Predicting Early Viral Control under Direct-Acting Antiviral Therapy for Chronic Hepatitis C Virus Using Pretreatment Immunological Markers

Telomerase Expression Related with Poor Immune Response to HCV Core Antigen in Egyptian HCV Patients' PBMCs

Background

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver.

Aim

This study aimed to assess serum human telomerase enzyme (hTERT) levels and their relation to the progression of liver disease. Also, it aimed to assess the effect of hepatitis C virus (HCV) core protein on memory T-cells in HCV patients with or without HCC and the correlation between memory cell phenotype and the progression of the disease in the same patients.

Methods

HTERT level in serum was assessed through relative quantitative RT-PCR. Flow cytometric analysis was used to assess T-cell responsiveness (as IFN- γ secretion) before and after stimulation with HCV core protein and the memory CD8+ cell phenotype using several differentiation markers.

Results

HTERT was found to be increased in a stepwise manner upon comparing its level in controls, chronic hepatitis patients, cirrhotic patients, and HCC patients. T-cells showed a similar manner of stepwise decrease in response (decreased IFN- γ secretion) in HCC patients compared to HCV patients without HCC and controls. Also, late differentiated memory cells (CD8+, CD27-, CD28-, CD45RA+, and CCR7-) were depleted in HCC patients compared to HCV patients without HCC.

Conclusion

These results suggest a negative correlation between hTERT and IFN- γ secretion by T-cells in HCV patients and that this relationship, along with the depletion of late differentiated memory cells, could help the progression of liver disease to HCC.

Efficacy and safety of direct-acting antiviral therapies and baseline predictors for treatment outcomes in hepatitis C patients: a multi-center, real-world study in Guangdong, China

 : The data on direct acting antivirals (DAA) in chronic hepatitis C (CHC) patients in southern China with multiple genotypes circulating are limited. This study aims to evaluate the efficacy and safety of DAA regimens among CHC patients in Guangdong, China. A total of 220 patients receiving a variety of DAA were enrolled. The primary outcome was sustained virologic response (SVR) at 12 weeks. Resistance associated substations (RAS) were evaluated by deep sequencing. The overall SVR rate was 96.4%, and was 97.7% for genotype 1, 100% for genotype 2, 91.9% for genotype 3, 95.7% for genotype 6, and 100% for untyped. The overall incidence of adverse events (AEs) was 8.2% (18/220) and all the AEs were mild. Nonstructural protein 5A RAS, 30K/31M and Y93H, were most prevalent at baseline and the end of treatment in non-SVR patients, respectively. Logistics regression showed that elevated ALT and AST at baseline were specifically associated with non-SVR in patients with genotype 3 and 6 infections (P = 0.029 and P = 0.017) but not genotype 1 infection (P = 0.746 and P = 0.971), and baseline AST was the best predictor for SVR in genotype 3 and 6 patients (area under curve = 0.890). CONCLUSION: All DAA regimens achieved ideal SVR and were well tolerated. NS5A RAS were prevalent in non-SVR patients. ALT and AST as baseline predictors for non-SVR in genotype 3 and 6 infections warrant further research in a larger cohort. This article is protected by copyright. All rights reserved.

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.

Ribavirin Improves NK Cell IFNγ Response During Sofosbuvir-based DAA Therapy in CV-infected Liver Transplant Recipients

BACKGROUND

Chronic hepatitis C virus (HCV) infection is characterized by activation of natural killer (NK) cells. Here, we asked whether HCV-elimination by sofosbuvir-based direct-acting antivirals (DAAs) and addition of RBV improves NK cell function in liver transplant (LTx) recipients.

METHODS

We analyzed NK cell degranulation and IFNγ-response along with STAT-1 and STAT-4 phosphorylation in 29 HCV-infected LTx-recipients and 17 HCV-infected patients during DAA-treatment.

RESULTS

Compared to uninfected LTx-recipients, NK cells from HCV-infected LTx-recipients were polarized towards cytotoxicity with increased CD107a-degranulation (10.1% vs 14.6%; P=0.0263) and reduced capacity to produce IFNγ (43.0% vs 26.7%; P=0.0002). The altered phenotype of NK cells in HCV-infected LTx-recipients was accompanied by increased STAT-1 (44.6% vs 87.4%; P<0.0001) and STAT-1 phosphorylation (0.7% vs 8.9%; P=0.0005) compared to pSTAT-4 IFNα-induction (29.9% vs 17.6%; P=0.0014). Successful DAA-therapy did not affect CD107a-degranulation, but decreased STAT-1. RBV cotreatment with DAA-therapy for HCV increased CD56Bright NK cell IFNγ-responses in LTx-recipients (70.9% vs 89.2%; P=0.002) and this correlated to an increase in the inducibility of pSTAT-4 (MFI 157 vs 173; P=0.0002).

CONCLUSION

RBV cotreatment of HCV-infection improved pSTAT4-dependent IFNγ-production in NK cells. This is relevant especially for immunocompromised patients such as LTx-recipients or patients with end-stage liver disease.

