title: Preservation of immunological and colony-forming capacities of long-term (15 years) cryopreserved cord blood cells.
abstract: BACKGROUND
  Cryopreserved cord blood may be stored for decades before being used for allogeneic stem cell transplantation. Little is known about the effect of long-term cryopreservation in liquid nitrogen on the viability and function of cord blood cells. We examined the recovery, viability, clonogenic capacity, and T-cell reactivity to HLA alloantigens of cord blood samples cryopreserved up to 15 years.
  
  
  METHODS
  Progenitor cell recoveries were studied by (colony-forming unit-granulocyte-macrophage) clonogenic assays from 18 cord blood samples short-term frozen for 2-8 weeks and from 8 samples cryopreserved for 15 years. Proliferative and cytotoxic responses against HLA antigens of thawed cord blood mononuclear cells after short-term or long-term cryopreservation were tested in standard mixed lymphocyte cultures and cell-mediated lympholysis assays.
  
  
  RESULTS
  After thawing, the mononuclear cell recovery from long-term frozen cord blood low-density fractions averaged 80% (range, 64% to 92%). The presented data show that long-term frozen cord blood cells keep their clonogenic potential. No damaging effect was seen on the proliferative and cytotoxic capacities of long-term frozen cord blood T cells.
  
  
  CONCLUSIONS
  The results support the possibility of long-term storage of progenitor cells from umbilical cord blood for future bone marrow reconstitution.
authors.affiliation: Institute of Haematology and Blood Transfusion, Department for Cryopreservation, Prague, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Kobylka
authors.forename: P
authors.initials: P
authors.lastname: Ivanyi
authors.forename: B S
authors.initials: BS
authors.lastname: Breur-Vriesendorp
mesh_terms: D001773:Blood Cells / Q000276:immunology*; D002455:Cell Division / Q000502:physiology; D003114:Colony-Forming Units Assay; D015925:Cryopreservation; D005312:Fetal Blood / Q000166:cytology* / Q000276:immunology / Q000502:physiology*; D006098:Granulocytes / Q000502:physiology; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000502:physiology; D009000:Monocytes / Q000166:cytology / Q000276:immunology; D013234:Stem Cells / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology; D013997:Time Factors
chemical_list: D006680:HLA Antigens