Characterization of acute undifferentiated leukemia by combined analysis of
plasma membrane-associated gamma-glutamyltranspeptidase and soluble
terminal transferase
D Heumann, G Losa, C Barras, A Morell and V von Fliedner
gamma-Glutamyltranspeptidase (gamma-GT) is a plasma membrane-associated
enzyme present in blasts of certain acute leukemias. We analyzed 90 cases
of undifferentiated and differentiated acute leukemias for gamma- GT, using
a colorimetric assay. Blasts of all patients with common acute
lymphoblastic leukemia (ALL) and T-ALL were negative for gamma-GT (less
than 5 units). In contrast, gamma-GT was significantly elevated in acute
myeloblastic or monoblastic leukemia blasts (P less than .001). In 16 cases
of acute undifferentiated leukemia (AUL) studied, the levels of gamma-GT
ranged from 0 to 93 units; in eight cases, gamma- GT was positive (greater
than 5 units), and six of these had 2% to 5% Sudan black-positive leukemic
cells in the blast-enriched suspension. Combined gamma-GT/TdT analysis
revealed that both enzyme markers were mutually exclusive in 75% of AUL
cases, suggesting that gamma-GT+/TdT- blasts are of nonlymphoid origin, and
gamma-GT-/TdT+ blasts are of lymphoid origin. Two cases were devoid of both
enzyme activities and could represent truly undifferentiated leukemia.
Thus, combined gamma- GT/TdT analysis underlines the heterogeneity of AUL
and appears to be useful in defining the lineage commitment of
undifferentiated leukemic blasts.
Volume 66,
Issue 2,
pp. 255-258,
08/01/1985
Copyright © 1985 by The American Society of Hematology
