Immunological Analysis During Interferon-Free Therapy for Chronic Hepatitis C Virus Infection Reveals Modulation of the Natural Killer Cell Compartment

Immune activation in prolonged cART-suppressed HIV patients is comparable to that of healthy controls

Sustained immune activation during chronic HIV infection is considered to augment co-morbidity and mortality. Effective combination antiretroviral therapy (cART) has shown to dampen immune activation especially during the first year cART, but the effects of long-term cART in patients without major comorbidities remains under-investigated. We performed a comprehensive analysis including cellular, intracellular and plasma biomarkers to study the effect of cART on immune parameters in 5 groups of 10 HIV patients. All patients were without major co-morbidities and grouped based on cART duration (0, 1, 3, 5, and 10 years). We included 10 matched healthy controls for comparison. Our data show that after the first year of cART, no additional effect on the level of inflammatory markers is observed in HIV infected patients without major co morbidities. Residual immune activation status in well-treated HIV-infection is similar to levels observed in healthy controls.

On-treatment decrease of NKG2D correlates to early emergence of clinically evident hepatocellular carcinoma after interferon-free therapy for chronic hepatitis C

Background and aims

Interferon (IFN)- free direct antiviral agents (DAAs) with rapid HCV eradication might evoke immunological reconstitutions, and some early recurrences of HCC after IFN-free DAAs have been reported. This study aimed to investigate whether natural killer group 2, member D (NKG2D) predicts early emergence of HCC after IFN-free DAAs.

Methods

We conducted a clinical practice-based observational study of 101 patients infected with genotype 1 HCV who received IFN-free (DAAs), and stratified them into those who did or did not develop early (i.e., during the 6-month surveillance period following treatment.) recurrence or occurrence of clinically evident HCC. We also analyzed the peripheral blood mononuclear cells, both before treatment and at end of treatment (EOT), of 24 of the patients who received IFN-free DAAs, and 16 who received IFN-combined protease inhibitor.

Results

We found early emergence of clinically evident HCC after IFN-free DAAs in 12 (12%) patients. Higher pre-treatment NKG2D expression, higher FIB-4 score, previous HCC history and failure to achieve sustained viral response were significant factors correlating to early HCC emergence. After IFN-free DAAs, a rapid decrease of NKG2D at EOT correlated with early HCC emergence in the IFN-free DAA-treated patients, but not in patients treated with the IFN-combined regimen. The decrease of NKG2D until EOT was predictive of early HCC emergence at a cut-off of -52% (AUC = 0.92).

Conclusions

On-treatment decrease of NKG2D may be a useful predictor of early emerging HCC in patients treated with IFN-free DAAs.

Hepatitis C virus drives increased type I interferon-associated impairments associated with fibrosis severity in antiretroviral treatment-treated HIV-1-hepatitis C virus-coinfected individuals

BACKGROUND

Viral coinfections might contribute to the increased immune activation and inflammation that persist in antiretroviral treatment (ART)-treated HIV-1 patients. We investigated whether the hepatitis C virus (HCV) coinfection contributes to such alterations by impairing the plasmacytoid dendritic cell (pDC) IFNα/TLR7 pathway in a highly homogeneous group of ART-treated HIV-1-HCV-coinfected patients.

METHODS

Twenty-nine HIV-1-infected patients with fully suppressive ART were included, 15 of whom being HCV-coinfected with mild-to-moderate fibrosis and matched for their HIV-1 disease, and 13 control healthy donors. Cellular activation, plasma levels of inflammatory cytokines and pDC transcriptome associated with IFNα/TLR7 pathway were characterized.

RESULTS

Higher plasma levels of type-I interferon (IFN)-associated cytokines [interferon gamma-induced protein 10 (IP-10), MIP-1β, IL-8 and IFN-inducible T-cell alpha chemoattractant) were observed in HIV-1-HCV-coinfected than in HIV-1-monoinfected patients (P = 0.0007, 0.028, 0.028 and 0.035, respectively). The pDCs and T cells displayed a more exhausted (LAG-3+ and CD57+, respectively) phenotype. The pDC IFNα pathway (defined by phosphorylated STAT1 expression) was constitutively activated in all patients, irrespective of HCV coinfection. Expression of interferon-stimulated genes (ISGs) EI2AK2, ISG15, Mx1 and IFI44 was increased in pDCs from HIV-1-HCV-coinfected individuals and was correlated with fibrosis score (Fibroscan, www.echosens.com, Paris, France and aspartate-aminotransferase/platelet-ratio index score, P = 0.026 and 0.019, respectively). Plasma levels of IP-10, STAT1 expression in pDCs and Mx1 mRNA levels in pDCs decreased after interferon-free anti-HCV treatment.

