Guidelines for efficient peripheral blood progenitor cell collection.

In recent years peripheral blood progenitor cells (PBPC) have increasingly been used to support hematological recovery after high-dose chemotherapy treatment. PBPC are collected by leukopheresis after mobilization by chemotherapy and/or hematopoietic growth factors. Efficient mobilization and correct timing of leukopheresis is essential to minimize the number of leukophereses required for collection of sufficient PBPC for transplantation. Mobilization efficiency is influenced by various factors and recruitment of cells can be assessed by cell assays and FACS analysis. Target values of cells required for rapid hematological reconstitution after high-dose chemotherapy have been reported, but threshold values for various conditions still need to be established. CD34+ selection of the leukopheresis is of value for tumor cell purging and may be important for reduction of relapse rate of solid tumors and hematological malignancies.