CD34(-CELL TRANSPLANTATION FROM 2 HLA-MISMATCHED HEALTHY FATHERS TO 2INFANTS WITH SEVERE APLASTIC-ANEMIA() PROGENITOR)

Pluripotent stem cells of hematopoiesis are included among CD34(+) cel ls in the blood and bone marrow. After granulocyte-colony stimulating factor (G-CSF) mobilization, 1-2% of the mononuclear cells in the bloo d are CD34(+) cells, which can be obtained by leukapheresis. We perfor med CD34(+) progenitor cell transplantation in two children with sever e aplastic anemia (SAA) who lacked HLA-matched donors. The donors were treated with G-CSF, 600 mu g/body/day subcutaneously, for 4-5 days. C D34(+) cell selection was performed from the apheresis concentrate wit h mouse anti-CD34 antibody 9C5 and magnet beads coated with sheep anti -mouse IgG1. After the transplantation, the patients received tacrolim us to prevent graft-versus-host disease (GVHD). G-CSF was given to bot h patients. A mean number of 4.96 x 10(6) CD34(+) cells per kilogram o f body weight were transplanted. The hematopoietic recovery after the CD34(+) cell transplantation was rapid, except for platelets, and acut e GVHD was less than or equal to grade I. Case 1, who demonstrated mix ed chimerism, anemia and thrombocytopenia after the graft, received a second transplant with intensified preconditioning, and now sustains c omplete and stable hematopoiesis after a follow-up of 314 days posttra nsplant. Although Case 2 showed early rejection and received a second transplant, sustained engraftment was never achieved. However, the pat ient's own hematopoiesis appeared. For SAA patients who do not have HL A-matched donors, this type of approach seems to be a feasible and use ful method. However, an intensified preconditioning regimen to overcom e the high likelihood of rejection should be employed. (C) 1998 Elsevi er Science Ireland Ltd. All rights reserved.