Can the stem cell mobilization technique influence CD34+cell collection efficiency of leukapheresis procedures in patients with hematologic malignancies?

A total of 415 leukaphereses in 201 patients stimulated with growth factor (GF; n = 119) or chemotherapy-GF ( n = 296) were studied to determine CD34+ cell collection efficiency (CE). The pre-apheresis leukocyte count was 1 - 93 x 10(9)/l (median 20), and peripheral blood CD34 count (PBCD34) was 1 - 1104/mul (median 19). The total number of CD34+ cells collected was 4 - 6531 x 10(6) ( median 151); corresponding to 0.1 - 111.4 x 10(6) ( median 2.3) per kg. There was strong correlation between PBCD34 and the number of CD34+ cells collected (r =0.9; P<.0001). CE was 7 - 145% (median 46). On multiple regression analysis, a higher leukocyte count (P<.0001) was the most important predictor of lower CE. CE with leukocytes <0 was 7 - 145% ( median 53%) compared to 10 - 132% ( median 40%) with leukocyte >= 20 (P<.0001). In all, 61% of the apheresis procedures performed after chemotherapy-GF occurred when leukocytes were <0 compared to 21% of those performed after GF alone (P<.0001). We conclude that mobilizing patients with the combination of chemotherapy and GF rather than GF alone leads to leukapheresis being performed when the leukocyte count is low - in a range that results in optimum CD34+ cell CE. Autologous stem cells should be mobilized with chemotherapy-GF rather than GF alone whenever possible.