AMP deaminase as a cell-age marker in transient erythroblastopenia of
childhood and its role in the adenylate economy of erythrocytes
DE Paglia, WN Valentine, M Nakatani and RA Brockway
Department of Pathology and Laboratory Medicine, University of California,
Los Angeles 90024.
Erythrocytes from 11 patients with presumptive diagnoses of transient
erythroblastopenia of childhood were evaluated retrospectively (six) or
prospectively (five) for a possible relationship between erythrocyte
adenosine 5'-monophosphate aminohydrolase, adenylic acid deaminase (AMP
deaminase) activity and intracellular concentrations of adenine
nucleotides. Older red blood cell (RBC) cohorts in these patients
consistently exhibited significantly decreased activities of AMP deaminase
(approximately 5% to 70% of normal control mean) in association with
increased concentrations (up to threefold) of adenosine triphosphate (ATP)
and total adenine nucleotides. We postulate that the latter is a direct
consequence of the former, since diminishing AMP deaminase activity in
aging cells should reduce the drain on the adenine nucleotide pool imposed
by irreversible deamination of AMP to inosine 5'-monophosphate. Consistent
reductions in AMP deaminase activity indicate that this enzyme should also
serve as a reliable marker of mean RBC age useful in diagnostic
confirmation of transient erythroblastopenia. The observed increases in ATP
and total adenine nucleotides in older RBCs require a reevaluation of the
traditional view that age-related losses of these compounds mediate the
ultimate demise of senescent erythrocytes. Similar alterations in the
balance of degradative and salvage pathways in RBC nucleotide metabolism
may also underlie certain cases of so-called "high ATP syndrome."
Volume 74,
Issue 6,
pp. 2161-2165,
11/01/1989
Copyright © 1989 by The American Society of Hematology
