Dynamic changes in innate immune responses during direct-acting antiviral therapy for HCV infection

Single-cell atlas of the liver myeloid compartment before and after cure of chronic viral hepatitis

BACKGROUND & AIMS

Chronic viral infections present serious public health challenges; however, direct-acting antivirals (DAAs) are now able to cure nearly all patients infected with hepatitis C virus (HCV), representing the only cure of a human chronic viral infection to date. DAAs provide a valuable opportunity to study immune pathways in the reversal of chronic immune failures in an in vivo human system.

METHODS

To leverage this opportunity, we used plate-based single-cell RNA-seq to deeply profile myeloid cells from liver fine needle aspirates in patients with HCV before and after DAA treatment. We comprehensively characterised liver neutrophils, eosinophils, mast cells, conventional dendritic cells, plasmacytoid dendritic cells, classical monocytes, non-classical monocytes, and macrophages, and defined fine-grained subpopulations of several cell types.

RESULTS

We discovered cell type-specific changes post-cure, including an increase in MCM7+STMN1+ proliferating CD1C+ conventional dendritic cells, which may support restoration from chronic exhaustion. We observed an expected downregulation of interferon-stimulated genes (ISGs) post-cure as well as an unexpected inverse relationship between pre-treatment viral load and post-cure ISG expression in each cell type, revealing a link between viral loads and sustained modifications of the host's immune system. We found an upregulation of PD-L1/L2 gene expression in ISG-high neutrophils and IDO1 expression in eosinophils, pinpointing cell subpopulations crucial for immune regulation. We identified three recurring gene programmes shared by multiple cell types, distilling core functions of the myeloid compartment.

CONCLUSIONS

This comprehensive single-cell RNA-seq atlas of human liver myeloid cells in response to cure of chronic viral infections reveals principles of liver immunity and provides immunotherapeutic insights.

CLINICAL TRIAL REGISTRATION

This study is registered at ClinicalTrials.gov (NCT02476617).

IMPACT AND IMPLICATIONS

Chronic viral liver infections continue to be a major public health problem. Single-cell characterisation of liver immune cells during hepatitis C and post-cure provides unique insights into the architecture of liver immunity contributing to the resolution of the first curable chronic viral infection of humans. Multiple layers of innate immune regulation during chronic infections and persistent immune modifications after cure are revealed. Researchers and clinicians may leverage these findings to develop methods to optimise the post-cure environment for HCV and develop novel therapeutic approaches for other chronic viral infections.

Hepatitis C Virus and the Host: A Mutual Endurance Leaving Indelible Scars in the Host's Immunity

Hepatitis C virus (HCV) has spread worldwide, and it is responsible for potentially severe chronic liver disease and primary liver cancer. Chronic infection remains for life if not spontaneously eliminated and viral persistence profoundly impairs the efficiency of the host's immunity. Attempts have been made to develop an effective vaccine, but efficacy trials have met with failure. The availability of highly efficacious direct-acting antivirals (DAA) has created hope for the progressive elimination of chronic HCV infections; however, this approach requires a monumental global effort. HCV elicits a prompt innate immune response in the host, characterized by a robust production of interferon-α (IFN-α), although interference in IFN-α signaling by HCV proteins may curb this effect. The late appearance of largely ineffective neutralizing antibodies and the progressive exhaustion of T cells, particularly CD8 T cells, result in the inability to eradicate the virus in most infected patients. Moreover, an HCV cure resulting from DAA treatment does not completely restore the normal immunologic homeostasis. Here, we discuss the main immunological features of immune responses to HCV and the epigenetic scars that chronic viral persistence leaves behind.

The Complex Interplay Relationship between HCV Infection, Direct-Acting Antiviral Therapy, and Hepatocellular Carcinoma Occurrence

The new direct-acting antivirals (DAAs) for chronic hepatitis C (CHC) are highly effective, despite the short duration of treatment, and very tolerable [...].

