1. ¹Department of Epidemiology and Biostatistics, University Hospitals of Cleveland, Cleveland, OH, USA
2. ²Comprehensive Cancer Center of Case Western Reserve University, Cleveland, OH, USA
3. ³Department of Medicine, University Hospitals of Cleveland, Cleveland, OH, USA
4. ⁴Department of Pathology, University Hospitals of Cleveland, Cleveland, OH, USA

Correspondence: Dr HM Lazarus, University Hospitals of Cleveland, Department of Medicine, 11100 Euclid Avenue, Cleveland, OH 44106, USA. E-mail: hillard.lazarus@case.edu

⁵Current address: Cleveland Clinic Foundation, Beachwood Medical Oncology-Hematology, Beachwood, OH, USA.

Received 11 January 2006; Revised 12 April 2006; Accepted 20 May 2006.

Abstract

We examined pre-mobilization blood CD34⁺ cell count to predict ability to mobilize adequate peripheral blood progenitor cells (PBPC) in 106 cancer patients and 36 allogeneic donors. Mean pre-mobilization therapy blood CD34⁺ cell count was 3.1 cells 10⁶/l (s.d.=3.9, r=0.3–37) and mean CD34⁺ cells collected were 5.3 10⁶ cells/kg/leukapheresis procedure (s.d.=7.0, r=0.03–53). Yields correlated with pre-mobilization CD34⁺ cells 10⁶/l (r=0.37, P-value<0.0001); correlation was stronger in allogeneic donors (r=0.56, P-value=0.0004) and males (r=0.46, P-value<0.0001). Based on classification and regression tree multivariate analysis, the predictive value of pre-mobilization blood CD34⁺ cell count was confounded by other variables, including age, gender, mobilization regimen and malignancy type. We generated an algorithm to predict a minimum PBPC yield of 1 10⁶ CD34⁺ cells/kg/leukapheresis procedure after mobilization. A threshold pre-mobilization blood CD34⁺ cell count of 2.65 cells 10⁶/l was the most important decision point in predicting successful mobilization. Only 2% of subjects with pre-mobilization blood CD34⁺ cell counts >2.65 cells 10⁶/l did not achieve the minimum per apheresis, whereas 24% with pre-mobilization values below threshold had inadequate mobilization. Prospectively identifying individuals at risk for mobilization failure would allow for improved treatment planning, resource utilization and time saving.