Immunological recovery in T-cell activation after sustained virologic response among HIV positive and HIV negative chronic Hepatitis C patients

CD4+ T-cell recovery in HIV/hepatitis C co-infected patients following successful hepatitis C treatment

INTRODUCTION

Hepatitis C virus (HCV)/HIV co-infection has been identified as a risk for impaired CD4+ T-cell recovery, possibly mediated by HCV-induced liver fibrosis and/or immune activation. As HCV direct-acting antivirals (DAAs) may partially reverse liver fibrosis and immune activation, sustained HCV virological response (SVR) may lead to improved CD4 recovery. We explored the effect of HCV DAA-induced SVR on CD4 recovery among patients living with both HCV and HIV, including those with poor CD4 recovery on antiretroviral therapy (immunological non-responders [INRs]).

METHODS

Subjects aged ≥18 years living with both HIV and HCV who achieved SVR with DAA were included. Pre-DAA CD4 counts were included only after sustained HIV viral suppression and HIV viral suppression was maintained for the duration of the study. Segmented regression of interrupted time series analysis was used to evaluate changes in median CD4 count in the pre-DAA period (-36 months) versus the post-DAA period (+36 months).

RESULTS

In total, 156 patients were included. In the full cohort, median CD4 counts increased by 15% (p = 0.002) in the 6-month period following DAA initiation, whereafter CD4 counts decreased by 2.7% per 6-month period (p = 0.004). Among the 13 INRs, there was no immediate effect on median CD4 in the first 6 months after DAA initiation, whereafter there was a sustained CD4 increase (4.1% per 6-month time interval [p = 0.02]). In total, 54% of INRs recorded a post-DAA CD4 count of >350 cells/mm3.

CONCLUSIONS

Successful DAA therapy induced a modest immediate CD4 immunological reconstitution among this cohort of patients living with both HIV and HCV, although this effect waned with time. By contrast, among INRs, achieving HCV SVR led to slower but sustained CD4 count recovery.

Biomarkers in Detection of Hepatitis C Virus Infection

The hepatitis C virus (HCV) infection affects 58 million people worldwide. In the United States, the incidence rate of acute hepatitis C has doubled since 2014; during 2021, this increased to 5% from 2020. Acute hepatitis C is defined by any symptom of acute viral hepatitis plus either jaundice or elevated serum alanine aminotransferase (ALT) activity with the detection of HCV RNA, the anti-HCV antibody, or hepatitis C virus antigen(s). However, most patients with acute infection are asymptomatic. In addition, ALT activity and HCV RNA levels can fluctuate, and a delayed detection of the anti-HCV antibody can occur among some immunocompromised persons with HCV infection. The detection of specific biomarkers can be of great value in the early detection of HCV infection at an asymptomatic stage. The high rate of HCV replication (which is approximately 1010 to 1012 virions per day) and the lack of proofreading by the viral RNA polymerase leads to enormous genetic diversity, creating a major challenge for the host immune response. This broad genetic diversity contributes to the likelihood of developing chronic infection, thus leading to the development of cirrhosis and liver cancer. Direct-acting antiviral (DAA) therapies for HCV infection are highly effective with a cure rate of up to 99%. At the same time, many patients with HCV infection are unaware of their infection status because of the mostly asymptomatic nature of hepatitis C, so they remain undiagnosed until the liver damage has advanced. Molecular mechanisms induced by HCV have been intensely investigated to find biomarkers for diagnosing the acute and chronic phases of the infection. However, there are no clinically verified biomarkers for patients with hepatitis C. In this review, we discuss the biomarkers that can differentiate acute from chronic hepatitis C, and we summarize the current state of the literature on the useful biomarkers that are detectable during acute and chronic HCV infection, liver fibrosis/cirrhosis, and hepatocellular carcinoma (HCC).

