title: Microprocessor-controlled vs. "dump-freezing"platelet and lymphocyte cryopreservation: a quantitative and qualitative comparative study.
abstract: OBJECTIVE
  Thermodynamical and cryobiological parameters responsible for cell damages during cryopreservation (cryoinjuries) have not yet been completely explained. Thus, freezing procedures should be revised, exactly optimized to obtain an enhanced structural and functional recovery of frozen-thawed cells. The aim of this study was to compare microprocessor-controlled (controlled-rate) with the compensation of the released fusion heat and "dump-freezing" (uncontrolled-rate) of the platelet and lymphocyte cryopreservation efficacy.
  
  
  METHODS
  Platelet quantitative recovery (post-thaw vs. unfrozen cell count), viability (using hypotonic shock response--HSR), morphological score (PMS), ultrastructural (electron microscopy) properties and expression of different surface antigens were investigated. In lymphocyte setting, cell recovery and viability (using trypan blue exclusion test) as well as functionality (by plant mitogens) were determined. Controlled-rate freezing and uncontrolled-rate cryopreservation were combined with 6% (platelets) and 10% (lymphocytes) dimethyl sulfoxide (DMSO).
  
  
  RESULTS
  Platelet recovery and functionality were superior in the controlled-rate system. The majority of surface antigen expression was reduced in both freezing groups vs. unfrozen cells, but GP140/CD62p was significantly higher in controlled-rate vs. uncontrolled-rate setting. Controlled-rate freezing resulted with better lymphocyte recovery and viability (trypan blue-negative cell percentage). In mitogen-induced lymphocyte proliferative response no significant intergroup difference (controlled-rate vs. uncontrolled-rate) were found.
  
  
  CONCLUSIONS
  The data obtained in this study showned the dependence of cell response on the cryopreservation type. Controlled-rate freezing provided a superior platelet quantitative and functional recovery. Lymphocyte recovery and viability were better in the controlled-rate group, although only a minor intergroup difference for cell proliferative response was obtained.
authors.affiliation: Military Medical Academy, Institute of Transfusiology, Belgrade. belab@imi.bg.ac.yu
authors.forename: Bela
authors.initials: B
authors.lastname: Balint
authors.forename: Dusan
authors.initials: D
authors.lastname: Vucetić
authors.forename: Biljana
authors.initials: B
authors.lastname: Drasković
authors.forename: Danilo
authors.initials: D
authors.lastname: Vojvodić
authors.forename: Goran
authors.initials: G
authors.lastname: Brajusković
authors.forename: Miodrag
authors.initials: M
authors.lastname: Colić
authors.forename: Miroljub
authors.initials: M
authors.lastname: Trkuljić
mesh_terms: D001792:Blood Platelets / Q000166:cytology / Q000648:ultrastructure; D002455:Cell Division; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000648:ultrastructure