Hematopoietic engraftment from a minimal number of apheresis procedures after mobilization of peripheral blood stem cells with chemotherapy and rhG-CSF.

In a cohort of 13 patients, peripheral blood stem cells (PBSC) were harvested by apheresis after mobilization with chemotherapy and rhG-CSF. Nine patients who had excellent mobilization were transplanted with PBSC concentrates from a minimal number of apheresis procedures (mean of 1.5, range = 1-3). During collection, the number of circulating progenitors was on average 50 times higher than those observed at the steady state in the peripheral blood of healthy unstimulated individuals. The mean number of CFU-GM/kg reinfused per patient was 28.1 x 10(4) (range = 18.0-50 x 10(4)). The use of rhG-CSF, at either 1 or 5 micrograms/kg/day, resulted in a significantly greater yield of CFU-GM per mononuclear cells than that observed previously in a comparable group of patients receiving chemotherapy alone. Prompt and durable engraftment occurred after myeloablative chemotherapy. The average duration of absolute neutropenia was 9 days. Transfusion requirements were low with an average of four packed red cell units and two platelet transfusions per patient. The shortest follow-up is 5 months and the longest is 20+ months. The convenience of this new approach to support myeloablative therapy offers new possibilities for the administration of a higher dose-intensity of chemotherapeutic agents. A limited number of apheresis procedures timely harvested will improve the cost effectiveness of transplant programs.

Blood-derived stem cell collection in acute nonlymphoblastic leukemia: predictive factors for a good yield.

Blood-derived stem cell (BDSC) autografting represents an interesting theoretical approach to the treatment of acute nonlymphoblastic leukemia (ANLL). The feasibility and safety of this procedure have now been established by several observations of rapid hematopoietic recovery following high-dose chemotherapy and autologous reinfusion of BDSCs harvested during remission. Using clonogenic assays for granulocyte-macrophage colony-forming units (CFU-GM) and granulocyte erythrocyte monocyte colony-forming units (CFU-GEM), we tested peripheral blood samples from 20 consecutive patients recovering from induction chemotherapy for ANLL. Results were correlated with other clinical and hematological factors in order to define optimal criteria for successful BDSC harvesting. Two different patterns of increment were observed in the number of peripheral blood progenitor cells during early recovery from chemotherapy in our patients, suggesting that a total period of 10-12 days should be covered for ideal BDSC harvesting by cytapheresis. Associated clinical factors that appear predictive for a better yield are: 1) chemotherapy with daunorubicin, cytosine arabinoside, and thioguanine (DAT), 2) synchronous recovery of monocytes and platelets, and 3) a good overall performance status of the patient. Complete remission status and absence of ongoing infection should also be considered when selecting patients for BDSC harvesting. No correlation was found between the number of circulating CFUs, as indicated by the clonogenic assays, and that of either My-10- or HLA-Dr-positive cells identified by immunofluorescence on the same blood samples. In this study, less than 50% of patients with newly diagnosed ANLL would have been considered good candidates for a BDSC harvesting program.