Mucosal-associated invariant T-cell frequency and function in blood and liver of HCV mono- and HCV/HIV co-infected patients with advanced fibrosis

__Background & Aims:__ Mucosal-associated invariant T (MAIT) cells are important innate T cells with antimicrobial and immunoregulatory activity, recently found to be depleted in blood of patients with HIV and HCV mono-infections. In this study, we assessed the impact of HIV, HCV and HCV/HIV co-infection on circulating and intrahepatic MAIT-cells and correlations with liver fibrosis. __Methods:__ In this cross-sectional study, nine healthy subjects, nine HIV, 20 HCV and 22 HCV/HIV co-infected patients were included. Blood and liver fine needle aspirate biopsies were studied using flowcytometry for CD3+CD161+Vα7.2+ MAIT-cell frequency, phenotype and function in HCV mono-infected and HCV/HIV co-infected patients without or with mild fibrosis (Metavir-score F0-F1) or severe fibrosis to cirrhosis (Metavir-score F3-F4). __Results:__ Circulating MAIT-cells were decreased in blood of HCV, HIV and HCV/HIV patients with F0-F1. In HCV/HIV co-infected individuals with severe fibrosis to cirrhosis, the frequency of circulating MAIT-cells was even further depleted, whereas their function was comparable to HCV/HIV co-infected patients with low or absent fibrosis. In contrast, in HCV mono-infected patients, MAIT-cell frequencies were not related to fibrosis severity; however, MAIT-cell function was impaired in mono-infected patients with more fibrosis. More advanced liver fibrosis in HCV or HCV/HIV-infected patients was not reflected by increased accumulation of MAIT-cells in the affected liver. __Conclusions:__ Severe liver fibrosis is associated with dysfunctional MAIT-cells in blood of HCV mono-infected patients, and lower MAIT frequencies in blood of HCV/HIV co-infected patients, without evidence for accumulation in the liver

Antibody dynamics and spontaneous viral clearance in patients with acute hepatitis C infection in Rio de Janeiro, Brazil

Submitted by Sandra Infurna ([email protected]) on 2017-01-18T10:31:05Z No. of bitstreams: 1 clara_yoshida_etal_IOC_2011.pdf: 146042 bytes, checksum: 8ec889224534b76d755828a99d0660c2 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-01-18T10:59:52Z (GMT) No. of bitstreams: 1 clara_yoshida_etal_IOC_2011.pdf: 146042 bytes, checksum: 8ec889224534b76d755828a99d0660c2 (MD5)Made available in DSpace on 2017-01-18T10:59:52Z (GMT). No. of bitstreams: 1 clara_yoshida_etal_IOC_2011.pdf: 146042 bytes, checksum: 8ec889224534b76d755828a99d0660c2 (MD5) Previous issue date: 2011Innsbruck Medical University. Department of Medical Statistics, Informatics and Health Economics. Innsbruck, Austria.Harvard Medical School. Boston, MA, USA / Massachussets General Hospital. Division of Infectious Diseases. Boston, MA, USA.Harvard Medical School. Boston, MA, USA / Massachussets General Hospital. Gastrointestinal Unit. Boston, MA, USA.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Laboratório Central de Saúde Pública Noel Nutels. Divisão de Hepatites. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil / Universidade Federal do Estado do Rio de Janeiro. Hospital Universitário Gaffrée Guinle. Unidade de Hepatologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Desenvolvimento Tecnológico em Virologia. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Universitätsklinikum Eppendorf. Medizinische Klinik I. Hamburg, Germany.Fondation Merieux. Emerging Pathogens Laboratory. Lyon, France.University of Innsbruck. Institute of Statistics. Innsbruck, Austria.National Institute on Aging. Gerontology Research Center. Baltimore, USA.Innsbruck Medical University. Department of Medical Statistics, Informatics and Health Economics. Innsbruck, Austria.Innsbruck Medical University. Department of Medical Statistics, Informatics and Health Economics. Innsbruck, Austria.Innsbruck Medical University. Department of Medical Statistics, Informatics and Health Economics. Innsbruck, Austria.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hepatites Virais. Rio de Janeiro, RJ. Brasil.Background: The anti-HCV antibody response has not been well characterized during the early phase of HCV infection and little is known about its relationship to the clinical course during this period. Methods: We analyzed serial anti-HCV antibodies longitudinally obtained from a prospective cohort of 65 patients with acute HCV infection by using a microparticle enzyme immunoassay AxSYM HCV 3.0 (Abbott Diagnostics) during the first 12 months from HCV acquisition in Rio de Janeiro, Brazil. Spontaneous viral clearance (SVC) was defined as undetectable HCV RNA in serum, in the absence of treatment, for three consecutive HCV PCR tests within 12-months of follow-up. Results: Baseline antibody values were similar among patient groups with self-limiting HCV evolution (n = 34) and persistent viremia (n = 31) [median (interquartile range) signal/cut-off ratio (s/co) 78.7 (60.7-93.8) vs. 93.9 (67.8- 111.9), p = 0.26]. During 12-months follow-up, patients with acute spontaneous resolving HCV infection showed significantly lower serial antibody response in comparison to individuals progressing to chronic infection [median (interquartile range) s/co 62.7 (35.2-85.0) vs. 98.4 (70.4-127.4), p < 0.0001]. In addition, patients with self-limiting HCV evolution exhibited an expeditious, sharp decline of serial antibody values after SVC in comparison to those measured before SVC [median (interquartile range) s/co 56.0 (25.4-79.3) vs. 79.4 (66.3-103.0), p < 0.0001]. Conclusion: Our findings indicate a rapid short-term decline of antibody values in patients with acute spontaneous resolving HCV infection

