Loss of CD34 Cells and Effect of the Number of Viable Cryopreserved CD34 Cells in the Infused Blood Grafts on Hematologic Recovery, Progression-Free Survival and Overall Survival in NHL Patients After Autologous Stem Cell Transplantation.

PATIENTS

This post-hoc study aimed to find out factors affecting graft viable CD34 cell loss during processing and cryopreservation in 129 non-Hodgkin lymphoma (NHL) patients receiving autologous stem cell transplantation (auto-SCT) and the impact of a low (< 2.0 × 10/kg, group A) and a decent number (≥ 2 × 10/kg, group B) of viable CD34 cells infused on the hematologic recovery, progression-free survival (PFS) and overall survival (OS) after auto-SCT.

RESULTS

The median loss of viable CD34 cells during cryopreservation was higher in group A (47% vs. 19%, p < .001). A higher yield of CD34 cells at the first apheresis in group B (p = .002) was linked with greater loss of viable graft CD34 cells after cryopreservation. Filgrastim (FIL) use for mobilization seemed to associate with higher viable CD34 cell loss compared to pegfilgrastim (PEG) or lipegfilgrastim (LIPEG) in both groups (in group A FIL 66 vs. PEG 35%, p = .006; in group B FIL 37 vs. PEG 15 vs. LIPEG 13%, p < .001). Hematologic recovery after auto-SCT was faster in group B. Neither viable CD34 cell loss during storage nor viable CD34 cell number < 2.0 × 10/kg infused affected on PFS or OS.

CONCLUSIONS

G-CSF type used in mobilization and mobilization capacity were found to correlate with viable CD34 cell loss during processing and storage. Most importantly, low infused viable CD34 cell count did not seem to impact on PFS or OS.