Mathematical model of peripheral blood stem cell harvest kinetics

Abstract

Summary: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 þ 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 Â 10 6 CD34 þ 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 Â 10 6 , 0.87 Â 10 6 , and 0.32 Â 10 6 CD34 þ 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.

Determining factors predictive of CD34+ cell collection efficiency in an effort to avoid extended and repeated apheresis sessions

“…Several studies have concluded to the presence of intra‐apheresis CD34+ cell recruitment into the blood ; however, this recruitment phenomenon has not always been reported . Mayer et al developed a mathematical model of peripheral blood stem cell harvests which demonstrated that recruitment played an important role and contributed significantly to the final harvest . However, recruitment was significantly influenced by pre‐treatment with chemotherapy and/or radiotherapy with much lower values for patients with moderate and extensive pretreatment.…”

Allogeneic donor peripheral blood “stem cell” apheresis: prospective comparison of two apheresis systems

“…As we are showing, a greater stem cell yield and significantly lower PLT reinfusion rate were achieved 9‐11 . These tangible advantages must be balanced against a higher contamination with granulocytes and granulocytic precursors in Spectra Optia v.5.0 apheresis products, which, however, remained markedly below numbers reported for alternative apheresis systems 7,12‐15 .…”

Evaluation of peripheral blood mononuclear cell collection by leukapheresis

“…As a result, the number of circulating WBCs is much lower in MNC collection, resulting in a thinner layer of WBCs (also known as buffy coat). Second, the circulating MNCs decrease more rapidly during collection as compared to HPC collection because of a lack of active MNC replenishment from bone marrow mobilization . Moreover, the procedure time and processed blood volume for collection of MNCs is usually shorter or less than that of HPC collections because fewer MNCs are typically required.…”