Evaluation of peripheral blood stem cell collection in the Japan Marrow Donor Program (JMDP).

BACKGROUND: For peripheral blood stem cell (PBSC) collection of unrelated donors, the Japan Marrow Donor Program (JMDP) sets the target CD34+ cell dose as the minimum of 2 × 106 cells/kg of recipient body weight (RBW) and recommends a processing blood volume (PBV) as high as 200 mL/kg of donor body weight (DBW) with ≤250 mL/kg per day within two consecutive days. Here, we retrospectively reviewed this guideline. STUDY DESIGN AND METHODS: We analyzed 1656 unrelated donor PBSC collections between January 2012 and November 2022 from the JMDP database. RESULTS: The target CD34+ cell dose was achieved within 2 days in all but 40 cases (2.4%), suggesting that the current JMDP guideline largely meets its objectives. The distribution of PBV per DBW showed three peaks. The most prominent peak, consisting of 834 (50.4%) cases, occurred around the recommended PBV (180-220 mL/kg of DBW), whereas 659 (39.8%) cases were in the lower PBV range (<180 mL/kg), and, notably, there was no significant difference between these groups in the collected CD34+ cells/kg RBW. On the other hand, among the 163 (9.8%) cases in the higher PBV group (>220 mL/kg), the number of collected CD34+ cells/kg of RBW was significantly lower than in the other two groups. DISCUSSION: These results suggest that the target PBV in the lower and higher PBV groups was determined using CD34+ enumeration before or during apheresis procedure. CD34+ enumeration may help reduce the burden on donors, although further investigations are needed to confirm.