PREDICTION OF THE ABILITY TO PURGE CLONOGENIC-B CELL LYMPHOMA FROM NORMAL BM INVITRO BY HEAT - THEIR SURVIVAL CURVES CORRESPOND TO A CURVE REFLECTING MORTALITY IN HUMANS

To develop new purging regimens for ABMT the ability to predict potent ial for purging of tumor cells from BM is important. Since the sensiti vity of human B cell lymphoma to hyperthermia is not known, we examine d its effect on the growth of B cell lymphoma cell lines (Raji and Dau di) in vitro to evaluate potential for purging clonogenic tumor cells from normal marrow by heat, using a limiting dilution assay to measure log depletion of tumor cells in a 20-fold excess of normal BM. When e xposed to heat (42-43-degrees-C) for 120 min, both clonogenic Raji and Daudi cells were dramatically reduced (a 4-to-6 log reduction) with t ime, whereas at 42-degrees-C over half and at 43-degrees-C 10% of norm al granulocyte-macrophage progenitor cells survived for the same time period. This high level of lymphoma cell depletion by heat correlated with that of immunologic and pharmacologic studies. In addition, these survival curves during heating were found to correlate with the Gompe rtz-Makeham formula - a law of human mortality. This formula may be us eful in predicting the purging effect of heat. These results suggest t hat in vitro hyperthermia could be applied effectively for the elimina tion of residual, clonogenic lymphoma cells in autologous marrow graft s before ABMT.