COMPETITIVE REPOPULATION IN LEUKEMIC AND NORMAL BONE-MARROW

The success of chemotherapy in leukemias in which the marrow appears e ntirely replaced by leukemic cells must be due to the persistence of s ome normal stem cells. The implied competition between leukemic and no rmal stem cells is thus akin to the competition between donor and host cells in irradiated animals. A review of that competition points to t he importance of the quantitative relationships between the competing stem cells, even when one of the competing stem cell clones has a prol iferative advantage. Pursuing that analogy, it is suggested that stimu lating the surviving normal stem cells by appropriate combinations of cytokines may be of therapeutic benefit, once the tumor load has been reduced by chemotherapy, Complete eradication of leukemic cells may no t be necessary, if surviving normal cells could gain ascendancy over t he residual leukemic cell clones.