Uncontrolled-rate freezing of peripheral blood progenitor cells allows successful engraftment by sparing primitive and committed hematopoietic progenitors.
OBJECTIVE
Uncontrolled-rate freezing (URF) techniques, which are fast and easy, could represent an attractive alternative to controlled-rate cryopreservation procedures which are time consuming and require high-level technical abilities. It was the aim of the present study to evaluate, on a routine basis, whether URF might spare primitive hematopoietic progenitors and maintain engrafting capacity.


METHODS
One-hundred and nineteen peripheral blood progenitor cells (PBPC) collections from 104 patients with hematologic malignancies were cryopreserved in bags, with an URF procedure, in a cryoprotectant solution consisting of PBS, HSA and 10% DMSO and stored in liquid nitrogen. PBPC bags were tested before cryopreservation and at thawing for primitive (LTC-IC) and committed hematopoietic progenitors (CFU-Mix, BFU-E, CFU-GM) by means of long- and short-term culture assays, respectively. In addition, PBPC bags were evaluated for CD34+ cell numbers.


RESULTS
Although thawing was associated with a statistically significant reduction of the absolute number of nucleated cells, recovery of LTC-IC, CFU-Mix, BFU-E, CFU-GM and CD34+ cells was not affected by the freezing/thawing procedures. No adverse effects were reported at thawing and only mild transient reactions were recorded in 22 patients during reinfusion of cryopreserved PBPC. All the patients underwent myeloablative therapy followed by reinfusion of PBPC, and prompt and rapid hematopoietic recovery was obtained in all patients.


CONCLUSIONS
Our freezing procedure is fast and easy, and allows rapid hematopoietic recovery after myeloablative therapy by sparing primitive and committed hematopoietic progenitors. Our study strongly supports technical improvements aimed at cost reduction and feasibility of routine freezing procedures.
Almici
Camillo
C
Department of Hematology, BMT Unit, Spedali Civili di Brescia, University of Brescia, Italy. almici@osp.unibs.it
Ferremi
Piero
P
Lanfranchi
Arnalda
A
Ferrari
Emilio
E
Verardi
Rosanna
R
Marini
Mirella
M
Rossi
Giuseppe
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use; D001793:Blood Preservation / Q000379:methods*; D002452:Cell Count; D002478:Cells, Cultured / Q000166:cytology; D003114:Colony-Forming Units Assay; D003131:Combined Modality Therapy; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005260:Female; D006085:Graft Survival; D019337:Hematologic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000628:therapy*; D006412:Hematopoietic Stem Cells / Q000145:classification / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D036102:Peripheral Blood Stem Cell Transplantation / Q000379:methods*; D010710:Phosphates / Q000494:pharmacology; D012709:Serum Albumin; D012965:Sodium Chloride / Q000494:pharmacology; D019172:Transplantation Conditioning; D016896:Treatment Outcome
D003451:Cryoprotective Agents; D010710:Phosphates; D012709:Serum Albumin; D012965:Sodium Chloride; D004121:Dimethyl Sulfoxide