Abnormal Marker Expression in Acute Leukemia (AL) Characterized by Monoclonal Antibodies and Flow Cytometry

The application of refined immunologic and enzymatic markers to conventional morphologic and cytochemical techniques has revealed an unexpected heterogeneitiy in acute leukemia (AL). Since the development of monoclonal antibodies (MoAbs) to lineage specific differentiation markers, there have been several reports of AL patients whose blast cells represent relatively homogeneous populations with phenotypic features of more than one cell line [1–5] or are characterized by the coexistence of separate cell populations each demonstrating either lymphoid or myeloid features [6–10].