Targeting p53 and histone methyltransferases restores exhausted CD8+ T cells in HCV infection.

Hepatitis C virus infection (HCV) represents a unique model to characterize, from early to late stages of infection, the T cell differentiation process leading to exhaustion of human CD8+ T cells. Here we show that in early HCV infection, exhaustion-committed virus-specific CD8+ T cells display a marked upregulation of transcription associated with impaired glycolytic and mitochondrial functions, that are linked to enhanced ataxia-telangiectasia mutated (ATM) and p53 signaling. After evolution to chronic infection, exhaustion of HCV-specific T cell responses is instead characterized by a broad gene downregulation associated with a wide metabolic and anti-viral function impairment, which can be rescued by histone methyltransferase inhibitors. These results have implications not only for treatment of HCV-positive patients not responding to last-generation antivirals, but also for other chronic pathologies associated with T cell dysfunction, including cancer.

Ombitasvir/paritaprevir/ritonavir plus ribavirin for 24 weeks in patients with HCV GT4 and compensated cirrhosis (AGATE-I Part II).

BACKGROUND AND AIMS: AGATE-I Part I previously reported high sustained virologic response rates in hepatitis C genotype 4 patients with cirrhosis, with 12 and 16 weeks' treatment with a combination of two direct-acting antivirals, ombitasvir and paritaprevir (codosed with ritonavir), plus ribavirin. Part II, reported here, extended the trial to include a 24-week treatment arm to fully assess treatment duration in patients with chronic hepatitis C genotype 4 infection and compensated cirrhosis. METHODS: Enrollment took place between June and November of 2015. Treatment-naive and interferon-experienced patients with chronic hepatitis C genotype 4 infection and compensated cirrhosis were enrolled into Arm C; patients previously treated with a sofosbuvir-based regimen were enrolled into Arm D. All patients received a 24-week treatment with ombitasvir, paritaprevir, and ritonavir plus ribavirin. The primary outcome was the proportion of patients with a sustained virologic response (hepatitis C virus RNA < 25 IU/mL) at posttreatment week 12 in the intention-to-treat population. The safety population included all patients who received at least one dose of study drug. RESULTS: In total, 64 patients were enrolled into AGATE-I Part II. Sustained virologic response at posttreatment week 12 was achieved in 57 of 61 patients (93.4%; 97.5% confidence interval, 92.6-97.7) in Arm C and 3 of 3 patients (100%) in Arm D. Two patients were missing SVR12 data, and two prematurely discontinued treatment. The most common adverse events for Arm C were fatigue (16 [26%]) and asthenia (15 [25%]). Results were comparable with those reported in Part I. CONCLUSIONS: AGATE-I Part II indicates that extending treatment beyond 12 weeks in genotype 4-infected patients with compensated cirrhosis does not offer additional benefit.

SVR12 Higher than 97% in GT3 Cirrhotic Patients with Evidence of Portal Hypertension Treated with SOF/VEL without Ribavirin: A Nation-Wide Cohort Study.

In clinical trials, a sofosbuvir/velpatasvir (SOF/VEL) pangenotypic single-tablet regimen was associated with high sustained virological response (SVR) rates at 12 weeks (SVR12) after the end of treatment, regardless of genotype and fibrosis stage. No real-life data on genotype 3 (GT3) cirrhotic patients with portal hypertension are available. The aim of this study was to assess the effectiveness of SOF/VEL in GT3 cirrhotics with portal hypertension. Patients with GT3 and advanced cirrhosis were treated for 12 weeks with SOF/VEL without ribavirin at five different centers in Italy from June 2017 to August 2018 and their SVR12 was assessed. Of the 227 GT3 cirrhotics evaluated, 205 met the inclusion criteria and 111 had transient elastography results ≥20 KPa. SVR12 was 97.6% (95% CI 94.4-98.9), rates were 99.1% (95% CI 95.7-99.8) in patients with ≥20 KPa and 95.8% (95% CI 89.5-98.3) in those with <20 KPa (p = 0.18). Analyzed by presence of esophageal varices, the SVR12 rates were 98.4% (95% CI 91.4-99.7) and 97.1% (95% CI 92.9-98.9) in patients without and with varices, respectively (p = 1.0). In real life, SOF/VEL GT3 cirrhotic patients with evidence of portal hypertension can achieve SVR12 levels comparable to those of patients without portal hypertension. These SVR12 rates are similar to what is reported in compensated cirrhosis treated within clinical trials.

