title: Bioequivalence comparison of a new freezing bag (CryoMACS(®)) with the Cryocyte(®) freezing bag for cryogenic storage of human hematopoietic progenitor cells.
abstract: OBJECTIVE
  We investigated two different plastic freezing bags, namely the most recently U.S. Food and Drug Administration (FDA)-approved CryoMACS(®) freezing bag (200-074-402) from Miltenyi Biotec and the familiar Cryocyte(®) freezing bag (R4R9955) from (Baxter Healthcare, Deerfield, IL, United States) for the cryogenic storage of human hematopoietic progenitor cells (HPC).
  
  
  METHODS
  The study material consisted of 12 frozen HPC pairs (= 24 transplant units) that were no longer needed for autologous treatment of patients. After thawing, one unit of a pair was transferred into the Miltenyi (M) bag; the other unit remained in the original Baxter (B) bag. After refreezing both units, all units were stored again under cryogenic conditions either partially immersed in liquid nitrogen (n = 22) or in the vapor phase over liquid nitrogen, n = 2, <-170°) before thawing.
  
  
  RESULTS
  The correlation coefficients (r) between the results obtained from the two bag types were high for white blood cells (WBC) content (r = 0.98), mononuclear cells (MNC) (r = 0.97), lymphocytes (r = 0.98), monocytes (r = 0.96), membrane integrity (r = 0.93), concentration of 'free' hemoglobin (r = 0.97) and hemolysis rate (r = 0.95). With regard to clonogenicity, there were no significant differences (Student's paired t-test) for the three parameters investigated [i.e. total number of colonies, including the numbers of burst-forming units-erythroid (BFU-E) and colony-forming units-granulocyte-macrophage (CFU-GM) colonies, respectively).
  
  
  CONCLUSIONS
  The CryoMACS freezing bag 200-074-402 is bioequivalent to the Cryocyte freezing container R4R9955. An advantageous feature of the CryoMACS is that its double-sterile wrapping provides additional safety regarding potential cross-contamination during cryogenic storage.
authors.affiliation: University Medical Center Hamburg-Eppendorf, Department of Transfusion Medicine, Hamburg, Germany. sputtek@uke.uni-hamburg.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Sputtek
authors.forename: Michael
authors.initials: M
authors.lastname: Lioznov
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Kröger
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Rowe
mesh_terms: D015925:Cryopreservation / Q000379:methods*; D005615:Freezing; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006461:Hemolysis; D006801:Humans; D007962:Leukocytes / Q000166:cytology; D007963:Leukocytes, Mononuclear / Q000166:cytology; D008214:Lymphocytes / Q000166:cytology