title: Differences in hepatitis C virus (HCV)-specific CD8 T-cell phenotype during pegylated alpha interferon and ribavirin treatment are related to response to antiviral therapy in patients chronically infected with HCV.
abstract: CD8 T cells play a major role in antiviral immune responses. Their importance for progression to chronic hepatitis C and response to treatment are still unclear. To address these issues, hepatitis C virus (HCV)-specific CD8 T-cell responses were monitored, at the single-cell level, using HLA class I pentamers specific for HCV core and HCV NS3 epitopes, in 23 chronically infected patients during treatment with pegylated alpha interferon and ribavirin. Patients who presented a sustained-response to therapy had stronger HCV-specific CD8 T-cell responses at all time points studied. Moreover, there were clear differences in the phenotypes of these cells during therapy: in responder patients, terminally differentiated effector cells increased more rapidly, and their frequency was always higher than in nonresponder patients. Sustained-responder patients also showed a higher frequency of HCV-specific CD8 T cells producing cytotoxic factors. Overall, a late and inefficient differentiation process of HCV-specific CD8 T cells might be associated with lack of response to treatment. A better knowledge of the mechanisms underlying this impairment may be important for the development of new therapeutic strategies to maintain, restore, or increase CD8 T-cell effectiveness in chronic HCV infection.
authors.affiliation: Molecular Biology Laboratory, Histocompatibility Center of Coimbra, Coimbra, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Caetano
authors.forename: António
authors.initials: A
authors.lastname: Martinho
authors.forename: Artur
authors.initials: A
authors.lastname: Paiva
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pais
authors.forename: Cristina
authors.initials: C
authors.lastname: Valente
authors.forename: Cristina
authors.initials: C
authors.lastname: Luxo
mesh_terms: D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D005260:Female; D053804:Granzymes / Q000032:analysis; D016174:Hepacivirus / Q000276:immunology*; D018936:Hepatitis C Antigens / Q000276:immunology; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000276:immunology*; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D054353:Perforin / Q000032:analysis; D011092:Polyethylene Glycols / Q000627:therapeutic use*; D011994:Recombinant Proteins; D012254:Ribavirin / Q000627:therapeutic use*; D014758:Viral Core Proteins / Q000276:immunology; D017361:Viral Nonstructural Proteins / Q000276:immunology; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000998:Antiviral Agents; D000939:Epitopes; D053804:Granzymes; D018936:Hepatitis C Antigens; D000077190:Interferon alpha-2; D016898:Interferon-alpha; D054353:Perforin; D011092:Polyethylene Glycols; D011994:Recombinant Proteins; D012254:Ribavirin; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C499352:core protein p22, Hepatitis C virus; C417083:peginterferon alfa-2b; C100416:peginterferon alfa-2a