Memory-like HCV-specific CD8+ T cells retain a molecular scar after cure of chronic HCV infection.

In chronic hepatitis C virus (HCV) infection, exhausted HCV-specific CD8+ T cells comprise memory-like and terminally exhausted subsets. However, little is known about the molecular profile and fate of these two subsets after the elimination of chronic antigen stimulation by direct-acting antiviral (DAA) therapy. Here, we report a progenitor-progeny relationship between memory-like and terminally exhausted HCV-specific CD8+ T cells via an intermediate subset. Single-cell transcriptomics implicated that memory-like cells are maintained and terminally exhausted cells are lost after DAA-mediated cure, resulting in a memory polarization of the overall HCV-specific CD8+ T cell response. However, an exhausted core signature of memory-like CD8+ T cells was still detectable, including, to a smaller extent, in HCV-specific CD8+ T cells targeting variant epitopes. These results identify a molecular signature of T cell exhaustion that is maintained as a chronic scar in HCV-specific CD8+ T cells even after the cessation of chronic antigen stimulation.

Early Transcriptional Divergence Marks Virus-Specific Primary Human CD8+ T Cells in Chronic versus Acute Infection.

Distinct molecular pathways govern the differentiation of CD8+ effector T cells into memory or exhausted T cells during acute and chronic viral infection, but these are not well studied in humans. Here, we employed an integrative systems immunology approach to identify transcriptional commonalities and differences between virus-specific CD8+ T cells from patients with persistent and spontaneously resolving hepatitis C virus (HCV) infection during the acute phase. We observed dysregulation of metabolic processes during early persistent infection that was linked to changes in expression of genes related to nucleosomal regulation of transcription, T cell differentiation, and the inflammatory response and correlated with subject age, sex, and the presence of HCV-specific CD4+ T cell populations. These early changes in HCV-specific CD8+ T cell transcription preceded the overt establishment of T cell exhaustion, making this signature a prime target in the search for the regulatory origins of T cell dysfunction in chronic viral infection.

TOX reinforces the phenotype and longevity of exhausted T cells in chronic viral infection.

Cytotoxic T cells are essential mediators of protective immunity to viral infection and malignant tumours and are a key target of immunotherapy approaches. However, prolonged exposure to cognate antigens often attenuates the effector capacity of T cells and limits their therapeutic potential1-4. This process, known as T cell exhaustion or dysfunction1, is manifested by epigenetically enforced changes in gene regulation that reduce the expression of cytokines and effector molecules and upregulate the expression of inhibitory receptors such as programmed cell-death 1 (PD-1)5-8. The underlying molecular mechanisms that induce and stabilize the phenotypic and functional features of exhausted T cells remain poorly understood9-12. Here we report that the development and maintenance of populations of exhausted T cells in mice requires the thymocyte selection-associated high mobility group box (TOX) protein13-15. TOX is induced by high antigen stimulation of the T cell receptor and correlates with the presence of an exhausted phenotype during chronic infections with lymphocytic choriomeningitis virus in mice and hepatitis C virus in humans. Removal of its DNA-binding domain reduces the expression of PD-1 at the mRNA and protein level, augments the production of cytokines and results in a more polyfunctional T cell phenotype. T cells with this deletion initially mediate increased effector function and cause more severe immunopathology, but ultimately undergo a massive decline in their quantity, notably among the subset of TCF-1+ self-renewing T cells. Altogether, we show that TOX is a critical factor for the normal progression of T cell dysfunction and the maintenance of exhausted T cells during chronic infection, and provide a link between the suppression of effector function intrinsic to CD8 T cells and protection against immunopathology.

'Unusual' HCV genotype subtypes: origin, distribution, sensitivity to direct-acting antiviral drugs and behaviour on antiviral treatment and retreatment.

