Relative preservation of natural killer cell cytotoxicity and number in healthy AIDS patients with low CD4 cell counts.
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.
Ironson
G
G
Department of Psychology, University of Miami, Florida 33124-2070, USA.
Balbin
E
E
Solomon
G
G
Fahey
J
J
Klimas
N
N
Schneiderman
N
N
Fletcher
M A
MA
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
D011480:Protease Inhibitors