Antiretroviral therapy partially improves the abnormalities of dendritic cells and lymphoid and myeloid regulatory populations in recently infected HIV patients

This study aimed to evaluate the effects of antiretroviral therapy on plasmacytoid (pDC) and myeloid (mDC) dendritic cells as well as regulatory T (Treg) and myeloid-derived suppressor (MDSC) cells in HIVinfected patients. Forty-five HIV-infected patients (20 of them with detectable HIV load −10 recently infected and 10 chronically infected patients-, at baseline and after antiretroviral therapy, and 25 with undetectable viral loads) and 20 healthy controls were studied. The influence of HIV load, bacterial translocation (measured by 16S rDNA and lipopolysaccharide-binding protein) and immune activation markers (interleukin –IL- 6, soluble CD14, activated T cells) was analyzed. The absolute numbers and percentages of pDC and mDC were significantly increased in patients. Patients with detectable viral load exhibited increased intracellular expression of IL-12 by mDCs and interferon -IFN- α by pDCs. Activated population markers were elevated, and the proportion of Tregs was significantly higher in HIV-infected patients. The MDSC percentage was similar in patients and controls, but the intracellular expression of IL-10 was significantly higher in patients. The achievement of undetectable HIV load after therapy did not modify bacterial translocation parameters, but induce an increase in pDCs, mDCs and MDSCs only in recently infected patients. Our data support the importance of early antiretroviral therapy to preserve dendritic and regulatory cell function in HIV-infected individuals

Mechanisms of CD8+ T cell failure in chronic hepatitis E virus infection

Background and aims In immunosuppressed patients, persistent hepatitis E virus (HEV) infection is common and may lead to cirrhosis and liver failure. HEV clearance depends on an effective virus-specific CD8+ T cell response, however, the knowledge gap of HEV-specific CD8+ T cell epitopes hindered analysis of the mechanisms of T cell failure in persistent infection thus far. Methods We comprehensively studied HEV-specific CD8+ T cell responses in 46 patients with self-limiting (n=34) or chronic HEV infection (n=12), by epitope-specific expansion, functional testing, ex vivo peptide HLA class I tetramer multi-parametric staining, and viral sequence analysis. Results We identified 25 HEV-specific CD8+ T cell epitopes restricted by 9 different HLA class I alleles. In self-limiting HEV infection, HEV-specific CD8+ T cells were vigorous, contracted after resolution of infection, and formed functional memory responses. In contrast, in chronic infection, the HEV-specific CD8+ T cell response was diminished, declined over time, and displayed phenotypic features of exhaustion. However, improved proliferation and interferon-γ production of HEV-specific CD8+ T cells and evolution of a memory-like phenotype was observed upon reduction of immunosuppression and/or ribavirin treatment and was associated with viral clearance. In one patient, mutational viral escape in a targeted CD8+ T cell epitope contributed to CD8+ T cell failure. Conclusion Chronic HEV infection is associated with HEV-specific CD8+ T cell exhaustion, indicating that T cell exhaustion driven by persisting antigen recognition also occurs in severely immunosuppressed hosts. Functional reinvigoration of virus-specific T cells is at least partially possible when antigen is cleared. In a minority of patients, viral escape also contributes to HEV-specific CD8+ T cell failure and thus needs to be taken into account in personalized immunotherapeutic approaches. Lay Summary In immunosuppressed patients, chronic HEV infection is common. For resolution of infection a functional HEV-specific CD8+ T cell response is essential, however, in immunosuppressed individuals CD8+ T cell exhaustion and viral escape contribute to CD8+ T cell failure

Evidence of CD4+ T cell-mediated immune pressure on the Hepatitis C virus genome

Hepatitis C virus (HCV)-specific T cell responses are critical for immune control of infection. Viral adaptation to these responses, via mutations within regions of the virus targeted by CD8+ T cells, is associated with viral persistence. However, identifying viral adaptation to HCV-specific CD4+ T cell responses has been difficult although key to understanding anti-HCV immunity. In this context, HCV sequence and host genotype from a single source HCV genotype 1B cohort (n = 63) were analyzed to identify viral changes associated with specific human leucocyte antigen (HLA) class II alleles, as these variable host molecules determine the set of viral peptides presented to CD4+ T cells. Eight sites across the HCV genome were associated with HLA class II alleles implicated in infection outcome in this cohort (p ≤ 0.01; Fisher’s exact test). We extended this analysis to chronic HCV infection (n = 351) for the common genotypes 1A and 3A. Variation at 38 sites across the HCV genome were associated with specific HLA class II alleles with no overlap between genotypes, suggestive of genotype-specific T cell targets, which has important implications for vaccine design. Here we show evidence of HCV adaptation to HLA class II-restricted CD4+ T cell pressure across the HCV genome in chronic HCV infection without a priori knowledge of CD4+ T cell epitopes

