PBSC harvests individually optimized by using pre-collection CD34(+) values and on-line flow cytometric analysis of the mononuclear cell enrichment

Background We have investigated how the amount of blood processed during co llection of PBSC affects the yield of CD34(+) cells. Methods We first established a method of significantly increasing the enric hment of mononuclear cells (MNC), CD34(+) cells and granulocyte-macrophage progenitors (GM-CFU) hy on-line flow cytometric (FCM) analysis of the leuko cyte populations in the collect line. A total of 166 PBSC collections from 94 patients, were divided into Fee groups according to the blood volume pro cessed: < 12 L of processed blood 12-13 L, 13-14 L, 14-15 L and > 15 L. Results When the yield of CD34(+) cells was compared between these groups, a positive correlation was seen (r = 0.97) between the processed blood volu me and the yield, expressed as a ratio between total number of CD34(+) cell s in the harvest and the CD34(+) cell concentration ii blood. This correlat ion can he used to estimate the volume that must be processed to exceed a s pecific target number of CD34(+) cells. The implications of these results o n the need for one, two or more leukapheresis procedures in order to collec t a sufficient amount of stem and progenitor cells for a given patient are discussed in relation to clinical logistics and the benefits for the patien ts. Discussion PBSC harvests can lie improved by individually-adjusted leukaphe resis according to on-line FCM analysis and pre-harvest levels of CD34(+) c ells and the processed blood volume can be used to pi-edict the CD34(+) yie ld.