IMMUNOPHENOTYPIC HETEROGENEITY OF CD7(+)CD4(-)CD8(-) ACUTE LEUKEMIAS

Fourteen cases of lymphoid and myeloid acute leukemia (AL) were studied for expression on blast cells of CD7 antigen, a cell surface marker found early during T lineage differentiation. This heterogenic group of CD7(+)CD4(-)CD8(-) AL includes distinct cytological subvariants with: myeloid (AML MO, M1, M4, M5) and lymphoid (pre-T-cell) commitment, biphenotypic or mixed lineage AL and AL with minimal signs of blast cell differentiation, which appear not to follow lineage restriction. The latter subset of AL may represent the transformed counterpart of an early stem cell prior to lineage commitment.