Aspects of donation and processing of stem cell transplants from umbilical cord blood

Background: In 1996, the Institute of Transfusion Medicine and Immunology started the banking of unrelated cord blood (CB) transplants in collaboration with the Department of Gynecology and obstetrics at the Mannheim University Hospital. Up to now, more than 2000 placental blood samples have been cryopreserved. We analyze the results of CB collection and processing, and describe the legal background of CB collection in Germany. Materials and Methods: CB is only collected with informed consent of the mothers, and without evidence of neither maternal infection nor deformity of the baby. Units with a volume of > 60 ml or > 5 x 10(8) total nucleated cells (NC) are processed as potential transplants. All specimens are evaluated for cell count, HLA typing, sterility testing, ABO/Rh blood groups and clonogenic capacity of hematopoietic progenitor cells. The maternal blood is screened for various infectious disease markers. To reduce the volume of the transplants, we per-form buffy coat processing by centrifugation. Finally, we cryopreserve the transplant using a 5.5 percent final concentration of DMSO, and store it in the vapour phase of liquid nitrogen. Results: We collected on average 86 +/- 21 ml CB containing 8.87 +/-3.41 x 10(8) NC (mean +/- SD). 45 percent of the collected units had to be discarded for various reasons. We achieved a mean mononucleated cell recovery by the buffy coat preparation method of 93.4 percent. Defining a threshold dose of 3.0 x 10(7) NC per kg body weight (BW) for transplantation, the mean BW of patients to be sufficiently treated with the stored transplants showed to be 29.6 kg. Conclusions: In a very close collaboration between transfusion medicine and obstetricians, a routine collection program for unrelated and related allogeneic CB transplants was established, The CB donation needs to be in accordance with the German drug law. On the other hand, in terms of evidence based medicine, it seems not to be reasonable to collect autologous placental blood for a future transplantation.