Heterologous T cell immunity in severe hepatitis C virus infection

Hepatitis C virus (HCV) can cause liver disease of variable severity. Expansion of preexisting memory CD8 T cells by cross-reactivity with a new heterologous virus infection has been shown in mice to shape the repertoire of the primary response and to influence virus-related immunopathology (Selin, L.K. 2004. Immunity. 20:5–16). To determine whether this mechanism can influence the course of HCV infection, we analyzed the features of the HCV-specific CD8 T cell response in eight patients with acute HCV infection, two of whom had a particularly severe illness. Patients with severe hepatitis, but not those with mild disease, showed an extremely vigorous CD8 T cell response narrowly focused on a single epitope (NS3 1073–1081), which cross-reacted with an influenza neuraminidase sequence. Our results suggest that CD8 T cell cross-reactivity influences the severity of the HCV-associated liver pathology and depicts a model of disease induction that may apply to different viral infections

The Impairment of CD8 Responses Limits the Selection of Escape Mutations in Acute Hepatitis C Virus Infection

Abstract 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

Metabolic regulation of the HBV-specific T cell function.

Chronically HBV infected subjects are more than 260 million worldwide; cirrhosis and liver cancer represent possible outcomes which affect around 700,000 patients per year. Both innate and adaptive immune responses are necessary for viral control and both have been shown to be defective in chronic patients. Metabolic remodeling is an essential process in T cell biology, particularly for T cell activation, differentiation and survival. Cellular metabolism relies on the conversion of nutrients into energy to support intracellular processes, and to generate fundamental intermediate components for cell proliferation and growth. Adaptive immune responses are the central mechanisms for the resolution of primary human infections leading to the activation of pathogen-specific B and T cell functions. In chronic HBV infection the anti-viral immune response fails to contain the virus and leads to persistent hepatic tissue damage which may finally result in liver cirrhosis and cancer. This T cell failure is associated with metabolic alterations suggesting that control of nutrient uptake and intracellular utilization as well as correct regulation of intracellular metabolic pathways are strategic for T cell differentiation during persistent chronic infections. This review will discuss some of the main features of the T cell metabolic processes which are relevant to the generation of an efficient antiviral response, with specific focus on their clinical relevance in chronic HBV infection in the perspective of possible strategies to correct deregulated metabolic pathways underlying T cell dysfunction of chronic HBV patients

Alpha-synuclein/synapsin III pathological interplay boosts the motor response to methylphenidate

: Loss of dopaminergic nigrostriatal neurons and fibrillary α-synuclein (α-syn) aggregation in Lewy bodies (LB) characterize Parkinson's disease (PD). We recently found that Synapsin III (Syn III), a phosphoprotein regulating dopamine (DA) release with α-syn, is another key component of LB fibrils in the brain of PD patients and acts as a crucial mediator of α-syn aggregation and toxicity. Methylphenidate (MPH), a monoamine reuptake inhibitor (MRI) efficiently counteracting freezing of gait in advanced PD patients, can bind α-syn and controls α-syn-mediated DA overflow and presynaptic compartmentalization. Interestingly, MPH results also efficient for the treatment of attention deficits and hyperactivity disorder (ADHD), a neurodevelopmental psychiatric syndrome associated with Syn III and α-syn polymorphisms and constituting a risk factor for the development of LB disorders. Here, we studied α-syn/Syn III co-deposition and longitudinal changes of α-syn, Syn III and DA transporter (DAT) striatal levels in nigrostriatal neurons of a PD model, the human C-terminally truncated (1-120) α-syn transgenic (SYN120 tg) mouse, in comparison with C57BL/6J wild type (wt) and C57BL/6JOlaHsd α-syn null littermates. Then, we analyzed the locomotor response of these animals to an acute administration of MPH (d-threo) and other MRIs: cocaine, that we previously found to stimulate Syn III-reliant DA release in the absence of α-syn, or the selective DAT blocker GBR-12935, along aging. Finally, we assessed whether these drugs modulate α-syn/Syn III interaction by fluorescence resonance energy transfer (FRET) and performed in silico studies engendering a heuristic model of the α-syn conformations stabilized upon MPH binding. We found that only MPH was able to over-stimulate a Syn III-dependent/DAT-independent locomotor activity in the aged SYN120 tg mice showing α-syn/Syn III co-aggregates. MPH enhanced full length (fl) α-syn/Syn III and even more (1-120) α-syn/Syn III interaction in cells exhibiting α-syn/Syn III inclusions. Moreover, in silico studies confirmed that MPH may reduce α-syn fibrillation by stabilizing a protein conformation with increased lipid binding predisposition. Our observations indicate that the motor-stimulating effect of MPH can be positively fostered in the presence of α-syn/Syn III co-aggregation. This evidence holds significant implications for PD and ADHD therapeutic management

