SUCCESSFUL ENGRAFTMENT OF HLA NONIDENTICAL BONE-MARROW TRANSPLANTATION WITHOUT CONDITIONING IN 2 SIBLINGS WITH ADENOSINE-DEAMINASE DEFICIENCY

HLA nonidentical bone marrow transplantation (BMT) was performed in tw o siblings with adenosine deaminase (ADA)-deficient severe combined im munodeficiency. Both patients received 10(8)/kg of marrow cells from h er father without any conditioning or T cell depletion on 42 days and 22 days of age. In the first patient, HLA analysis demonstrated one lo cus mismatch between the patient and the donor. Mixed lymphocyte cultu re (MLC) was negative when the donor cells were used as responders. Af ter BMT, grade I acute graft versus host disease (GVHD) appeared but i mmunologic reconstitution was rapid. She has been healthy without any complications for 3 years. The second patient's HLA was haploidentical to the donor's HLA, but the donor cells were nonresponsive against th e patient's cells by MLC. After BMT, grade I acute GVHD occurred but w as milder than that in patient 1. Immunologic reconstitution was delay ed. Age at BMT, severe lymphopenia at presentation, no T cell depletio n from donor bone marrow, and macrophage-colony-stimulating factor adm inistration might have contributed to successful engraftment of HLA no nidentical BMT without conditioning in two patients with ADA deficienc y.