Predicting Peripheral Blood Stem Cell Harvest Failure Using Circulating CD34 Levels: Developing Target-Based Cut-Points for Early Intervention

Peripheral Blood Stem Cells (PBSC) are usually mobilized using granulocyte colony stimulating factor (G-CSF) with or without chemotherapy. With the emergence of newer mobilizing agents, predicting poor mobilization may allow early intervention and prevent the costs and complications associated with remobilization. We retrospectively evaluated a cohort of 1556 patients seen between January 2000 and December 2008 with Multiple Myeloma (MM) (565; 36%), Non-Hodgkin’s Lymphoma (NHL) (562; 36%), Amyloidosis (345; 22%) or Hodgkin’s disease (HD) (94; 6%) initially mobilized with single agent G-CSF. Sensitivity-specificity analysis was used to identify ideal peripheral blood CD34 count (PB-CD34) cut-points that predicted successful collection. In patients with plasma-cell disorders a PB-CD34 of 11/uL, 17/uL, 21/uL, and 28/uL by day 4 or 5 were required to collect a target of 2, 4, 8 or 12 million/kg respectively. A CD34 yield <0.8 million cells/kg on first apheresis also predicted for <2 million CD34/kg. For patients with NHL or HD, a PB-CD34 <6/uL and <15/uL on day 4 or 5 predicted failure to achieve a target collection of 2 and 4 million/kg respectively. This study suggests that PB-CD34 thresholds should be based on collection target to allow for early intervention and prevent collection failures.