Tracking Virus-Specific CD4+ T Cells during and after Acute Hepatitis C Virus Infection

CD4+ T cell help is critical in maintaining antiviral immune responses and such help has been shown to be sustained in acute resolving hepatitis C. In contrast, in evolving chronic hepatitis C CD4+ T cell helper responses appear to be absent or short-lived, using functional assays. Here we used a novel HLA-DR1 tetramer containing a highly targeted CD4+ T cell epitope from the hepatitis C virus non-structural protein 4 to track number and phenotype of hepatitis C virus specific CD4+ T cells in a cohort of seven HLA-DR1 positive patients with acute hepatitis C in comparison to patients with chronic or resolved hepatitis C. We observed peptide-specific T cells in all seven patients with acute hepatitis C regardless of outcome at frequencies up to 0.65% of CD4+ T cells. Among patients who transiently controlled virus replication we observed loss of function, and/or physical deletion of tetramer+ CD4+ T cells before viral recrudescence. In some patients with chronic hepatitis C very low numbers of tetramer+ cells were detectable in peripheral blood, compared to robust responses detected in spontaneous resolvers. Importantly we did not observe escape mutations in this key CD4+ T cell epitope in patients with evolving chronic hepatitis C. During acute hepatitis C a CD4+ T cell response against this epitope is readily induced in most, if not all, HLA-DR1+ patients. This antiviral T cell population becomes functionally impaired or is deleted early in the course of disease in those where viremia persists

DCs Pulsed with Novel HLA-A2-Restricted CTL Epitopes against Hepatitis C Virus Induced a Broadly Reactive Anti-HCV-Specific T Lymphocyte Response

OBJECTIVE: To determine the capacity of dendritic cells (DCs) loaded with single or multiple-peptide mixtures of novel hepatitis C virus (HCV) epitopes to stimulate HCV-specific cytotoxic T lymphocyte (CTL) effector functions. METHODS: A bioinformatics approach was used to predict HLA-A2-restricted HCV-specific CTL epitopes, and the predicted peptides identified from this screen were synthesized. Subsequent IFN-γ ELISPOT analysis detected the stimulating function of these peptides in peripheral blood mononuclear cells (PBMCs) from both chronic and self-limited HCV infected subjects (subjects exhibiting spontaneous HCV clearance). Mature DCs, derived in vitro from CD14(+) monocytes harvested from the study subjects by incubation with appropriate cytokine cocktails, were loaded with novel peptide or epitope peptide mixtures and co-cultured with autologous T lymphocytes. Granzyme B (GrB) and IFN-γ ELISPOT analysis was used to test for epitope-specific CTL responses. T-cell-derived cytokines contained in the co-cultured supernatant were detected by flow cytometry. RESULTS: We identified 7 novel HLA-A2-restricted HCV-specific CTL epitopes that increased the frequency of IFN-γ-producing T cells compared to other epitopes, as assayed by measuring spot forming cells (SFCs). Two epitopes had the strongest stimulating capability in the self-limited subjects, one found in the E2 and one in the NS2 region of HCV; five epitopes had a strong stimulating capacity in both chronic and self-limited HCV infection, but were stronger in the self-limited subjects. They were distributed in E2, NS2, NS3, NS4, and NS5 regions of HCV, respectively. We also found that mDCs loaded with novel peptide mixtures could significantly increase GrB and IFN-γ SFCs as compared to single peptides, especially in chronic HCV infection subjects. Additionally, we found that DCs pulsed with multiple epitope peptide mixtures induced a Th1-biased immune response. CONCLUSIONS: Seven novel and strongly stimulating HLA-A2-restricted HCV-specific CTL epitopes were identified. Furthermore, DCs loaded with multiple-epitope peptide mixtures induced epitope-specific CTLs responses

T Regulatory Cells Are Markers of Disease Activity in Multiple Sclerosis Patients

FoxP3+ Treg cells are believed to play a role in the occurrence of autoimmunity and in the determination of clinical recurrences. Contradictory reports are, however, available describing frequency and function of Treg cells during autoimmune diseases. We examined, by both polychromatic flow cytometry, and real-time RT-PCR, several Treg markers in peripheral blood mononuclear cells from patients with multiple sclerosis (MS), an autoimmune disease affecting the central nervous system. We found that Tregs, as defined by CD25, CD39, FoxP3, CTLA4, and GITR expression, were significantly decreased in stable MS patients as compared to healthy donors, but, surprisingly, restored to normal levels during an acute clinical attack. We conclude that Treg cells are not involved in causing clinical relapses, but rather react to inflammation in the attempt to restore homeostasis