Sarcopenia in chronic viral hepatitis: From concept to clinical relevance

Although the frequency of metabolic risk factors for cirrhosis and hepatocellular carcinoma (HCC) is increasing, chronic hepatitis B (CHB) and chronic hepatitis C (CHC) remain the most relevant risk factors for advanced liver disease worldwide. In addition to liver damage, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are associated with a myriad of extrahepatic manifestations including mixed cryoglobulinaemia, lymphoproliferative disorders, renal disease, insulin resistance, type 2 diabetes, sicca syndrome, rheumatoid arthritis-like polyarthritis, and autoantibody production. Recently, the list has grown to include sarcopenia. Loss of muscle mass or muscle function is a critical feature of malnutrition in cirrhotic patients and has been found in approximately 23.0%-60.0% of patients with advanced liver disease. Nonetheless, among published studies, there is significant heterogeneity in the aetiologies of hepatic diseases and measurement methods used to determine sarcopenia. In particular, the interaction between sarcopenia, CHB and CHC has not been completely clarified in a real-world setting. Sarcopenia can result from a complex and multifaceted virus-host-environment interplay in individuals chronically infected with HBV or HCV. Thus, in the present review, we provide an overview of the concept, prevalence, clinical relevance, and potential mechanisms of sarcopenia in patients with chronic viral hepatitis, with an emphasis on clinical outcomes, which have been associated with skeletal muscle loss in these patients. A comprehensive overview of sarcopenia in individuals chronically infected with HBV or HCV, independent of the stage of the liver disease, will reinforce the necessity of an integrated medical/nutritional/physical education approach in the daily clinical care of patients with CHB and CHC.

Immunological scars after cure of hepatitis C virus infection: Long-HepC?

Hepatitis C virus (HCV) infection provides a unique opportunity to study the effects of spontaneous or treatment-induced viral elimination on the human immune system. Twenty to 50% of patients with acute HCV infection spontaneously clear the virus, which is related to the quality of the individual's immune response, while the chronic infection is associated with an altered and impaired immune response. Direct-acting antiviral agents are now available that provide sustained viral elimination in more than 95% of patients with chronic HCV infection. Viral elimination leads to a decrease in disease sequelae such as cirrhosis and hepatocellular carcinoma, and extrahepatic manifestations also improve. However, some patients may still experience long-term complications, and viral elimination does not protect against HCV reinfection. This review addresses the question of whether the altered and impaired immune response caused by HCV normalizes after viral elimination and if this may affect the long-term clinical course after HCV cure.

Transcriptional responses define dysregulated immune activation in Hepatitis C (HCV)-naïve recipients of HCV-infected donor kidneys

Renal transplantation from hepatitis C (HCV) nucleic acid amplification test-positive (NAAT-positive) donors to uninfected recipients has greatly increased the organ donation pool. However, there is concern for adverse outcomes in these recipients due to dysregulated immunologic activation secondary to active inflammation from acute viremia at the time of transplantation. This includes increased rates of cytomegalovirus (CMV) DNAemia and allograft rejection. In this study, we evaluate transcriptional responses in circulating leukocytes to define the character, timing, and resolution of this immune dysregulation and assess for biomarkers of adverse outcomes in transplant patients. We enrolled 67 renal transplant recipients (30 controls, 37 HCV recipients) and performed RNA sequencing on serial samples from one, 3-, and 6-months post-transplant. CMV DNAemia and allograft rejection outcomes were measured. Least absolute shrinkage and selection operator was utilized to develop gene expression classifiers predictive of clinical outcomes. Acute HCV incited a marked transcriptomic response in circulating leukocytes of renal transplant recipients in the acute post-transplant setting, despite the presence of immunosuppression, with 109 genes significantly differentially expressed compared to controls. These HCV infection-associated genes were reflective of antiviral immune pathways and generally resolved by the 3-month timepoint after sustained viral response (SVR) for HCV. Differential gene expression was also noted from patients who developed CMV DNAemia or allograft rejection compared to those who did not, although transcriptomic classifiers could not accurately predict these outcomes, likely due to sample size and variable time-to-event. Acute HCV infection incites evidence of immune activation and canonical antiviral responses in the human host even in the presence of systemic immunosuppression. After treatment of HCV with antiviral therapy and subsequent aviremia, this immune activation resolves. Changes in gene expression patterns in circulating leukocytes are associated with some clinical outcomes, although larger studies are needed to develop accurate predictive classifiers of these events.

