Mixed megakaryocytic-granulocytic differentiation during diffusion chamber culture of peripheral blast cells from the blast crisis of chronic myelocytic leukemia

Abstract

Morphologically and cytochemically undifferentiated peripheral blast cells from three patients in blast crisis of Ph′-positive chronic myelocytic leukemia were analysed morphologically, immunologically and cytogenetically prior to and during in-vivo diffusion chamber culture (DC) to investigate their differentiation capacity. In two patients immunological markers characteristic of the megakaryocytic lineage were found on the original cells, but lineage-specific differentiation markers were absent on the blast cells of the third patient. During DC culture multilineage differentiation capacity could be demonstrated immunologically and morphologically in all three patients with expression of megakaryocytic and granulocytic markers as well as terminal differentiation along these lineages. Cytogenetic analysis prior to and during DC culture provided evidence that the cells differentiating in culture were derived from the blast crisis clones and that the event leading to blast crisis might have occurred in a pluripotent precursor cell which retained its differentiation capacity along several lineages.