Interferon (IFN)-γ-Inducible Protein-10: Association with Histological Results, Viral Kinetics, and Outcome during Treatment with Pegylated IFN-α2a and Ribavirin for Chronic Hepatitis C Virus Infection

BackgroundWe investigated associations between interferon (IFN)-γ-inducible protein (IP)-10 and liver histological results, viral kinetic response, and treatment outcome in patients infected with hepatitis C virus (HCV) genotypes 1-4 MethodsPlasma IP-10 was monitored before, during, and after treatment with pegylated IFN-α2a and ribavirin in 265 HCV-infected patients ResultsIn univariate analyses, a low baseline IP-10 level was significantly associated with low baseline viral load, rapid viral response (RVR), a sustained viral response (SVR), body mass index <25 kg/m2, and less-pronounced fibrosis, inflammation, and steatosis (for HCV genotypes other than 3). When the results of the univariate analyses were included in multivariate analyses, a low plasma IP-10 level, low baseline viral load, and genotype 2 or 3 infection were independent predictors of an RVR and SVR. IP-10 levels decreased 6 weeks into treatment and remained low in patients with an SVR. By contrast, plasma levels of IP-10 rebounded in patients who had detectable HCV RNA after the completion of treatment. Using cutoff IP-10 levels of 150 and 600 pg/mL for predicting an SVR in patients infected with HCV genotype 1 yielded a specificity and sensitivity of 81% and 95%, respectively ConclusionBaseline IP-10 levels are predictive of the response to HCV treatmen

IP-10 predicts viral response and therapeutic outcome in difficult-to-treat patients with HCV genotype 1 infection

Plasma from 173 patients with HCV genotype 1 infection was analyzed for IP-10 levels prior to treatment with pegylated interferon-α-2a and ribavirin. Significantly lower IP-10 levels were observed in patients achieving a rapid viral response (RVR) (P &lt; .0001), even in those with body mass index (BMI) ≥ 25 kg/m2 (P = .004) and with baseline viral load ≥ 2 million IU/mL (P = .001). Similarly, significantly lower IP-10 levels were observed in patients obtaining a sustained viral response (SVR) (P = .0002), including those having higher BMI (P &lt; .05), higher viral load (P = .0005), and both higher BMI and viral load (P &lt; .03). In multivariate logistic regression analyses, a low IP-10 value was independently predictive of both RVR and SVR. A baseline cutoff IP-10 value of 600 pg/mL yielded a negative predictive value (NPV) of 79% (19/24) for all genotype 1-infected patients, which was comparable with that observed using a reduction in HCY-RNA by at least 2 logs after 12 weeks of therapy (NPV 86%; 19/22); by combining the two, 30 of 38 patients (NPV 79%) potentially could have been spared unnecessary therapy. In patients having both higher BMI and viral load, cut-off levels of 150 and 600 pg/mL yielded a positive predictive value (PPV) of 71% and NPV of 100%, respectively. In conclusion, pretreatment IP-10 levels predict RVR and SVR in patients infected with HCV genotype 1, even in those with higher BMI and viral load. A substantial proportion of the latter patients may achieve SVR in spite of unfavorable baseline characteristics if their pretreatment IP-10 level is low. Thus, pretreatment IP-10 analysis may prove helpful in decision-making regarding pharmaceutical intervention.</p

Functional reconstitution of HBV-specific CD8 T cells by in vitro polyphenol treatment in chronic hepatitis B.

