title: HIV-1 viral replication below 50 copies/ml in patients on antiretroviral therapy is not associated with CD8+ T-cell activation.
abstract: OBJECTIVE
  To determine if the expression of CD38 on CD8+ T-cells could be used as a marker of viral replication <50 copies/ml in peripheral blood.
  
  
  METHODS
  In a cross-sectional study of patients attending a single HIV clinic in London, an ultra-sensitive HIV RNA viral load assay, with a limit of detection of 3 copies/ml, was used to determine HIV-1 replication in plasma in 70 patients who had sustained viral suppression <50 copies/ml by bDNA assays. Immune activation using the expression of CD38 on CD8+ T-cells was also assessed in patients on antiretroviral therapy (ART) with sustained viral suppression, individuals with persistent low-level viraemia <400 copies/ml and subjects failing ART (viral load >400 copies/mi).
  
  
  RESULTS
  There was no significant difference in the percentage of CD8+CD38++ T-cells between patients with <50 copies or <3 copies/ml. Immune activation was significantly increased in patients with persistent low-level viraemia and in subjects failing ART. CD4+ T-cell counts in patients on long-term successful ART are inversely associated with CD8+ T-cell activation.
  
  
  CONCLUSIONS
  T-cell activation in patients on long-term successful ART is not due to residual low-level viral replication in the blood compartment of HIV-1. CD8+ T-cell activation in this patient group appears to be associated with poor CD4+ T-cell recovery.
authors.affiliation: Department of Immunology, Imperial College, Chelsea and Westminster Hospital, London.
authors.forename: Alan
authors.initials: A
authors.lastname: Steel
authors.forename: Alison E
authors.initials: AE
authors.lastname: Cox
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Shamji
authors.forename: Laurence
authors.initials: L
authors.lastname: John
authors.forename: Mark
authors.initials: M
authors.lastname: Nelson
authors.forename: Don C
authors.initials: DC
authors.lastname: Henderson
authors.forename: Frances M
authors.initials: FM
authors.lastname: Gotch
authors.forename: Brian G
authors.initials: BG
authors.lastname: Gazzard
authors.forename: Peter
authors.initials: P
authors.lastname: Kelleher
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000032:analysis; D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D015497:HIV-1 / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D051997:ADP-ribosyl Cyclase 1