CONCLUSION

HCV replication appears to drive increases in type-I IFN-associated inflammation and ISGs expression in pDCs, in association with fibrosis severity in ART-treated HIV-1-infected patients with mild-to-moderate fibrosis. Preliminary results indicate reduction of these alterations with earlier interferon-free anti-HCV treatment in those patients.

Hepatitis B reactivation during or after direct acting antiviral therapy - implication for susceptible individuals

INTRODUCTION

The FDA issued a warning following 24 cases of HBV reactivation during DAA therapy for HCV, including individuals with inactive, occult and past HBV infection. Clinical presentations ranged from asymptomatic fluctuations in HBV DNA to fulminant hepatic failure, liver transplantation and death. The mechanism is unknown. Areas covered: HCV/HBV coinfection is common, particularly in regions endemic for HBV. HCV and HBV utilize host factors to support replication; both viruses evade/impair host immunity. Clinical presentations of HBV reactivation during DAAs are summarized. Other causes of HBV reactivation are revisited and recent data regarding HBV reactivation are presented. Expert opinion: HBV reactivation during DAAs for HCV occurs, with life-threatening consequences in some individuals. The risk of HBV reactivation is observed in all HBV stages. The rapid removal of HCV likely alters and liberates host-viral ± viral-viral interactions that lead to increased HBV replication. As immune reconstitution occurs with HCV removal, host recognition of HBV DNA likely ensues followed by vigorous host immune responses leading to liver injury (HBV flare). These cases highlight the importance of HBV testing prior to initiating DAA therapy, the need for close monitoring of HBV during therapy and timely administration of anti-HBV therapy to prevent serious sequelae.

Hepatitis C Virus and Human Cytomegalovirus-Natural Killer Cell Subsets in Persistent Viral Infections

Hepatitis C virus (HCV) and human cytomegalovirus (HCMV) are prominent examples of RNA and DNA viruses, respectively, that establish a persistent infection in their host. HCV affects over 185 million patients worldwide, who are at high risk for developing liver fibrosis, liver cirrhosis, and ultimately hepatocellular carcinoma. Recent breakthroughs in HCV therapy, using direct-acting antivirals have provided the opportunity to monitor natural killer (NK) cells after clearance of a chronic infection. There is now increasing evidence that the individual NK cell repertoire before infection is predictive for the course of disease. HCMV affects the majority of the global population. While being asymptomatic in healthy individuals, HCMV represents a severe clinical challenge in immunocompromised patients. Both viral infections, HCV and HCMV, lead to long-lasting and profound alterations within the entire NK cell compartment. This review article, will discuss the diverse range of changes in the NK cell compartment as well as potential consequences for the course of disease.

Dynamic Changes of the Frequency of Classic and Inflammatory Monocytes Subsets and Natural Killer Cells in Chronic Hepatitis C Patients Treated by Direct-Acting Antiviral Agents

OBJECTIVE

Up to now, little was known about the immunological changes of chronic hepatitis C (CHC) patients treated with direct-acting antiviral agents (DAAs); we try to explore the effect of DAAs on the frequency of monocytes, NK cells, and cytokines that promote their activation.

METHODS

15 treatment-naive CHC patients and 10 healthy controls were recruited. Patients were examined before DAAs therapy (0 w) and at week 4 (4 w) and week 12 (12 w) of therapy. Percentage of monocytes and NK cells of the peripheral blood was analyzed by flow cytometry. Serum cytokines IL-12, IL-18, CXCL10, CXCL11, sCD14, and sCD163 were measured by enzyme linked immunosorbent assay.

