Quantitative CD34 analysis may be used to guide peripheral blood stem cell harvests

Area of Science:

• Hematology
• Oncology
• Stem Cell Transplantation

Background:

• High-dose chemotherapy with stem cell rescue improves outcomes for advanced cancers.
• Delayed hematopoietic recovery remains a challenge despite growth factors and peripheral blood progenitor cells (PBPC).
• Reliable parameters to guide stem cell harvests are lacking.

Purpose of the Study:

• To investigate the utility of quantifying harvested CD34+ cells by flow cytometry to predict hematopoietic recovery.
• To assess the correlation between harvested CD34+ cell counts and the duration of neutropenia and thrombocytopenia.

Main Methods:

• 30 women with advanced breast cancer received cyclophosphamide (CY) or CY/G-CSF mobilized PBPC for stem cell rescue.
• Harvested CD34+ cell counts and CFU-GM were measured.
• Patients were analyzed based on reinfused CD34+ cell counts (<0.75 x 10^6/kg vs. >0.75 x 10^6/kg and <2.0 x 10^6/kg vs. >2.0 x 10^6/kg).

Main Results:

• Patients reinfused with <0.75 x 10^6 CD34+ cells/kg had significantly delayed neutrophil recovery (median 22 days vs. 12 days).
• Platelet recovery was also significantly delayed in patients receiving <0.75 x 10^6 CD34+ cells/kg (median 135 days vs. 18 days).
• A trend towards shortened platelet recovery was observed when reinfused CD34+ cells exceeded 2.0 x 10^6/kg.

Conclusions:

• CD34+ cell enumeration is a useful parameter for predicting hematopoietic recovery after stem cell transplantation.
• Quantifying harvested CD34+ cells can help identify patients at risk for delayed engraftment.
• This measurement may aid in optimizing stem cell harvest strategies.