[Collection, processing and cryopreservation of placental cord blood hematopoietic stem cells].

Objective: To establish methods of collection, processing and cryopreservation of placental cord blood units.

Methods: Between July 1997 and July 2000, 3,744 placental cord blood (CB) units were stored in Beijing Cord Blood Bank. All of CB units had been HLA-typed with molecular (sequence specific primer/sequence specific oligonucleotide, SSP/SSO) and serological methods. CB units were collected by trained midwives while the placentas remained in utero. Collected CB units were temporarily stored at room temperature and processed within 18 hours after collection. Depletion of red blood cells was performed using hydroxythyl starch with one time centrifuge. CB units were cryopreserved with DMSO and hydroxythyl starch.

Results: The mean volume collected from 3,744 CB units was (93 +/- 22) ml (mean +/- s, range 45-198 ml). The mean total nucleated cell count per unit was 11.2 x 10(8) +/- 5.3 x 10(8) (rang 4.5 x 10(8)-45.1 x 10(8)). After depletion of red blood cells, the mean nucleated cell count was 9.7 x 10(8) +/- 4.6 x 10(8) (rang 3.1 x 10(8)-30.5 x 10(8)) with mean nucleated cell recovery of 79%. Forty CB units were thawed for testing, and trypan blue viability of nucleated cells was 88.2%. The recoveries of CFU-GM and CD34+ cells (ProCOUNT) were 97.6%, 86.4% respectively.

Conclusion: We have established a CBB, and have shown that our system of the whole procedure and methods is functional for supplying qualified cord blood units in transplantation.