Increase in circulating stem cells following chemotherapy in man

Abstract

The number circulating circulation granulocytic stem cells (CFU C) was determined by the in vitro methylcellulose technique in cancer patients receiving intermittent chemotherapy. In 17 patients studied prior to therapy, the median CFU C concentration per 2 x 105 mononuclear cells plated was six, compared to a posttreatment median of 23 in 21 patients (p < 0.001). numbers number of stem cells were obtained by leukopheresis and cryopreserved with a 99.5% median CFU C recovery. Cyclical changes in the concentration of stem cells with maximum values of 20 times baseline were demonstrated in a patient studied at weekly intervals during multiple courses of treatment. It was estimated that, at peak CFU C concentrations, a quantity of stem cells equivalent to that present in a bulk bone marrow harvest could be obtained from the peripheral blood by a 17 liter pheresis. These results suggest that it may be practical to obtain an adequate number of stem cells from the peripheral blood to study autologous stem cell infusion as a means of averting myelosuppression in patients receiving intensive chemotherapy.