Abstract
Transplantation of umbilical-cord blood was successfully performed for the first time in 1988 to treat a boy with Fanconi's anemia; the donor, the boy's newborn sister, was a perfect HLA match for her brother.1 Since then, the advantages of cord blood as a source of hematopoietic stem cells for transplantation have become clear. First, the proliferative capacity of hematopoietic stem cells in cord blood is superior to that of cells in marrow or blood from adults. A 100-ml unit of cord blood contains 1/10 the number of nucleated cells and progenitor cells (CD34+ cells) present in 1000 ml of marrow, . . .