Bone marrow transplantation in severe combined immunodeficiency from a sibling who had received a paternal bone marrow transplant

Bone marrow transplantation to treat autosomal recessive severe combined immunodeficiency was undertaken in a one-month-old girl. The donor was the patient's HLA-mismatched six-year-old sister, who had previously received a marrow transplant from her father that was mismatched with regard to one HLA haplotype, to treat the same condition. The graft in the younger girl was not depleted of T cells, and no conditioning regimen was used before transplantation. The prompt engraftment in the girl and her uneventful course after transplantation indicated that the paternal T cells in the older sister's marrow had acquired immunologic tolerance of relevant HLA antigens and . . .