Distinct CD4+CD8+ Double-Positive T Cells in the Blood and Liver of Patients during Chronic Hepatitis B and C

CD4+ and CD8+ T cells, the main effectors of adaptive cellular immune responses, differentiate from immature, non-functional CD4+CD8+ double-positive T (DPT) cells in the thymus. Increased proportions of circulating DPT lymphocytes have been observed during acute viral infections; in chronic viral diseases, the role and repartition of extra-thymic DPT cells remain largely uncharacterized. We performed a phenotypic analysis of DPT cells in blood and liver from patients chronically infected by hepatitis C (HCV) or B (HBV) viruses. The highest percentages of DPT cells, predominantly CD4highCD8low, were observed in patients infected by HCV, while HBV-infected patients mostly displayed CD4lowCD8high and CD4highCD8high DPT cells. All proportions of DPT cells were higher in liver than in blood with, for each subpopulation referred to above, a correlation between their frequencies in these two compartments. In HCV patients, intra-hepatic DPT cells displayed more heterogeneous activation, differentiation and memory phenotypes than in the blood; most of them expressed CD1a, a marker of T cell development in the thymus. Ex vivo, the inoculation of liver slices with HCV produced in cell culture was accompanied by a disappearance of CD8high cells, suggesting a direct effect of the virus on the phenotype of DPT cells in the liver. Our results suggest that, in half of the patients, chronic HCV infection promotes the production of DPT cells, perhaps by their re-induction in the thymus and selection in the liver

Changes to the Natural Killer Cell Repertoire after Therapeutic Hepatitis B DNA Vaccination

BACKGROUND: Improvements to the outcome of adaptive immune responses could be achieved by inducing specific natural killer (NK) cell subsets which can cooperate with dendritic cells to select efficient T cell responses. We previously reported the induction or reactivation of T cell responses in chronic hepatitis B patients vaccinated with a DNA encoding hepatitis B envelope proteins during a phase I clinical trial. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we examined changes in the peripheral NK cell populations occurring during this vaccine trial using flow cytometry analysis. Despite a constant number of NK cells in the periphery, a significant increase in the CD56(bright) population was observed after each vaccination and during the follow up. Among the 13 different NK cell markers studied by flow cytometry analysis, the expression of CD244 and NKG2D increased significantly in the CD56(bright) NK population. The ex vivo CD107a expression by CD56(bright) NK cells progressively increased in the vaccinated patients to reach levels that were significantly higher compared to chronically HBV-infected controls. Furthermore, modifications to the percentage of the CD56(bright) NK cell population were correlated with HBV-specific T cell responses detected by the ELISPOT assay. CONCLUSIONS/SIGNIFICANCE: These changes in the CD56(bright) population may suggest a NK helper effect on T cell adaptive responses. Activation of the innate and adaptive arms of the immune system by DNA immunization may be of particular importance to the efficacy of therapeutic interventions in a context of chronic infections. TRIAL REGISTRATION: ClinicalTrials.gov NCT00988767

hepatitis b virus infection and the kidney renal abnormalities in hbv patients antiviral drugs handling and specific follow up

Chronic hepatitis B virus (CHB) infection is one of the most common causes of chronic liver disease, cirrhosis, and hepatocellular carcinoma (HCC) worldwide. Many patients with CHB have variable degrees of functional renal impairment, and approximately 2 to 15% of patients on hemodialysis have CHB. Several therapeutic regimens have been developed in the past years, among which oral nucleoside and nucleotide analogues have been demonstrated to be efficient and well tolerated. However, they all are excreted in the urine and may thus require dosage adjustment in patients with decreased renal function. Furthermore, a number of them may in addition be toxic to the kidneys, especially in those patients presenting with renal insufficiency

Impact of hepatitis B virus basic core promoter mutations on T cell response to an immunodominant HBx-derived epitope

The hepatitis B X (HBx) protein is a crucial component in HBV infection in vivo and has been implicated in HCC. In this study, we aimed to detect and characterize peripheral HBx-specific T cells in chronically infected patients at the inactive carrier state of the disease. HBx-specific IFN-gamma-secreting T cells were found in 36 of 52 patients (69%), and 78% (28/36) of responding patients had T cells targeting epitopes in the carboxy-terminal part of HBx. IL-10 secretion after the stimulation of T cells with HBx-derived peptides was weak or undetectable. IFN-gamma-secreting T cells recognized a previously unknown immunodominant CD4+ T cell epitope, HBx 126-140 (EIRLKVFVLGGCRHK), in 86% (24 of 28) of patients. This peptide bound several HLA-DR molecules (HLA-DRB1*0101, HLA-DRB1*0401, HLA-DRB1*1301, and HLA-DRB5*0101). Its coding sequence overlaps a domain of the HBV genome encompassing the basic core promoter (BCP) region. Taking into account the selection of viral core promoter mutants during HBV infection, we found that HBV variants with BCP mutations were present in patient sera. We further demonstrated that these viral mutant sequences activated T cells specific for the immunodominant epitope only weakly, if at all. This is the first study linking BCP mutations and HBx-specific T cell responses.CONCLUSION:Wild-type and variant peptides may represent potential tools for monitoring the HBV-specific T cell responses involved in sequence evolution during disease progression. Finally, the degenerate HLA-DR binding of this promiscuous, immunodominant peptide would make it a valuable component of vaccines for protecting large and ethnically diverse patient populations

