1. ¹Department of Internal Medicine – Hematooncology, University Hospital Brno, Brno Czech Republic
2. ²Department of Mathematical Analysis, Faculty of Science, Masaryk University, Brno, Czech Republic

Correspondence: Dr J Mayer, Department of Internal Medicine – Hematooncology, University Hospital Brno, Jihlavská 20, 625 00 Brno, Czech Republic. E-mail: jmayer@fnbrno.cz

Received 30 January 2003; Accepted 22 April 2003.

Abstract

A mathematical model of peripheral blood stem cell harvests was developed, taking two new parameters R (number of recruited cells/minute) and E_f (efficiency of collection) into consideration in addition to concentrations and collected amounts of cells. This model was tested on 241 harvest procedures in cancer patients (chemotherapy+G-CSF stimulation), donors of allogeneic PBSC, and platelet donors, using different collection procedures, with a Cobe Spectra Cell separator. The relationships between preapheresis concentrations, R, E_f and harvested amounts of cells were complex, and different for different harvest procedures and populations of donors. However, invariably, recruitment played an important role and contributed significantly to the final harvest in all types of cells studied. For example, for the patient group, mean recruitment was 1.3 10⁶ CD34+ cells/min and the amount of recruited cells corresponded to 65% of all collected cells. Recruitment was significantly influenced by pretreatment with chemo-therapy and/or radiotherapy. The mean recruitment values for the subgroups with limited, moderate, and extensive pretreatment were 1.65 10⁶, 0.87 10⁶, and 0.32 10⁶ CD34+ cells released per minute, respectively. The finding of a quick and massive recruitment phenomenon may stimulate further research into hematopoiesis in order to maximize harvested cells.