title: Baseline immune phenotypes and CD4+ T lymphocyte responses to antiretroviral therapy in younger versus older HIV-infected individuals.
abstract: OBJECTIVE
  The purpose of the study was to determine associations between pre-antiretroviral therapy (ART) senescent CD8+ T lymphocytes and naïve versus non-naive CD8+ and CD4+ T lymphocyte subpopulations and CD4+ responses after initiation of ART in younger versus older individuals.
  
  
  METHODS
  Retrospective analysis of 100 subjects with pre-ART cryopreserved peripheral blood mononuclear cells samples was performed with flow cytometry. Subjects were divided into four groups by age (30-50 years or > 50 years) and 96-week CD4+ response (<100 or >200 cells/mm(3)). All subjects had 96-week viral suppression to <50 copies/mm(3). Regression was utilized to investigate associations between pre-ART CD8+ and CD4+ T cell phenotypes with age and CD4+ response categories.
  
  
  RESULTS
  Individuals <50 years had a lower frequency of senescent CD8+ T lymphocytes of the CD56 + 57+, CD56+, and CD28- phenotypes (95%CI -3.6 to -0.02; 95%CI -4.2 to -0.03; 95%CI -12.5 to -1.4, respectively) and a higher frequency of naïve (CD45RA + CD28+) CD8+ T lymphocytes (95%CI 2.6 to 10.9). Younger age and good CD4+ response were associated with a higher frequency of pre-ART naïve CD4+ T cells (95%CI 2.0 to 16.4 and 95%CI 1.5 to 15.6, respectively).
  
  
  CONCLUSIONS
  Prior to ART, younger HIV-infected individuals have a higher frequency of naïve CD4+ and CD8+ T cells and lower frequency of senescent CD8+ T cell phenotypes.
authors.affiliation: UCLA Division of Infectious Diseases and Center for Clinical AIDS Research and Education, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA. rhoffman@mednet.ucla.edu
authors.forename: Risa M
authors.initials: RM
authors.lastname: Hoffman
authors.forename: Beth D
authors.initials: BD
authors.lastname: Jamieson
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Bosch
authors.forename: Judith
authors.initials: J
authors.lastname: Currier
authors.forename: Christina M R
authors.initials: CM
authors.lastname: Kitchen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Schmid
authors.forename: Yuda
authors.initials: Y
authors.lastname: Zhu
authors.forename: Kara
authors.initials: K
authors.lastname: Bennett
authors.forename: Ronald
authors.initials: R
authors.lastname: Mitsuyasu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D023241:Antiretroviral Therapy, Highly Active / Q000706:statistics & numerical data; D054316:Biomarkers, Pharmacological / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D002452:Cell Count; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006678:HIV / Q000472:pathogenicity / Q000502:physiology*; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014779:Virus Replication / Q000187:drug effects
chemical_list: D054316:Biomarkers, Pharmacological