Liver in infections: a single-cell and spatial transcriptomics perspective

The liver is an immune organ that plays a vital role in the detection, capture, and clearance of pathogens and foreign antigens that invade the human body. During acute and chronic infections, the liver transforms from a tolerant to an active immune state. The defence mechanism of the liver mainly depends on a complicated network of intrahepatic and translocated immune cells and non-immune cells. Therefore, a comprehensive liver cell atlas in both healthy and diseased states is needed for new therapeutic target development and disease intervention improvement. With the development of high-throughput single-cell technology, we can now decipher heterogeneity, differentiation, and intercellular communication at the single-cell level in sophisticated organs and complicated diseases. In this concise review, we aimed to summarise the advancement of emerging high-throughput single-cell technologies and re-define our understanding of liver function towards infections, including hepatitis B virus, hepatitis C virus, Plasmodium, schistosomiasis, endotoxemia, and corona virus disease 2019 (COVID-19). We also unravel previously unknown pathogenic pathways and disease mechanisms for the development of new therapeutic targets. As high-throughput single-cell technologies mature, their integration into spatial transcriptomics, multiomics, and clinical data analysis will aid in patient stratification and in developing effective treatment plans for patients with or without liver injury due to infectious diseases.

Impact of treatment with direct-acting antivirals on inflammatory markers and autoantibodies in HIV/HCV co-infected individuals

HCV infection could have extrahepatic manifestations due to an aberrant immune response. HCV/HIV co-infection increases such persistent immune activation. Aim of the present study is to describe the evolution of inflammatory markers used in clinical practice, mixed cryoglobulinemia (MC) and autoantibody reactivity in co-infected individuals who achieved sustained virological response (SVR) after DAA treatment. This prospective, observational study included all HIV/HCV co-infected subjects who started any DAA regimen from 2015 to 2020. Samples for laboratory measurements (ferritin, C reactive protein, C3 and C4 fractions, rheumatoid factor, MC, anti-thyroglobulin Ab, anti-thyroid peroxidase Ab, ANCA, ASMA, anti-LKM, anti-DNA, AMA, ANA, T CD4+ and CD8+ cell count, and CD4/CD8 ratio) were collected at baseline, after 4 weeks, at end of treatment, and at SVR12. The analysis included 129 individuals: 51.9% with a F0-F3 fibrosis and 48.1% with liver cirrhosis. Cryocrit, C3 fraction, and rheumatoid factor significantly improved at week 4; ferritin, anti-thyroglobulin Ab, and C4 fraction at EOT; total leukocytes count at SVR12. MC positivity decreased from 72.8% to 35.8% (p < .001). T CD4+ cell slightly increased at SVR12, but with an increase also in CD8+ resulting in stable CD4/CD8 ratio. Autoantibody reactivity did not change significantly. ANA rods and rings positivity increased from 14.8% to 28.6% (p = .099): they were observed in three subjects without exposure to RBV. DAA therapy may lead to improvement in inflammatory markers and MC clearance but without significant changes in autoantibodies reactivity and CD4/CD8 ratio over a follow up of 12 weeks.

Characteristics of CD8+ Stem Cell-Like Memory T Cell Subset in Chronic Hepatitis C Virus Infection

The dysfunction of memory CD8⁺ T cell cannot be reverted by successful clearance of hepatitis C virus (HCV) after direct-acting antivirals (DAAs) therapy, increasing the risk of reinfection with HCV. Stem cell-like memory T cells (Tscm) with superior properties of long-lasting, self-renewing, and multipotency contribute to the maintenance of immune function. We investigated the impact of HCV infection on CD8⁺ Tscm, and their possible role in disease progression, by using DAA-naive HCV-infected and human immunodeficiency virus (HIV)/HCV-coinfected cohorts. The distribution of memory CD8⁺ T cell subsets and the level of T cell immune activation were determined by flow cytometry. Associations between CD8⁺ Tscm and other memory T cell subsets, HCV viral load, as well as the level of T cell immune activation were analyzed. We observed that the proportion of CD8⁺ Tscm increased in both HCV and HIV/HCV individuals. The proportion of CD8⁺ Tscm had positive and negative correlation with CD8⁺ Tcm (central memory T cells) and CD8⁺ Tem (effector memory T cell), respectively, representing the contribution of CD8⁺ Tscm in T cell homeostasis. In addition, higher frequency of CD8⁺ Tscm indicated lower HCV viral load and less T cell immune activation in HCV infection, which suggested that CD8⁺ Tscm is likely associated with effective control of HCV replication for protective immunity. Considering the characteristics of Tscm, our current findings provide implications for Tscm-based vaccine design and immunotherapy development to achieve HCV elimination.

