Diminished Lymphoblast 5′-Nucleotidase Activity in Acute Lymphoblastic Leukemia with T-Cell Characteristics

SINCE leukemic cells express certain cell-surface markers common to normal human lymphocytes, acute lymphoblastic leukemia can be differentiated immunologically into T-cell, B-cell and null (non-T, non-B-cell) types.1 2 3 Classification of acute lymphoblastic leukemia in this manner has led to an increased awareness of the unusual biologic heterogeneity that exists in this lymphoid malignancy, and such classification has probable prognostic and therapeutic value.4 5 6 Studies of the activity of various enzymatic systems in leukemic cells have produced information about the biologic differences both between leukemic cells and their normal lymphoid counterparts and within immunologic subclasses of acute lymphoblastic leukemia.Consistent and well defined . . .