HCV Cure With Direct-Acting Antivirals Improves Liver and Immunological Markers in HIV/HCV-Coinfected Patients

Hepatitis C virus (HCV) cure after all-oral direct-acting antiviral (DAA) therapy greatly improves the liver and immune system. We aimed to assess the impact of this HCV clearance on immune system-related markers in plasma and the gene expression profile in human immunodeficiency virus (HIV)/HCV-coinfected patients with advanced cirrhosis. We performed a prospective study on 33 HIV/HCV-coinfected patients at baseline and 36 weeks after the sustained virological response. Gene expression was evaluated by RNA-seq analysis on peripheral blood mononuclear cells (PBMCs) and plasma biomarkers by multiplex immunoassays. We found a decrease in plasma biomarkers (PD1, PDL1, CXCL10, CXCL8, IL12p70, IL10, and TGFβ) and liver disease markers (stiffness measurement (LSM), hepatic venous pressure gradient (HVPG), and transaminases, among others). Furthermore, decreased plasma levels of CXCL8, CXCL10, IL10, and PD1 were associated with reduced LSM values. We also found two upregulated (HAS1 and IRG1) and 15 downregulated (CXCL11, CCL8, CCL7, CCL2, ADARB2, RRAD, MX1, SIGLEC1, IFI44L, IFI44, IFI27, IFI6, IFIT3, IFIT1B, and IFIT1) genes at the end of follow-up, all interferon-stimulated genes (ISGs) grouped into four pathways (“cytokine-cytokine receptor interaction”, “viral protein interaction with cytokine and cytokine receptor”, “chemokine signaling pathway”, and “hepatitis C”). Additionally, the decrease in most of these ISGs was significantly related to reduced LSM and HVPG values. In conclusion, HIV/HCV-coinfected patients with advanced-HCV-related cirrhosis who eradicated HCV following DAA therapy exhibited an improvement in liver disease markers and a significant decrease in plasma biomarkers and gene expression related to antiviral/inflammatory response, particularly in levels of several chemokines and ISGs.

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.

Differentiation of exhausted CD8+ T cells after termination of chronic antigen stimulation stops short of achieving functional T cell memory

T cell exhaustion is associated with failure to clear chronic infections and malignant cells. Defining the molecular mechanisms of T cell exhaustion and reinvigoration is essential to improving immunotherapeutic modalities. Here we confirmed pervasive phenotypic, functional, and transcriptional differences between memory and exhausted antigen-specific CD8+ T cells in human hepatitis C virus (HCV) infection before and after treatment. After viral cure, phenotypic changes in clonally stable exhausted T cell populations suggested differentiation towards a memory-like profile. However, functionally, the cells showed little improvement and critical transcriptional regulators remained in the exhaustion state. Notably, T cells from chronic HCV infection that were exposed to antigen for less time because of viral escape mutations were functionally and transcriptionally more similar to memory T cells from spontaneously resolved HCV infection. Thus, T cell stimulation duration impacts exhaustion recovery, with antigen removal after long-term exhaustion being insufficient for development of functional T cell memory.

Distinct Immune Imprints of Post-Liver Transplantation Hepatitis C Persist Despite Viral Clearance