HCV treatment in Sardinian HIV-HCV coinfected patients: a real-life perspective study on safety, efficacy, and immune reconstitution

BACKGROUND

HIV-HCV co-infected patients have long been considered difficult-to-treat. The introduction of direct-acting antivirals (DAAs) changed this paradigm.We evaluated the efficacy and safety of DAA-based regimens and the impact of DAAs-induced HCV clearance on the immunological status in HIV-HCV co-infected patients.

RESEARCH DESIGN AND METHODS

HIV patients starting HCV treatment with DAAs were included. Sustained virological response at 12 weeks after DAAs treatment (SVR12) was assessed. CD4+ and CD8+ blood cell count and CD4+/CD8+ ratio were recorded at baseline and six months post DAA treatment. We enrolled 201 patients, 76.1% males, median age 54 years, the most common genotypes 3 (29.8%) and 1a (29.4%), 40.3% with cirrhosis, 32.3% with prior interferon-based treatment. All patients were on antiretroviral treatment, 24.4% on methadone maintenance therapy and 22.6% on psychotropic drugs.

RESULTS

SVR12 was 98.4%, the most common side effects were pruritus (8.4%), headache (7.4%) and fatigue (5.9%). An increase in CD4+ and CD8+ cell count was observed six months after completion of DAAs treatment, in particular in patients with low CD4+ cell count at baseline.

CONCLUSIONS

DAAs treatment resulted in high SVR12 rates, was well tolerated and Increased CD4+ and CD8+, especially in patients with low CD4+ cell count at baseline.

Evaluation of Clinical Biomarkers Related to CD4 Recovery in HIV-Infected Patients—5-Year Observation

Human Immunodeficiency Virus infection leads to the impairment of immune system function. Even long-term antiretroviral therapy uncommonly leads to the normalization of CD4 count and CD4:CD8 ratio. The aim of this study was to evaluate possible clinical biomarkers which may be related to CD4 and CD4:CD8 ratio recovery among HIV-infected patients with long-term antiretroviral therapy. The study included 68 HIV-infected patients undergoing sustained antiretroviral treatment for a minimum of 5 years. Clinical biomarkers such as age, gender, advancement of HIV infection, coinfections, comorbidities and applied ART regimens were analyzed in relation to the rates of CD4 and CD4:CD8 increase and normalization rates. The results showed that higher rates of CD4 normalization are associated with younger age (p = 0.034), higher CD4 count (p = 0.034) and starting the therapy during acute HIV infection (p = 0.012). Higher rates of CD4:CD8 ratio normalization are correlated with higher CD4 cell count (p = 0.022), high HIV viral load (p = 0.006) and acute HIV infection (p = 0.013). We did not observe statistically significant differences in CD4 recovery depending on gender, HCV/HBV coinfections, comorbidities and opportunistic infections. The obtained results advocate for current recommendations of introducing antiretroviral therapy as soon as possible, preferably during acute HIV infection, since it increases the chances of sufficient immune reconstruction.

Reinfection and Risk Behaviors After Treatment of Hepatitis C Virus Infection in Persons Receiving Opioid Agonist Therapy : A Cohort Study

BACKGROUND

Hepatitis C virus (HCV) reinfection after successful treatment may reduce the benefits of cure among people who inject drugs.

OBJECTIVE

To evaluate the rate of HCV reinfection for 3 years after successful treatment among people receiving opioid agonist therapy (OAT).

DESIGN

A 3-year, long-term, extension study of persons enrolled in the CO-STAR (Hepatitis C Patients on Opioid Substitution Therapy Antiviral Response) study (ClinicalTrials.gov: NCT02105688).

SETTING

55 clinical trial sites in 13 countries.

PATIENTS

Aged 18 years and older with chronic HCV infection with genotypes 1, 4, or 6 receiving stable OAT.

INTERVENTION

No treatments were administered.

MEASUREMENTS

Serum samples were assessed for HCV reinfection. Urine drug screening was performed.

RESULTS

Among 296 participants who received treatment, 286 were evaluable for reinfection and 199 were enrolled in the long-term extension study. The rate of HCV reinfection was 1.7 [95% CI, 0.8 to 3.0] per 100 person-years; 604 person-years of follow-up). A higher rate of reinfection was seen among people with recent injecting drug use (1.9 [95% CI, 0.5 to 4.8] per 100 person-years; 212 person-years). Ongoing drug use and injecting drug use were reported by 59% and 21% of participants, respectively, at the 6-month follow-up visit and remained stable during 3 years of follow-up.

