The number of CD34(+) cells in peripheral blood as a predictor of the CD34(+) yield in patients going to autologous stem cell transplantation

The number of CD34(+) cells in peripheral blood (PB) is a guide to the optimal timing to harvest peripheral blood progenitor cells (PBPC). The objective was to determine the number of CD34(+) cells in PB that allows achieving a final apheresis product containing > or =1.5 x 10(6) CD34(+) cells/kg, performing up to three aphereses. Between March 1999 and August 2003, patients with hematological and solid malignancies who underwent leukapheresis for autologous bone marrow transplantation were prospectively evaluated. Seventy-two aphereses in 48 patients were performed (mean 1.45 per patient; range 1-3). PBPC were mobilized with cyclophosphamide plus recombinant human granulocyte-colony stimulating factor (G-CSF) (n = 40), other chemotherapy drugs plus G-CSF (n = 7), or G-CSF alone (n = 1). We found a strong correlation between the CD34(+) cells count in peripheral blood and the CD34(+) cells yielded (r = 0.903; P < 0.0001). Using receiver-operating characteristic (ROC) curves, the minimum number of CD34(+) cells in PB to obtain > or =1.5 x 10(6)/kg in the first apheresis was 16.48 cells/microL (sensitivity 100%; specificity 95%). The best cut-off point necessary to obtain the same target in the final harvest was 15.48 cells/microL, performing up to three aphereses (sensitivity 89%; specificity 100%). In our experience, > or =15 CD34(+) cells/microL is the best predictor to begin the apheresis procedure. Based on this threshold level, it is possible to achieve at least 1.5 x 10(6)/kg CD34(+) cells in the graft with < or =3 collections.