291 Hematopoietic stem cell mobilization and collection in the rhesus maqaque: the effect of high dose stem cell factor.
Monday November 16, 2015 from 11:00 to 12:30
Room 111-112

James V Harmon Jr., United States

Assistant Professor of Surgery


University of Minnesota


Hematopoietic stem cell mobilization and collection in the rhesus maqaque: the effect of high dose stem cell factor.

James Harmon1, Tun Jie3, Martin Wijkstrom4, Jeffrey McCullough2, Melanie Graham1, David Sutherland1, Bernhard Hering1.

1Department of Surgery, University of Minnesota, Minneapolis, MN, United States; 2Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, United States; 3Department of Surgery, University of Arizona , Tucson, AZ, United States; 4Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States

Introduction: The purpose of this study was to evaluate two mobilization protocols for the collection of high numbers of hematopoietic stem cells in the adult donor rhesus macaque model.Safe, effective hematopoietic stem cells (HSC) collection is a critical step in the use of stem cell therapy. The percentage variation in peripherally circulating CD 34+ cells was followed during the stem cell mobilization process. The effectiveness of a high-dose stem cell factor (SCF) protocol was compared to the effectiveness of the standard dose of SCF. The SCF was administered in combination with a standard dose G-CSF (100 μg//kg/day) in both of the protocols.
Methods:  24 HSC collections were performed in a total of 8 adult rhesus macaques. Five of the adult donor rhesus macaques completed a  hematopoietic stem cell transplantation (HSCT) protocol. Three of those five macaques completed a donor specific islet transplantation protocol. The stem cell collections were performed using a Fenwal® CS-3000 Plus cell separator equipped with a small volume stem cell collection chamber. Five of the stem cell collections were carried out following administration of low-dose SCF (200 μg//kg/day) and 19 collection procedures were performed following administration of high-dose SCF (400 μg//kg/day) mobilization protocol.  Peripheral blood counts and body weights in the macaques were followed daily. The HSC products were characterized by the number of cells collected and by the percentage of CD34+ cells obtained.
Results:  The stem cell mobilization and stem cell collection procedures were well tolerated by the adult rhesus macaque donors. The donor peripheral WBC counts increased from an average of 7.3 K/μL prior to mobilization to an average of 63.5 K/μL at completion of the mobilization period. The average donor hemoglobin value fell from 11.3 g/dL prior to 10.7 g/dL at completion of mobilization. Associated with the use of 5% human albumin to prime the apheresis instrument, the average hemoglobin value fell from 10.7 g/dL to 7.4 g/dL upon completion of the collection procedure. The donor platelet counts fell from an average of 397 thousand/μL to 206 thousand/μL at completion of stem cell mobilization period. At completion of the apheresis procedure the average platelet count in the donor macaques fell to 45 thousand/μL. The average volume of blood processed per procedure was 3,098 ml ± 196 ml. The average HSC product volume was 65.9 ml ± 4.6 ml. The average total number mononuclear cells collected per stem cell product was 2.9 ± 0.6 x109 cells. The average percentage of CD34+ cells (5.7 % ± 0.9 %) in the products collected using the high-dose SCF protocol was significantly higher than the average percentage of CD34+ cells (0.31 % ± 0.1 %) collected in the products collected using the low-dose SCF protocol. (p = 0.0144)
Conclusion: High numbers of HSCs can be safely collected using this HSC  mobilization protocol in the rhesus macaque. The high-dose SCF protocol was superior to the low dose SCF protocol for the mobilization and collection of CD34+ cells in this rhesus macaque model. 


[1] Stem Cells. 2004;22(6):1062-9.

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