LIMITATIONS

Participants were required to be 80% adherent to OAT at baseline and may represent a population with higher stability and lower risk for HCV reinfection. Rate of reinfection may be underestimated because all participants did not continue in the long-term extension study; whether participants who discontinued were at higher risk for reinfection is unknown.

CONCLUSION

Reinfection with HCV was low but was highest in the first 24 weeks after treatment completion and among people with ongoing injecting drug use and needle-syringe sharing.

PRIMARY FUNDING SOURCE

Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.

Immunological and Clinical Impact of DAA-Mediated HCV Eradication in a Cohort of HIV/HCV Coinfected Patients: Monocentric Italian Experience

HCV treatment became available for all infected patients regardless of their comorbidities, especially for HIV coinfected subjects, leading to an improvement in both clinical and immunological conditions. We retrospectively analyzed a cohort of HIV/HCV coinfected patients treated with DAA therapies; data regarding epidemiological, viral-immunological, and hepatic parameters before and after DAA administration have been collected. Drug-drug interactions between DAA and both antiretroviral therapy and non-ART-drugs were also evaluated; the study showed the efficacy of DAA schedules in HCV eradication also for HIV/HCV patients with multiple comorbidities and assuming many different drugs. Principal issues are still represented by drug interactions, pill burden, and patients' compliance. These concerns have to be taken into account, especially in HIV patients for whom the immunological state and ART interactions should always be considered.

Short- and Long-Term Immunological Responses in Chronic HCV/HIV Co-Infected Compared to HCV Mono-Infected Patients after DAA Therapy

Background: Direct-acting antivirals (DAAs) treatment, although highly efficacious for the treatment of hepatitis C virus (HCV) infection, may not completely reconstitute the HCV-mediated dysregulated immune system, especially in patients co-infected with human immunodeficiency virus (HIV) and HCV. Objectives: We aimed to evaluate the impact of HCV eradication following DAA therapy on the immune system and liver disease improvement through comparative monitoring of 10 HCV mono-infected and 10 HCV/HIV co-infected patients under combined antiretroviral therapy (cART). Early and late longitudinal phenotypic changes in peripheral blood mononuclear cell (PBMC) subsets, T-cell activation, differentiation and exhaustion, as well as inflammatory biomarkers, indoleamine 2-3 dioxygenase (IDO) activity, and liver stiffness, APRI and FIB-4 scores were assessed. Materials and Methods: Samples were obtained at baseline (T0), week 1 (T1), week 2 (T2), week 12 (T3, end of treatment, EOT), and month 9 (T4, end of follow-up, 36 weeks post EOT). Results: All patients achieved a sustained virological response (SVR 12) after DAA treatment. Overall, changes of the T-cell immune phenotypes were greater in HCV/HIV co-infected than in HCV mono-infected, due to an increase in CD4+ and CD8+ T-cell percentages and of CD8+ T-cell activation and memory markers, in particular at the end of follow-up. On the other end, HCV mono-infected showed changes in the activation profile and in the memory CD4+ T-cell compartment. In HCV/HIV co-infected, a decrease in the IDO activity by DAA treatment was observed; conversely, in HCV mono-infected, it resulted unmodified. Regarding inflammatory mediators, viral suppression was associated with a reduction in IP-10 levels, while interferon regulatory factor (IRF)-7, interferon (IFN)-β, and interferon (IFN)-γ levels were downregulated during therapy and increased post therapy. A decrease in liver stiffness, APRI, and FIB-4 scores was also observed. Conclusions: Our study suggests that, although patients achieved HCV eradication, the immune activation state in both HCV mono-infected and HCV/HIV co-infected patients remains elevated for a long time after the end of DAA therapy, despite an improvement of liver-specific outcomes, meanwhile highlighting the distinct immunophenotypic and inflammatory biomarker profile between the groups of patients.

