The cytotoxicity of alkyl-lysophospholipid on clonogenic leukemia cells and on normal bone marrow progenitor cells is highly, but differentially, increased by cryopreservation.

We studied the cytotoxic effect of alkyl-lysophospholipid (ALP) in combination with cryopreservation on human clonogenic leukemia cells from 10 patients with acute leukemia and on normal bone marrow progenitors (committed stem cells) from 10 donors, in order to assess the applicability of ALP as a purging agent in autologous bone marrow transplantation (ABMT). The tumoricidal effect of ALP was greatly increased by the cryopreservation procedure, both on leukemic progenitors and to a lesser extent on normal bone marrow progenitors. The cytotoxic effects of ALP and of cryopreservation were synergistic. As a consequence, the ALP dose for ex vivo purging has to be adjusted. Furthermore, the cryopreservation procedure itself is more cytotoxic for leukemic progenitors than for normal marrow progenitors, indicating that cryopreservation has a purging effect in AMBT.