Forecasting Hepatitis C liver disease burden on real-life data. Does the hidden iceberg matter to reach the elimination goals?

BACKGROUND & AIMS: Advances in direct-acting antiviral treatment of HCV have reinvigorated public health initiatives aimed at identifying affected individuals. We evaluated the possible impact of only diagnosed and linked-to-care individuals on overall HCV burden estimates and identified a possible strategy to achieve the WHO targets by 2030. METHODS: Using a modelling approach grounded in Italian real-life data of diagnosed and treated patients, different linkage-to-care scenarios were built to evaluate potential strategies in achieving the HCV elimination goals. RESULTS: Under the 40% linked-to-care scenario, viraemic burden would decline (60%); however, eligible patients to treat will be depleted by 2025. Increased case finding through a targeted screening strategy in 1948-1978 birth cohorts could supplement the pool of diagnosed patients by finding 75% of F0-F3 cases. Under the 60% linked-to-care scenario, viraemic infections would decline by 70% by 2030 but the patients eligible for treatment will run out by 2028. If treatment is to be maintained, a screening strategy focusing on 1958-1978 birth cohorts could capture 55% of F0-F3 individuals. Under the 80% linked-to-care scenario, screening limited in 1968-1978 birth cohorts could sustain treatment at levels required to achieve the HCV elimination goals. CONCLUSION: In Italy, which is an HCV endemic country, the eligible pool of patients to treat will run out between 2025 and 2028. To maintain the treatment rate and achieve the HCV elimination goals, increased case finding in targeted, high prevalence groups is required.

Safety and efficacy of ombitasvir/paritaprevir/ritonavir/dasabuvir plus ribavirin in patients over 65 years with HCV genotype 1 cirrhosis.

PURPOSE: To analyse safety and efficacy of treatment based on ombitasvir/paritaprevir/ritonavir/dasabuvir plus ribavirin in the sub-group of GT1 patients older than 65 years. METHODS: We collected data extracted from the ABACUS compassionate-use nationwide Italian programme, in patients with cirrhosis due to hepatitis C virus (HCV) Genotype-1 (GT1) or 4 and at high risk of decompensation. GT1-HCV-infected patients received once-daily ombitasvir/paritaprevir, with the pharmacokinetic enhancer ritonavir (25/150/100 mg) and twice-daily dasabuvir (250 mg) plus Ribavirin (RBV) (OBV/PTV/r + DSV + RBV) for 12 (GT1b) or 24 (GT1a) weeks. Endpoints were to evaluate safety and efficacy, the latter defined as HCV RNA negative 12 weeks after the end of treatment (SVR12). RESULTS: Patients who suffered any adverse event (AE) were 74/240 (30.8%); 13/240 (5.4%) discontinued the treatment. A multivariate analysis found albumin < 3.5 g/dL (OR 2.04: 95% CI 1.0-4.2, p < 0.05) and hypertension (OR 4.6: 95% CI 2.3-9.2, p < 0.001) as variables independently associated with AE occurrence. The SVR12 was 95% (228/240). Multivariate analysis identified baseline bilirubin < 2 mg/dL (OR 4.9: 95% CI 1.17-20.71, p = 0.029) as the only variable independently associated with SVR12. CONCLUSION: Our findings suggest that OBV/PTV/r + DSV + RBV is safe and effective in real-life use in patients with compensated cirrhosis, HCV-GT1 infection, and age over 65.

Impact of Safety-Related Dose Reductions or Discontinuations on Sustained Virologic Response in HCV-Infected Patients: Results from the GUARD-C Cohort.

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced ≥1 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with ≥1 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not ≥5. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin.

Individualized treatment of genotype 1 naïve patients: an Italian multicenter field practice experience.