Decreased Activated CD4+ T Cell Repertoire Diversity After Antiretroviral Therapy in HIV-1/HCV Coinfection Correlates with CD4+ T Cell Recovery

Dysfunctional immune activation accumulates during chronic viral infection and contributes to disease pathogenesis. In HIV-1, immune activation is exacerbated by concurrent infection with hepatitis C virus (HCV), accelerating depletion of CD4+ T cells. HIV-1 suppression with antiretroviral therapy (ART) generally reconstitutes CD4+ T cell counts, while also reducing the proportion that is activated. Whether this immune reconstitution also reduces the complexity of the CD4+ T cell population is unknown. We sought to characterize the relationship between activated CD4+ T cell repertoire diversity and immune reconstitution following ART in HIV-1/HCV coinfection. We extracted T cell receptor (TCR) sequences from RNA sequencing data obtained from activated CD4+ T cells of HIV-1/HCV coinfected individuals before and after treatment with ART (clinical trial NCT01285050). There was notable heterogeneity in both the extent of CD4+ T cell reconstitution and in the change in activated CD4+ TCR repertoire diversity following ART. Decreases in activated CD4+ TCR repertoire diversity following ART were predictive of the degree of CD4+ T cell reconstitution. The association of decreased activated CD4+ TCR repertoire diversity and improved CD4+ T cell reconstitution may represent loss of nonspecifically activated TCR clonotypes, and possibly selective expansion of specifically activated CD4+ clones. These results provide insight into the dynamic relationship between activated CD4+ TCR diversity and CD4+ T cell recovery of HIV-1/HCV coinfected individuals after suppression of HIV-1 viremia.

A Tale of Two Viruses: Immunological Insights Into HCV/HIV Coinfection

Nearly 2.3 million individuals worldwide are coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Odds of HCV infection are six times higher in people living with HIV (PLWH) compared to their HIV-negative counterparts, with the highest prevalence among people who inject drugs (PWID) and men who have sex with men (MSM). HIV coinfection has a detrimental impact on the natural history of HCV, including higher rates of HCV persistence following acute infection, higher viral loads, and accelerated progression of liver fibrosis and development of end-stage liver disease compared to HCV monoinfection. Similarly, it has been reported that HCV coinfection impacts HIV disease progression in PLWH receiving anti-retroviral therapies (ART) where HCV coinfection negatively affects the homeostasis of CD4⁺ T cell counts and facilitates HIV replication and viral reservoir persistence. While ART does not cure HIV, direct acting antivirals (DAA) can now achieve HCV cure in nearly 95% of coinfected individuals. However, little is known about how HCV cure and the subsequent resolution of liver inflammation influence systemic immune activation, immune reconstitution and the latent HIV reservoir. In this review, we will summarize the current knowledge regarding the pathogenesis of HIV/HCV coinfection, the effects of HCV coinfection on HIV disease progression in the context of ART, the impact of HIV on HCV-associated liver morbidity, and the consequences of DAA-mediated HCV cure on immune reconstitution and HIV reservoir persistence in coinfected patients.

Long-term evolution in liver fibrosis and immune profile after direct-acting antivirals therapy in hepatitis C virus-human immunodeficiency virus co-infected patients

OBJECTIVE

Hepatitis C virus (HCV) therapy with direct-acting antivirals (DAA) achieves high rates of sustained virological response in people living with human immunodeficiency virus (HIV) (PLWH). Information on its long-term clinical impact is scarce. The aim of this study was to analyse liver fibrosis and immune response evolution after DAA treatment.

METHODS

Retrospective, single centre cohort study of HIV-HCV co-infected patients treated with DAA between June 2013 and June 2018. We analysed the changes during follow up in liver fibrosis (assessed by transient elastography (TE), aspartate aminotransferase to platelet ratio index (APRI) and FIB-4 scores) and immunity (CD4 and CD8 cells counts and CD4/CD8 ratio).

RESULTS

We included 410 patients; 75% (308/407) men with a mean age of 50 years (SD 8); 78% (318/410) had long chronic HCV infection (median 21 years, interquartile range (IQR) 6-27 years) and 27% (107/393) had liver cirrhosis. Liver fibrosis improvement based on the decrease in TE value compared with the baseline occurred in 43% (131/302) of patients and 31% of patients based on biological scores (APRI: 124/398; FIB-4: 104/398) (p < 0.0001), being more frequent in those with advanced baseline fibrosis (83/144). The higher decrease was observed at 6 months after DAA therapy (-0.23; 95% CI -0.29 to -0.18), but a continuum in fibrosis regression of at least 30% from baseline value of TE was observed along the follow up (32% of patients at month 6, 51% at month 24 and 55% at month 48). Regarding the immunological profile, there was a significant decrease in CD8 counts at month 48 (-62.38; 95% CI -106.77 to -17.99; p 0.0001) and a progressive rise in the CD4/CD8 ratio after 24 months of follow up reaching an increment of +0.07 (95% CI 0.03-0.10, p 0.0001) at month 48.