The high genetic diversity of hepatitis C virus (HCV) has led to the emergence of eight genotypes and a large number of subtypes in limited geographical areas. Currently approved pangenotypic DAA regimens have been designed and developed to be effective against the most common subtypes (1a, 1b, 2a, 2b, 2c, 3a, 4a, 5a and 6a). However, large populations living in Africa and Asia, or who have migrated from these regions to industrialised countries, are infected with 'unusual', non-epidemic HCV subtypes, including some that are inherently resistant to currently available direct-acting antiviral (DAA) drugs due to the presence of natural polymorphisms at resistance-associated substitution positions. In this review article, we describe the origin and subsequent global spread of HCV genotypes and subtypes, the current global distribution of common and unusual HCV subtypes, the polymorphisms naturally present in the genome sequences of unusual HCV subtypes that may confer inherently reduced susceptibility to DAA drugs and the available data on the response of unusual HCV subtypes to first-line HCV therapy and retreatment. We conclude that the problem of unusual HCV subtypes that are inherently resistant to DAAs and its threat to the global efforts to eliminate viral hepatitis are largely underestimated and warrant vigorous action.

EASL position paper on clinical follow-up after HCV cure.

Following the advent of direct-acting antivirals (DAAs), hepatitis C virus (HCV) infection can be cured in almost all infected patients. This has led to a number of clinical questions regarding the optimal management of the millions of patients cured of HCV. This position statement provides specific guidance on the appropriate follow-up after a sustained virological response in patients without advanced fibrosis, those with compensated advanced chronic liver disease, and those with decompensated cirrhosis. Guidance on hepatocellular carcinoma risk assessment and the management of extrahepatic manifestations of HCV is also provided. Finally, guidance is provided on the monitoring and treatment of reinfection in at-risk patients. The recommendations are based on the best available evidence and are intended to help healthcare professionals involved in the management of patients after treatment for HCV.

Epigenetic scars in regulatory T cells are retained after successful treatment of chronic hepatitis C with direct-acting antivirals.

BACKGROUND & AIMS: Chronic HCV infection results in abnormal immunological alterations, which are not fully normalized after viral elimination by direct-acting antiviral (DAA) treatment. Herein, we longitudinally examined phenotypic, transcriptomic, and epigenetic alterations in peripheral blood regulatory T (Treg) cells from patients with chronic HCV infection before, during, and after DAA treatment. METHODS: Patients with chronic genotype 1b HCV infection who achieved sustained virologic response by DAA treatment and age-matched healthy donors were recruited. Phenotypic characteristics of Treg cells were investigated through flow cytometry analysis. Moreover, the transcriptomic and epigenetic landscapes of Treg cells were analyzed using RNA sequencing and ATAC-seq (assay for transposase-accessible chromatin with sequencing) analysis. RESULTS: The Treg cell population - especially the activated Treg cell subpopulation - was expanded in peripheral blood during chronic HCV infection, and this expansion was sustained even after viral clearance. RNA sequencing analysis revealed that viral clearance did not abrogate the inflammatory features of these Treg cells, such as Treg activation and TNF signaling. Moreover, ATAC-seq analysis showed inflammatory imprinting in the epigenetic landscape of Treg cells from patients, which remained after treatment. These findings were further confirmed by intracellular cytokine staining, demonstrating that Treg cells exhibited inflammatory features and TNF production in chronic HCV infection that were maintained after viral clearance. CONCLUSIONS: Overall, our results showed that during chronic HCV infection, the expanded Treg cell population acquired inflammatory features at phenotypic, transcriptomic, and epigenetic levels, which were maintained even after successful viral elimination by DAA treatment. Further studies are warranted to examine the clinical significance of sustained inflammatory features in the Treg cell population after recovery from chronic HCV infection. IMPACT AND IMPLICATIONS: During chronic HCV infection, several immune components are altered both quantitatively and qualitatively. The recent introduction of direct-acting antivirals has led to high cure rates. Nevertheless, we have demonstrated that inflammatory features of Treg cells are maintained at phenotypic, transcriptomic, and epigenetic levels even after successful DAA treatment. Further in-depth studies are required to investigate the long-term clinical outcomes of patients who have recovered from chronic HCV infection.

Performance of HCV core antigen and PCR testing in a predominantly genotype 3 population.