BACKGROUND: Triple therapy including Telaprevir or Boceprevir still represents in many European countries the standard of care for patients with Hepatitis C Virus genotype 1 infection. The number of patients who received this treatment resulted generally lower than expected. We investigated, among naïve patients, number and characteristics of treatment candidates who were started on triple or dual therapy in comparison to those who were deferred. PATIENTS AND METHODS: 621 naïve treatment candidates were prospectively evaluated at each center. Factors associated with decision to defer or treat with dual or triple therapy were investigated by univariate and multivariate analyses. Rates of Sustained Virological Response and safety profile were analysed. RESULTS: Of candidates to treatment, 33% did not received it. It was mostly due to high risk of Interferon-induced decompensation. Of 397 patients who were started on treatment, 266 (67%) received triple, 131 dual. Among patient receiving treatment, unfavorable IL28B, severe liver damage and higher albumin were independently associated with the physician decision to administer triple therapy. Sustained Virological Response after dual therapy was 66.4%, after triple 73.7% (p = 0.14). 142 patients received Telaprevir. The choice of Telaprevir-based therapy was associated with higher Body Mass Index and advanced liver disease. Sustained Virological Response rates were 71.1% after Telaprevir and 76.6% after Boceprevir. CONCLUSIONS: Individualizing treatment with available regimens allows to maximize Sustained Virological Response and to reduce the number of patients who remain untreated. High proportion of patients with severe liver damage urgently need Interferon free treatment.

Treatment Outcomes and Predictors of Response in Treatment-Naive HCV Patients Treated with Peginterferon Alfa/Ribavirin in Real-World Italian Clinics: Sub-Analysis from the PROPHESYS Cohort.

BACKGROUND/AIMS: Within Europe, Italy has the highest incidence of HCV. PROPHESYS was a large, non-interventional, multinational cohort study of patients treated with peginterferon alfa-2a or -2b/ribavirin for CHC; 22.4% of patients were from Italian centers. This sub-analysis evaluates real-life practice and treatment outcomes in Italy. METHODOLOGY: The PROPHESYS 2 cohort included 1604 HCV mono-infected, treatment-naive patients. All patients were prescribed peginterferon alfa/ribavirin at the discretion of the treating physician according to country-specific requirements. RESULTS: The majority of G1-3 patients were White/Caucasian and 48.4% had HCV G1 infection. Overall, SVR24 rates of 44.9%, 81.4% and 69.1% were achieved in G1-, 2- and 3-infected patients. In G1 patients, SVR24 rates declined with increasing FIB-4 score; this trend was not observed for G2/3-infected patients. Virologic response by Week 2 and 4 was highly predictive of SVR24 (G1: 91.7%, 84.8%; G2: 91.1%, 89.7%; G3: 92.9%, 86.7%, respectively). Absence of virologic response by Week 12 had the highest negative predictive value across genotypes. CONCLUSIONS: In Italian patients, a virologic response by Week 2 or 4 was highly predictive of SVR24 across genotypes. These data demonstrate the importance of monitoring on-treatment response to help guide treatment decisions. FIB-4 score correlated well with SVR24 in G1 patients.

Course of graves disease in interferon-treated patients with chronic hepatitis C virus infection and in uninfected patients.

BACKGROUND: The development of thyroid antibodies and the alteration of thyroid function are the most common disorders associated with interferon alfa therapy in individuals with chronic hepatitis C (CHC).In this study, we compared the course of Graves disease (GD) between patients diagnosed with CHC and treated with interferon alfa and uninfected patients. METHODS: We retrospectively analyzed data from 39 GD patients (15 men and 24 women, group 1) affected by CHC and treated with interferon alfa and from 43 uninfected GD patients (19 men and 24 women, group 2) who were seen at our institution from 1999 to 2011. All GD patients were treated with methimazole (MMI). Daily dose of MMI, duration of MMI therapy, and remission rate were evaluated in both groups. RESULTS: The daily dose of MMI was found to be lower in group 1 as compared with group 2 (9.74 ± 5.94 mg/d vs 14.12 ± 8.64 mg/d in group 1 vs group 2, respectively, P < 0.01). In addition, the duration of MMI treatment was found to be lower in group 1 as compared with group 2 (13.98 ± 13.0 months vs 38.86 ± 27.13 months in group 1 vs group 2, respectively; P < 0.01). The remission rate from GD was higher in the patients of group 1 in comparison with the patients of group 2 (87.17 % vs 48.86% in group 1 vs group 2, respectively, P < 0.005). CONCLUSION: Altogether, our data demonstrate a more favorable course of GD in the patients with CHC treated with interferon alfa compared with GD occurring in the patients without CHC.

