Transplantation of unrelated donor umbilical cord blood for nonmalignant diseases: a single institution's experience with 45 patients.

The potential benefits of unrelated donor bone marrow transplantation are offset by the immunologic complications of graft-versus-host disease (GVHD) and infection. We used cryopreserved umbilical cord blood (UCB) as a strategy to reduce the risks of GVHD and treatment-related mortality (TRM) and improved survival. Data on 45 patients with median age of 4.5 years who received transplants between October 2003 and February 2009 for the treatment of nonmalignant diseases were evaluated. As of May 15, 2009, the median follow-up was 25 months (range: 3-66). The majority (82%) of patients received an HLA-mismatched graft. The median infused total nucleated cell dose was 7.6 x 10(7)/kg and CD34(+) count 4.0 x 10(5)/kg. Primary graft failure was encountered after 4 transplantations (8%). Log-rank tests and Cox regression analyses were used to determine the effects of various demographic, graft-related, and treatment factors on engraftment, GVHD, TRM, graft failure, and survival. Incidences of neutrophil and platelet engraftment were 88% and 82%, respectively. The incidence of severe grade III-IV acute GVHD (aGVHD) was 42%. Five-year overall survival (OS) and disease-free survival (DFS) were 88.1% and 77.1%, respectively. The cumulative incidence of TRM at 2 years was 12.0%. When cell dose and other factors are optimal, unrelated CBT is a promising approach for curative therapy of nonmalignant diseases.