CONCLUSIONS

HCV treatment with DAA in PLWH is associated with significant progressive improvement in liver fibrosis and recovery of the immune system with an increase in the CD4/CD8 ratio in long-term follow up.

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.

The impact of DAA-mediated HCV eradication on CD4+ and CD8+ T lymphocyte trajectories in HIV/HCV coinfected patients: Data from the ICONA Foundation Cohort

HCV infection has been hypothesized as a contributor of poor CD4⁺ recovery in patients living with HIV (PLWHIV). Aim of this study was to evaluate CD4⁺ , CD8⁺ cells and CD4/CD8 ratio trends before and after HCV treatment with direct acting agents (DAA) in PLWHIV. HIV/HCV patients enrolled in ICONA and HepaICONA cohorts with HIV-RNA≤50 copies/ml who achieved a sustained viral response after DAA treatment were studied. A linear regression model was used to investigate CD4⁺ , CD8⁺ and CD4/CD8 changes 12 months before and after DAA treatment. A total of 939 HIV/HCV patients were included, 225 (24.0%) female, median age: 53 years (IQR 50-56). At DAA initiation, CD4⁺ T cell count was <350 cells/mm³ in 164 patients (17.5%), and 246 patients (26.2%) had liver stiffness>12.5 kPa. Trends of CD4⁺ and CD4/CD8 ratio were similar before and after DAA in all study populations (CD4⁺ change +17.6 cells/mm³ (95%CI -33.5; 69.4, p = 0.494); CD4/CD8 change 0.013 (95%CI -0.061; 0.036, p = 0.611). However, patients treated with ribavirin (RBV)-free DAA showed a significant decrease in CD8⁺ cells (-204.3 cells/mm³ , 95%CI -375.0;-33.4, p = 0.019), while patients treated with RBV experienced CD8⁺ cell increase (+141.2 cells/mm³ , 95%CI 40.3; 242.1, p = 0.006). In conclusion, HCV eradication following DAA treatment does not seem to have an impact on CD4⁺ T cell recovery in PLWHIV. However, a fast decline of CD8⁺ T cells has been observed in patients treated without RBV, suggesting a favourable effect of HCV clearance on the general state of immune activation.

Hepatitis C: clinical management and debated issues

Hepatitis C virus represents an important global health issue with 71 million of infected people in the word. Direct-acting antivirals are quite new molecules that hit specific Hepatitis C virus proteins useful for viral replication and assembly. Notably, Direct-acting antivirals bring to high sustained virological response rates showing also a great safety profile. This treatment revolution had an impact on transplantation world, in fact the number of liver transplants due to Hepatitis C virus-related cirrhosis and hepatocellular carcinoma is quickly decreasing. Even if this therapy has achieved excellent results in terms of morbility and mortality rates' reduction, there are some debated issues to consider. In the present review the main clinical challenges in every-day management of Hepatitis C virus patients treated with Direct-acting antivirals and the debated effects of viral clearance (metabolic, cardiovascular, immunologic and neoplastic) are discussed. The detection of barriers that can preclude the delivery of Hepatitis C virus care, is the most complex challenge for the scientific community. To obtain the Hepatitis C virus global eradication by 2030, as the World Health Organization has set, will be complex and laborious and will need a further multilevel effort.

