title: Cryopreservation of peripheral blood stem cell: the influence of cell concentration on cellular and hematopoietic recovery.
abstract: BACKGROUND
  The optimal cryopreservation cell concentration during the peripheral blood stem cell (PBSC) collection is a controversial topic. We evaluated the influence of cryopreservation concentration on the recovery of hematopoietic progenitor cells and the kinetics of hematopoietic recovery of autologous stem cell transplant patients.
  
  
  METHODS
  In this retrospective study, we compared two different cryopreservation protocols: 1×10(8) cells/mL (Protocol A) and 2×10(8) cells/mL (Protocol B). A total of 419 PBSCs were analyzed with regard to the number of viable cells and colony-forming units-granulocytes-monocytes (CFU-GM) progenitors. The hematopoietic recovery of 275 patients who received PBSCs cryopreserved at a dose of 1×10(8) cells/mL (Group A) and 2×10(8) cells/mL (Group B) were compared.
  
  
  RESULTS
  There were no significant differences in recovery of viable cells between Protocol A and Protocol B. The median of recovery of CFU-GM progenitors was significantly higher in Protocol B (41.2 vs. 57.3, p<0.01). The median times to neutrophil recovery (≥500×10(6) /L) and platelet (PLT) recovery (≥20×10(9) /L) in Groups A and B were 11 days versus 11 days and 12 days versus 12 days, respectively. However, by Kaplan and Meier analyses, Group B recovered neutrophils with a little delay (p=0.01). No difference was observed with regard to time to PLT recovery. On multivariate analysis, we found that the number of CD34+ cells and CFU-GM progenitors had a significant influence on hematopoietic recovery.
  
  
  CONCLUSIONS
  Cryopreservation of PBSCs at a dose of 2×10(8) cells/mL did not affect the recovery rate of viable cells or the hematopoietic recovery of autologous stem cell transplant patients.
authors.affiliation: University Hospital, Hematology Service, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil.
authors.forename: Sibelle
authors.initials: S
authors.lastname: Alencar
authors.forename: Márcia
authors.initials: M
authors.lastname: Garnica
authors.forename: Ronir R
authors.initials: RR
authors.lastname: Luiz
authors.forename: Carmen M
authors.initials: CM
authors.lastname: Nogueira
authors.forename: Radovan
authors.initials: R
authors.lastname: Borojevic
authors.forename: Angelo
authors.initials: A
authors.lastname: Maiolino
authors.forename: Hélio S
authors.initials: HS
authors.lastname: Dutra
mesh_terms: D001793:Blood Preservation / Q000379:methods*; D002452:Cell Count; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods*; D006085:Graft Survival; D019337:Hematologic Neoplasms / Q000628:therapy*; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D009504:Neutrophils / Q000166:cytology; D016016:Proportional Hazards Models; D020127:Recovery of Function; D012189:Retrospective Studies; D019172:Transplantation Conditioning; D014182:Transplantation, Autologous