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

Abstract

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 × 10⁶/kg, group A) and a decent number (≥ 2 × 10⁶/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 × 10⁶/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.

Keywords: CD34(+) cell loss; Cryopreservation; NHL; non-Hodgkin lymphoma; viable CD34(+) cells.