Lymphocyte Landscape after Chronic Hepatitis C Virus (HCV) Cure: The New Normal

Chronic HCV (CHC) infection is the only chronic viral infection for which curative treatments have been discovered. These direct acting antiviral (DAA) agents target specific steps in the viral replication cycle with remarkable efficacy and result in sustained virologic response (SVR) or cure in high (>95%) proportions of patients. These treatments became available 6–7 years ago and it is estimated that their real impact on HCV related morbidity, including outcomes such as cirrhosis and hepatocellular carcinoma (HCC), will not be known for the next decade or so. The immune system of a chronically infected patient is severely dysregulated and questions remain regarding the immune system’s capacity in limiting liver pathology in a cured individual. Another important consequence of impaired immunity in patients cleared of HCV with DAA will be the inability to generate protective immunity against possible re-infection, necessitating retreatments or developing a prophylactic vaccine. Thus, the impact of viral clearance on restoring immune homeostasis is being investigated by many groups. Among the important questions that need to be answered are how much the immune system normalizes with cure, how long after viral clearance this recalibration occurs, what are the consequences of persisting immune defects for protection from re-infection in vulnerable populations, and does viral clearance reduce liver pathology and the risk of developing hepatocellular carcinoma in individuals cured with these agents. Here, we review the recent literature that describes the defects present in various lymphocyte populations in a CHC patient and their status after viral clearance using DAA treatments.

Reversal of T Cell Exhaustion in Chronic HCV Infection

The long-term consequences of T cell responses’ impairment in chronic HCV infection are not entirely characterized, although they may be essential in the context of the clinical course of infection, re-infection, treatment-mediated viral clearance and vaccine design. Furthermore, it is unclear whether a complete reinvigoration of HCV-specific T cell response may be feasible. In most studies, attempting to reverse the effects of compromised immune response quality by specific blockades of negative immune regulators, a restoration of functional competence of HCV-specific T cells was shown. This implies that HCV-induced immune dysfunction may be reversible. The advent of highly successful, direct-acting antiviral treatment (DAA) for chronic HCV infection instigated investigation whether the treatment-driven elimination of viral antigens restores T cell function. Most of studies demonstrated that DAA treatment may result in at least partial restoration of T cell immune function. They also suggest that a complete restoration comparable to that seen after spontaneous viral clearance may not be attained, pointing out that long-term antigenic stimulation imprints an irreversible change on the T cell compartment. Understanding the mechanisms of HCV-induced immune dysfunction and barriers to immune restoration following viral clearance is of utmost importance to diminish the possible long-term consequences of chronic HCV infection.

Mild profile improvement of immune biomarkers in HIV/HCV-coinfected patients who removed hepatitis C after HCV treatment: A prospective study

OBJECTIVE

There are a lack of consistency among articles in regards to the evolution of peripheral immune biomarkers after HCV therapy. We aimed to detect the most relevant changes in peripheral immune biomarkers among HIV/HCV-coinfected patients who achieved sustained virologic response (SVR) following peg-IFN-α/ribavirin therapy and to evaluate its normalization with respect to an HIV-monoinfected control group.

METHODS

We performed a prospective cohort study in 99 HIV/HCV-coinfected patients with samples at baseline (HIV/HCV-b-group) and at week 24 after SVR (HIV/HCV-f-group). We also used a control group of 39 HIV-monoinfected patients (HIV-group) negative for HCV and HBV infections, and who had undetectable HIV viral load and CD4⁺ >500 cells/mm³. Peripheral T cell subsets were assessed by flow cytometry and plasma biomarkers by immunoassays.

RESULTS

HIV/HCV-coinfected patients had higher values of in IL-10, IL-4, IP-10, IL-8, IL-1β, IL-18, IL-6, IFN-γ, IL-12p70, TNF-α, sVCAM-1, sICAM-1, and sTNFR-1 than HIV control subjects, both at the beginning and at the end of follow-up. Moreover, three biomarkers (CD4⁺CD38⁺, telomere length, and IL-1RA) were normalized in relation to the control group at the end of follow-up (the HIV/HCV-b group had higher values and the HIV/HCV-f group had similar values as the HIV-group). Additionally, LPS, IL-2, and IL-17A levels were higher in the HIV/HCV-f group than the HIV-group (24 weeks after SVR). During the follow-up, HIV/HCV-coinfected patients had a significant decrease by the end of follow-up in CD8⁺CD45RA^-CD28⁺, CD4⁺CD38⁺, CD4⁺CD25⁺CD127^-/low, CD4⁺CD25⁺CD127^-/low CD45RA^-, FABP2, LBP, IP-10, sVCAM1. Only CD4⁺CD38⁺ was normalized.

CONCLUSION

HIV/HCV-patients showed a slight improvement in the overall profile of immune biomarkers after achieving SVR.

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.