Researchers from Italy have designed a closed circuit, where Umbilical cord blood (UCB) collection and RBC depletion are performed, in order to reduce the contamination risk and to speed the nucleated cell separation.
Their findings appear in the journal Blood Cells, Molecules, and Diseases (available online 19 August 2005)
Umbilical cord blood is a source of hematopoietic progenitor cells and is used as an alternative to the bone marrow or peripheral blood for treatment of several onco-hematological diseases.
Because of the limited number of CD34+ hematopoietic stem cells present in UCB units and of the elevated costs of cryopreservation, it is of paramount importance to select the UCB units that are clinically useful before storage and optimize banking efficiency by designing reliable procedures to process and freeze the selected units.
Nucleated cell (NC) and CD34+ cell content provides useful criteria to select UCB units since clinical data documented that the infused cell load (both NC and CD34+ cells) plays an important role in the successful outcome of transplants.
By evaluating volume, CD34+ cell content, NC total amount, and NC density of 117 UCB units, the researchers found a significant association between CD34+ cell content and NC density and total amount, indicating these parameters as useful to decide UCB clinical utility.
Furthermore, the author set up a fast procedure to process UCB units for storage. A system for NC separation and volume reduction of UCB samples in a dedicated, germ-free, closed circuit was developed, where plasma and red blood cells (RBC) depletion was obtained by sedimentation in the presence of a 3.5% Polygeline solution.
The separation by the closed circuit, where RBC depletion is obtained by Polygeline sedimentation, proved to be faster and provided a higher recovery of stem cells.
Since Polygeline has been clinically used as a plasma expander and no toxic effects on patients were reported, the protocol can be applied in the large-scale banking of UCB.