Analysis of engraftment, graft-versus-host disease, and immune recovery following unrelated donor cord blood transplantation

Unrelated cord blood (UCB) is being used as a source of alternative hematop oietic stem cells for transplantation with increasing frequency. From Novem ber 1994 to February 1999, 30 UCB transplant procedures were performed for both malignant and nonmalignant diseases in 27 children, aged 0.4 to 17.1 y ears. Patients received either HLA-matched (n = 3) or 1- or 2-antigen-misma tched (0 = 27) UCB following 1 of 2 standardized preparative and graft-vers us-host disease regimens (hyperfractionated total body irradiation, cycloph osphamide, and antithymocyte globulin [ATG] with cyclosporine A and methotr exate; or busulfan, melphalan, and ATG with cyclosporine A and prednisone), The median time to neutrophil and platelet engraftment was 27 days (12-60 days) and 75 days (33-158 days) posttransplantation, respectively. No corre lation was noted between neutrophil and platelet engraftment and nucleated cells per kilogram, CD34(+) cells per kilogram infused, or cytomegalovirus status of recipient. The cumulative probability of acute grade 2 or greater graft-versus-host disease (GVHD) was 37.2%, and of grade 3 or greater GVHD was 8.8%, No patients developed chronic GVHD, CD4, CD19, and natural kille r cell recovery was achieved at a median of 12, 6, and 2 months, respective ly. CD8 recovery was delayed at a median of 9 months. Normal mitogen respon se was achieved at 6 to 9 months. The probability of survival, disease-free survival, and event-free survival at 1 year was 52.3% (34.1%-70.5%), 54.7% (34.5%-74.9%) and 49.6% (29.9%-69.4%), respectively. This series of 30 UCB transplants suggests that although CD8 cell recovery is delayed, the patte rn of immune reconstitution with UCB is similar to that reported for other stem cell sources. (C) 2000 by The American Society of Hematology.