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

Abstract

We have investigated how the amount of blood processed during collection of PBSC affects the yield of CD34 cells. We first established a method of significantly increasing the enrichment of mononuclear cells (MNC), CD34(+) cells and granulocyte-macrophage progenitors (GM-CFU) by on-line flow cytometric (FCM) analysis of the leukocyte populations in the collect line. A total of 166 PBSC collections from 94 patients, were devided into five groups according to the blood volume processed: < 12 L of processed blood, 12-13L, 13-14L, 14-15L and > 15L. When the yield of CD34(+) cells war compared between these groups, a positive correlation was seen (r=0.97) between the processed blood volume and the yield, expressed as a ratio between total number of CD34(+) cells in the harvest and the CD34(+) cell concentration in blood. This correlation can be used to estimate the volume that must be processed to exceed a specific target number of CD34(+) cells. The implications of these results on the need for one, two or more leukapheresis procedures in order to collect a sufficient amount of stem and progenitor cells for a given patient are discussed, i n relation to clinical logistics and the benefits for the patients. PBSC harvest can be improved by individually-adjusted leukapheresis according to on-line FCM analysis and pre-harvest levels of CD34(+) cells and the processed blood volume can be used to predict the CD34(+) yield.