Sialyltransferase activity in leukemia

Sialyltransferase activity in blasts from acute lymphoblastic leukemia (ALL) was markedly lower (1.68 ± 1.23 pmol/mg protein) than those (6.18 ± 2.22 pmol/mg protein) of lymphocytes from normal volunteers (t < 0.001). On the contrary, enzyme activity was significantly increased in blasts (1.21 ± 0.38 pmol/mg protein) from acute non-lymphoblastic leukemia, compared to the level (0.53 ± 0.32 pmol/mg protein) of mature granulocytes (t < 0.001). In TdT-negative CML in blast crisis, sialyltransferase activity (2.11 ± 0.88 pmol/mg protein) was significantly higher than those of mature granulocytes (t < 0.001), whereas no significant difference in the enzyme activity was noted between the blasts from TdT-positive CML in blast crisis and from ALL. In TdT-positive ALL cases, there was an inverse relationship (r = ?0.85, t < 0.01) between sialyltransferase activity and terminal deoxynucleotidyl transferase (TdT) activity of the blasts. Therefore, sialyltransferase in leukocytes may be a unique enzyme in which changes in activity relate to the differentiation or malignant transformation of leukocytes.