Influential factors for the collection of peripheral blood stem cells and engraftment in acute myeloid leukemia patients in first complete remission.

Although several studies have investigated factors influencing peripheral blood stem cell (PBSC) mobilization in patients with nonmyeloid malignancies in an effort to increase the efficiency of autologous PBSC transplantation (APBSCT), there are very few reports on the efficiency of PBSC mobilization in patients with leukemia. We analyzed the effects of influential variables on successful mobilization and the correlation between infused cell doses and engraftment in acute myeloid leukemia (AML) patients in first complete remission (CR1) who received APBSCT. Between May 1998 and May 2003, 34 patients with AML underwent APBSC collections at our institution. All patients were in CR1 at the time of transplantation. Except for 1 patient, all patients successfully achieved the target CD34(+) cell yield of > or = 2 x 10(6)/kg. Among progenitor cells, the CD34(+) cell dose and the colony-forming unit-granulocyte-macrophage count showed significant correlations with neutrophil and platelet engraftments. The time to neutrophil engraftment was inversely correlated to the number of infused CD34(+) cells (r = -0.67; P < .001), whereas the time to neutrophil engraftment was not significantly correlated with the number of monocytes (r = 0.20; P = .701) or the number of nucleated cells (r = 0.35; P = .062). The time to platelet engraftment was significantly correlated with the dose of infused CD34(+) cells (r = -0.47; P = .012). The univariate analysis showed that more CD34(+) cells per kilogram and more CD34(+) cells per kilogram per day were collected from patients who had a shorter interval (less than 2 months) between diagnosis and PBSC harvest (P = .0111). In conclusion, this study showed that the CD34(+) cell dose was most strongly correlated with a successful engraftment in AML CR1 patients who underwent APBSCT. The proper timing of PBSC collections should be explored to optimize the outcome of APBSCT in AML CR1 patients.