, our findings should prove valuable in prioritizing candidate loci where DNA methylation may influence traits and help develop mechanistic insight into the aetiology of complex disease.

Clinical isolates of the modern Mycobacterium tuberculosis lineage 4 evade host defense in human macrophages through eluding IL-1\u03b2-induced autophagy

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), has infected over 1.7 billion people worldwide and causes 1.4 million deaths annually. Recently, genome sequence analysis has allowed the reconstruction of Mycobacterium tuberculosis complex (MTBC) evolution, with the identification of seven phylogeographic lineages: four referred to as evolutionarily “ancient”, and three “modern”. The MTBC strains belonging to “modern” lineages appear to show enhanced virulence that may have warranted improved transmission in humans over ancient lineages through molecular mechanisms that remain to be fully characterized. To evaluate the impact of MTBC genetic diversity on the innate immune response, we analyzed intracellular bacterial replication, inflammatory cytokine levels, and autophagy response in human primary macrophages infected with MTBC clinical isolates belonging to the ancient lineages 1 and 5, and the modern lineage 4. We show that, when compared to ancient lineage 1 and 5, MTBC strains belonging to modern lineage 4 show a higher rate of replication, associated to a significant production of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and induction of a functional autophagy process. Interestingly, we found that the increased autophagic flux observed in macrophages infected with modern MTBC is due to an autocrine activity of the proinflammatory cytokine IL-1β, since autophagosome maturation is blocked by an interleukin-1 receptor antagonist. Unexpectedly, IL-1β-induced autophagy is not disadvantageous for the survival of modern Mtb strains, which reside within Rab5-positive phagosomal vesicles and avoid autophagosome engulfment. Altogether, these results suggest that autophagy triggered by inflammatory cytokines is compatible with a high rate of intracellular bacilli replication and may therefore contribute to the increased pathogenicity of the modern MTBC lineages.

Opposed elevational variation in prevalence and intensity of endoparasites and their vectors in a lizard.

Studying the causes of parasite geographic distribution is relevant to understand ecological and evolutionary processes that affect host populations as well as for species conservation. Temperature is one of the most important environmental variables affecting parasite distribution, as raising temperatures positively affect development, reproduction, and rate of transmission of both endo- and ectoparasites. In this context, it is generally accepted that, in mountains, parasite abundance decreases with elevation. However, empirical evidence on this topic is limited. In the present study, we analyzed the elevational variation of hemoparasites and ectoparasites of a lizard, Psammodromus algirus, along a 2,200-m elevational gradient in Sierra Nevada (SE Spain). As predicted, ectoparasite (mites, ticks, mosquitoes, and sandflies) abundance decreased with elevation. However, hemoparasite prevalence and intensity in the lizard augmented with altitude, showing a pattern contrary to their vectors (mites). We suggest that tolerance to hemoparasites may increase with elevation as a consequence of lizards at high altitudes taking advantage of increased body condition and food availability, and reduced oxidative stress. Moreover, lizards could have been selected for higher resistance against hemoparasites at lowlands (where higher rates of replication are expected), thus reducing hemoparasite prevalence and load. Our findings imply that, in a scenario of climate warming, populations of lizards at high elevation may face increased abundance of ectoparasites, accompanied with strong negative effects.

Infection of fattening pigs by a virulent strain of Aujeszky's disease virus and its spread in the pig

In this paper, the spread of the virulent 75V19 strain of Aujeszky's disease virus (ADV) in fattening pigs has been examined, and the association of this parameter to the development of relative symptoms has being sought. Four fattening pigs without antibodies against ADV have been oronasally inoculated by instillation of 1075 TCID50 of the infective strain, whilst another four seronegative pigs have been infected by the same dose of the strain administered in aerosol form. The pigs were euthanised at 4 days post inoculation and their tissues were examined by virus isolation and quantification in cell cultures. An extended spread of the virus was seen with both inoculation methods. However, the nasopharyngeal mucosa, the diaphragmatic lobes of the lungs and the pulmonary macrophages were more extensively infected in aerosol inoculated pigs compared to those of the other group. No difference was observed as regards the appearance of clinical disease between the two groups of fattening pigs. The results have also shown that, despite the high replication rate of ADV in the nasal mucosa and its ability to invade the central nervous system of fattening pigs, the degree of its replication in the nervous tissue in these pigs is limited when compared to suckling pigs.

