Predictive factors for successful hematopoietic stem cell collection in healthy allogeneic donors

Background

Collection of peripheral blood stem cells (PBSC) from healthy donors after mobilization with G-CSF is performed routinely. We aimed to identify factors predictive of successful CD34+ PBSC collection and established a formula capable of predicting the CD34+ cell yield.

Methods

We retrospectively evaluated 588 healthy adult donors (median age 29 years, range 18–69 years) at our institution from 2017 to 2022. The predicted minimal number of CD34+ cells was calculated as follows: [(peripheral CD34+ cells/µL × adjusted collection efficiency of 30%] × total liters processed. This formula was further modified taking the donor and recipient body weight (BW) into account.

Results

Total CD34+ collection was in median 8.0 × 10⁶ CD34+ cells/kg of recipient BW (range 1.0–47.1 × 10⁶ cells/kg BW) with 522 donors (89%) collecting ≥5.0 × 10⁶ cells/kg of recipient BW. A second leukapheresis (LP) session the following day was required in 49 donors (8%). Female donors (p<0.001), donors with higher age (p=0.003), donors with WBC count <30 × 10⁹/L after 5 days of G-CSF stimulation (p=0.004), and a donor/recipient weight ratio <1 (p<0.001) had a higher risk for a second LP session. Predictive factors for optimal LP were peripheral blood CD34+ cell count >50/µL (p<0.001), male donor (p=0.04), and a donor/recipient weight ratio >1 (p=0.001).

Conclusion

Of the routinely monitored indicators in PBSC donors, CD34+ cell count in peripheral blood is the most important factor in predicting G-CSF-induced PBSC yields. Risk factors for suboptimal mobilizers were higher age, female sex, WBC <30 × 10⁹/L, and a donor/recipient weight ratio <1. We applied a formula that has shown successful and consistent performance in the prediction of key outcome measures.

Offenlegung Interessenkonflikt:

All authors declare no competing conflicts of interest.