Clinical application of Percoll gradient-separated bone marrow.

We have evaluated the transplantation potential of bone marrow stem cell concentrates isolated from the 40/60% interface of discontinuous Percoll gradients. This mononuclear fraction is free from platelets and depleted of granulocytes, and contains the majority of granulocyte-macrophage colony-forming cells (GM-CFC), erythroid burst-forming units (BFU-E), and granulocyte, erythroid, macrophage, megakaryocyte colony-forming cells (GEMM-CFC) in less than 10% of the cell number of the original buffy coat. This preparation allows further manipulation without the clumping and cell loss associated with buffy coat cell preparations. Cells isolated by this technique were evaluated for hematopoietic restoration potential in 14 patients who received allogeneic bone marrow transplants as supportive therapy after high dose cytoreduction to treat leukemias or lymphoma. The number of nucleated cells infused varied from 1.6-5.5 X 10(7)/kg, and the number of GM-CFC infused ranged from 0.4 to 3.7 X 10(5)/kg. There was an inverse relationship between the time to recovery of granulocytes and platelets and the number of GM-CFC infused when fewer than 10(5) GM-CFC/kg were transplanted. Above this dose, there was recovery within 10-15 days after transplantation. The stem cell-enriched fraction contained 30-40% of the original number of T lymphocytes, and acute graft-versus-host disease was observed in seven of these patients.