Influence of Cell-Cell Interactions on the Population Growth Rate in a Tumor**Supported by the National Natural Science Foundation of China under Grant Nos. 11675008 and 21434001

The understanding of the macroscopic phenomenological models of the population growth at a microscopic level is important to predict the population behaviors emerged from the interactions between the individuals. In this work, we consider the influence of the population growth rate R on the cell-cell interaction in a tumor system and show that, in most cases especially small proliferative probabilities, the regulative role of the interaction will be strengthened with the decline of the intrinsic proliferative probabilities. For the high replication rates of an individual and the cooperative interactions, the proliferative probability almost has no effect. We compute the dependences of R on the interactions between the cells under the approximation of the nearest neighbor in the rim of an avascular tumor. Our results are helpful to qualitatively understand the influence of the interactions between the individuals on the growth rate in population systems.

Mechanisms and Factors That Drive Extensive Human Immunodeficiency Virus Type-1 Hypervariability: An Overview

The extensive hypervariability of human immunodeficiency virus type-1 (HIV-1) populations represents a major barrier against the success of currently available antiretroviral therapy. Moreover, it is still the most important obstacle that faces the development of an effective preventive vaccine against this infectious virus. Indeed, several factors can drive such hypervariability within and between HIV-1 patients. These factors include: first, the very low fidelity nature of HIV-1 reverse transcriptase; second, the extremely high HIV-1 replication rate; and third, the high genomic recombination rate that the virus has. All these factors together with the APOBEC3 proteins family and the immune and antiviral drugs pressures drive the extensive hypervariability of HIV-1 populations. Studying these factors and the mechanisms that drive such hypervariability will provide valuable insights that may guide the development of effective therapeutic and preventive strategies against HIV-1 infection in the near future. To this end, in this review, we summarized recent advances in this area of HIV-1 research.

Natural killer cells migrate into and control simian immunodeficiency virus replication in lymph node follicles in African green monkeys.

Natural killer (NK) cells play an essential role in antiviral immunity, but knowledge of their function in secondary lymphoid organs is incomplete. Lymph node follicles constitute a major viral reservoir during infections with HIV-1 and simian immunodeficiency virus of macaques (SIVmac). In contrast, during nonpathogenic infection with SIV from African green monkeys (SIVagm), follicles remain generally virus free. We show that NK cells in secondary lymphoid organs from chronically SIVagm-infected African green monkeys (AGMs) were frequently CXCR5+ and entered and persisted in lymph node follicles throughout the follow-up (240 d post-infection). These follicles were strongly positive for IL-15, which was primarily presented in its membrane-bound form by follicular dendritic cells. NK cell depletion through treatment with anti-IL-15 monoclonal antibody during chronic SIVagm infection resulted in high viral replication rates in follicles and the T cell zone and increased viral DNA in lymph nodes. Our data suggest that, in nonpathogenic SIV infection, NK cells migrate into follicles and play a major role in viral reservoir control in lymph nodes.

Targeting metabolic pathways for head and neck cancers therapeutics.

Cancer cells have distinctive energy metabolism pathways that support their rapid cell division. The preference for anaerobic glycolysis under the normal oxygen condition is known as the Warburg effect and has been observed in head and neck cancers. These metabolic changes are controlled by cancer-related transcription factors, such as tumor suppressor gene and hypoxia inducible factor 1α. In addition, various metabolic enzymes also actively regulate cancer-specific metabolism including the switch between aerobic and anaerobic glycolysis. For a long time, these metabolic changes in cancer cells have been considered a consequence of transformation required to maintain the high rate of tumor cell replication. However, recent studies indicate that alteration of metabolism is sufficient to initiate tumor transformation. Indeed, oncogenic mutations in the metabolic enzymes, isocitrate dehydrogenase and succinate dehydrogenase, have been increasingly found in various cancers, including head and neck cancers. In the present review, we introduce recent findings regarding the cancer metabolism, including the molecular mechanisms of how they affect cancer pathogenesis and maintenance. We also discuss the current and future perspectives on therapeutics that target metabolic pathways, with an emphasis on head and neck cancer.

