title: Methods of freezing cord blood hematopoietic stem cells.
abstract: BACKGROUND
  Cord blood (CB) is a valuable source of hematopoietic stem cells (HSCs). Extended storage of CB is possible provided that validated cryopreservation procedures are used. The study objective was to determine optimal methods of CB cryopreservation.
  
  
  METHODS
  In the study we 1) compared the effect of two-step cryopreservation and controlled-rate freezing method on the postthaw quality of CB (Study A) and 2) evaluated the postthaw quality of HSC fractions isolated from CB with various methods and frozen with controlled-rate freezing method (Study B). The same cryoprotectant mixture was used for 20 CB units (Study A) and 122 CB units (Study B).
  
  
  RESULTS
  In Study A, 13.79 × 10(8) and 13.29 × 10(8) initial white blood cell (WBC) counts decreased to 6.38 × 10(8) and 6.02 × 10(8) after thaw for the two methods, respectively. The mononuclear cell (MNC) counts decreased from 5.90 × 10(8) to 3.71 × 10(8) and from 5.64 × 10(8) to 3.47 × 10(8) dependent on the method. MNC viability decreased from 99.0% to 97.4% for the former and from 98.5% to 97.2% for the latter method. The differences were insignificant. In Study B, postthaw WBC recovery in HSC fractions was 74.4% to 103.5%, MNC recovery 106.4% to 118.5%, CD34+ cell recovery 102.5% to 150.2%, and MNC viability 94.1% to 97.4%.
  
  
  CONCLUSIONS
  Neither the cryopreservation procedure nor the freezing of isolated HSCs affected product quality, which may indicate that various freezing methods can be used for cell banking provided the they follow recommendations of good manufacturing practice and Directive 2004/33/EC.
authors.affiliation: Department of Transfusion Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland; Department of Diagnostics for Hematology, Institute of Hematology and Transfusion Medicine, Warsaw, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Antoniewicz-Papis
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Lachert
authors.forename: Jolanta
authors.initials: J
authors.lastname: Woźniak
authors.forename: Karolina
authors.initials: K
authors.lastname: Janik
authors.forename: Magdalena
authors.initials: M
authors.lastname: Łętowska
mesh_terms: D001793:Blood Preservation / Q000379:methods; D002469:Cell Separation / Q000379:methods / Q000592:standards; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology*; D005615:Freezing; D006412:Hematopoietic Stem Cells; D006801:Humans; D007958:Leukocyte Count; D011786:Quality Control
chemical_list: D003451:Cryoprotective Agents