title: Cryopreserving human peripheral blood progenitor cells with 5-percent rather than 10-percent DMSO results in less apoptosis and necrosis in CD34+ cells.
abstract: BACKGROUND
  The grade of toxicity experienced by patients when cryopreserved peripheral blood progenitor cells (PBPCs) are reinfused is related to the amount of DMSO present in the PBPC concentrate. This study was initiated to investigate whether cell viability, apoptosis, and necrosis would be altered in CD34+ cells if PBPCs were cryopreserved with 5-percent as opposed to the conventional 10-percent DMSO.
  
  
  METHODS
  Samples of PBPCs from consecutive patients were mixed in parallel with 5- and 10-percent DMSO, frozen at a controlled rate, and stored in liquid nitrogen for periods of 3 to 22 months. Two different flow cytometric methods were used to measure both the absolute count of total and viable CD34+ cells as well as the fraction of apoptotic and necrotic cells in the post-thaw samples frozen with 5- and 10-percent DMSO.
  
  
  RESULTS
  Both the number of total and viable CD34+ cells were higher (n = 18) or equal (n = 1) in all the samples cryopreserved with 5-percent as opposed to 10-percent DMSO. The percentage of viable CD34+ cells in the PBPC sample was significantly higher, and the fraction of apoptotic and necrotic CD34+ cells was significantly lower in the samples frozen with 5-percent as compared to 10-percent DMSO.
  
  
  CONCLUSIONS
  Cryopreserving PBPC with 5-percent rather than 10-percent DMSO results in improved CD34+ cell viability and possibly a higher potential for in vivo engraftment and ex vivo manipulations of HPCs.
authors.affiliation: Blood Bank, Haukeland University Hospital, Bergen, Norway. jenny.abrahamsen@haukeland.no
authors.forename: Jenny Foss
authors.initials: JF
authors.lastname: Abrahamsen
authors.forename: Anne M
authors.initials: AM
authors.lastname: Bakken
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Bruserud
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects; D001793:Blood Preservation / Q000379:methods* / Q000592:standards; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation / Q000379:methods* / Q000592:standards; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D009336:Necrosis
chemical_list: D018952:Antigens, CD34; D004121:Dimethyl Sulfoxide