Leukocyte recovery from umbilical cord blood by poligeline

Umbilical cord blood (UCB) collected at delivery is a source of transplanta ble stem/progenitor cells; it represents an alternative to bone marrow to r estore hematopoiesis in patients affected by malignant and non-malignant di sease. Therefore, large-scale UCB banks would be a natural complement to bo ne marrow doctor registries. Storage of unmanipulated whole UCB units requi res a great number of liquid nitrogen containers. Separation of leukocytes allows UCB storage in smaller space, thus lowering banking costs; unfortuna tely, UCB processing may cause significant losses of stem cells. We report about the use of poligeline to remove erythrocytes from UCB units. After er ythrocyte sedimentation at 1xg (30' or 40') or 50xg, leukocyte-rich superna tant was collected and centrifuged to recover the leukocyte pool in view of stem cell transplantation. Erythrocyte depletion was always satisfactory, ranging from 82.6% to 88.9%, but 1xg sedimentation for 40' enabled us to ac hieve the best CD34+ cell recovery (mean value 80.5%). The proposed UCB-pro cessing method allowed us to lower the final sample volume down to 1/10 of the initial one, in this way making UCB banking feasible. Erythrocyte deple tion took place directly in the collection bag, thus reducing microbial con tamination risk.