Prospective, randomized, sequential, crossover trial of large-volume vs. normal-volume leukapheresis procedures: effects on subpopulations of CD34(+) cells.

Some data exist on the influence of leukapheresis volume on the number of harvested peripheral blood hematopoietic progenitor cells (HPC), but less is known about the influence on the composition of HPC. We therefore performed a prospective, randomized crossover trial to evaluate the effect of large-volume (LVL) vs. normal-volume leukapheresis (NVL) on subpopulations of CD34(+) cells in the harvest product of 15 patients with breast cancer and 8 patients with non-Hodgkin's lymphoma. Patients were randomly assigned to start either with an LVL on day 1 followed by an NVL on day 2 or vice versa. The number of HPC, the extraction efficiency defined as difference between yield in the harvest and decrease in peripheral blood, and the relative proportion as well as the absolute numbers of CD34(+) cells coexpressing CD38, CD90, HLA-DR, CD117, CD7, CD19, CD41, or CD33 were evaluated. There was no significant difference with regard to the percentages of the subsets on comparison of LVL to NVL procedures. Only the absolute median number of CD34(+)HLA-DR(-) cells was significantly (P=0.02) higher in LVL harvests compared with the corresponding NVL components, which can be explained on the basis of the higher yield and the higher extraction efficiency in LVL compared with NVL. LVL results in a higher yield of CD34(+) cells and leads to an intra-apheresis recruitment of HPC but the relative composition of the harvested CD34(+) cells is not changed significantly. In addition, the amount of early, HLA-DR(-), hematopoietic HPC seems to be increased by an LVL.