RESULTS

The frequency of CD3-CD16+CD56+ NK cells and classic CD14++CD16- monocytes decreased, while CD14+CD16+ monocytes and cytokines IL-12, IL-18, CXCL10, CXCL11, sCD14, and sCD163 increased at 0 w compared to healthy controls. During DAAs treatment, the decreased NK cells and classic monocytes gradually increased to normal levels; the increased inflammatory monocytes and cytokines IL-12 and CXCL11 decreased to normal levels, but the increased cytokines IL-18, CXCL10, sCD14, and sCD163 still remained at high levels at 12 w though they decreased rapidly from 0 w.

CONCLUSION

Our results showed that DAAs treatment attenuated the activation of monocytes and NK cells in CHC patients. Trial registration number is NCT03063723.

Increased peripheral CD4+ regulatory T cells persist after successful direct-acting antiviral treatment of chronic hepatitis C

BACKGROUND & AIMS

CD4⁺ regulatory T cells (Tregs) expand during chronic hepatitis C virus (HCV) infection, inhibit antiviral immunity and promote fibrosis. Direct-acting antiviral agents (DAA) have revolutionized HCV therapy. However, it is unclear if Tregs are normalized after DAA-induced HCV elimination.

METHODS

We analyzed Tregs before (baseline), at end of therapy (EOT), 12 and 24weeks (SVR12, SVR24) and long-term (51±14weeks) after EOT in 26 genotype-1-infected patients who were successfully treated with sofosbuvir (SOF) plus interferon (IFN)/ribavirin (n=12) and IFN-free DAA regimens (SOF plus daclatasvir or simeprevir; n=14). Frequency, phenotype and suppressor function of peripheral Foxp3⁺ CD25⁺ CD4⁺ T cells were studied by multi-color flow cytometry and co-culture inhibition assays.

RESULTS

Frequencies and activation status of Foxp3⁺ CD25⁺ CD4⁺ T cells remained elevated above those of normal controls in both treatment groups even long-term after HCV elimination. Co-culture assays indicated a dose-response relationship for functional inhibition of autologous CD4⁺ effector T cells and confirmed that activation of Tregs remained largely unchanged over the observation period. Unlike IFN-free regimens, SOF plus IFN/ribavirin induced a transiently increased frequency of Foxp3⁺ CD25⁺ CD4⁺ T cells at EOT (5.0% at baseline to 6.1% at EOT; p=0.001). These Foxp3⁺ CD25⁺ CD4⁺ T cells co-expressed the activation markers glycoprotein A repetitions predominant (GARP; p=0.012) and tumor necrosis factor receptor superfamily, member 4 (OX-40; p=0.001) but showed unchanged in vitro inhibitory activity.

CONCLUSION

Although IFN-based DAA therapy induced transient expansion of activated Foxp3⁺ CD25⁺ CD4⁺ T cells, neither IFN-based nor IFN-free DAA regimens normalized frequencies and activation status of Tregs one year after viral elimination. Persistence of immunosuppressive Tregs may thus contribute to complications of liver disease even long-term after HCV cure.

LAY SUMMARY

In chronic hepatitis C virus (HCV) infection, CD4⁺ regulatory T cells (Tregs) can reduce antiviral immune responses, promote liver fibrosis and may increase the risk for liver cancer, because they gradually expand during disease. Modern direct-acting antiviral agents (DAA) can "cure" hepatitis C in almost all treated patients. However, our study shows that DAA do not normalize the increased frequency and activation status of Tregs even long-term after HCV elimination. Tregs may persistently modulate functions of the immune system even after "cure" of hepatitis C.

Immunological Predictors of Nonresponse to Directly Acting Antiviral Therapy in Patients With Chronic Hepatitis C and Decompensated Cirrhosis

BACKGROUND

Sustained virological response rates (SVRs) to directly acting antiviral (DAA) therapy for hepatitis C virus (HCV) are lower in decompensated cirrhosis. Markers of innate immunity predict nonresponse to interferon-based HCV treatment; however, whether they are associated with the response to DAAs in patients with decompensation is not known.

METHODS

Information on demographics, adherence, viral kinetics, and resistance were gathered prospectively from a cohort with decompensated cirrhosis treated with 12 weeks of DAAs. C-X-C motif chemokine-10 (CXCL-10) level and T-cell and natural killer (NK) cell phenotype were analyzed pretreatment and at 4 and 12 weeks of treatment.