Full-genome dengue virus sequencing in mosquito saliva shows lack of convergent positive selection during transmission by Aedes aegypti.

Like other pathogens with high mutation and replication rates, within-host dengue virus (DENV) populations evolve during infection of their main mosquito vector, Aedes aegypti. Within-host DENV evolution during transmission provides opportunities for adaptation and emergence of novel virus variants. Recent studies of DENV genetic diversity failed to detect convergent evolution of adaptive mutations in mosquito tissues such as midgut and salivary glands, suggesting that convergent positive selection is not a major driver of within-host DENV evolution in the vector. However, it is unknown whether this conclusion extends to the transmitted viral subpopulation because it is technically difficult to sequence DENV genomes in mosquito saliva. Here, we achieved DENV full-genome sequencing by pooling saliva samples collected non-sacrificially from 49 to 163 individual Ae. aegypti mosquitoes previously infected with one of two DENV-1 genotypes. We compared the transmitted viral subpopulations found in the pooled saliva samples collected in time series with the input viral population present in the infectious blood meal. In all pooled saliva samples examined, the full-genome consensus sequence of the input viral population was unchanged. Although the pooling strategy prevents analysis of individual saliva samples, our results demonstrate the lack of strong convergent positive selection during a single round of DENV transmission by Ae. aegypti. This finding reinforces the idea that genetic drift and purifying selection are the dominant evolutionary forces shaping within-host DENV genetic diversity during transmission by mosquitoes.

Hypervariable Domain of Eastern Equine Encephalitis Virus nsP3 Redundantly Utilizes Multiple Cellular Proteins for Replication Complex Assembly.

Eastern equine encephalitis virus (EEEV) is a representative member of the New World alphaviruses. It is pathogenic for a variety of vertebrate hosts, in which EEEV induces a highly debilitating disease, and the outcomes are frequently lethal. Despite a significant public health threat, the molecular mechanism of EEEV replication and interaction with hosts is poorly understood. Our previously published data and those of other teams have demonstrated that hypervariable domains (HVDs) of the alphavirus nsP3 protein interact with virus-specific host factors and play critical roles in assembly of viral replication complexes (vRCs). The most abundantly represented HVD-binding proteins are the FXR and G3BP family members. FXR proteins drive the assembly of vRCs of Venezuelan equine encephalitis virus (VEEV), and G3BPs were shown to function in vRC assembly in the replication of chikungunya and Sindbis viruses. Our new study demonstrates that EEEV exhibits a unique level of redundancy in the use of host factors in RNA replication. EEEV efficiently utilizes both the VEEV-specific FXR protein family and the Old World alphavirus-specific G3BP protein family. A lack of interaction with either FXRs or G3BPs does not affect vRC formation; however, removal of EEEV's ability to interact with both protein families has a deleterious effect on virus growth. Other identified EEEV nsP3 HVD-interacting host proteins are also capable of supporting EEEV replication, albeit with a dramatically lower efficiency. The ability to use a wide range of host factors with redundant functions in vRC assembly and function provides a plausible explanation for the efficient replication of EEEV and may contribute to its highly pathogenic phenotype.IMPORTANCE Eastern equine encephalitis virus (EEEV) is one of the most pathogenic New World alphaviruses. Despite the continuous public health threat, to date, the molecular mechanisms of its very efficient replication and high virulence are not sufficiently understood. The results of this new study demonstrate that North American EEEV exhibits a high level of redundancy in using host factors in replication complex assembly and virus replication. The hypervariable domain of the EEEV nsP3 protein interacts with all of the members of the FXR and G3BP protein families, and only a lack of interaction with both protein families strongly affects virus replication rates. Other identified HVD-binding factors are also involved in EEEV replication, but their roles are not as critical as those of FXRs and G3BPs. The new data present a plausible explanation for the exceptionally high replication rates of EEEV and suggest a new means of its attenuation and new targets for screening of antiviral drugs.

