title: Hepatitis C virus-specific cellular immune responses in sustained virological responders with viral persistence in peripheral blood mononuclear cells.
abstract: OBJECTIVE
  Hepatitis C virus (HCV)-RNA detection in peripheral blood mononuclear cells (PBMCs) after recovery from HCV infection, is a type of occult HCV infection although is unclear how the viral persistence in PBMCs affects HCV-specific T-cell responses. The aim of this study was to investigate if cellular immune responses are modified by HCV persistence in PBMCs.
  
  
  METHODS
  HCV-specific CD4(+) and CD8(+) T-cell responses against six HCV peptides, situated within the non-structural (NS) proteins NS3, NS4b and NS5b, were measured by flow cytometry-through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) and CD69 expression- in 27 sustained virological responders (SVR): 13 with and 14 without occult HCV infection in PBMCs, detected by strand-specific real-time PCR. Ten healthy individuals and 14 chronically infected patients with viraemia, were included as controls.
  
  
  RESULTS
  SVR without occult infection showed a higher percentage of activated CD4(+) cells against peptides belonging to NS3 (p124, p153) and NS5b (p257, p294), activated CD8(+) cells against NS3 (p124, p153, p158) and NS5b-p294, as well as an elevated percentage of CD4(+) cells releasing IFN-γ + IL-4 against NS3-p153, and by CD8(+) cells against NS3 (p124, p153). SVR without occult infection showed a higher percentage of activation and release of IFN-γ + IL-4 by both cell subpopulations than the two group of controls, in contrast to SVR with occult infection.
  
  
  CONCLUSIONS
  The lower HCV-specific T-cell response found in SVR with occult infection indicates that the immune response may be impaired when the virus persists in PBMCs.
authors.affiliation: Biomedicine Institute of Seville (IBIS), University of Seville CSIC, University Hospital Virgen del Rocio, Seville, Spain.
authors.forename: María C
authors.initials: MC
authors.lastname: Roque-Cuéllar
authors.forename: Berta
authors.initials: B
authors.lastname: Sánchez
authors.forename: José R
authors.initials: JR
authors.lastname: García-Lozano
authors.forename: Juan M
authors.initials: JM
authors.lastname: Praena-Fernández
authors.forename: José L
authors.initials: JL
authors.lastname: Márquez-Galán
authors.forename: Antonio
authors.initials: A
authors.lastname: Núñez-Roldán
authors.forename: José
authors.initials: J
authors.lastname: Aguilar-Reina
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D000998:Antiviral Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D016022:Case-Control Studies; D005260:Female; D005434:Flow Cytometry; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D006526:Hepatitis C / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology* / Q000821:virology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D037181:Lectins, C-Type / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology; D012367:RNA, Viral / Q000097:blood; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load; D017361:Viral Nonstructural Proteins / Q000276:immunology; D000099192:CD69 Antigens; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; D012324:RNA-Dependent RNA Polymerase
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D000998:Antiviral Agents; D015415:Biomarkers; D007371:Interferon-gamma; D015847:Interleukin-4; D037181:Lectins, C-Type; D010446:Peptide Fragments; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D000099192:CD69 Antigens; C573415:IFNG protein, human; C508598:IL4 protein, human; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C080107:NS4B protein, flavivirus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase
keywords: T-cell response; flow cytometry; occult HCV infection; peripheral blood mononuclear cells; real-time PCR; sustained virological responders