Elevated adenosine deaminase and purine nucleoside phosphorylase activity
in peripheral blood null lymphocytes from patients with acquired immune
deficiency syndrome
JL Murray, KC Loftin, CG Munn, JM Reuben, PW Mansell and EM Hersh
The purine metabolic enzymes adenosine deaminase (ADA) and purine
nucleoside phosphorylase (PNP) are important in lymphocyte differentiation,
and genetic deficiencies of either enzyme have been associated with
hereditary immunodeficiency states. Both ADA and PNP activity were measured
in null cell-enriched and T cell-enriched peripheral blood lymphocytes from
16 patients with the acquired immune deficiency syndrome (AIDS), seven
patients with the AIDS-related symptom complex (ARC), and seven
asymptomatic homosexuals. ADA activity in nmol/10(6) lymphocytes/h was
significantly elevated in null lymphocytes from AIDS (161 +/- 12) as
compared with 23 healthy heterosexual controls (127 +/- 8;P less than
.025). PNP activity was also significantly increased in null lymphocytes
from AIDS patients (96 +/- 10;P less than .005) as well as those from ARC
patients (84 +/- 11:P less than .025) relative to controls (61 +/- 5). No
significant differences in enzyme activity were noted in T cell-enriched
cells in any group. Along with elevated enzyme activity, AIDS patients had
small yet significant increases in the percentages of HLA-DR (P less than
.025), terminal deoxynucleotidyl transferase (TdT) (P less than .0001), and
peanut agglutinin receptor (P less than .0001) positive lymphocytes in the
null fraction compared with controls. TdT-positive cells appeared
morphologically as large lymphoblasts with irregular nuclei. The data imply
that the cellular immune deficiency in AIDS is not a result of deficiencies
in lymphocyte ADA or PNP activity, but is more likely associated with an
increase in an immature and/or activated lymphocyte subset.
Volume 65,
Issue 6,
pp. 1318-1324,
06/01/1985
Copyright © 1985 by The American Society of Hematology
