title: Alterations of the NK cell pool in HIV/HCV co-infection.
abstract: BACKGROUND
  A relevant proportion of human immunodeficiency virus (HIV) infected patients is co-infected with the hepatitis C virus (HCV). HCV co-infection in HIV-positive patients is associated with faster progression of liver disease in comparison to HCV mono-infection. Natural killer (NK) cells critically modulate the natural course of HCV infection. Both HIV and HCV mono-infection are associated with alterations of the NK cell pool. However, little data is available concerning phenotype and function of NK cells in HIV/HCV co-infection.
  
  
  METHODS
  A total of 34 HIV/HCV co-infected, 35 HIV and 39 HCV mono-infected patients and 43 healthy control persons were enrolled into this study. All HIV-positive patients were under effective antiretroviral therapy. NK cell phenotype, IFN-γ production and degranulation were studied by flow cytometry.
  
  
  RESULTS
  NK cell frequency in HIV/HCV co-infection was significantly lower than in healthy individuals but did not differ from HIV and HCV mono-infection. HIV/HCV co-infection was associated with significantly decreased expression of the maturation/differentiation markers CD27/62L/127 on NK cells but increased expression of CD57 compared to healthy controls. Of note, expression also differed significantly from HCV mono-infection but was similar to HIV mono-infection, suggesting a pronounced impact of HIV on these alterations. Similar findings were made with regard to the NK cell receptors NKG2A/C and NKp30. More importantly, NK cells in co-infection displayed a highly impaired functional activity with significantly lower IFN-γ production and degranulation than in healthy donors as well as HIV and HCV mono-infection, suggesting a synergistic effect of both viruses.
  
  
  CONCLUSIONS
  Our data indicate that HIV/HCV co-infection is associated with significant alterations of the NK cell pool, which might be involved in the rapid progression of liver disease in co-infected patients and which mainly reflect alterations observed in HIV mono-infection.
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Dominik J
authors.identifier: http://orcid.org/0000-0003-0093-7832
authors.initials: DJ
authors.lastname: Kaczmarek
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Pavlos
authors.initials: P
authors.lastname: Kokordelis
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Krämer
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Glässner
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Wolter
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Goeser
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Lutz
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Carolynne
authors.initials: C
authors.lastname: Schwarze-Zander
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Boesecke
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Strassburg
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Jürgen K
authors.initials: JK
authors.lastname: Rockstroh
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Spengler
authors.affiliation: Department of Internal Medicine I, University of Bonn, Bonn, Germany.|German Center for Infection Research (DZIF), Bonn, Germany.
authors.forename: Jacob
authors.initials: J
authors.lastname: Nattermann
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D060085:Coinfection / Q000276:immunology* / Q000821:virology; D003430:Cross-Sectional Studies; D005434:Flow Cytometry; D015658:HIV Infections / Q000150:complications* / Q000276:immunology; D006526:Hepatitis C / Q000150:complications* / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007694:Killer Cells, Natural / Q000502:physiology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D007371:Interferon-gamma