RESULTS

Of 32 patients, 24 of 32 (75%) achieved SVR (responders). Eight of 32 (25%) experienced relapse after the end of treatment (nonresponders). There were no differences in demographics or adherence between groups. Nonresponders had higher CXCL-10; 320 pg/mL (179461) vs 109 pg/mL (88170) in responders (P < .001) and differential CXCL-10 dynamics. Nonresponders had lower NK cell frequency, higher expression of activation receptor NKp30, and lower frequency of the NK subset CD56^-CD16⁺.

CONCLUSIONS

Nonresponders to DAAs displayed a different NK phenotype and CXCL-10 profile to responders. Nonresponders did not have poorer adherence or baseline virological resistance, and this shows that immunological parameters are associated with treatment response to interferon-free treatment for HCV in individuals with decompensated cirrhosis.

Hepatitis C-related hepatocellular carcinoma in the era of new generation antivirals

Hepatitis C virus infection is a major cause of hepatocellular carcinoma worldwide. Interferon has been the major antiviral treatment, yielding viral clearance in approximately half of patients. New direct-acting antivirals substantially improved the cure rate to above 90%. However, access to therapies remains limited due to the high costs and under-diagnosis of infection in specific subpopulations, e.g., baby boomers, inmates, and injection drug users, and therefore, hepatocellular carcinoma incidence is predicted to increase in the next decades even in high-resource countries. Moreover, cancer risk persists even after 10 years of viral cure, and thus a clinical strategy for its monitoring is urgently needed. Several risk-predictive host factors, e.g., advanced liver fibrosis, older age, accompanying metabolic diseases such as diabetes, persisting hepatic inflammation, and elevated alpha-fetoprotein, as well as viral factors, e.g., core protein variants and genotype 3, have been reported. Indeed, a molecular signature in the liver has been associated with cancer risk even after viral cure. Direct-acting antivirals may affect cancer development and recurrence, which needs to be determined in further investigation.

Immune regulation in chronic hepatitis C virus infection

The immunological result of infection with Hepatitis C virus (HCV) depends on the delicate balance between a vigorous immune response that may clear the infection, but with a risk of unspecific inflammation and, or a less inflammatory response that leads to chronic infection. In general, exhaustion and impairment of cytotoxic function of HCV-specific T cells and NK cells are found in patients with chronic HCV infection. In contrast, an increase in immune regulatory functions is found primarily in form of increased IL-10 production possibly due to increased level and function of anti-inflammatory Tregs. Thus, the major immune players during chronic HCV infection are characterized by a decrease of cytotoxic function and increase of inhibitory functions. This may be an approach to diminish intrahepatic and systemic inflammation. Finally, there has been increasing awareness of regulatory functions of epigenetic changes in chronic HCV infection. A vast amount of studies have revealed the complexity of immune regulation in chronic HCV infection, but the interplay between immune regulation in virus and host remains incompletely understood. This review provides an overview of regulatory functions of HCV-specific T cells, NK cells, Tregs, IL-10, and TGF-β, as well as epigenetic changes in the setting of chronic HCV infection.

Ledipasvir plus sofosbuvir fixed-dose combination for 6 weeks in patients with acute hepatitis C virus genotype 1 monoinfection (HepNet Acute HCV IV): an open-label, single-arm, phase 2 study

BACKGROUND

Early treatment of acute hepatitis C virus (HCV) infection with interferon alfa is highly effective, but can be associated with frequent side-effects. We investigated the safety and efficacy of an interferon-free regimen for treatment of acute HCV infection.

METHODS

In this prospective, open-label, multicentre, single-arm pilot study, we enrolled adults (≥18 years) with acute HCV genotype 1 monoinfection from ten centres in Germany. Patients were given ledipasvir (90 mg) plus sofosbuvir (400 mg) as a fixed-dose combination tablet once daily for 6 weeks. The primary efficacy outcome was the proportion of patients with sustained virological response (defined as undetectable HCV RNA 12 weeks after the end of treatment; other primary outcomes were safety and tolerability of ledipasvir plus sofosbuvir. The primary analysis population consisted of all patients who received at least one dose of study drug. Safety was also assessed in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, number NCT02309918.

