Zdravniški Vestnik (Jun 2015)
Quality of thawed hematopoietic progenitor cell grafts
Abstract
Background:The appropriate dose of compatible and viable hematopoietic progenitor cells (HPC) is crucial for successful engraftment of transplanted cells within patients. In the study we therefore checked the viability of HPC in thawed HPC grafts which were transplanted into haematology patients in one year. Methods:We acquired HPC by apheresis and froze them in a programmable freezer in autologous plasma with 10 % DMSO and stored them in liquid nitrogen vapour. We thawed the bags with HPC in a water bath at the patient's bedside and in the eluate residues from the bags after the addition of saline solution we determined the viability (7-AAD) of HPC (CD34 +) and lymphocytes by flow cytometry.Results:After the transplantation of HPC, the viability of HPC was 79.9 ± 12.4 % and of leukocytes 62.2 ± 12.2 % (paired t-test, P < 0.001) in cell suspension residues (n = 88). The average viability of HPC in samples which were frozen immediately after collection (n = 58) was 79.9 ± 9.2 % and in samples frozen the next day after 18 hours in the fridge, the viability was 80.5 ± 11.3 % (n = 67). Storing samples overnight did not significantly affect the viability of cells in comparison with samples which were frozen immediately (t-test, P > 0.5). Rinsing of HPC bags and storing cells after thawing in saline solution significantly (n = 7; paired t-test, P <0.01) increased the mortality of HPC, since the viability immediately after thawing was 84.1 ± 4.5 % and in samples diluted with saline solution 60.1 ± 15.7 %.Conclusions:In our laboratory, cca 20 % of HPC are lost during freezing and thawing of HPC grafts. Freezing HPC grafts 18 hours after cell collection does not affect the viability of thawed cells in comparison with grafts which are frozen immediately. Saline solution is not suitable for rinsing bags and storing HPC residuals after thawing HPC products.
