Characterization of acute undifferentiated leukemia by combined analysis of plasma membrane-associated gamma-glutamyltranspeptidase and soluble terminal transferase.
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.
Heumann
D
D
Losa
G
G
Barras
C
C
Morell
A
A
von Fliedner
V
V
D000208:Acute Disease; D000954:Antigens, Surface / Q000032:analysis; D002462:Cell Membrane / Q000201:enzymology; D004253:DNA Nucleotidylexotransferase / Q000032:analysis*; D004254:DNA Nucleotidyltransferases / Q000032:analysis*; D006801:Humans; D007938:Leukemia / Q000145:classification* / Q000201:enzymology; D007945:Leukemia, Lymphoid / Q000201:enzymology; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology; D007962:Leukocytes / Q000201:enzymology*; D005723:gamma-Glutamyltransferase / Q000032:analysis*
D000954:Antigens, Surface; D005723:gamma-Glutamyltransferase; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase