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

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

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

Intrahepatic and circulating HLA class II-restricted, hepatitis C virus-specific T cells: Functional characterization in patients with chronic hepatitis C

To compare the functional features of circulating and intrahepatic hepatitis C virus (HCV)-specific CD4+ T cells in chronic HCV infection, peripheral blood and liver-infiltrating lymphocytes from 29 patients with chronic hepatitis C were stimulated with structural and nonstructural HCV proteins to produce antigen-specific T-cell lines and clones. Antigen specificity, fine specificity, phenotype, cytokine production, and T-cell receptor (TCR)-vβ chain expression were analyzed. The results indicate a hierarchy of stimulatory capacity by the different HCV proteins, core being the antigen most frequently recognized by CD4+ intrahepatic lymphocytes, followed by NS4 and NS5. The CD4 response was directed simultaneously against different HCV proteins in individual patients, but fine-specificity analysis indicated that the response was generally focused on a limited number of immunodominant epitopes. Although the narrowly focused nature of this response may favor the emergence of escape mutations, this event was not observed by following-up over time the sequence of 2 epitopes strongly immunodominant for intrahepatic CD4 cells of a patient with chronic HCV infection. In conclusion, simultaneous analysis of peripheral blood and intrahepatic CD4 cells in the same patients indicated a predominant Th1 profile of HCV-specific CD4 cells and suggests a specific compartmentalization of virus-specific T cells into the liver

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

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-γ, TNF-α) 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 CD 127 and PD-1, and in vitro after peripheral blood mononuclear cells (PBMC) culture in the presence of anti-PD-L1 monoclonal antibodies. IFN-γ 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-α. 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. Copyright © 2007 by the American Association for the Study of Liver Diseases

HLA and killer immunoglobulin-like receptor genes as outcome predictors of hepatitis C virus-related hepatocellular carcinoma

Purpose: We evaluated the impact of the killer immunoglobulin-like receptors (KIR) of natural killer (NK) cells and of their HLA ligands over the clinical outcome of hepatitis C virus (HCV)-related hepatocellular carcinoma after curative treatment by either surgical resection or radiofrequency thermal ablation (RTA). Experimental Design: Sixty-one consecutive patients with HCV-related hepatocellular carcinoma underwent KIR genotyping and HLA typing. A phenotypic/functional characterization of NK cells was carried out in patients with different KIR/KIR-ligand genotype. Results: Activating KIR2DS5 was associated with significantly longer time to recurrence (TTR) and overall survival (OS; P < 0.03 each). Homozygous HLA-C1 (P < 0.02) and HLA-Bw4I80 (P < 0.05) were expressed by patients with significantly better OS, whereas HLA-C2 (P < 0.02) and HLA-Bw4T80 (P < 0.01) were associated with a worse OS. Multivariate analysis identified as parameters independently related to TTR the type of treatment (surgical resection vs. RTA; P < 0.03) and HLA-C1 (P < 0.03), whereas only KIR2DS5 was an independent predictor of longer OS (P < 0.05). Compound KIR2DL2-C1 and KIR3DS1-Bw4T80 genotypes were associated with better TTR (P < 0.03) and worse OS (P = 0.02), respectively. A prevalent cytotoxic (CD56dim) NK phenotype was detected in patients with both longer TTR and OS. Cytotoxic capacity measured by upregulation of CD107a was significantly higher in subjects with HLA-C1 alone or combined with KIR2DL2/KIR2DL3. Conclusions: These results support a central role of NK cells in the immune response against hepatocellular carcinoma, providing a strong rationale for therapeutic strategies enhancing NK response and for individualized posttreatment monitoring schemes. © 2013 American Association for Cancer Research

Preliminary results from whole-genome expression analysis in patients with secondary adrenal insufficiency treated with modified-release hydrocortisone

Purpose Conventional (CONV) treatment of adrenal insufficiency (AI) is associated with risk of overtreatment: glyco-metabolic impairment, bone loss, and reduced quality of life. Recent findings suggest that modified-release hydrocortisone (MOD) may restore a more physiological cortisol profile. Our aims were: (1) to compare the gene expression profile of peripheral blood mononuclear cells derived from patients, with secondary AI (SAI), under CONV (cortisone acetate or hydrocortisone) or MOD versus healthy controls; and (2) to evaluate MOD effects on serum cortisol profile, glucose, lipid, bone, and clinical parameters.Methods Thirteen patients with SAI were switched from CONV to MOD at equivalent dose. Area under curve (AUC) of both formulations was calculated in six patients. Clinical, metabolic and bone parameters were measured at baseline and 3 months after MOD in all patients. In six patients and six age- and sex-matched healthy controls, a whole-genome expression analysis was performed at baseline, 1 month, and 3 months after MOD.Results (1) The number of genes differentially expressed (n = 235; mainly involved in immune response and metabolism) in SAI patients compared to controls progressively and significantly decreased switching from CONV to MOD (n = 78 at 3 months). (2) Under MOD: AUC of cortisol exposure tended to be smaller and cortisol levels showed a more physiological profile; no significant changes of clinical, metabolic and bone parameters were observed, likely due to the short follow-up, but triglycerides tended slightly to increase.Conclusions MOD may restore a normal gene expression profile as soon as 1 month after switching from CONV

Radiofrequency Thermal Ablation for Hepatocellular Carcinoma Stimulates Autologous NK-Cell Response

Background & Aims: Radiofrequency thermal ablation (RFA) is a minimally invasive technique used as standard local therapy of hepatocellular carcinoma and second-line treatment for metastatic liver tumors. Studies in preclinical models and in patients have shown that thermal destruction of tumor tissue can enhance anti-tumor cellular responses, but our knowledge of its impact on natural killer (NK) cells is still very limited. Methods: Thirty-seven patients undergoing RFA for hepatocellular carcinoma were studied for peripheral blood lymphocytes counts followed by phenotypic and functional characterization of NK-cell population. Results: Peripheral blood lymphocytes kinetics revealed an increased frequency and absolute number of NK cells expressing higher levels of activatory along with reduced levels of inhibitory NK receptors, and increased functional NK-cell activity. A prevalent expansion of the CD3-CD56dim NK subset was observed compared to the CD3-CD56bright counterpart. Interferon-γ production, anti-K562 cell cytotoxicity, and antibody-dependent cell cytotoxicity, appeared consistently increased in terms of both absolute activity and killing efficiency at 4 weeks after RFA, as compared to baseline. Interestingly, when recurrence-free survival was assessed in 2 groups of patients separated according to higher vs lower enhancement of cytotoxicity and/or interferon-γ production, a significant difference was observed, thus suggesting a potential predictive role of NK functional assays on efficacy of RFA. Conclusions: RFA can lead to stimulation of NK cells with a more differentiated and proactivatory phenotypic profile with general increase of functional activities. This observation may be relevant for development of adjuvant immunotherapeutic strategies aimed at enhancing NK-cell responses against primary and metastatic liver tumors. © 2010 AGA Institute