Selection and use of chemotherapy with hematopoietic growth factors for mobilization of peripheral blood progenitor cells

Peripheral blood progenitor cells (PBPCs) have become the preferred means o f stem cell support for high-dose chemotherapy in recent years. The biology of PBPC mobilization is complex and may be influenced by several variables , Signals from both stromal and hemopoietic cells may induce downregulation of adhesion molecules and upregulate the expression of metalloproteinases. Cytokines alone can mobilize PBPCs but a synergistic effect has been shown when they are used in conjunction with chemotherapy. Disease-specific mobi lization strategies appear to have the advantage of less toxicity, greater stem cell yield, and enhanced antitumor activity. Studies have demonstrated that the number of peripheral blood CD34(+) cells can be used as a predict or for the timing of apheresis and for estimating PBPC yield, Similarly the CD34(+) cell dose is the strongest predictor of hematologic recovery after PBPC transplant. Age, prior radiotherapy, marrow involvement, and prior ch emotherapy (especially with alkylating agents) are important factors influe ncing the yield of stem cells. (C) 2000 Lippincott Williams & Wilkins, Inc.