Hepatitis C core antigen (HCVcAg) is becoming increasingly recognized as an alternative to molecular testing for the confirmation of chronic hepatitis C. However, there are limited data on the performance of this assay in a genotype 3 (GT3) predominant country like Pakistan. We conducted a study to evaluate the diagnostic performance of HCVcAg against the HCV polymerase chain reaction (PCR) molecular test. HCV antibody-positive patients requiring confirmatory testing were recruited from August to October 2018 at the Pakistan Kidney and Liver Institute and Research Center (PKLI&RC), Lahore, Pakistan. Patients with previously known diagnoses or treatment histories were excluded. The Abbott HCV Ag assay was used for HCVcAg testing. Results ≥3.00 fmol/L were considered positive for HCVcAg. The Abbott RealTime HCV assay was used for PCR testing with a lower detection limit of ≥12 IU/mL. We computed the sensitivity, specificity and correlation of HCVcAg against HCV PCR. A total of 394 patients were recruited. The median age of the patients was 42 years. Most participants were females (51.5%, n = 203), 30.7% (n = 121) had HTN, 10.4% DM (n = 41) and 5% had APRI ≥2. The overall sensitivity was 98.0% and the specificity was 98.6%. The lowest detection limit of cAg was an HCV RNA value of 4657 IU/mL. The levels of cAg were highly correlated with those of HCV RNA by Spearman's rank correlation test (r = 0.935, p < .001). HCVcAg represents a suitable alternative with high sensitivity and specificity compared with HCV PCR in the GT3-predominant population and can be incorporated into algorithms to improve linkage to care.

Mixed-Genotype HCV Direct Acting Antiviral Outcomes: A CANUHC Analysis.

The prevalence of mixed hepatitis C virus (HCV) genotype infection in a representative Canadian HCV cohort is reported and virological response with direct acting antiviral (DAA) treatment was evaluated. 3272 HCV-positive participants were enrolled, of which 2945 (90.0%) initiated DAA therapy. 0.8% were identified with mixed genotype infection. Overall sustained virological response (SVR) was 99.1% and did not differ based on mixed genotype status. Any historical disadvantage to achieving cure with HCV treatment in mixed genotype infection has been overcome by current DAA regimens.

Four weeks of off-treatment follow-up is sufficient to determine virologic responses at off-treatment week 12 in patients with hepatitis C virus infection receiving fixed-dose pangenotypic direct-acting antivirals.

Early confirmation of sustained virologic response (SVR) or viral relapse after direct-acting antivirals (DAAs) for hepatitis C virus (HCV) infection is essential based on public health perspectives, particularly for patients with high risk of nonadherence to posttreatment follow-ups. A total of 1011 patients who achieved end-of-treatment virologic response, including 526 receiving fixed-dose pangenotypic DAAs, and 485 receiving other types of DAAs, who had available off-treatment weeks 4 and 12 serum HCV RNA data to confirm SVR at off-treatment week 12 (SVR12) or viral relapse were included. The positive predictive value (PPV) and negative predictive value (NPV) of SVR4 to predict patients with SVR12 or viral relapse were reported. Furthermore, we analyzed the proportion of concordance between SVR12 and SVR24 in 943 patients with available SVR24 data. The PPV and NPV of SVR4 to predict SVR12 were 98.5% (95% confidence interval [CI]: 98.0-98.9) and 100% (95% CI: 66.4-100) in the entire population. The PPV of SVR4 to predict SVR12 in patients receiving fixed-dose pangenotypic DAAs was higher than those receiving other types of DAAs (99.8% [95% CI: 98.9-100] vs. 97.1% [95% CI: 96.2-97.8], p < 0.001). The NPVs of SVR4 to predict viral relapse were 100%, regardless of the type of DAAs. Moreover, the concordance between SVR12 and SVR24 was 100%. In conclusion, an off-treatment week 4 serum HCV RNA testing is sufficient to provide an excellent prediction power of SVR or viral relapse at off-treatment week 12 among patients with HCV who are treated with fixed-dose pangenotypic DAAs.

Hepatitis C virus-induced differential transcriptional traits in host cells after persistent infection elimination by direct-acting antivirals in cell culture.

Chronic hepatitis C virus infection (HCV) causes liver inflammation and fibrosis, leading to the development of severe liver disease, such as cirrhosis or hepatocellular carcinoma (HCC). Approval of direct-acting antiviral drug combinations has revolutionized chronic HCV therapy, with virus eradication in >98% of the treated patients. The efficacy of these treatments is such that it is formally possible for cured patients to carry formerly infected cells that display irreversible transcriptional alterations directly caused by chronic HCV Infection. Combining differential transcriptomes from two different persistent infection models, we observed a major reversion of infection-related transcripts after complete infection elimination. However, a small number of transcripts were abnormally expressed in formerly infected cells. Comparison of the results obtained in proliferating and growth-arrested cell culture models suggest that permanent transcriptional alterations may be established by several mechanisms. Interestingly, some of these alterations were also observed in the liver biopsies of virologically cured patients. Overall, our data suggest a direct and permanent impact of persistent HCV infection on the host cell transcriptome even after virus elimination, possibly contributing to the development of HCC.

