title: Interleukin 21 augments the hepatitis B virus-specific CD8+ T-cell response in vitro in patients coinfected with HIV-1.
abstract: OBJECTIVE
  Hepatitis B virus (HBV) and HIV-1 share similar transmission routes, therefore, coinfection with both viruses is frequently observed. In HIV-1-infected patients reduced interleukin 21 (IL-21) serum levels have been reported, which may impair virus-specific CD8 T-cell responses.
  
  
  METHODS
  The HBV-specific CD8 T cells in patients with and without HIV-1 coinfection were analyzed cross-sectionally and it was tested whether addition of IL-21 in vitro augments HBV-specific CD8 T-cell responses.
  
  
  METHODS
  Patients with persistent HBV monoinfection as well as HIV-1-positive patients with persistent or resolved HBV-infection were studied. The IL-21 serum levels were determined by ELISA and the HBV-specific CD8 T-cell response was determined after antigen-specific expansion by intracellular staining of interferon γ.
  
  
  RESULTS
  The HBV-specific CD8 T-cell response was significantly higher in HIV-1-negative patients compared with HIV-1-positive patients. Interestingly, within the HIV-1-positive group the magnitude of the response did not differ between patients with chronic or resolved HBV-infection. The IL-21 serum levels were significantly lower in the HIV-1-positive group. Importantly, addition of IL-21 in vitro significantly increased the HBV-specific CD8 T-cell response in HIV-1-positive patients, whereas there was no beneficial effect of IL-21 on cells from HBV-monoinfected patients.
  
  
  CONCLUSIONS
  HIV-1 coinfection is associated with a decreased HBV-specific CD8 T-cell response that can be partially rescued in vitro by addition of IL-21.
authors.affiliation: Institute of Virology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: Guangxu
authors.initials: G
authors.lastname: Ren
authors.forename: Stefan
authors.initials: S
authors.lastname: Esser
authors.forename: Christoph
authors.initials: C
authors.lastname: Jochum
authors.forename: Joerg F
authors.initials: JF
authors.lastname: Schlaak
authors.forename: Guido
authors.initials: G
authors.lastname: Gerken
authors.forename: Dirk
authors.initials: D
authors.lastname: Schadendorf
authors.forename: Ulf
authors.initials: U
authors.lastname: Dittmer
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Yuan
authors.forename: Joerg
authors.initials: J
authors.lastname: Timm
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D000163:Acquired Immunodeficiency Syndrome / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D000328:Adult; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003430:Cross-Sectional Studies; D004279:DNA, Viral; D018450:Disease Progression; D005260:Female; D015497:HIV-1 / Q000276:immunology*; D006509:Hepatitis B / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D007378:Interleukins / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D000098546:Interleukin-21
chemical_list: D004279:DNA, Viral; D007378:Interleukins; D000098546:Interleukin-21