Marrow transplantation: what determines success or failure of hematologic reconstitution?

The technique of marrow transplantation serves to replace diseased marrow by normal hemopoiesis. Successful restoration of hemopoiesis is predicated upon the ability of the preparative regimen to ablate both the diseased marrow and the host immune system and upon the capacity of the injected undifferentiated self-renewing stem cells to produce progeny. If these conditions are met, hemopoiesis and an immune system consisting almost exclusively of donor cells will be established although a minority of patients may show a mixture of host and donor cells. If not, graft failure may ensue, a clinical syndrome having at least two etiologies: spontaneous graft resistance and transfusion-induced sensitization. The present report contrasts the immunological findings made with successful hemopoietic engraftment to those seen with graft failure.