Implementation of Universal Hepatitis C Virus Screening in a Tertiary Cancer Center.

BACKGROUND: The prevalence of chronic hepatitis C virus (HCV) infection in the United States is ≤1%. Universal HCV screening is recommended nationwide. Here we describe our experience implementing universal HCV screening at a cancer center. METHODS: In October 2016, universal HCV screening with HCV antibody (anti-HCV) was initiated for all new outpatients. Universal screening was promoted through widespread provider education, orders in the Epic electronic health records (EHRs), SmartSets, and automated EHR reminders. The effort focused on patients with solid tumors, because universal screening in patients with hematologic malignancies was already standard practice. Primary outcomes were the proportion of patients screened and the proportion of patients with reactive anti-HCV test results linked to HCV care. The secondary outcome was the incidence of HCV-associated hepatocellular carcinoma as a second primary malignancy (HCC-SPM) in patients with a history of other cancers before HCC diagnosis. Epic's Reporting Workbench Business Intelligence tools were used. Statistical significance was defined as P<.05 on chi-square analysis. RESULTS: From April 2016 through April 2023, 56,075 patients with solid tumors were screened for HCV, of whom 1,300 (2.3%) had reactive anti-HCV test results. The proportion of patients screened was 10.1% in the 6 months before study implementation and 34.4% in the last 6 months of the study (P<.001). HCV screening was ordered using SmartSets in 39,332 (45.8%) patients and in response to automated EHR reminders in 10,972 (12.8%) patients. Most patients with reactive anti-HCV test results were linked to care (765/1,300; 59%), most with proven HCV infection were treated (425/562; 76%), and most treated patients achieved sustained virologic response (414/425; 97%). The incidence of HCC-SPMs was 15% in historical controls treated from 2011 to 2017 and 5.7% following implementation of universal screening (P=.0002). CONCLUSIONS: Universal HCV screening can be successfully implemented in cancer hospitals using an EHR-based multipronged approach to eliminate HCV and prevent HCV-associated HCC-SPMs.

Efficacy and safety of direct-acting antiviral regimen for patients with hepatitis C virus genotype 2: a systematic review and meta-analysis.

BACKGROUND: Direct-acting antivirals (DAAs) show high cure rates in treating chronic hepatitis C virus (HCV). However, the effect of DAAs on patients infected with genotype 2 (GT2) is difficult to determine despite the availability of several DAA regimens. METHODS: A systematic search of six databases (PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Clinicaltrial.gov) was conducted through April 20, 2022. We considered the sustained virological response 12 weeks after treatment (SVR12) as the efficacy outcome, and adverse events (AEs) as the safety outcome. By calculating the mean SVR12 and the proportion of AEs among patients, we considered the intervention effect for each DAA regimen. The random effect model was then used in all meta-analyses. This systematic review and meta-analysis aimed to summarize the evidence on efficacy and safety of DAAs in patients infected with HCV GT2. The Bayesian Markov Chain Monte Carlo (MCMC) network metanalysis was used to indirectly compare regimen in GT2 patients. RESULTS: Among 31 articles included (2,968 participants), consisting of 1,387 treatment-naive patients and 354 patients with cirrhosis. The overall pooled SVR12 rate was 94.62% (95% CI: 92.43-96.52%) among the participants who received all doses of treatment. Meta-analysis results of AEs revealed that fatigue was the most common AE (14.0%, 95% CI: 6.4-21.6%), followed by headache (13.1%, 95% CI: 9.2-17.1%), whereas death and serious adverse events were uncommon. CONCLUSIONS: We compared DAA-based treatments indirectly using meta-analysis and found the combination of Sofosbuvir plus Velpatasvir and Glecaprevir plus Pibrentasvir, each administered over a 12-week period, were identified as the most effective and relatively safe in managing chronic hepatitis C virus genotype 2 (HCV GT2) infection. Both treatments achieved a SVR12 of 100% (95% CI 99-100%).

Predictive Value of Interleukin 6 and Interleukin 8 in Response to Treatment of Hepatitis C Virus.

