Large volume leukapheresis for collecting hemopoietic progenitors: role ofCD 34+ precount in predicting successful collection

In this work we evaluated the efficacy of stem cell collection with Large V olume Procedures. (LVP), and analysed the importance of the CD34+ cell prec ount in promoting the collection of a sufficient number of CD34+ cells for transplantation, using the Univariate Logistic Regression analysis. Eighty- nine leukapheresis were performed in 49 patients with hematological maligna ncies and solid tumors, mobilized with chemotherapy plus Granulocyte Colony Stimulating Factor (G-CSF). For each procedure 15.8 liters of blood were p rocessed. The median value of Nucleated Cells (NC) and CD34+ cells precount was respectively 8.29 x 10(9)/ml (range 1.13 divided by 45.4) and 43.08 x 103/ml (range 1.06 divided by 795.2). Results show the capability of LVP to collect large quantities of hemopoietic progenitors with a median CD34+ ce ll total yield of 215.02 x 10(6) (range 5.03 divided by 2210). The yields p er patients' body weight were: CD34+ cells 3.23 x 10(6)/kg (range 0.081 div ided by 41.58). The regression analysis between blood cell precounts and co llection yields gave the following correlations: the CD34+ cell precount co rrelates with CD34+ yield (r = 0.78 p < 0.00) and with CD34+ cell yield/kg (r = 0.76 p < 0.00). The number of CD34+ cells processed correlated with th e number of CD34+ cells collected/kg (r = 0.83 p < 0.000). To investigate t he importance of CD 341 cell precount in promoting CD34+ cell yields greate r than or equal to 2.5 x 10(6)/kg we performed a Univariate Logistic Regres sion analysis that showed in our patients a probability of collecting great er than or equal to 2.5 x 106 CD34+/kg that rose from 0.6 to 0.95 for CD34 precounts that oscillated from 30 to 40 x 10(3) CD34+ cells/ml, respective ly. The Univariate Logistic Regression gave a probability of collecting gre ater than or equal to 2.5 x 10(6) CD34(+) cells/kg that oscillated between 0.64 divided by 0.98 for Values of CD34+ cells processed from 6 x 10(6)/kg to 8 x 10(6)/kg, p < 0.000. Sixty-three percent of patients reached the tar get dose of 2.5 x 10(6) CD34+ cells/kg with only one LVP. Until now 12 pati ents have been transplanted and all have had a prompt and complete lasting recovery. These results confirm the efficacy of LVP in harvesting hemopoiet ic progenitors and their ability in reconstituting hemopoiesis of transplan ted patients, enabling the estimation of CD34+ precounts and CD34+ cells pr ocessed values, highly predictive for the collection of 12.5 x 10(6) CD34cells/kg. Furthermore, the Logistic Model suggests that the best strategy t o plan a successful CD34+ cell collection procedure is to identify for each patient the amount of CD34+ cells/kg to be processed rather than the fixed processing of 3 divided by 5 blood volumes in all patients.