Transplants of umbilical-cord blood or bone marrow from unrelated donors in adults with acute leukemia.

Promising results of cord-blood transplants from unrelated donors have been reported in adults. We compared outcomes in 682 adults with acute leukemia who received a hematopoietic stem-cell transplant from an unrelated donor: 98 received cord blood and 584 received bone marrow. The transplantations were performed from 1998 through 2002 and reported to Eurocord and the European Blood and Marrow Transplant Group. Recipients of cord blood were younger than recipients of bone marrow (median, 24.5 vs. 32 years of age; P<0.001), weighed less (median, 58 vs. 68 kg; P<0.001), and had more advanced disease at the time of transplantation (52 percent vs. 33 percent, P<0.001). All marrow transplants were HLA matched, whereas 94 percent of cord-blood grafts were HLA mismatched (P<0.001). The median number of nucleated cells that were infused was 0.23x10(8) per kilogram of the recipient's body weight for cord blood and 2.9x10(8) per kilogram for bone marrow (P<0.001). Multivariate analysis showed lower risks of grade II, III, or IV acute graft-versus-host disease (GVHD) after cord-blood transplantation (relative risk, 0.57; 95 percent confidence interval, 0.37 to 0.87; P=0.01), but neutrophil recovery was significantly delayed (relative risk, 0.49; 95 percent confidence interval, 0.41 to 0.58; P<0.001). The incidence of chronic GVHD, transplantation-related mortality, relapse rate, and leukemia-free survival were not significantly different in the two groups. Cord blood from an unrelated donor is an alternative source of hematopoietic stem cells for adults with acute leukemia who lack an HLA-matched bone marrow donor.