FINDINGS

Between Nov 19, 2014, and Nov 10, 2015, we enrolled 20 patients. Median HCV RNA viral load at baseline was 4·04 log₁₀ IU/mL (1·71-7·20); 11 patients were infected with HCV genotype 1a and nine patients with genotype 1b. All patients achieved a sustained virological response 12 weeks after the end of treatment (20 [100%] of 20 patients). Treatment was well tolerated; there were no drug-related serious adverse events. Up to 12 weeks after treatment, 22 possible or probable drug-related adverse events were reported. There was one serious adverse event, which was judged unrelated to the study drug; one patient was admitted to hospital for surgery of a ruptured cruciate ligament.

INTERPRETATION

Treatment for 6 weeks with ledipasvir plus sofosbuvir was well tolerated and highly effective in patients with acute HCV genotype 1 monoinfection. Short-duration treatment of acute hepatitis C might prevent the spread of HCV in high-risk populations.

FUNDING

Gilead Sciences, HepNet Study-House/German Liver Foundation, and German Centre for Infection Research (DZIF).

Early occurrence and recurrence of hepatocellular carcinoma in HCV-related cirrhosis treated with direct-acting antivirals

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) represents a serious complication of HCV-related cirrhosis. New direct-acting antivirals (DAA) cure HCV infection in over 90% of patients. The aim of this study was to evaluate the early occurrence and recurrence of HCC in cirrhotic patients treated with DAA.

METHODS

We analysed 344 consecutive cirrhotic patients, without HCC, who were treated with DAA, and followed for 24weeks. Fifty-nine patients had previous HCC.

RESULTS

DAA therapy induced sustained virological response in 91% of patients. During 24-week follow-up, HCC was detected in 26 patients (7.6%, 95% CI: 4.99-10.84): 17 of 59 patients (28.81%, 95% CI: 17.76-42.07) with previous HCC and 9 of 285 patients (3.16%, 95% CI: 1.45-5.90) without previous HCC. Child-Pugh Class B, more severe liver fibrosis, lower platelet count, and previous HCC were significantly associated with HCC development, at univariate analysis. At multivariate analysis, Child-Pugh class (p=0.03, OR: 4.18, 95% CI: 1.17-14.8) and history of HCC (p<0.0001, OR: 12.0, 95% CI: 4.02-35.74) resulted independently associated with HCC development. Among the 59 patients with previous HCC, younger age and more severe liver fibrosis were significantly associated with HCC recurrence, both at univariate and at multivariate analysis.

CONCLUSIONS

In patients with HCV-related cirrhosis, DAA-induced resolution of HCV infection does not seem to reduce occurrence of HCC, and patients previously treated for HCC have still a high risk of tumour recurrence, in the short term. For these reasons, all cirrhotic patients should be closely monitored and followed during and after antiviral therapy.

LAY SUMMARY

New direct-acting antivirals are able to eradicate HCV infection in over 90% of patients with advanced liver disease. Unfortunately, the occurrence of liver cancer is not reduced in effectively treated cirrhotic patients. In addition, patients previously treated for HCC have still a high risk of tumour recurrence in the short term, despite DAA treatment.

Herpes virus reactivation after initiation of interferon-free antiviral agents in HIV-HCV-coinfected subjects: a new immune restoration disease?

We report four HCV-HIV-coinfected patients who developed herpes zoster or muco-cutaneous herpes virus disease shortly after starting interferon-free antiviral treatment for HCV. We suggest that in our patients the prompt clearance of HCV following direct-acting antivirals leads to a paradoxical effect on the innate and adaptive immune system mediating the reactivation of herpetic infection.