Innate and Adaptive Immune Responses in Chronic HCV Infection.

Hepatitis C virus (HCV) remains a public health problem of global importance, even in the era of potent directly-acting antiviral drugs. In this chapter, I discuss immune responses to acute and chronic HCV infection. The outcome of HCV infection is influenced by viral strategies that limit or delay the initiation of innate antiviral responses. This delay may enable HCV to establish widespread infection long before the host mounts effective T and B cell responses. HCV's genetic agility, resulting from its high rate of replication and its error prone replication mechanism, enables it to evade immune recognition. Adaptive immune responses fail to keep up with changing viral epitopes. Neutralizing antibody epitopes may be hidden by decoy structures, glycans, and lipoproteins. T cell responses fail due to changing epitope sequences and due to exhaustion, a phenomenon that may have evolved to limit immune-mediated pathology. Despite these difficulties, innate and adaptive immune mechanisms do impact HCV replication. Immune-mediated clearance of infection is possible, occurring in 20-50% of people who contract the disease. New developments raise hopes for effective immunological interventions to prevent or treat HCV infection.

The Incidence and the Implications of Natural Infection with Nomuraea rileyi (Farlow) Samson on the Life-Table Parameters of Laboratory-Reared Culex pipiens L. Mosquitoes

During routine mass rearing of Culex pipiens L., 46 % mortality rate was recorded among 3-day-old larvae in the late summer, 2014, at Cairo University, Giza, Egypt. An analysis of the water in the rearing plastic cups and the dead larvae revealed the presence of the fungus Nomuraea rileyi (Farlow) Samson. A comparative study was carried out using life-table parameters of the fungal-infected population of Cx. pipiens and fungus-free population (control) under laboratory conditions (30 ± 0.10 °C, RH 52.5 ± 7.8 % and photoperiod 16L:8D). Fungal-infected stages of Cx. pipiens exhibited a decrease in longevity (larvae, 5.89 ± 0.063 days; adult males, 7.8 ± 0.75 days; adult females, 10.83 ± 1.6 days). The mean generation time of the healthy population (22.09 ± 0.82 days) was not significantly different from that of the infected population (22.25 ± 0.08 days), nearly the same mean generation time. The fungal-infected Cx. pipiens population replicated itself 4.62 ± 1.45 times with a very low exponential rate of daily increase of 0.0688 ± 0.0154/day. However, the fungus-free population showed a higher replication rate of 38.10 ± 11.80 times, with a higher daily rate of increase (0.1648 ± 0.0167/day). Females of the fungal-infected Cx. pipiens, exhibited a decrease in the fertility, 25.67 ± 7.70 eggs/female, as compared to the females from the control population, 163.29 ± 40.64 eggs/female. Data of the present study suggested the possibility of using N. rileyi as a safe bio-control agent against the development of the larvae of Cx. pipiens.

Best practices for germ-free derivation and gnotobiotic zebrafish husbandry.

All animals are ecosystems with resident microbial communities, referred to as microbiota, which play profound roles in host development, physiology, and evolution. Enabled by new DNA sequencing technologies, there is a burgeoning interest in animal-microbiota interactions, but dissecting the specific impacts of microbes on their hosts is experimentally challenging. Gnotobiology, the study of biological systems in which all members are known, enables precise experimental analysis of the necessity and sufficiency of microbes in animal biology by deriving animals germ-free (GF) and inoculating them with defined microbial lineages. Mammalian host models have long dominated gnotobiology, but we have recently adapted gnotobiotic approaches to the zebrafish (Danio rerio), an important aquatic model. Zebrafish offer several experimental attributes that enable rapid, large-scale gnotobiotic experimentation with high replication rates and exquisite optical resolution. Here we describe detailed protocols for three procedures that form the foundation of zebrafish gnotobiology: derivation of GF embryos, microbial association of GF animals, and long-term, GF husbandry. Our aim is to provide sufficient guidance in zebrafish gnotobiotic methodology to expand and enrich this exciting field of research.

