engleski

Post-thaw viability of cryopreserved hematopoietic progenitor cell grafts : does it matter?

Cell viability in peripheral blood progenitor cell (PBPC) grafts and its influence on the clinical course following transplantation was evaluated in 81 consecutive transplantations (72 autologous, 9 allogeneic) performed in patients with hematological diseases. Viability of cells in PBPC grafts immediately upon collection was 98.6±3.5%, after addition of dimethyl sulfoxide (DMSO) 73.3±21.8%, and post-thaw 65.2±16.1%. It did not differ significantly between patients with different diagnoses, gender, age, type of priming used, dose of G-CSF administered or number of CD34+ cells collected. However, grafts stored for more than 60 days showed lower post-thaw viability compared to the ones thawed in the 60 days following cryopreservation (56.6±15.2% vs. 67.6±15.5%, p=0.04). Post-thaw graft viability did not influence engraftment time, but there was a predisposition towards infectious complications in the post-transplant period in patients receiving grafts with lower percentage of viable cells. These patients developed febrile neutropenia more often (72.2% vs. 50% of patients, p=0.05) and had more febrile days (2.4±2.6 vs. 1.5±2.3, p=0.05) following transplantation. Our results demonstrate that PBPC grafts are capable of long term engraftment regardless of the graft storage time or percentage of viable cells post-thaw, which confirms the robustness of CD34+ cells during the freeze/thaw procedures carried out in daily clinical practice. Granulocyte concentration in PBPC grafts could have an influence on infectious complications following transplantation. This intriguing finding needs to be further investigated on a larger number of patients.

hematopoietic progenitor cells; cryopreservation; viability

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