Allogeneic transplantation of blood-derived, T cell-depleted hemopoietic stem cells after myeloablative treatment in a patient with acute lymphoblastic leukemia

This report describes an allogeneic peripheral blood stem cell transplant in a patient who had received marrow ablative therapy. The patient was an 18-year-old white male with acute lymphocytic leukemia in third remission for whom an allogeneic bone marrow transplant was recommended. His HLA-identical sibling preferred to donate peripheral blood stem cells rather than marrow. The donor cells were collected with 10 apheresis procedures and depleted of T lymphocytes to prevent excessive graft-versus-host disease. Nine collections were cryopreserved. The patient received high-dose cytosine arabinoside and 12 Gy of total body irradiation, followed by infusion of all cryopreserved donor cells. A portion of the tenth apheresis product collected on the day of transplant containing 1.8 x 10⁹ T lymphocytes was infused without further processing to approximate the number of T lymphocytes given in an allogeneic bone marrow transplant; the remainder was T lymphocyte depleted and infused. More than 1 x 10⁹/l granulocytes were present on day +11. A bone marrow biopsy on day +27 showed trilineage engraftment. Cytogenetic studies demonstrated that the recipient's marrow and peripheral blood were populated exclusively with donor cells. Allogeneic peripheral stem cell transplantation produced an early hematopoietic engraftment. Since the patient died on day +32, sustained engraftment could not be evaluated.