STUDY OF THE COLLECTION AND SEPARATION OF UMBILICAL-CORD BLOOD FOR USE IN HEMATOPOIETIC PROGENITOR-CELL TRANSPLANTATION

Human umbilical cord blood has been used as an alternative source of c ells for repopulating bone marrow in allogenic bone marrow transplanta tion in children. The number of transplantations of umbilical cord blo od cells is increasing worldwide. Umbilical cord blood was collected f rom 52 subjects at a single collection at the time of delivery, and se parated using the red blood cell sedimentation technique. Nucleated ce lls harvested from the fraction enriched with white blood cells were u sed for an assay to detect colony-forming unit granulocyte-macrophage (CFU-GM) derived cell colonies and a flow cytometric analysis of CD34( +) cells under variable conditions. The number of hematopoietic progen itor cells that might be reconstituted to bone marrow was estimated. T he mean duration time from the beginning of delivery to complete colle ction of cord blood was 9.9 min (range 5 similar to 20 min). The mean volume of umbilical cord blood for the 52 collections was 69.1 ml (ran ge 15-135 ml), containing 1.001% CD34(+) cells (range 0.21% similar to 2.63%) and 4 x 10(5) cells of CFU-GM derived colonies (range 0.2 x 10 (5) similar to 10.0 x 10(5) cells) within 24 h at 4 degrees C after de livery of the infant. There was no contamination by the mother's lymph ocytes according to cytogenetic analysis using pYNH24, which is a prob e with a variable number of tandem repeat markers. These findings indi cated that umbilical cord blood can be easily collected using the syri nge method and separated by the red blood cell sedimentation technique using 6% hydroxyethylstarch, Within 24 h at 4 degrees C, hematopoieti c progenitor cells were well detected using an assay for CFU-GM derive d colonies and were measured by flow cytometric analysis. However, the instability of the number of hematopoietic progenitor cells must be r esolved for safe transplantation of hematopoietic progenitor cells as a source of cells for repopulating bone marrow in children.