Recurrence or de novo infection of hepatitis C virus (HCV) after liver transplantation (LT) has been associated with progressive graft hepatitis that can be improved by treatment with novel direct-acting antivirals. Cases of rejection episodes have been described during and after HCV treatment. The evolution of innate and adaptive immune response during and after cure of HCV LT is unknown. We studied 74 protein biomarkers in the plasma of LT patients receiving antiviral therapy. In addition, deep immune phenotyping of both the myeloid and lymphoid immune cell subsets in peripheral blood mononuclear cells was performed. We found that LT patients with active HCV infection displayed distinct alterations of inflammatory protein biomarkers, such as C-X-Cmotif chemokine 10 (CXCL10), caspase 8, C-C motif chemokine 20 (CCL20), CCL19, interferon γ, CUB domain-containing protein 1 (CDCP1), interleukin (IL)-18R1, CXCL11, CCL3, IL8, IL12B, tumor necrosis factor-beta, CXCL6, osteoprotegerin, IL10, fms-related tyrosine kinase 3 ligand, hepatocyte growth factor, urokinase-type plasminogen activator, neurotrophin-3, CCL4, IL6, tumornecrosis factor receptor superfamily member 9, programmed death ligand 1, IL18, and monocyte chemotactic protein 1, and enrichment of peripheral immune cell subsets unlike patients without HCV infection who received transplants. Interestingly, patients who cleared HCV after LT did not normalize the altered inflammatory milieu nor did the peripheral immune cell subsets normalize to what would be seen in the absence of HCV recurrence. Overall, these data indicate that HCV-specific imprints on inflammatory analytes and immune cell subsets after LT are not completely normalized by therapy-induced HCV elimination. This is in line with the clinical observation that cure of HCV after LT did not trigger rejection episodes in many patients.

Immunological Mechanisms for Hepatocellular Carcinoma Risk after Direct-Acting Antiviral Treatment of Hepatitis C Virus Infection

Direct-acting antiviral agents (DAAs) that allow for rapid clearance of hepatitis C virus (HCV) may evoke immunological changes. Some cases of rapid de novo hepatocellular carcinoma (HCC) development or early recurrence of HCC after DAA treatment have been reported. During chronic HCV infection, natural killer (NK) cells exhibited a deviant functional phenotype with decreased production of antiviral cytokines and increased cytotoxicity; however, DAA treatment rapidly decreased their cytotoxic function. Effective DAA therapy also suppressed the intrahepatic activation of macrophages/monocytes. This was followed by a decrease in mucosal-associated invariant T (MAIT) cell cytotoxicity without normalization of cytokine production. Rapid changes in the phenotypes of NK and MAIT cells after DAA treatment may attenuate the cytotoxicity of these cells against cancer cells. Moreover, DAA treatment did not normalize the increased frequencies of regulatory T cells even after clearance of HCV infection. Thus, the persistently increased frequency of regulatory T cells may contribute to a local immunosuppressive milieu and hamper the clearance of cancer cells. This review will focus on recent studies describing the changes in innate and adaptive immune responses after DAA treatment in patients with chronic HCV infection in the context of de novo occurrence or recurrence of HCC.

Reconstitution of T follicular helper-humoral immune axis with elimination of hepatitis C virus

Exhaustion of Hepatitis C Virus (HCV)-specific T cells and abnormal B cell function is a hallmark of chronic HCV infection. Direct-acting antiviral (DAA) therapies are effective in achieving sustained virologic response (SVR), however, whether successful DAA treatment reconstitute T follicular helper (T_FH)-B cell axis in HCV patients is unclear. Here, we aimed to evaluate the immunological changes in global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and B cells in 20 HCV patients who achieved SVR with Sofosbuvir and Ledipasvir for 12 weeks and compared with 15 healthy controls (HC). Global and HCV-specific CD4 + CXCR5 + T_FH, CD4 + CXCR5-T and CD19 + B cells had significant phenotypic and functional reconstitution post DAA therapy. Reconstitution of effector, central and terminally differentiated memory cell population and increased ICOS and BCL6 expression was seen in HCV patients at SVR12. HCV-specific cytokines were also improved post DAA. Exhausted and regulatory B cells were declined whereas memory B cells were expanded post DAA therapy. Importantly, frequencies of T_FH cells were significantly associated with HCV RNA reduction, expansion of memory B and plasmablasts, while negatively associated with exhausted/regulatory B cells. Our results demonstrate that SVR with DAA therapy is effective in the reconstitution of phenotypic and functional abnormalities of T_FH-B cell axis.