Background & aims In chronic HBV infection, mitochondrial functions and proteostasis are dysregulated in exhausted HBV-specific CD8 T cells. To better characterise the potential involvement of deregulated protein degradation mechanisms in T cell exhaustion, we analysed lysosome-mediated autophagy in HBV-specific CD8 T cells. Bioactive compounds able to simultaneously target both mitochondrial functions and proteostasis were tested to identify optimal combination strategies to reconstitute efficient antiviral CD8 T cell responses in patients with chronic HBV infection. Methods Lysosome-mediated degradation pathways were analysed by flow cytometry in virus-specific CD8 T cells from patients with chronic HBV infection. Mitochondrial function, intracellular proteostasis, and cytokine production were evaluated in HBV-peptide-stimulated T cell cultures, in the presence or absence of the polyphenols resveratrol (RSV) and oleuropein (OLE) and their metabolites, either alone or in combination with other bioactive compounds. Results HBV-specific CD8 T cells from patients with CHB showed impaired autophagic flux. RSV and OLE elicited a significant improvement in mitochondrial, proteostasis and antiviral functions in CD8 T cells. Cytokine production was also enhanced by synthetic metabolites, which correspond to those generated by RSV and OLE metabolism in vivo, suggesting that these polyphenols may also display an effect after transformation in vivo. Moreover, polyphenolic compounds improved the T cell revitalising effect of mitochondria-targeted antioxidants and of programmed cell death protein 1/programmed cell death ligand 1 blockade. Conclusions Simultaneously targeting multiple altered intracellular pathways with the combination of mitochondria-targeted antioxidants and natural polyphenols may represent a promising immune reconstitution strategy for the treatment of chronic HBV infection. Lay summary In chronic hepatitis B, antiviral T lymphocytes are deeply impaired, with many altered intracellular functions. In vitro exposure to polyphenols, such as resveratrol and oleuropein, can correct some of the deregulated intracellular pathways and improve antiviral T cell function. This effect can be further strengthened by the association of polyphenols with antioxidant compounds in a significant proportion of patients. Thus, the combination of antioxidants and natural polyphenols represents a promising strategy for chronic hepatitis B therapy

IP-10 predicts viral response and therapeutic outcome in difficult-to-treat patients with HCV genotype 1 infection

Plasma from 173 patients with HCV genotype 1 infection was analyzed for IP-10 levels prior to treatment with pegylated interferon-α-2a and ribavirin. Significantly lower IP-10 levels were observed in patients achieving a rapid viral response (RVR) (P &lt; .0001), even in those with body mass index (BMI) ≥ 25 kg/m2 (P = .004) and with baseline viral load ≥ 2 million IU/mL (P = .001). Similarly, significantly lower IP-10 levels were observed in patients obtaining a sustained viral response (SVR) (P = .0002), including those having higher BMI (P &lt; .05), higher viral load (P = .0005), and both higher BMI and viral load (P &lt; .03). In multivariate logistic regression analyses, a low IP-10 value was independently predictive of both RVR and SVR. A baseline cutoff IP-10 value of 600 pg/mL yielded a negative predictive value (NPV) of 79% (19/24) for all genotype 1-infected patients, which was comparable with that observed using a reduction in HCY-RNA by at least 2 logs after 12 weeks of therapy (NPV 86%; 19/22); by combining the two, 30 of 38 patients (NPV 79%) potentially could have been spared unnecessary therapy. In patients having both higher BMI and viral load, cut-off levels of 150 and 600 pg/mL yielded a positive predictive value (PPV) of 71% and NPV of 100%, respectively. In conclusion, pretreatment IP-10 levels predict RVR and SVR in patients infected with HCV genotype 1, even in those with higher BMI and viral load. A substantial proportion of the latter patients may achieve SVR in spite of unfavorable baseline characteristics if their pretreatment IP-10 level is low. Thus, pretreatment IP-10 analysis may prove helpful in decision-making regarding pharmaceutical intervention.</p

