Large-scale collection of circulating haematopoietic progenitors in cancer patients treated with high-dose cyclophosphamide and recombinant human GM-CSF

Circulating haematopoietic progenitors from 36 cancer patients were collected by continuous-flow leukapheresis during the phase of rapid haematopoietic recovery after pancytopenia induced by high-dose cyclophosphamide and then cryopreserved for autologous transplantation. 20 of the patients also received intravenous infusion of recombinant human granulocyte macrophage-colony stimulating factor (rhGM-CSF) for 7, 10 or 14 days after cyclophosphamide. 106 leukapheresis procedures were done for 2-5 consecutive days. Leukapheresis was started significantly earlier in patients receiving rhGM-CSF. In these patients, yields of peripheral blood elements (leucocytes, mononuclear cells, haematopoietic progenitors and platelets) were significantly higher than in controls treated with cyclophosphamide only. In particular, the mean number of granulocyte-monocyte colony-forming cells was 43.88 X 10(4) vs. 6.16 X 10(4) per kg patient body weight per leukapheresis. Side-effects of leukapheresis were limited to central venous catheter occlusion and fever in 4% and 2% of all procedures, respectively.