title: Relative preservation of natural killer cell cytotoxicity and number in healthy AIDS patients with low CD4 cell counts.
abstract: OBJECTIVE
  This study examines whether there may be an immune component that protects a relatively rare group of HIV-infected people with very low CD4 cell counts (< or = 50 x 10(6)/l) who have prolonged asymptomatic periods.
  
  
  METHODS
  Three groups were recruited in Miami: (i) healthy low CD4 cell count patients (HLC; n = 30) who, for 9 months had < 50 x 10(6) CD4 cells/l, were asymptomatic and were not on protease inhibitors during that time; (ii) HIV comparison group (Comp; n = 60) who had CD4 cell counts predominantly 150 x 10(6) to 400 x 10(6)/l and never had AIDS Category C symptoms; this group was also followed for CD4 cell count and viral load change over 6 months; and (iii) healthy community controls (n = 33). The study was replicated at the University of California at Los Angeles (UCLA) with HLC (n = 31) versus HIV-negative laboratory controls (n = 28).
  
  
  RESULTS
  The HLC patients were significantly higher than the Comp group on natural killer cell cytotoxicity (NKCC) and natural killer cell number (NK#) despite their lower CD4 cell numbers and higher viral loads. In fact, there was no difference between the HLC group and the healthy community control group in NK# or NKCC. The NK findings were replicated at UCLA. A retrospective analysis showing that higher NKCC was related to fewer prior symptoms in the HLC group, and prospective analysis in the Comp group showing that NK# predicted a lower increase in viral load over 6 months further supported the importance of NK# and NKCC.
  
  
  CONCLUSIONS
  Non-specific cellular immunity may be a factor protecting the health of HIV sero-positive individuals with very low CD4 cell counts.
authors.affiliation: Department of Psychology, University of Miami, Florida 33124-2070, USA.
authors.forename: G
authors.initials: G
authors.lastname: Ironson
authors.forename: E
authors.initials: E
authors.lastname: Balbin
authors.forename: G
authors.initials: G
authors.lastname: Solomon
authors.forename: J
authors.initials: J
authors.lastname: Fahey
authors.forename: N
authors.initials: N
authors.lastname: Klimas
authors.forename: N
authors.initials: N
authors.lastname: Schneiderman
authors.forename: M A
authors.initials: MA
authors.lastname: Fletcher
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy / Q000276:immunology* / Q000503:physiopathology*; D000328:Adult; D018791:CD4 Lymphocyte Count; D003602:Cytotoxicity, Immunologic; D018450:Disease Progression; D005260:Female; D015497:HIV-1 / Q000302:isolation & purification / Q000502:physiology; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D008297:Male; D011480:Protease Inhibitors / Q000627:therapeutic use; D019562:Viral Load
chemical_list: D011480:Protease Inhibitors