Development and validation of a nomogram based on clinical factors and standard laboratory tests for prediction of clinically significant liver fibrosis in chronic hepatitis C virus infection.

OBJECTIVES: Staging liver fibrosis in chronic viral hepatitis C (HCV) patients is essential for prompting surveillance and treatment. The aim of this study was to develop a nomogram, on the basis of simple clinical and laboratory variables, to predict three clinically significant stages of fibrosis (nil-mild, moderate, advanced/cirrhosis), using histology as reference, and to compare its performance with that of FibroTest, a widely used noninvasive fibrosis score. MATERIALS AND METHODS: Nomograms are graphical representations of a mathematical formula, used as predictive tools. The study retrospectively recruited 406 HCV patients undergoing liver biopsy. Nomogram was developed in a training set of 252 patients and tested in a validation set of 154 patients. Histology was staged according to the Metavir system. Fibrosis stages were subgrouped as follows: advanced fibrosis/cirrhosis (F3/F4, 24%), nil-mild (F0/F1, 36%), and moderate (F2, 40%). Age at biopsy, aspartate aminotransferase, γ-glutamyl transpeptidase, albumin, platelet count, and prothrombin activity formed the basis for the so-called Fibro-Nomogram, which, in one graphical representation, estimates probability for different stages of fibrosis. RESULTS: Areas under the receiver-operating characteristic curves for advanced fibrosis/cirrhosis were similar for training (0.86) and validation sets (0.87). For nil-mild fibrosis, area under the receiver-operating characteristics were 0.81 and 0.79. Compared with FibroTest, Fibro-Nomogram performed slightly better at predicting severe fibrosis (F3/F4) with positive likelihood ratio (LR+) 5.07 (95% confidence interval 3.08-8.37) versus LR+ 3.82 (95% confidence interval 2.56-5.71) for FibroTest. For nil-mild fibrosis, the two tests showed limited but comparable performances. CONCLUSION: In HCV patients, Fibro-Nomogram, an inexpensive and readily available predictive tool, could enable clinicians to interpret patients' profile, concurrently stratifying patients into three clinically relevant probability categories with good overall performance.

Lack of full CD8 functional restoration after antiviral treatment for acute and chronic hepatitis C virus infection.

BACKGROUND: Hepatitis C virus (HCV) persistence is associated with impaired CD8 functions. Whether functional restoration of CD8 T cells chronically exposed to antigen can be obtained once the antigen is removed remains to be clarified. OBJECTIVE: To determine whether clearance of HCV by antiviral treatment can fully restore the antiviral function of HCV-specific CD8 cells. DESIGN: Peripheral blood HCV-, Flu- and cytomegalovirus (CMV)-specific CD8 cells were quantified by tetramer staining in 28 patients whose HCV infection resolved after peginterferon or peginterferon/ribavirin treatment for either acute or chronic hepatitis and in eight subjects with acute HCV infection which resolved spontaneously for comparison. HCV-specific CD8 cells were evaluated for their phenotypic and functional characteristics by comparing different patient groups and CD8 cells with different viral specificities in the same patients. RESULTS: Sustained viral response (SVR) did not lead to full maturation of a functional memory CD8 cell response. In particular, SVR in chronic infection was associated with a greater level of T cell dysfunction than responders after acute infection, who showed HCV-specific CD8 responses comparable to those of spontaneous resolvers but weaker than those of Flu-specific CD8 cells. Higher programmed death (PD)-1 expression was detected on HCV than on Flu- and CMV-specific CD8 cells and the effect of PD-1/PD-L1 blockade was better in SVRs after chronic than after acute HCV infection. CONCLUSION: A better restoration of HCV-specific CD8 function was detectable after SVR in patients with acute hepatitis than in those with chronic disease. Thus, the difficulty in achieving a complete restoration of the antiviral T cell function should be considered in the design of immunomodulatory therapies.

