Application of hypothermia to autologous stem cell purging

Autologous stem cell transplantation is used widely after high-dose chemoth erapy for treating hematological and other malignancies. Bone marrow harves ted for autologous bone marrow transplantation may contain residual maligna nt cells even when the cancer is judged to be in remission. Attempts to pur ge marrow of its putative residual malignant cells may delay hemopoietic re constitution and are of uncertain efficacy. In this report, we demonstrate the possibility of applying hypothermia to autologous stem cell purging. Us ing clonogenic assay, we compared the surviving fraction of human leukemia (HL60. K562) and human small cell lung cancer (H69) cell lines with that of normal human bone marrow CFU-GM and BFU-E cells after incubation at 4 +/- 0.1 degreesC for 24 and 48 h. Hypothermia decreased the surviving fraction of HL60. H69, and K562 cells. In contrast. the surviving fractions of stem cells were not affected by the temperature shift. The surviving fraction of HL60 cells at 4 degreesC cooling was significantly lower than that at 22 d egreesC cooling. These findings suggest that in vitro hypothermia may selec tively purge residual malignant cells in stored remission bone marrow and m ay be applicable before autologous bone marrow transplantation. In addition , the method is very simple and cost effective. (C) 2001 Academic Press.