Umbilical cord blood (UCB) is cryopreserved and stored in cord blood banks (CBBs)
for allogeneic transplantation in pediatric and adult patients [
[1]
]. It is known that cord blood unit (CBU) cell viability is deeply affected by both
cryopreservation and thawing processes [
2
,
3
]. Cell viability is determined by flow cytometry using 7-Aminoactinomycin D (7-AAD)
before and after cryopreservation. However, some authors report that the obtained
data may be inaccurate when performing post-thawing assays due to membrane instability
and cellular unspecific uptake of 7-AAD [
[4]
]. It is possible that this phenomenon varies during the staining protocols and, consequently,
affects the flow cytometry results. On the other hand, clonogenic efficiency (CLONE;
percentage of effective colonies from a known number of seeded CD34+ cells) is a complementary assessment to flow cytometry and provides information about
cell viability, lineage commitment and proliferation ability. Therefore, it may be
a more suitable quality control of the unit. The correlation between CD34+ cell viability, as assessed using flow cytometry and CLONE, is a subject under research
and may depend on several pre-freezing variables [
5
,
6
]. We hypothesize that if the thawing and staining procedure-associated biases are
removed, a real correlation factor may be determined.To read this article in full you will need to make a payment
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References
- Challenges in umbilical cord blood stem cell banking for stem cell reviews and reports.Stem Cell Rev and Rep. 2010; 6: 8-14
- Assessing the toxic effects of DMSO on cord blood to determine exposure time limits and the optimum concentration for cryopreservation.Vox Sang. 2015; 109: 181-190
- Comparison of cord blood thawing methods on cell recovery, potency, and infusion.Transfusion. 2010; 50: 2670-2675
- Hydroxyethyl starch as a substitute for dextran 40 for thawing peripheral blood progenitor cell products.Cytotherapy. 2015; 17: 1813-1819
- Effect of umbilical cord blood prefreeze variables on postthaw viability.Transfusion. 2015; 55: 629-635
- Effects of interruptions of controlled-rate freezing on the viability of umbilical cord blood stem cells.Transfusion. 2015; 55: 70-78
- How we handled the dextran shortage: an alternative washing or dilution solution for cord blood infusions.Transfusion. 2015; 55: 1147-1153
- A new strategy for umbilical cord blood collection developed at the first Colombian public cord blood bank increases total nucleated cell content.Transfusion. 2017; 57: 2225-2233
Article Info
Publication History
Published online: April 18, 2018
Accepted:
March 27,
2018
Received:
December 6,
2017
Identification
Copyright
© 2018 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.