Hepatitis B-related outcomes following direct-acting antiviral therapy in Taiwanese patients with chronic HBV/HCV co-infection

BACKGROUND & AIMS

The outcome of HBV infection, including the dynamics of HBsAg and HBV virological reactivation, among patients coinfected with HCV receiving direct-acting antivirals (DAAs) remains unclear. Thus, we aimed to analyze HBV-related outcomes in these patients.

METHODS

Serial HBsAg and HBV DNA levels were measured in 79 HBV/HCV-coinfected patients receiving DAAs (13 receiving anti-HBV nucleot(s)ide analog [NUC] therapy simultaneously). The endpoints included HBsAg dynamics and seroclearance, HBV reactivation (HBV DNA >1 log increase or >100 IU/ml if undetectable at baseline) and HBV-related clinical reactivation.

RESULTS

HBsAg levels declined from a median of 73.3 IU/ml at baseline to 16.2 IU/ml at the end-of-DAA treatment and increased to 94.1 IU/ml at 12 months post-treatment. During a mean 11.1-months of follow-up, 8 (10.1%) patients experienced HBsAg seroclearance and 30 (38.0%) HBV reactivation (12-month cumulative incidence, 10.3% and 40.4%, respectively). Patients with pre-treatment HBsAg ≤10 IU/ml had a significantly higher rate of HBsAg seroclearance (hazard ratio [HR] 8.52; 95% CI 1.048-69.312) and lower risk of HBV reactivation than those with pre-treatment HBsAg >10 IU/ml (HR 2.88; 95% CI 1.057-7.844) in multivariate analyses. Six patients (4 cirrhotics) not receiving NUC therapy experienced HBV-related clinical reactivation; 3 of the 4 cirrhotics developed liver failure and 2 died despite immediate NUC therapy. Compared to untreated HBV-monoinfected patients, HBV/HCV-coinfected patients without NUC prophylaxis had a similar rate of HBsAg seroclearance, but a significantly higher risk of HBV reactivation following DAA therapy (HR 6.59; 95% CI 2.488-17.432).

CONCLUSIONS

DAA-treated HBV/HCV-coinfected patients had significantly higher rates of HBV seroclearance, particularly among those with low pre-treatment HBsAg titer, but were at higher risk of HBV reactivation, particularly among those with higher pre-treatment HBsAg titer. Prophylactic anti-HBV therapy is essential for cirrhotic patients, irrespective of baseline HBV DNA levels.

LAY SUMMARY

We studied outcomes relating to hepatitis B virus (HBV) in patients coinfected with both hepatitis B and C. Patients receiving direct-acting antiviral treatment for hepatitis C were more likely to experience seroclearance (or functional cure of HBV), but were also more likely to experience HBV reactivation, which can lead to hepatitis, liver failure and death. In coinfected cirrhotic patients being treated for HCV, prophylactic treatment for HBV is mandatory.

Interferon Response in Hepatitis C Virus-Infected Hepatocytes: Issues to Consider in the Era of Direct-Acting Antivirals

When interferons (IFNs) bind to their receptors, they upregulate numerous IFN-stimulated genes (ISGs) with antiviral and immune regulatory activities. Hepatitis C virus (HCV) is a single-stranded, positive-sense RNA virus that affects over 71 million people in the global population. Hepatocytes infected with HCV produce types I and III IFNs. These endogenous IFNs upregulate a set of ISGs that negatively impact the outcome of pegylated IFN-α and ribavirin treatments, which were previously used to treat HCV. In addition, the IFNL4 genotype was the primary polymorphism responsible for a suboptimal treatment response to pegylated IFN-α and ribavirin. However, recently developed direct-acting antivirals have demonstrated a high rate of sustained virological response without pegylated IFN-α. Herein, we review recent studies on types I and III IFN responses to in HCV-infected hepatocytes. In particular, we focused on open issues related to IFN responses in the direct-acting antiviral era.

