[Allogeneic bone marrow transplantation in children from related donors other than HLA-identical siblings]

Thirty-five children with poor-prognosis disease underwent allogeneic bone marrow transplantation (BMT) from related donors other than HLA identical siblings (parents in 18 cases, non-identical siblings in 14, and other relatives in 3). Phenotypically identical donors were involved in 12 cases, donors with one mismatched locus in 17, and donors with two or more mismatched loci in 6. Thirty-two of the children received total-body irradiation as part of their conditioning regimen, followed by unpurged marrow-cell infusions (averaging 4.09 x 10(8) cells/kg). Methotrexate and cyclosporin were administered for graft-versus-host disease (GVHD) prophylaxis; 15 of the children also received antithymocyte globulin (ATG) infusions. The effective graft rate for the group was 84. 8%; of 5 patients who experienced rejections, 4 had non-malignant diseases. The incidence of grade II-IV acute GVHD was 48.4%, significantly higher than that for groups that received allogeneic BMT from matched sibling donors. Three children (8.8%) died of severe GVHD. The incidence of acute GVHD in phenotypically matched patients was the same as that in the one-locus mismatched cases. MLC reactivity affected the incidence of acute GVHD (60.0% MLC-positive, 28.6% negative). ATG reduced the severity of acute GVHD. The event-free survival rate was 40.8 +/- 8.5% for the entire group (N = 35; 32.9 +/- 10.5% for the 22 children with malignancies, and 53.8 +/- 13.8% for the 13 with non-malignant diseases). Despite the risk of severe GVHD, allogeneic BMT from related donors other than HLA-identical siblings seems to be an effective treatment for patients with poor-prognosis diseases.