Peripheral blood stem cells harvested after chemotherapy and GM-CSF for treatment intensification in patients with advanced lymphoproliferative diseases.

Peripheral blood stem cells (PBSC) from 15 patients with advanced non-Hodgkin's lymphoma (NHL), two patients with chronic lymphocytic leukemia, and two patients with myeloma were collected by continuous-flow leukapheresis after chemotherapy with MIV (mitoxantrone, ifosfamide, and etoposide, five patients) or high-dose cyclophosphamide (14 patients), followed by administration of GM-CSF. Sixteen patients (84%) had persistent marrow involvement at time of inclusion. Results were compared to those obtained in a control group of similar age and disease status in whom collection had been performed after MIV chemotherapy alone. The number of mononuclear cells, granulocyte-macrophage colony-forming units (CFU-GM), CD34+ cells were higher in GM-CSF treated patients with a lower mean number of leukapheresis (3.5 versus 6.4). Among the 19 patients harvested after chemotherapy plus GM-CSF, more progenitor cells were obtained in the cyclophosphamide group than in the MIV group. In all these patients except one, the number of mononuclear cells was sufficient to realize a transplantation. Seventeen patients received intensification with BEAM regimen (8 patients) or cyclophosphamide plus etoposide and total body irradiation (9 patients). Two patients failed to reconstitute correct hematopoiesis and three early toxic deaths occurred for a total of five procedure-related deaths. Nine of these 17 patients are in persistent complete remission with a median post-transplant follow-up of 18 months. Time to reach granulocyte and platelet recovery was not correlated with the number of mononuclear cells, CFU-GM, granulocyte-erythroid-macrophage-megakaryocyte colony-forming units (CFU-GEMM), CD34+ cells, and CD34+ CD33- cells but with the number of previous chemotherapy regimens. PBSC harvesting is achievable after chemotherapy plus GM-CSF in heavily pretreated patients with persistent marrow involvement. Moreover, these cells are able to reconstitute correct hematopoiesis after intensive treatment in these patients.