Immunological and Molecular Correlates of Disease Recurrence after Liver Resection for Hepatocellular Carcinoma

The definition of the risk of hepatocellular carcinoma (HCC) recurrence after resection represents a central issue to improve the clinical management of patients. In this study we examined the prognostic relevance of infiltrating immune cell subsets in the tumor (TIL) and in nontumorous (NT) liver (LIL), and the expression of immune-related and lineage-specific mRNAs in HCC and NT liver derived from 42 patients. The phenotype of infiltrating cells was analyzed by flow cytometry, and mRNA expression in liver tissue was examined by real-time reverse transcription (RT)-PCR. The tumor immune microenvironment was enriched in inhibitory and dysfunctional cell subsets. Enrichment in CD4+ T-cells and in particular CD4 and CD8+ memory subsets within TIL was predictive of better overall survival (OS) and time to recurrence (TTR). Increased programmed death ligand 1 (PDL1) mRNA content and higher prevalence of invariant NKT (iNKT) cells were associated with shorter OS and TTR, respectively. By combined evaluation of infiltrating cell subsets along with mRNA profiling of immune and tumor related genes, we identified the intratumoral frequency of memory T-cells and iNKT-cells as well as PDL1 expression as the best predictors of clinical outcome. HCC infiltrate is characterized by the expression of molecules with negative regulatory function that may favor tumor recurrence and poor survival

Response Prediction in Chronic Hepatitis C by Assessment of IP-10 and IL28B-Related Single Nucleotide Polymorphisms

Background: High baseline levels of IP-10 predict a slower first phase decline in HCV RNA and a poor outcome following interferon/ribavirin therapy in patients with chronic hepatitis C. Several recent studies report that single nucleotide polymorphisms (SNPs) adjacent to IL28B predict spontaneous resolution of HCV infection and outcome of treatment among HCV genotype 1 infected patients. Methods and Findings: In the present study, we correlated the occurrence of variants at three such SNPs (rs12979860, rs12980275, and rs8099917) with pretreatment plasma IP-10 and HCV RNA throughout therapy within a phase III treatment trial (HCV-DITTO) involving 253 Caucasian patients. The favorable SNP variants (CC, AA, and TT, respectively) were associated with lower baseline IP-10 (P = 0.02, P = 0.01, P = 0.04) and were less common among HCV genotype 1 infected patients than genotype 2/3 (P<0.0001, P<0.0001, and P = 0.01). Patients carrying favorable SNP genotypes had higher baseline viral load than those carrying unfavorable variants (P = 0.0013, P = 0.029, P = 0.0004 respectively). Among HCV genotype 1 infected carriers of the favorable C, A, or T alleles, IP-10 below 150 pg/mL significantly predicted a more pronounced reduction of HCV RNA from day 0 to 4 (first phase decline), which translated into increased rates of RVR (62%, 53%, and 39%) and SVR (85%, 76%, and 75% respectively) among homozygous carriers with baseline IP-10 below 150 pg/mL. In multivariate analyses of genotype 1-infected patients, baseline IP-10 and C genotype at rs12979860 independently predicted the first phase viral decline and RVR, which in turn independently predicted SVR. Conclusions: Concomitant assessment of pretreatment IP-10 and IL28B-related SNPs augments the prediction of the first phase decline in HCV RNA, RVR, and final therapeutic outcome