Dynamic Changes in Ex Vivo T-Cell Function After Viral Clearance in Chronic HCV Infection

BACKGROUND

Direct-acting antiviral (DAA) agents can successfully treat chronic hepatitis C virus (HCV) infection. However, the ex vivo HCV-specific T-cell function following viral clearance remains unknown.

METHODS

We investigated functional alterations and phenotypic changes in ex vivo HCV-specific CD8+ T cells with a longitudinal analysis of 41 patients with chronic HCV infection who were undergoing DAA treatment.

RESULTS

A patient subset exhibited a significantly increased T-cell response (mainly CD8+ T cells) at week 4 of treatment. However, this increased T-cell response diminished in later weeks. Relative to pretreatment levels, the ex vivo HCV-specific CD8+ T-cell frequency decreased at 12 weeks after the end of treatment, along with a decreased antigen-experienced CD8+ T-cell population. DAA treatment increased the proliferative capacity of HCV-specific CD8+ T cells, but this change was not correlated with ex vivo function. Patients experiencing viral breakthrough or relapse exhibited defective restoration of T-cell function.

CONCLUSION

Our present results indicated that DAA-mediated viral clearance only transiently restored ex vivo T-cell function, suggesting a need to enhance T-cell function in DAA-treated patients.

Peripheral PD-1+ T Cells Co-expressing Inhibitory Receptors Predict SVR With Ultra Short Duration DAA Therapy in HCV Infection

Direct acting antiviral (DAA) regimens of 12 weeks result in HCV clearance in vast majority of patients across genotypes. We previously demonstrated an ultra-short regimen of 4 weeks DAA cleared HCV in a subset of patients. Here, we hypothesized that individual level of antiviral immunity differentially influenced viral clearance and investigated biomarkers of a successful response. Cohorts of HCV patients treated for 4 weeks with DAA therapy who either achieved sustained virologic response (SVR) or relapsed were compared at baseline and at end of therapy (EOT) for immune cell phenotypes and HCV specific immunity. Higher levels of PD-1⁺ CD8⁺ and CD4⁺ T lymphocytes co-expressing inhibitory receptors (IR) were present at baseline and at EOT in HCV patients who eventually achieved SVR compared with those who relpased. HCV specific CD8⁺ T cells were predominantly contained within these IR expressing PD-1⁺ subsets. Patients in the SVR group had significantly higher CD8⁺ T cell degranulation in response to HCV peptides at baseline and higher levels of cytokine producing T cells at EOT time-point, relative to those who relapsed. In ex vivo cultures, PD-1⁺CD160⁺ CD8⁺ T cells had higher HCV specific degranulation and PD-1⁺2B4⁺ CD8⁺ T cells had higher cytokine expression (IFNγ⁺TNFα⁺ or IFNγ⁺CD107a⁺) compared with single or no IR expressing subsets, indicating higher virus specific functional capacity of these subsets. Receiver operating characteristics curve (ROC) for baseline circulating frequencies of PD-1⁺CD160⁺, PD-1⁺Tim-3⁺ CD8⁺ T cells and PD-1⁺CD160⁺, PD-1⁺Blimp-1⁺, PD-1^-CTLA4⁺ CD4⁺ T cells respectively, had associated C-statistics of 0.8214 and 0.9451 for discriminatin of patients who successfully cleared HCV with 4 weeks treatment. Thus, PD-1⁺ virus-specific CD8⁺ T cell subsets with cytotoxic capacity are present in a subset of chronic HCV infected individuals that associate with ability to achieve SVR, indicating role of immunity in DAA mediated viral clearance with short duration therapy.

In Chronic Hepatitis C Infection, Myeloid-Derived Suppressor Cell Accumulation and T Cell Dysfunctions Revert Partially and Late After Successful Direct-Acting Antiviral Treatment

Chronic HCV infection is characterized by several immunological alterations, such as the accumulation of suppressor cells and of hyperactivated T lymphocytes. However, it is unclear whether direct-acting antiviral (DAA)-mediated HCV clearance restores immune dysfunctions. We performed a phenotypic characterization by flow cytometry of different immune cell subsets, including monocytic myeloid-derived suppressor cells (M-MDSCs) and T lymphocytes in 168 patients with persistent HCV infection not treated, under DAA therapies and sustained virological responders. Chronic HCV infection prompted the accumulation of M-MDSCs independently of patient and clinical characteristics, and altered their metabolic properties. HCV RNA was undetectable in the majority of patients just after few weeks of DAA therapy, whereas M-MDSC levels normalized only 6 months after therapy. In addition, HCV infection deeply perturbed the T cell compartment since a re-distribution of memory CD4⁺ and CD8⁺ T cells was observed at the expenses of naïve cells, and memory T lymphocytes displayed increased activation. Notably, these features were only partially restored by DAA therapies in the CD4, but not in the CD8, compartment as high immune activation levels persisted in the terminally differentiated memory CD8⁺ T cells even more than 1 year after sustained virological response. Together, these results suggest that successful DAA therapies do not lead to full immunological reconstitution as fast as viral clearance.