Quality of umbilical cord blood CD34+ cells in a double-compartment freezing bag cryopreserved without a rate-controlled programmed freezer.
The aim of this study was to evaluate how a simple method of cryopreservation influences the quality of CD34+ cells in umbilical cord blood (UCB). The cells were dispensed into a double-compartment freezing bag, cryopreserved at -85 degrees C without a rate-controlled programmed freezer, and stored in the liquid phase of nitrogen. The viability of the CD34+ cells before freezing and after thawing was assessed by flow cytometry with 7-aminoactinomycin D and by colony-forming assays. Twenty UCB units cryopreserved for a median of 92 days were analyzed. Mean CD34+ cell viabilities before freezing were 99.8% +/- 0.4% and after thawing were 99.5% +/- 0.8% in large chambers, 99.6% +/- 0.5% in small chambers, and 99.4% +/- 0.6% in sample tubes. The mean values from colony-forming assays of the viable CD34+ cells before freezing were 30.7 +/- 6.8 (colony-forming units-granulocyte-macrophage [CFU-GM] per 100 viable CD34+ cells) and 68.5 +/- 14.8 (total CFUs per 100 viable CD34+ cells). The CFU-GM and total CFU values after thawing were, respectively, 32.7 +/- 9.0 and 66.0 +/- 13.4 in large chambers, 32.4 +/- 8.1 and 64.5 +/- 16.1 in small chambers, and 30.9 +/- 5.4 and 64.7 +/- 12.4 in sample tubes. The results of the colony-forming assays before freezing and after thawing were not significantly different. Our findings overall indicated that our simple method for the cryopreservation of UCB cells without a rate-controlled programmed freezer does not impair the clonogenic capacity of UCB progenitor cells. This cryopreservation method could provide cellular products adequate for hematopoietic stem cell transplantation.
Minegishi
Masayoshi
M
Division of Blood Transfusion, Tohoku University Hospital, Sendai, Japan. minegisi@idac.tohoku.ac.jp
Itoh
Tsuneo
T
Fukawa
Narumi
N
Kitaura
Tamie
T
Miura
Junko
J
Takahashi
Hiroyuki
H
Suzuki
Akira
A
Kudo
Yoshinori
Y
Narita
Ayuko
A
Sato
Yuko
Y
Suzuki
Masakuni
M
Watanabe
Takanori
T
Wada
Yuichi
Y
Takeyama
Yoichi
Y
Tsuchiya
Shigeru
S
D018952:Antigens, CD34; D002470:Cell Survival; D003114:Colony-Forming Units Assay; D015925:Cryopreservation / Q000295:instrumentation* / Q000379:methods*; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006801:Humans; D009584:Nitrogen; D013696:Temperature
D018952:Antigens, CD34; D009584:Nitrogen