Tyrosine kinase/phosphatase inhibitors decrease dengue virus production in HepG2 cells

Dengue virus is the causative agent of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. High rates of dengue virus replication and virion production are related to disease severity. To identify anti-DENV compounds, we performed cell-based ELISA testing to detect the level of DENV E protein expression. Among a total of 83 inhibitors, eight were identified as inhibitors with antiviral activity. Epidermal growth factor receptor inhibitor II (EGFR/ErbB-2/ErbB-4 inhibitor II) and protein tyrosine phosphatase inhibitor IV (PTP inhibitor IV) significantly inhibited dengue virus production and demonstrated low toxicity in hepatocyte cell lines. Our results suggest the efficacy of tyrosine kinase/phosphatase inhibitors in decreasing dengue virus production in HepG2 cells.

A comparative study on the characterization of hepatitis B virus quasispecies by clone-based sequencing and third-generation sequencing

Hepatitis B virus (HBV) has a high mutation rate due to the extremely high replication rate and the proofreading deficiency during reverse transcription. The generated variants with genetic heterogeneity are described as viral quasispecies (QS). Clone-based sequencing (CBS) is thought to be the ‘gold standard’ for assessing QS complexity and diversity of HBV, but an important issue about CBS is cost-effectiveness and laborious. In this study, we investigated the utility of the third-generation sequencing (TGS) DNA sequencing to characterize genetic heterogeneity of HBV QS and assessed the possible contribution of TGS technology in HBV QS studies. Parallel experiments including 3 control samples, which consisted of HBV full gene genotype B and genotype C plasmids, and 10 patients samples were performed by using CBS and TGS to analyze HBV whole-genome QS. Characterization of QS heterogeneity was conducted by using comprehensive statistical analysis. The results showed that TGS had a high consistency with CBS when measuring the complexity and diversity of QS. In addition, to detect rare variants, there were strong advantages conferred by TGS. In summary, TGS was considered to be practicable in HBV QS studies and it might have a relevant role in the clinical management of HBV infection in the future.Emerging Microbes & Infections (2017) 6, e100; doi:10.1038/emi.2017.88; published online 8 November 2017

Treatment of fulminant acute Hepatitis B with nucles(t)id analogues is safe and does not lead to secondary chronification of Hepatitis B.

Background: Acute hepatitis B virus (HBV) infection is still a major cause of acute liver failure (ALF), necessitating a high rate of emergency liver transplantation (LTx). Acute infection is followed by high viral replication rates leading to hepatocyte death and, ultimately, ALF. The objective of treating HBV-induced ALF thus is to eliminate, or significantly suppress, HBV replication and therefore reduce cell death and support regeneration. Objective: In this retrospective study, we want to evaluate the timing, the safety, and the long-term virological outcome of this approach. Methods/results: In this study, we included 32 patients (16 female and 16 males; median age 39.5years) with ALF due to hepatitis B, who were transferred to the university hospital Essen, Germany between January 2009 and December 2013. Before treatment, transaminases were highly elevated, bilirubin was increased, and elevated international normalized ratio (INR) revealed impaired liver function. HBV-DNA and HBsAg were positive. All 32 patients received oral antiviral treatment (3 lamivudine, 21 entecavir, and 8 tenofovir) between 1day and 4 months after diagnosis of acute hepatitis B. One patient died, 2 were transplanted, one died shortly after LTx the other patient survived after LTx. These 3 patients received treatment inastate of advanced liver failure, and 1 patient 4months after initial diagnosis of hepatitis B. Twenty-nine patients survived without LTx. Five patients were discharged without further follow-up. All 24 remaining patients became HBV-DNA negative in median of 100 days. Twenty-two patients were followed further, and all patients lost their HBsAg in median of 108 days. Sixteen of the 22 patients experienced a seroconversion to anti-HBs in median of 137 days. Four patients who were followed for 1more year after HBsAg did not develop anti-HBs. None of the patients developed chronic hepatitis B. Conclusion: Immediate treatment of HBV-induced ALF with nucleos(t)id-analogues (NUCs) appears save and prevents LTx and death, and there is no indication for increased chronicity.