Long-term stable hematopoietic chimerism following marrow transplantation for acute lymphoblastic leukemia: a case report with in vitro marrow culture studies

This article describes the course of a patient who received an allogeneic marrow graft from his HLA-identical sister for acute lymphoblastic leukemia in second remission. In the second month after grafting, marrow aspirates showed the presence of 7%-10% lymphoblasts. In addition, cytogenetic examination indicated the persistence of host cells. Thereafter, the patient had morphologically normal marrow examinations, with no evidence for recurrent leukemia. In addition, stable hematopoietic chimerism in both the lymphoid and myeloid cell lines has persisted for over 5 yr. Between 20% and 50% of phytohemagglutinin-stimulated peripheral blood mononuclear cells were host-derived on repeated studies. A marrow sample 4 yr after transplantation was established in long-term culture and produced 2% host granulocyte-macrophage colonies at its inception, but 24% host colonies by week 4. Despite this persistent chimerism, no in vitro or in vivo abnormalities of hematopoiesis have been detected.