BACKGROUND: Chronic hepatitis C (CHC) infection is a major public health problem in many low- and middle-income countries. The study aimed to find out how interleukin IL-6 and IL-8 levels in the blood affect the virological response to directacting antivirals (DAAs) and to find useful clinical or immunological markers for the response to HCV treatment. METHODS: CHC patients from a real Egyptian population (n = 4,300), who were treated during the Egyptian national initiative to eliminate HCV at the Sherbin Central Hospital, Dakahlia Governorate, Ministry of Health, Egypt, were enrolled in our study. They were all patients who did not obtain a sustained virological response (SVR) (n = 75; non-responder; the response rate was 98.26%), and a total of 100 patients were randomly selected from patients who obtained SVR (responder) and were age- and gender-matched (p > 0.05) with non-responder patients. Serum levels of IL-6 and IL-8 were measured by commercial ELISA kits. RESULTS: Non-responder patients were associated with significantly high levels of ALT, AST, ALP, and total bilirubin. Non-responders had significantly (p < 0.05) higher baseline IL-6 (16.7 ± 4.92 pg/mL) and IL-8 (37.81 ± 10.55 pg/mL) levels compared to responders (12.68 ± 2.06, 29.06 ± 5.94 pg/mL, respectively). There was a substantial (p < 0.05) association between the combination of two cytokines and a high likelihood of treatment failure, as indicated by all parameters examined, with the highest correlation values seen. CONCLUSIONS: The present study showed that increased IL-6 and IL-8 were associated with HCV treatment failure. Also, IL8 was associated with hepatic fibrosis.

Serum Phosphatidylcholine Species 32:0 as a Biomarker for Liver Cirrhosis Pre- and Post-Hepatitis C Virus Clearance.

Phosphatidylcholine (PC) is an essential lipid for liver health and lipoprotein metabolism, but its circulating levels have rarely been studied in patients with cirrhosis. Chronic hepatitis C virus (HCV) infection causes lipid abnormalities and is a major cause of cirrhosis. Effective HCV elimination with direct-acting antivirals (DAAs) is associated with the normalization of serum low-density lipoprotein cholesterol levels. Since PC is abundant in all lipoprotein particles, this study analyzed the association between serum PC species levels and liver cirrhosis before and after HCV eradication. Therefore, 27 PC species were measured by Fourier Transform Mass Spectrometry in the serum of 178 patients with chronic HCV infection at baseline and in 176 of these patients at the end of therapy. The PC species did not correlate with viral load, and the levels of 13 PC species were reduced in patients infected with genotype 3a compared to those affected with genotype 1. Four PC species were slightly elevated 12 weeks after DAA initiation, and genotype-related changes were largely normalized. Patients with HCV and cirrhosis had higher serum levels of PC 30:0 and 32:0 before and at the end of therapy. PC species containing polyunsaturated fatty acids were mostly decreased in cirrhosis. The levels of polyunsaturated, but not saturated, PC species were inversely correlated with the model of the end-stage liver disease score. A receiver operating characteristic curve analysis showed area under the curve values of 0.814 and 0.826 for PC 32:0 and 0.917 and 0.914 for % PC 32:0 (relative to the total PC levels) for the classification of cirrhosis at baseline and at the end of therapy, respectively. In conclusion, the specific upregulation of PC 32:0 in cirrhosis before and after therapy may be of diagnostic value in HCV-related cirrhosis.

After the Storm: Persistent Molecular Alterations Following HCV Cure.

The development of direct-acting antivirals (DAAs) against hepatitis C virus (HCV) has revolutionized the management of this pathology, as their use allows viral elimination in a large majority of patients. Nonetheless, HCV remains a major public health problem due to the multiple challenges associated with its diagnosis, treatment availability and development of a prophylactic vaccine. Moreover, HCV-cured patients still present an increased risk of developing hepatic complications such as hepatocellular carcinoma. In the present review, we aim to summarize the impact that HCV infection has on a wide variety of peripheral and intrahepatic cell populations, the alterations that remain following DAA treatment and the potential molecular mechanisms implicated in their long-term persistence. Finally, we consider how recent developments in single-cell multiomics could refine our understanding of this disease in each specific intrahepatic cell population and drive the field to explore new directions for the development of chemo-preventive strategies.

Adenovirus-vectored T cell vaccine for hepacivirus shows reduced effectiveness against a CD8 T cell escape variant in rats.

