PERIPHERAL-BLOOD PRECURSOR CELLS INSTEAD OF BONE-MARROW CELLS FOR ALLOGENEIC TRANSPLANTATION

In a pilot study we tested the feasibility and safety of peripheral bl ood precursor cells instead of bone marrow cells for allogeneic transp lantation. 13 patients - 7 male and 6 female between 24 and 52 years o f age with hematological malignancies (10 with acute leukemias, 3 with myeloproliferative syndromes - were conditioned for bone marrow trans plantation with VP-16, cyclophosphamide and total body irradiation fol lowed by graft-versus-host disease prophylaxis with cyclosporin and me thotrexate. Precursor cells were mobilized in the donors by granulocyt e colony stimulating factor (G-CSF, Neupogen(R)) 10 mu g/kg s.c. from day -5 on. A total of 14.05x10(8) nucleated cells/kg recipient body we ight (range 9.52-20.23x10(8)/kg), corresponding 6.82x10(6)/kg CD 34(+) cells (range 1.43-15.84x10(8)/kg) or 113.9x10(4) CFU/kg (range 45.15- 431.64x10(4)/kg) were collected by 3 phereses (1 patient 5 phereses) o f 27-45 liters and infused without further manipulation. All patients engrafted with a recovery of total white blood cell count >1x10(9)/l o n day 15 (day 10-26) and of platelets >20x10(9)/l on day +18 (day 12-3 9). 11 of the 12 patients developed aGvHD, 8 with grade II, 3 with gra de greater than or equal to II. 9 of 13 patients are alive and well +4 to +16 months posttransplant, 3 patients died of aCvHD, one of veno-o cclusive disease. These preliminary results confirm the capacity of pe ripheral blood precursor cells for rapid and complete engraftment in t he allogeneic setting. Whether they induce more or equal aGvHD is an o pen question. Their value in allogeneic transplantation is currently u nder investigation in prospective randomized trials.