Serum ferritin as a predictor of treatment outcome in patients with chronic hepatitis C.

OBJECTIVES: Antiviral treatment in chronic hepatitis C (CHC) involves ribavirin, a hemolytic agent. We planned a prospective study to evaluate whether drug-induced iron perturbation is clinically relevant as it relates to therapeutic outcome. METHODS: Iron variables were sequentially assessed in 206 CHC patients undergoing antiviral therapy and were correlated with pretreatment iron status and histology, hemolysis, and therapeutic outcome. RESULTS: At week 1 of therapy, serum iron (SI), transferrin saturation (TS), and serum ferritin (SF) increased markedly in all patients. All iron parameters correlated with hemolysis up to week 4; this correlation was lost for SF at later time points. SF rise during treatment was inversely related to baseline SF and iron deposits in hepatic mesenchymal/Kupffer cells. Both baseline SF and mesenchymal iron significantly correlated with fibrosis at multivariate analysis (P=0.015 and 0.008, respectively). Interestingly, baseline SF, despite good specificity (89%), had low sensitivity in predicting siderosis (25%). During therapy, SI, TS, and hemolysis parameters did not correlate with sustained virological response (SVR), whereas SF rise became an independent predictor of therapeutic response: a 2.5-fold increase of SF at week 12 associated with higher likelihood of SVR (odds ratio 1.91, P=0.032). Accordingly, lack of mesenchymal iron deposits at the baseline biopsy correlated with SVR (odds ratio 3.02, P=0.043). CONCLUSIONS: In CHC, SF is a useful marker for assessing disease duration and progression before starting treatment and for predicting therapeutic response while on therapy. SF rise during antiviral therapy is largely independent of hemolysis and likely indicates activation of macrophages in response to antivirals.

The characteristics of the cell-mediated immune response identify different profiles of occult hepatitis B virus infection.

BACKGROUND & AIMS: Hepatitis B virus (HBV) DNA detection in serum and/or in the liver of hepatitis B surface antigen (HBsAg)-negative patients with or without serologic markers of previous viral exposure is defined as occult HBV infection. Because the role of the adaptive response in keeping HBV replication under control in occult infection still is undefined, this study was performed to characterize the features of the HBV-specific T-cell response in this condition. METHODS: HBV-specific T-cell frequency and function were tested ex vivo and after in vitro expansion in 32 HBsAg-negative patients undergoing diagnostic liver biopsy for chronic hepatitis C: 18 with occult HBV infection (11 anti-HBc-negative and 7 anti-HBc-positive patients) defined by the detection of intrahepatic HBV DNA by polymerase chain reaction; 14 without detectable intrahepatic HBV DNA (5 anti-HBc-positive and 9 anti-HBc-negative patients). Six patients with chronic hepatitis B and 7 HBsAg-inactive carriers were studied for comparison. RESULTS: The presence or absence of serologic HBV markers defined 2 profiles of HBV-specific T-cell responses in occult infection. Anti-HBc-positive patients showed a T-cell response typical of protective memory, suggesting that this condition represents a resolved infection with immune-mediated virus control. In contrast, HBV-specific T cells in anti-HBc-negative patients did not readily expand and produce interferon-gamma in vitro, suggesting the possibility of a low-dose infection insufficient to allow maturation of protective memory. CONCLUSIONS: Our results suggest different mechanisms of control of viral replication in seropositive and seronegative occult infections. Additional studies aimed at understanding possible different clinical implications are needed.

Restoration of HCV-specific T cell functions by PD-1/PD-L1 blockade in HCV infection: effect of viremia levels and antiviral treatment.