Relation of Reduction of Antibodies against Hepatitis B Virus to Hepatocellular Carcinoma Recurrence in the Patients with Resolved Hepatitis B Virus Infection Following Direct-acting Antiviral Therapy for Hepatitis C Virus Infection

Background

A possible interaction of hepatitis viruses at cellular and molecular levels has been suggested. Eradication of hepatitis C virus (HCV) has been reported to induce activation of hepatitis B virus (HBV)-related liver diseases.

Materials and methods

The present study examined association of HBV markers with recurrence of hepatocellular carcinoma (HCC) in patients with resolved HCV infection by direct-acting antiviral (DAA) therapy. In a patient pool of 378 patients with sustained virologic response (SVR) by DAA, the antibody to the hepatitis B surface antigen (anti-HBs), the antibody to the hepatitis B core antigen (anti-HBc), and HBV-DNA levels were estimated before and at the end of DAA therapy. These patients were HBsAg negative. Eighty-nine patients had a history of curative treatment of HCC by resection or radiofrequency ablation. A Cox proportional hazards model was used to identify risk factors for HCC recurrence, including the change ratio of the antibody against HBV proteins.

Results

Although 188 patients had resolved HBV infection, no patient showed HBV reactivation, but anti-HBs and anti-HBc levels decreased significantly. No significant difference in the HCC recurrence rate was evident between patients with and without resolved HBV infection. Changes of immune responses to HBV proteins did not affect HCC recurrence after DAA therapy for HCV infection in this cohort.

Conclusion

The mechanisms underlying diverse roles of DAA-induced SVR of HCV on HBV kinetics need to be resolved in future.

How to cite this article

Joko K, Mashiba T, Ochi H, et al. Relation of Reduction of Antibodies against Hepatitis B Virus to Hepatocellular Carcinoma Recurrence in the Patients with Resolved Hepatitis B Virus Infection Following Direct-acting Antiviral Therapy for Hepatitis C Virus Infection. Euroasian J Hepato-Gastroenterol 2019;9(2):78–83.

Outcome of cutaneous psoriasis in hepatitis C virus-infected patients treated with Direct-Acting Antiviral therapy

Apart from chronic liver disease, hepatitis C virus (HCV) may be responsible for several extra-hepatic manifestations. Its involvement in psoriasis development is still controversial. The aim of this study was to evaluate the possible effect of anti-HCV direct-acting antiviral (DAA) treatment on cutaneous psoriasis. Thirty-seven consecutive HCV patients with cutaneous psoriasis underwent efficacious DAA treatment, and all of them were efficiently cured as shown by HCV RNA negativity 24 weeks after stopping therapy (PT24W). An expert dermatologist evaluated the skin lesions at baseline, end of treatment (EOT) and PT24W using the psoriasis area severity index (PASI) scoring system. The impact on quality of life was measured with the Dermatologic Quality of Life Index (DLQI). Six patients had a stable disease throughout the study period, whereas 31/37 patients (83.8%) showed a significant improvement of the skin lesions at EOT (P < .0001). However, 24 of these 31 patients (77.4%) had a dramatic worsening of the psoriatic lesions at PT24W compared with EOT (P < .001), with lesion severity comparable to baseline. The outcome of psoriasis during and after treatment was independent of baseline PASI score, age, sex, HCV genotype, liver disease stage and of the presence of arterial hypertension, diabetes and autoimmune diseases. In conclusion, DAA-based HCV cure has only a transient effect on skin lesions of patients with concomitant cutaneous psoriasis.

Intrahepatic immune changes after hepatitis c virus eradication by direct-acting antiviral therapy

BACKGROUND & AIMS

The recent approval of direct acting anti-virals (DAA) has dramatically changed the landscape of hepatitis C virus (HCV) therapy. Whether viral clearance could promote liver carcinogenesis is debated. It has been hypothesized that changes in intrahepatic immune surveillance following viral cure could favour tumour growth. This study aimed at characterizing the intrahepatic immune changes induced by HCV cure following DAA therapy.

METHODS

Patients with compensated cirrhosis who underwent surgical resection for hepatocellular carcinoma (HCC) after sustained virological response (SVR) to DAA therapy were included. A control group of untreated HCV-infected patients with compensated cirrhosis was selected. RNA was extracted from tumoral and non-tumoral tissues and analysed using the Nanostring Immuno-Oncology-360 panel. Immune cells were quantified by immunohistochemistry.

