title: Different rates of CD4+ and CD8+ T-cell proliferation in interleukin-2-treated human immunodeficiency virus-positive subjects.
abstract: BACKGROUND
  Interleukin-2 (IL-2) has been used successfully to increase CD4 cell counts in patients who are human immunodeficiency virus (HIV) positive. The mechanisms involved in this phenomenon are unknown. We hypothesized that a differential proliferation rate of CD4+ compared with CD8+ lymphocytes could be related to the increase of CD4 counts and of CD4/CD8 ratios that occur in HIV+ patients during IL-2 treatment.
  
  
  METHODS
  We enrolled in our study 14 HIV+ patients treated with IL-2 or with highly active antiretroviral therapy (HAART) during a 96-week observation period. Using flow cytometry, we measured longitudinally the expression of the Ki67 antigen in peripheral blood CD4+ and CD8+ lymphocyte subsets.
  
  
  RESULTS
  Compared with HAART alone, IL-2 produced a rapid increase of Ki67+ proliferating CD4 cells and a concomitant increase of the CD4/CD8 ratios, whereas the corresponding CD8 proliferation increased slightly. On the contrary, HAART alone was effective in suppressing equally both CD4 and CD8 proliferation.
  
  
  CONCLUSIONS
  Our results suggest a selective activity of IL-2 on CD4 T-cell proliferation; on the contrary, CD8-specific proliferation is affected minimally during treatment. This information may offer the potential to plan correctly immune activating regimens.
authors.affiliation: Division of Microbiology, Immunology and Virology, Centro di Riferimento Oncologico, IRCCS, 33081 Aviano, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Caggiari
authors.forename: S
authors.initials: S
authors.lastname: Zanussi
authors.forename: C
authors.initials: C
authors.lastname: Crepaldi
authors.forename: M T
authors.initials: MT
authors.lastname: Bortolin
authors.forename: C
authors.initials: C
authors.lastname: Caffau
authors.forename: M
authors.initials: M
authors.lastname: D'Andrea
authors.forename: P
authors.initials: P
authors.lastname: De Paoli
mesh_terms: D023241:Antiretroviral Therapy, Highly Active; D017209:Apoptosis / Q000187:drug effects; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002455:Cell Division / Q000276:immunology; D004359:Drug Therapy, Combination; D005434:Flow Cytometry; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D007167:Immunotherapy; D007376:Interleukin-2 / Q000627:therapeutic use*; D019394:Ki-67 Antigen / Q000378:metabolism
chemical_list: D007376:Interleukin-2; D019394:Ki-67 Antigen