SURVIVAL AND CHARACTERISTICS OF MURINE LEUKEMIC AND NORMAL STEM-CELLS AFTER HYPERTHERMIA - A MURINE MODEL FOR HUMAN BONE-MARROW PURGING

The effect of hyperthermia in vitro on the survival and leukaemogenic effectiveness of WEHI 3-B cells and on the survival and transplantation efficiency of bone marrow cells was compared in a murine model system. Normal murine clonogenic haemopoietic cells (day 9 CFU-S and CFU-GM) proved to be significantly less sensitive to 42.5°C hyperthermia (D0 values: 54.3 and 41.1 min, respectively) than leukaemic clonogenic cells (CFU-L) derived from suspension culture or from bone marrow of leukaemic mice (D0: 17.8 min). Exposure for 120 min to 42.5°C reduced the surviving fraction of CFU-L to 0.002 and that of CFU-S to 0.2. If comparable graft sizes were transplanted from normal or heat exposed bone marrow, 60-day survival of supralethally irradiated mice was similar. Surviving WEHI 3-B cells were capable of inducing leukaemia in vivo. The two log difference in the surviving fraction of CFU-L and CFU-S after 120 min exposure to 42.5°C suggests that hyperthermia ex vivo may be a suitable purging method for autologous bone marrow transplantation. © 1990.