Application of serum-free liquid bone marrow cultures to bone marrow purging for autologous bone marrow transplantation in acute lymphoblastic leukemia.

ABSTRACT

We have previously established a serum-free (SF) culture medium which allows normal haematopoietic progenitor cells to be maintained for at least 4 weeks as in the conventional serum dependent SD) medium. In the present study we investigated the efficiency of the SF liquid system to sustain normal residual haemopoiesis to the detriment of the leukemic population in patients with ALL. Probes for a potential selective effect were brought through leukemic progenitor cell assay (CFU-ALL) and the polymerase chain reaction (PCR) study of the bcr/abl translocation. In 13 experiments done in 12 patients, morphological blast cells and the ALL-CFU were dramatically reduced within 3 weeks of incubation in both SF and SD cultures. In 5/5 experiments in SD conditions and 2/5 experiments in SF conditions, leukemic cells expressing the bcr/abl fusion gene also disappeared within the same period. There was no difference in the CFU-GM production between SF and SD mediums. Erythropoiesis exhibited a slower decline in conditions SF, compared to the conditions SD. These results indicate that the liquid marrow culture may selectively deplete the leukemic lymphoblastic cells and enable repopulation by residual normal hemopoietic cells. It may be useful to purge leukemic cells for clinical autologous bone marrow transplantation in patients with ALL.