When to harvest peripheral-blood stem cells after mobilization therapy: prediction of CD34-positive cell yield by preceding day CD34-positive concentration in peripheral blood

To evaluate whether the CD34+ yield from a single peripheral-blood stem-cell (PBSC) harvest could be predicted by measurement of the patient's circulating WBC and CD34+ cell concentrations on the day before harvest. Thirty-nine patients with hematologic or nonhematologic malignancy underwent 41 stem-cell mobilization episodes with cytotoxic chemotherapy and/or granulocyte colony-stimulating factor (G-CSF), and a total of 63 leukapheresis procedures were performed. Peripheral-blood samples were analyzed for WBC and CD34+ cell concentration both on the day before and the day of leukapheresis. The median WBC and CD34+ concentrations on the day preceding leukapheresis were 10.0 x 10(9)/L (range, 0.4 to 44.4) and 24.9 x 10(6)/L (range, 0.1 to 349.4), respectively. On the day of harvest, the corresponding figures were 15.1 x 10(9)/L (range, 1.5 to 52.6) and 29.3 x 10(6)/L (range, 0.1 to 543.1), respectively. The median CD34+ cell number collected in a single leukapheresis was 2.6 x 10(6)/kg body weight (range, 0.1 to 26.1). Both the preceding day (r = .84, P < .001) and harvest day (r = .95, P < .001) CD34+ circulating concentrations correlated significantly with the number of CD34+ cells per kilogram collected at leukapheresis. The correlation between CD34+ cells per kilogram collected and harvest day WBC count was also significant (r = .43, P