BACKGROUND/AIMS: HCV-specific T cells in acute hepatitis C with subsequent chronic evolution are dysfunctional and most of them express PD-1. The aim of the study was to investigate to what extent the antiviral T cell function can be restored by reversing T cell exhaustion by PD-1/PD-L1 blockade and to assess whether this restoration is favored by IFN-alpha treatment. METHODS: PD-1 and PD-L1 expression was studied on T cells and dendritic cells, respectively, of 14 patients with acute hepatitis C and different evolutions of infection. The effect of anti-PD-L1 was analyzed on proliferation, cytokine production and cytolytic activity of CD4 and CD8 T cells. RESULTS: While PD-1 expression dropped concurrently with spontaneous or IFN-alpha induced HCV-RNA decline, PD-L1 levels on dendritic cells increased during IFN-alpha treatment. Anti-PD-L1 antibodies improved expansion and cytokine production but not the cytolytic activity of HCV-specific T cells. This restoration tended to be greater at lower levels of viremia and PD-1 expression and during PEG-IFNalpha treatment. CONCLUSIONS: PD-1/PD-L1 blockade has an immunoregulatory activity which may synergize with the antiviral effect of IFN-alpha therapy and should be thus explored further in long-lasting chronic HCV infections in the perspective of improving the efficacy of available antiviral treatments.

HCV-specific T-cell response in relation to viral kinetics and treatment outcome (DITTO-HCV project).

BACKGROUND & AIMS: The second slope of viral decline induced by interferon treatment has been suggested to be influenced mainly by the hepatitis C virus (HCV)-specific T-cell response; however, this hypothesis needs to be validated by results derived from experimental studies. METHODS: To address this issue, the HCV-specific T-cell response of 32 genotype-1-infected patients of the 270 patients enrolled in the dynamically individualized treatment of hepatitis C infection and correlates of viral/host dynamics phase III, open-label, randomized, multicenter trial was studied in relation to viral kinetics and treatment outcome. RESULTS: Greater proliferative responses by HCV-specific CD8 cells were found before treatment in patients with a fast viral decline and with a sustained viral response. However, no significant improvement of HCV-specific CD8 responses was observed in the first weeks of therapy in both rapid viral responder and non-rapid viral responder patients. A mild enhancement of proliferative T-cell responses and a partial restoration of the cytotoxic T-cell potential was expressed only late during treatment, likely favored by HCV clearance. CONCLUSIONS: Early restoration of an efficient T-cell response does not seem to be an essential requirement for a rapid viral decline in the first weeks of treatment. However, patients presenting a better HCV-specific CD8 cell proliferative potential at baseline are more likely to present a rapid and sustained viral response. Therefore, future treatment protocols should consider the development of strategies aimed at improving HCV-specific T-cell responses.

Dysfunction and functional restoration of HCV-specific CD8 responses in chronic hepatitis C virus infection.

UNLABELLED: The functional impairment of HCV-specific T cell responses is believed to be an important determinant of HCV persistence, but the functional T cell defects of patients with chronic hepatitis C (CH-C) are only partially defined. CD8 responses to HLA-A2-restricted epitopes of HCV and other unrelated viruses were studied in 23 HLA-A2-positive patients both ex vivo and after in vitro culture. Degranulation capacity, intracellular perforin, and granzyme-A content and cytokine production (IFN-gamma, TNF-alpha) by HCV- and non-HCV-specific CD8 cells were tested both ex vivo and in vitro, whereas cytolytic activity was studied after 10 days' expansion in vitro. Memory maturation and role of exhaustion were assessed ex vivo by HCV-specific CD8 staining for CD127 and PD-1, and in vitro after peripheral blood mononuclear cells (PBMC) culture in the presence of anti-PD-L1 monoclonal antibodies. IFN-gamma production and cytolytic activity were expressed less efficiently by HCV-specific than by non-HCV specific CD8 cells derived from the same CH-C patients. The amount of stored granzyme-A within single cells was always lower in HCV-specific CD8 cells, which were less efficient also in the release of lytic granules and in the production of TNF-alpha. The CD8 dysfunction was associated with high PD-1 expression by most HCV-specific CD8 cells, and PD-1/PD-L1 blockade by anti-PD-L1 antibodies in vitro was able to improve the HCV-specific CD8 function. CONCLUSION: Our study characterizes CD8 defects that may be important in maintaining HCV persistence; identification of strategies to correct these defects may help to define novel approaches to treat HCV infection.

