UMBILICAL-CORD BLOOD AS A SOURCE OF HEMATOPOIETIC STEM-CELLS - FROM RESEARCH TO CLINICAL-APPLICATION

The clonogenic capacity of human umbilical cord blood (UCB) has been e valuated in several studies which found high numbers of primitive hema topoietic progenitor cells. Recently, UCB progenitor cells were shown to possess significant advantages over bone marrow (BM) in terms of pr oliferative capacity and immunologic reactivity. Therefore UCB has com e to be considered an attractive source of hematopoietic stem cells fo r both research and clinical applications. UCB has been used in the tr eatment of diseases potentially curable by bone marrow transplantation (BMT). Seventy-one transplants have been performed world-wide using U CB cells, and the results have been reported to the International Cord Blood Transplant Registry (ICBTR). Since UCB cells appear to be less alloreactive than BM cells, studies are under way to determine the fea sibility of UCB banking for use in unrelated transplants. Because of t he limited volume of UCB that can be obtained in a single collection, studies have been carried out to determine the most successful procedu res for collection and fractionation of UCB and to quantify precisely the progenitor/stem cell content. The different techniques for quantif ying progenitor/stem cells as well as the results of related and unrel ated UCB transplants will be reviewed. Further clinical applications o f UCB involving gene therapy and stem cell expansion will be discussed .