There is an urgent need for a vaccine to prevent chronic infection by hepatitis C virus (HCV) and its many genetic variants. The first human vaccine trial, using recombinant viral vectors that stimulate pan-genotypic T cell responses against HCV non-structural proteins, failed to demonstrate efficacy despite significant preclinical promise. Understanding the factors that govern HCV T cell vaccine success is necessary for design of improved immunization strategies. Using a rat model of chronic rodent hepacivirus (RHV) infection, we assessed the impact of antigenic variation and immune escape upon success of a conceptually analogous RHV T cell vaccine. Naïve Lewis rats were vaccinated with a recombinant human adenovirus expressing RHV non-structural proteins (NS)3-5B and later challenged with a viral variant containing immune escape mutations within major histocompatibility complex (MHC) class I-restricted epitopes (escape virus). Whereas 7 of 11 (64%) rats cleared infection caused by wild-type RHV, only 3 of 12 (25%) were protected against heterologous challenge with escape virus. Uncontrolled replication of escape virus was associated with durable CD8 T cell responses targeting escaped epitopes alone. In contrast, clearance of escape virus correlated with CD4 T cell helper immunity and maintenance of CD8 T cell responses against intact viral epitopes. Interestingly, clearance of wild-type RHV infection after vaccination conferred enhanced protection against secondary challenge with escape virus. These results demonstrate that the efficacy of an RHV T cell vaccine is reduced when challenge virus contains escape mutations within MHC class I-restricted epitopes and that failure to sustain CD8 T cell responses against intact epitopes likely underlies immune failure in this setting. Further investigation of the immune responses that yield protection against diverse RHV challenges in this model may facilitate design of broadly effective HCV vaccines.

Single-cell transcriptomic analyses of T cells in chronic HCV-infected patients dominated by DAA-induced interferon signaling changes.

Chronic infection with HCV is manifested by dysregulation of innate immune responses and impaired T cell function at multiple levels. These changes may impact susceptibility to other infections, responsiveness to antiviral therapies, vaccine responsiveness, and development of complications such as hepatocellular carcinoma. Highly effective direct-acting antiviral (DAA) therapy has revolutionized the management of chronic HCV, with expected cure rates exceeding 95%. DAA treatment represents a unique opportunity to investigate to what extent elimination of viral replication and chronic antigen stimulation can restore immunologic phenotype. In this study we interrogated the global transcriptional profile of isolated peripheral blood T cells before, during and after IFN-free DAA therapy using single-cell mRNA sequencing. Our results demonstrate that T cells mapped at single-cell resolution have dramatic transcriptomic changes early after initiation of DAA and many of these changes are sustained after completion of DAA therapy. Specifically, we see a significant reduction in transcripts associated with innate immune activation and interferon signaling such as ISG15, ISG20, IFIT3, OAS and MX1 in many different T cell subsets. Furthermore, we find an early upregulation of a gene involved in suppression of immune activation, DUSP1, in circulating T cells. Conclusion: This study provides the first in-depth transcriptomic analysis at the single-cell level of patients undergoing DAA therapy, demonstrating that IFN-free antiviral therapy in chronic HCV infection induces hitherto unrecognized shifts in innate immune and interferon signaling within T cell populations early, during, and long-term after treatment. The present study provides a rich data source to explore the effects of DAA treatment on bulk T cells.

Inhibition of Long Noncoding RNA Linc-Pint by Hepatitis C Virus in Infected Hepatocytes Enhances Lipogenesis.

BACKGROUND AND AIMS: HCV often causes chronic infection in liver, cirrhosis, and, in some instances, HCC. HCV encodes several factors' those impair host genes for establishment of chronic infection. The long noncoding RNAs (lncRNAs) display diverse effects on biological regulations. However, their role in virus replication and underlying diseases is poorly understood. In this study, we have shown that HCV exploits lncRNA long intergenic nonprotein-coding RNA, p53 induced transcript (Linc-Pint) in hepatocytes for enhancement of lipogenesis. APPROACH AND RESULTS: We identified a lncRNA, Linc-Pint, which is significantly down-regulated in HCV-replicating hepatocytes and liver specimens from HCV infected patients. Using RNA pull-down proteomics, we identified serine/arginine protein specific kinase 2 (SRPK2) as an interacting partner of Linc-Pint. A subsequent study demonstrated that overexpression of Linc-Pint inhibits the expression of lipogenesis-related genes, such as fatty acid synthase and ATP-citrate lyase. We also observed that Linc-Pint significantly inhibits HCV replication. Furthermore, HCV-mediated enhanced lipogenesis can be controlled by exogenous Linc-Pint expression. Together, our results suggested that HCV-mediated down-regulation of Linc-Pint enhances lipogenesis favoring virus replication and liver disease progression. CONCLUSIONS: We have shown that SRPK2 is a direct target of Linc-Pint and that depletion of SRPK2 inhibits lipogenesis. Our study contributes to the mechanistic understanding of the role of Linc-Pint in HCV-associated liver pathogenesis.

