A simple controlled-rate freezing method without a rate-controlled programmed freezer provides optimal conditions for both large-scale and small-scale cryopreservation of umbilical cord blood cells.
BACKGROUND
Umbilical cord blood (CB) is being used as a source of alternative HPCs for transplantation with increasing frequency. The goal of CB banks for unrelated transplantation is to provide good quality-controlled CB units that can be transplanted for HPCs into the largest possible number of patients.


METHODS
Large CB samples in freezing bags wrapped with insulators and small samples in cryotubes placed into double styrene-foam boxes were cryopreserved at -85 degrees C without a rate-controlled freezing machine, followed by storage in the liquid phase of nitrogen. After thawing these cells, the viability and recovery of cells, as well as the recovery rate of HPCs such as CD34+ cells, CFU-GM, and total CFU were evaluated.


RESULTS
Measurement of the freezing rate in CB bags and cryotubes demonstrated that this simple method for cryopreservation of CB cells provided optimal conditions for both large-scale and small-scale cryopreservation. Recovery of CB progenitor cells after cryopreservation was also shown to be potentially acceptable when evaluated with CD34+ cells, CFU-GM, and total CFU. These results were comparable to the method using a rate-controlled programmed freezer.


CONCLUSIONS
A simple method for cryopreservation of CB cells without a rate-controlled programmed freezer could provide a sufficient-enough potential for the transplantability of HPCs after thawing.
Itoh
Tsuneo
T
Division of Blood Transfusion, Tohoku University Hospital, Japan.
Minegishi
Masayoshi
M
Fushimi
Junko
J
Takahashi
Hiroyuki
H
Kudo
Yoshinori
Y
Suzuki
Akira
A
Narita
Ayuko
A
Sato
Yuko
Y
Akagi
Kozo
K
Wada
Yuichi
Y
Saito
Akira
A
Kikuchi
Miwako
M
Okamura
Kunihiro
K
Kaku
Mitsuo
M
Tsuchiya
Shigeru
S
D001771:Blood Banks / Q000191:economics; D001793:Blood Preservation / Q000191:economics / Q000379:methods*; D002452:Cell Count; D017046:Cost Savings; D015925:Cryopreservation / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D005312:Fetal Blood / Q000166:cytology*; D005615:Freezing; D006801:Humans; D015203:Reproducibility of Results; D000094902:Blood Banking / Q000379:methods