Peripheral blood stem cell harvesting in young children weighing less than 15 kg
Chih-Ying Lee1, Ting-Yen Yu2, Fen-Lan Lin3
1Division of Pediatric Hematology and Oncology, Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, School of Medicine, National Yang-Ming Chiao-Tung University, Taipei, Taiwan.
Insights
Collecting stem cells for pediatric cancer patients under 15kg is challenging. A predictive model using preapheresis cell counts and patient factors improves collection success for transplantation.
Area of Science:
- Pediatric Hematology Oncology
- Stem Cell Transplantation
- Cancer Therapeutics
Background:
- Autologous peripheral blood stem cell (PBSC) transplantation is vital for pediatric cancer treatment.
- Tandem transplantation offers benefits for specific pediatric malignancies.
- Collecting sufficient PBSCs in low-body-weight children (<15 kg) presents significant challenges.
Purpose of the Study:
- To retrospectively analyze the feasibility and outcomes of autologous PBSC collection in pediatric cancer patients weighing less than 15 kg.
- To identify factors influencing successful stem cell yield for single or tandem transplantation.
- To develop a predictive model for achieving target stem cell doses.
Main Methods:
- Retrospective analysis of PBSC collection data from pediatric cancer patients (<15 kg) between April 2006 and August 2021.
- Collections performed over 2-3 days in the pediatric intensive care unit, aiming for ≥2 × 10^6 CD34+ cells/kg per apheresis.
- Statistical analysis including correlation of preapheresis hematopoietic progenitor cell (HPC) count with CD34+ yield and development of a predictive model using logistic regression.
Main Results:
- 129 collections were performed in 40 patients (median age 1.9 years, median weight 11.0 kg).
- Median CD34+ cell yield was 4.2 × 10^6/kg per apheresis.
- 78% and 56% of mobilizations achieved sufficient cells for single and tandem transplantation, respectively.
- Preapheresis HPC count strongly correlated with CD34+ yield (r=0.555, P<0.001).
- Granulocyte colony-stimulating factor alone was insufficient for mobilization in children ≥2 years.
- A predictive model combining HPC count (≥20/μL) and factors (age <2 years, no radiation, chemotherapy use) achieved an AUC of 0.787.
Conclusions:
- Autologous PBSC collection is feasible in pediatric cancer patients <15 kg, with high success rates for single transplantation.
- Preapheresis HPC count is a key predictor of stem cell yield.
- A predictive model incorporating patient and treatment factors can enhance the success rate of achieving target stem cell doses for transplantation in this vulnerable population.
Abstract:
Autologous peripheral blood stem cell (PBSC) transplantation is crucial in pediatric cancer treatment, and tandem transplantation is beneficial in certain malignancies. Collecting PBSCs in small children with low body weight is challenging. We retrospectively analyzed data of pediatric cancer patients weighing <15 kg who underwent autologous PBSC harvesting in our hospital. Collections were performed in the pediatric intensive care unit over 2 or 3 consecutive days, to harvest sufficient stem cells (goal ≥2 × 106 CD34+ cells/kg per apheresate). From April 2006 to August 2021, we performed 129 collections after 50 mobilizations in 40 patients, with a median age of 1.9 (range, 0.6-5.6) years and a body weight of 11.0 (range, 6.6-14.7) kg. The median CD34+ cells in each apheresate were 4.2 (range, 0.01-40.13) × 106/kg. 78% and 56% of mobilizations achieved sufficient cell dose for single or tandem transplantation, respectively, without additional aliquoting. The preapheresis hematopoietic progenitor cell (HPC) count was highly correlated with the CD34+ cell yield in the apheresate (r = 0.555, P < 0.001). Granulocyte colony-stimulating factor alone was not effective for mobilization in children ≥2 years of age, even without radiation exposure. By combining the preapheresis HPC count ≥20/μL and the 3 significant host factors, including age <2 years, no radiation exposure and use of chemotherapy, the prediction rate of goal achievement was increased (area under the curve 0.787).