Adaptive Natural Killer Cell Functional Recovery in Hepatitis C Virus Cured Patients.

BACKGROUND AND AIMS: Current evidence suggests that dysfunctional natural killer (NK) cell responses during hepatitis C virus (HCV) infection can be restored after viral eradication with direct acting antivirals (DAAs). However, the fate of the recently described adaptive NK cell population, endowed with increased ability to mediate antibody-dependent cell-mediated cytotoxicity (ADCC), during HCV infection is poorly defined, while no study has explored the effects of DAAs on this NK subset. APPROACH AND RESULTS: We performed multicolor flow cytometry to investigate CD57+ FcεRIγneg adaptive and FcεRIγpos conventional NK cell phenotype and function before and after DAA treatment in 59 patients chronically infected with HCV, 39 with advanced liver fibrosis, and 20 with mild-moderate liver fibrosis. Moreover, bulk NK cell phenotype and function were analyzed after cytokine activation following contact with K562 target cells. The proportion of FcεRIγneg NK cells in patients with HCV was associated with increased HCV load at baseline, and it was significantly reduced after treatment. Patients with an advanced fibrosis stage displayed increased NK cell activation and exhaustion markers that normalized after therapy. Of note, adaptive NK cells from patients with HCV were characterized by increased programmed death receptor 1 expression and reduced ADCC activity at baseline. DAA treatment restored ADCC ability and reduced programmed death receptor 1 expression. CONCLUSIONS: HCV profoundly affects the frequency, phenotype, and function of adaptive NK cells. DAA therapy restores a normal adaptive NK phenotype and enhances interferon-gamma production by this cell subset.

Pharmacokinetics, Safety, and Efficacy of Glecaprevir/Pibrentasvir in Children With Chronic HCV: Part 2 of the DORA Study.

BACKGROUND AND AIMS: Glecaprevir/pibrentasvir (GLE/PIB) has shown high efficacy and safety in chronic HCV-infected adults and adolescents; data in children were limited. DORA part 2 is a phase 2/3, nonrandomized, open-label study evaluating the pharmacokinetics, efficacy, and safety of a pediatric formulation of GLE and PIB in children ages 3 to < 12 years. APPROACH AND RESULTS: Children with chronic HCV infection, genotype 1-6, with or without compensated cirrhosis, were divided into three cohorts by age-cohort 2 (9 to < 12 years), cohort 3 (6 to < 9 years), and cohort 4 (3 to < 6 years)-and given weight-based doses of GLE and PIB for 8, 12, or 16 weeks. Primary endpoints were sustained virologic response at posttreatment week 12 (SVR12) and steady-state exposure; secondary endpoints were rates of persistent viremia, relapse, and reinfection. Safety and laboratory abnormalities were assessed. Final pediatric dosages determined to be efficacious were 250 mg GLE + 100 mg PIB (in children weighing ≥ 30 to < 45 kg), 200 mg GLE + 80 mg PIB (≥ 20 to < 30 kg), and 150 mg GLE + 60 mg PIB (12 to < 20 kg). Of 80 participants enrolled and dosed, 96% (77/80) achieved SVR12. One participant, on the initial dose ratio, relapsed by posttreatment week 4; no participants had virologic failures on the final dose ratio of GLE 50 mg/PIB 20 mg. Two nonresponders prematurely discontinued the study. Most adverse events (AEs) were mild; no drug-related serious AEs occurred. Pharmacokinetic exposures were comparable to those of adults. CONCLUSIONS: A pediatric formulation of GLE/PIB was highly efficacious and well tolerated in chronic HCV-infected children 3 to < 12 years old.