PERIPHERAL-BLOOD STEM-CELLS USED TO AUGMENT AUTOLOGOUS BONE-MARROW TRANSPLANTATION

Peripheral blood stem cells (PBSC) were used to augment autologous bone marrow transplantation (ABMT), aiming to hasten engraftment after high dose treatment in a group of heavily pretreated patients. PBSC were obtained by leukapheresis during the rebound after standard chemotherapy. In 11 patients aged 7-17 years, high dose chemotherapy consisted of busulphan 16 mg/kg orally with melphalan 160 mg/m(2) intravenously for seven patients, and melphalan 200 mg/m(2) intravenously alone for four. The median number of granulocyte-macrophage colony forming units in the reinfused PBSC was 3.42X10(4)/kg (3.03-18.01) and bone marrow 12.4X10(4)/kg (4.16-28.6). Neutrophil recovery to greater than or equal to 0.5X10(9)/l and platelet transfusion independence occurred at a median of 14 days (11-18) and 22 days (9-84) respectively. In five patients the early engraftment was transient with neutrophils again dropping below 0.5X10(9)/l then slowly recovering. There was one toxic death due to sepsis. PBSC harvesting in these children was undertaken without interrupting routine chemotherapy and without the use of bone marrow growth factors. In some patients PBSC failed to influence engraftment and the use of combined chemotherapy and growth factor priming for PBSC collection may give improved results.