Outcome of acute hepatitis C is related to virus-specific CD4 function and maturation of antiviral memory CD8 responses.

A timely, efficient, and coordinated activation of both CD4 and CD8 T cell subsets following HCV infection is believed to be essential for HCV control. However, to what extent a failure of the individual T cell subsets can contribute to the high propensity of HCV to persist is still largely undefined. To address this issue, we analyzed the breadth, vigor, and quality of CD4 and CD8 responses simultaneously with panels of peptides covering the entire HCV sequence or containing the HLA-A2-binding motif, and with recombinant HCV proteins in 16 patients with acute HCV infection by tetramer staining, ELISPOT, and intracellular cytokine staining for interferon gamma, interleukin (IL)-2, IL-4, and IL-10. Our results indicate that at clinical onset, CD8 responses are similarly weak and narrowly focused in both self-limited and chronically evolving infections. At this stage, CD4 responses are deeply impaired in patients with a chronic outcome as they are weak and of narrow specificity, unlike the strong, broad and T helper 1-oriented CD4 responses associated with resolving infections. Only patients able to finally control infection show maturation of CD8 memory sustained by progressive expansion of CD127+ CD8 cells. Thus, a poor CD8 response in the acute stage of infection may enhance the overall probability of chronic viral persistence. In conclusion, the presence of functional CD4 responses represents one of the factors dictating the fate of infection by directly contributing to control of the virus and by promoting maturation of protective memory CD8 responses.

The impairment of CD8 responses limits the selection of escape mutations in acute hepatitis C virus infection.

Evasion from protective CD8 responses by mutations within immunodominant epitopes represents a potential strategy of HCV persistence. To investigate the pathogenetic relevance of this mechanism, a careful search for immunodominant CD8 epitopes was conducted in six patients with chronic evolution of HCV infection by analyzing their global CD8 response with a panel of overlapping synthetic peptides covering the overall HCV sequence and by studying the CD8 frequency by tetramer staining. Immunodominant responses were followed longitudinally from the time of acute onset in relation to the evolution of the epitopic sequences. Although intensity of CD8 responses and frequency of HCV-specific CD8 cells declined over time in all patients, mutations emerged in only three of the six acute patients studied. Variant sequences were less efficiently recognized by CD8 cells than parental epitopes and were poorly efficient in inducing a CD8 response in vitro. CD8 epitopes undergoing mutations were targeted by high avidity CD8 cells more efficient in effector function. Our data support the view that immunodominant CD8 responses are affected by inhibitory mechanisms operating early after infection and that the emergence of escape mutations represents an additional mechanism of virus evasion from those CD8 responses that are functionally preserved.

Ex vivo characterization of tumor-derived melanoma antigen encoding gene-specific CD8+cells in patients with hepatocellular carcinoma.

BACKGROUND/AIMS: Members of the melanoma antigen encoding gene family are expressed in tumors of different histological types but not in normal tissue. For this reason, they are attractive targets for cancer immunotherapy. METHODS: In the present study, we analyzed the expression of MAGE-1 and -3 genes in the hepatocellular carcinoma (HCC) tissue as well as frequency, phenotype and function of circulating and tumor infiltrating CD8+ cells specific for HLA-A1 and -A2 restricted epitopes of MAGE-1 and -3. RESULTS: Our study shows for the first time the presence of MAGE/tetramer+ CD8 cells in the tumor tissue of patients with HCC. These cells are able to recognize the MAGE-1 sequence 161-169 and the MAGE-3 sequence 271-279. In a patient with a particularly high frequency of MAGE-1 sequence 161-169-specific T cells, phenotypic and functional analysis was performed showing a phenotype of recently-primed CD8 cells (CD28+CD27+CD45RA-CCR7). CONCLUSIONS: The observation of a spontaneous in vivo priming of a MAGE-specific T cell response in patients with HCC and the high frequency of MAGE antigens expression in this tumor, makes this antigen a potential candidate for a MAGE-specific immunotherapy in hepatocellular carcinoma.