Interferon Alpha Induces Sustained Changes in NK Cell Responsiveness to Hepatitis B Viral Load Suppression In Vivo

NK cells are important antiviral effectors, highly enriched in the liver, with the potential to regulate immunopathogenesis in persistent viral infections. Here we examined whether changes in the NK pool are induced when patients with eAg-positive CHB are 'primed' with PegIFNα and importantly, whether these changes are sustained or further modulated long-term after switching to nucleos(t)ides (sequential NUC therapy), an approach currently tested in the clinic. Longitudinal sampling of a prospectively recruited cohort of patients with eAg+CHB showed that the cumulative expansion of CD56bright NK cells driven by 48-weeks of PegIFNα was maintained at higher than baseline levels throughout the subsequent 9 months of sequential NUCs. Unexpectedly, PegIFNα-expanded NK cells showed further augmentation in their expression of the activating NK cell receptors NKp30 and NKp46 during sequential NUCs. The expansion in proliferating, functional NK cells was more pronounced following sequential NUCs than in comparison cohorts of patients treated with de novo NUCs or PegIFNα only. Reduction in circulating HBsAg concentrations, a key goal in the path towards functional cure of CHB, was only achieved in those patients with enhancement of NK cell IFNγ and cytotoxicity but decrease in their expression of the death ligand TRAIL. In summary, we conclude that PegIFNα priming can expand a population of functional NK cells with an altered responsiveness to subsequent antiviral suppression by NUCs. Patients on sequential NUCs with a distinct NK cell profile show a decline in HBsAg, providing mechanistic insights for the further optimisation of treatment strategies to achieve sustained responses in CHB.

Frequencies of Circulating MAIT Cells Are Diminished in Chronic HCV, HIV and HCV/HIV Co-Infection and Do Not Recover during Therapy

OBJECTIVE

Mucosal-associated invariant T (MAIT) cells comprise a subpopulation of T cells that can be activated by bacterial products and cytokines to produce IFN-γ. Since little is known on MAIT cells during HCV infection, we compared their phenotype and function in comparison to HIV and HCV/HIV co-infected patients, and determined the effect of IFN-α-based and direct-acting antiviral therapy on MAIT cells of HCV patients.

METHODS

Blood samples from patients with chronic HCV (CHCV), virologically suppressed HIV, acute HCV/HIV co-infection (AHCV/HIV) and healthy individuals were examined by flowcytometry for phenotype and function of MAIT and NK cells.

RESULTS AND CONCLUSIONS

Compared to healthy individuals, the frequency of CD161+Vα7.2+ MAIT cells was significantly decreased in patients with CHCV, HIV and AHCV/HIV co-infection. CD38 expression on MAIT cells was increased in AHCV/HIV patients. MAIT cells were responsive to IFN-α in vitro as evidenced by enhanced frequencies of IFN-γ producing cells. IFN-α-based therapy for CHCV decreased the frequency of IFN-γ+ MAIT cells, which was still observed 24 weeks after successful therapy. Importantly, even after successful IFN-α-based as well as IFN-α-free therapy for CHCV, decreased frequencies of MAIT cells persisted. We show that the frequencies of MAIT cells are reduced in blood of patients with CHCV, HIV and in AHCV/HIV co-infection compared to healthy individuals. Successful therapy for CHCV did not normalize MAIT cell frequencies at 24 weeks follow up. The impact of HIV and HCV infection on the numbers and function of MAIT cells warrant further studies on the impact of viral infections and the antimicrobial function of MAIT cells.

Natural Killer Cells in Viral Hepatitis

Natural killer (NK) cells are traditionally regarded as first-line effectors of the innate immune response, but they also have a distinct role in chronic infection. Here, we review the role of NK cells against hepatitis C virus (HCV) and hepatitis B virus (HBV), two agents that cause acute and chronic hepatitis in humans. Interest in NK cells was initially sparked by genetic studies that demonstrated an association between NK cell-related genes and the outcome of HCV infection. Viral hepatitis also provides a model to study the NK cell response to both endogenous and exogenous type I interferon (IFN). Levels of IFN-stimulated genes increase in both acute and chronic HCV infection and pegylated IFNα has been the mainstay of HCV and HBV treatment for decades. In chronic viral hepatitis, NK cells display decreased production of antiviral cytokines. This phenotype is found in both HCV and HBV infection but is induced by different mechanisms. Potent antivirals now provide the opportunity to study the reversibility of the suppressed cytokine production of NK cells in comparison with the antigen-induced defect in IFNγ and tumor necrosis factor-α production of virus-specific T cells. This has implications for immune reconstitution in other conditions of chronic inflammation and immune exhaustion, such as human immunodeficiency virus infection and cancer.