Recent decrease in acute graft-versus-host disease in children with leukemia receiving unrelated donor bone marrow transplants.

Unrelated donor (URD) bone marrow transplantation (BMT) is an effective treatment for leukemia in children, but its success is threatened by graft-versus-host disease (GVHD) and relapse. In this report, we describe the incidence of and risk factors for GVHD over time in children receiving URD BMT. We analyzed outcomes of 638 myeloablative URD BMTs performed between 1990 and 2003 to treat acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia, or myelodysplastic syndrome MDS, using the Center for International Blood and Marrow Transplant Research (CIBMTR) database. All recipients were under age 18 years and had available high-resolution HLA typing for HLA-A, -B, -C, and -DRB1. Overall, 27% of the recipients developed acute GVHD (aGVHD) grade III-IV; the risk was significantly higher in children receiving T cell-replete grafts compared with those receiving T cell-depleted grafts (odds ratio [OR] = 3.12; 95% confidence interval [CI] = 2.02 to 4.83; P < .0001). Acute GVHD significantly reduced the risk of relapse in children with ALL (OR = 0.34; 95% CI = 0.13 to 0.86; P = .0052), but not in those with AML (OR = 0.58; 95% CI = 0.22 to 2.98; P = .26). The risk of aGVHD was higher in children undergoing transplantation in 1990-1998 (n = 365) compared with those doing so in 1999-2003 (OR = 1.93; 95% CI = 1.27 to 2.91; P = .002). We conclude that outcomes have changed significantly over time, with a reduced risk of aGVHD associated with the more recent transplantations.