RESULTS

Twenty patients were included: 10 patients with a DAA-induced SVR and 10 untreated controls. All of them had a de novo BCLC 0/A HCC. Non-tumoral tissue profiling showed down-regulation of interferon-related genes (including MX1, ISG15 and IFIT1) after DAA therapy. No other differences in immune profiles/immune cell densities were identified between the two groups. The intra-tumoral immune profiles of HCCs that occurred after DAA therapy were not qualitatively or quantitatively different from those of tumours occurring in untreated patients.

CONCLUSION

In conclusion, removal of HCV infection after DAA-based therapy results only in a down-regulation of interferon-stimulated genes in non-tumoral tissues from patients with cirrhosis who develop HCC. These minor changes in the liver immune microenvironment are unlikely to favour HCC occurrence or recurrence after DAA-induced SVR.

APASL HCV guidelines of virus-eradicated patients by DAA on how to monitor HCC occurrence and HBV reactivation

In the direct-acting antiviral (DAA) era for hepatitis C virus (HCV) infection, sustained virological response (SVR) is very high, but close attention must be paid to the possible occurrence of hepatocellular carcinoma (HCC) and reactivation of hepatitis B virus (HBV) in patients with co-infection who achieved SVR in short term. HCC occurrence was more often observed in patients with previous HCC history. We found occurrence of HCC in 178 (29.6%) of 602 patients with previous HCC history (15.4 months mean follow-up post-DAA initiation) but, in contrast, in only 604 (1.3%) of 45,870 patients without previous HCC history (18.2 months mean follow-up). Thus, in these guidelines, we recommend the following: in patients with previous HCC history, surveillance at 4-month intervals for HCC by ultrasonography (US) and tumor markers should be performed. In patients without previous HCC history, surveillance at 6- to 12-month intervals for HCC including US is recommended until the long-term DAA treatment effects, especially for the resolution of liver fibrosis, are confirmed. This guideline also includes recommendations on how to follow-up patients who have been infected with both HCV and HBV. When HCV was eradicated in these HBsAg-positive patients or patients with previous HBV infection (anti-HBc and/or anti-HBs-positive), it was shown that HBV reactivation or HBV DNA reappearance was observed in 67 (41.4%) of 162 or 12 (0.9%) of 1317, respectively. For these co-infected patients, careful attention should be paid to HBV reactivation for 24 weeks post-treatment.

Restoration of HCV-Specific Immune Responses with Antiviral Therapy: A Case for DAA Treatment in Acute HCV Infection

Worldwide, 71 million individuals are chronically infected with Hepatitis C Virus (HCV). Chronic HCV infection can lead to potentially fatal outcomes including liver cirrhosis and hepatocellular carcinoma. HCV-specific immune responses play a major role in viral control and may explain why approximately 20% of infections are spontaneously cleared before the establishment of chronicity. Chronic infection, associated with prolonged antigen exposure, leads to immune exhaustion of HCV-specific T cells. These exhausted T cells are unable to control the viral infection. Before the introduction of direct acting antivirals (DAAs), interferon (IFN)-based therapies demonstrated successful clearance of viral infection in approximately 50% of treated patients. New effective and well-tolerated DAAs lead to a sustained virological response (SVR) in more than 95% of patients regardless of viral genotype. Researchers have investigated whether treatment, and the subsequent elimination of HCV antigen, can reverse this HCV-induced exhausted phenotype. Here we review literature exploring the restoration of HCV-specific immune responses following antiviral therapy, both IFN and DAA-based regimens. IFN treatment during acute HCV infection results in greater immune restoration than IFN treatment of chronically infected patients. Immune restoration data following DAA treatment in chronically HCV infected patients shows varied results but suggests that DAA treatment may lead to partial restoration that could be improved with earlier administration. Future research should investigate immune restoration following DAA therapies administered during acute HCV infection.