Plasmacytoid dendritic cells initiate a complex chemokine and cytokine network and are a viable drug target in chronic HCV patients

Plasmacytoid dendritic cells (pDCs) are the professional type I interferon (IFN)-producing cells, and upon activation they traffic to lymph organs, where they bridge innate and adaptive immunity. Using multianalyte profiling (MAP), we have mapped the key chemokines and cytokines produced in response to pDC activation, taking into consideration the role of autocrine IFN, as well as paracrine effects on other innate cells (e.g., monocytes and conventional DCs). Interestingly, we identify four distinct cytokine/chemokine loops initiated by Toll-like receptor engagement. Finally, we applied this analytic approach to the study of pDC activity in chronic hepatitis C patients. Based on the activation state of pDCs in fresh blood, the lack of agonistic activity of infectious virions, the production of a broad array of cytokines/chemokines once stimulated, and the direct effects of pDCs on other PBMCs, we conclude that the pDCs from hepatitis C virus (HCV)-infected individuals are fully functional and are, indeed, a viable drug target. In sum, this study provides insight into the use of MAP technology for characterizing cytokine networks, and highlights how a rare cell type integrates the activation of other inflammatory cells. Furthermore, this work will help evaluate the therapeutic application of pDC agonists in diseases such as chronic HCV infection

Liver fibrosis staging using supersonic shear imaging : a clinical study on 142 patients

International audienceI. Background, Motivation and ObjectiveFibrosis staging can be assessed by a rough estimation of the liver stiffness averaged along an ultrasonic A-line. Providing a complete 2D map of liver stiffness would thus be of great clinical interest for the diagnosis of hepatic fibrosis and help prevent upcoming cirrhosis. However, such measurement requires both a quantitative value of shear elasticity and a great precision to discriminate between different fibrosis levels. Beyond the scope of non-invasive fibrosis quantification, it is also envisioned that quantitative elasticity imaging of liver will have potential interest for liver cancer diagnosis. In this work, the Supersonic Shear Imaging technique (SSI) is proposed to map the in vivo viscoelastic parameters of liver on patients with hepatitis C and derive a mean elasticity of liver tissues. The results are compared to biological tests (Fib4, Apri, Forns) and Fibroscan® measurements. II. Statement of Contribution / MethodsThe SSI technique is based on the radiation force induced by a conventional ultrasonic probe to generate a planar shear wave deep into tissues. The shear wave propagation throughout the medium is caught in real time thanks to an ultrafast ultrasound scanner (up to 5000 frames/s). Using modified sequences and post-processing, this technique is implemented on curved arrays in order to get a larger field of view of liver tissues. A study on 150 HCV patients with different fibrosis stages F has been conducted in order to investigate the accuracy of the technique (F ϵ [0;4]). Quantitative maps of liver elasticity are produced for each volunteer with a linear and a curved array. III. ResultsB-mode images of 120x75 mm² and corresponding elasticity maps are obtained using a 2.5 MHz curved ultrasonic probe with a good reproducibility and accuracy. The shear wave phase velocity dispersion is also calculated. This study shows a good correlation between the values obtained by SSI and the fibrosis levels diagnosed by biological tests (p-index 0.9 for F>3 and Y> 0.8 for F>2). Results are also compared (r2 > 0.92) to the Fibroscan® elasticity measurement by fitting the velocity dispersion curves obtained by SSI at 50 Hz.IV. Discussion and ConclusionsThis real-time elasticity mapping using an ultrasonic curved probe offers better signal to noise ratio than linear arrays and a larger area in the patient's liver (13.3±2.8 cm² estimation area). This gives more confidence on the accuracy of the diagnosis of the fibrosis stage. Furthermore, the elasticity parameters obtained with SSI give access to the shear wave group velocity and the phase velocity. As a consequence, the SSI assessment of liver stiffness could potentially give more information on the viscoelasticity properties of the liver

Hepatitis C virus treatment in the real world: optimising treatment and access to therapies

Chronic HCV infections represent a major worldwide public health problem and are responsible for a large proportion of liver related deaths, mostly because of HCV-associated hepatocellular carcinoma and cirrhosis. The treatment of HCV has undergone a rapid and spectacular revolution. In the past 5 years, the launch of direct acting antiviral drugs has seen sustained virological response rates reach 90% and above for many patient groups. The new treatments are effective, well tolerated, allow for shorter treatment regimens and offer new opportunities for previously excluded groups. This therapeutic revolution has changed the rules for treatment of HCV, moving the field towards an interferon-free era and raising the prospect of HCV eradication. This manuscript addresses the new challenges regarding treatment optimisation in the real world, improvement of antiviral efficacy in `hard-to-treat' groups, the management of patients whose direct acting antiviral drug treatment was unsuccessful, and access to diagnosis and treatment in different parts of the world