Mobilization of Cytogenetically ‘Normal’ Blood Progenitors Cells by Intensive Conventional Chemotherapy for Chronic Myeloid and Acute Lymphoblastic Leukemia

Abstract

Various lines of evidence suggest that substantial numbers of very primitive normal hematopoietic cells persist in the marrow of most patients with CML, despite the presence of an expanded Philadelphia-Chromosome (Ph) positive population, and that normal clones might, in certain circumstances, have a proliferative advantage over leukemic populations. We have recently demonstrated in 5/8 CML patients with blastic phase (BP) that the blood progenitor cells/(BPC) harvested during early recovery from marrow aplasia were Ph-negative on cytogenetic analysis, suggesting that leukapheresis may provide a useful source of 'normal' progenitors for subsequent reinfusions. We report here an update on 40 patients with Ph + CML and 9 patients with ALL in first or subsequent relapses with associated cytogenetic translocations including t(8;14) t(4;8) t(4;11) and t(9;22). All these patients received intensive conventional chemotherapy and during early recovery from marrow aplasia, when the WBC reached 0.5-2.0 x 10(9)/L, BPC were collected by 4-8 leukapheresis and tested for the persistence of the marker translocations and, when possible, for the presence of the hybrid bcr/abl transcripts by polymerase chain reaction (PCR). In seven out of 10 patients with chronic phase CML, BPC were Ph-negative and in 5 PCR negative. In both accelerated phase patients, BPC were Ph-negative but PCR-positive and in eight out of 28 blastic CML patients, BPC were Ph-negative and in two cases also PCR-negative. Six out of 9 ALL patients, lost the cytogenic translocations. After complete recovery, 16 patients were subsequently given high-dose therapy followed by reinfusion of 'normal' BPC.(ABSTRACT TRUNCATED AT 250 WORDS)

Difficulties in collecting peripheral blood stem cells in chronic myeloid leukemia related to persistence of the leukemic cell clone

“…* These data suggest that using such a "mobilizing" chemotherapy we have, in fact, unfortunately promoted the expansion of the Ph' clone instead of the proliferation of normal stem cells. These results contrast strangely with the results reported by Carella et al [3] in a similar series of CML patients who had received a cytoreductive and mobilizing chemotherapy not so different in intensity from the one we administered to our patients. Perhaps a difference in specificity of clonogenic cell sensitivity might exist between different, although structurally close, chemotherapy agents.…”

“…Korbling et al [2] proposed in 1981 such an alternative approach, namely in vivo purging from one patient who had been treated with high doses of busulphan and of cyclophosphamide, who was later transplanted with the stored stem cells collected after this intensive therapy, and in whom recovering hematopoiesis proved to be entirely Ph-. Ten years later, as reported by Carella et al, [3] six out of nine CML patients in CP were treated with a myeloablative chemotherapy consisting of idarubicin (6-8 mg/m2 per day x5) and etoposide (150 mg/m2 per day x3), and had complete suppression of Ph-positive (Ph+) metaphases at the time of leukaphereses. Our approach is similar, and we have used it within past years in CML patients ineligible for allogeneic BMT.…”

Persistence of dormant leukemic progenitors during interferon-induced remission in chronic myelogenous leukemia. Analysis by polymerase chain reaction of individual colonies.

“…This patient subsequently had a minor cytogenetic relapse (though complete cytogenetic remission was again reinduced with ongoing therapy). Explanations for this observation may include unequal distribution of residual leukemic progenitors in the blood and bone marrow (22) (23). Thus, the shift in cell population may result in false-negative BCR-ABL-based RT-PCR assays in the peripheral blood.…”

Results of MDR-1 vector modification trial indicate that granulocyte/macrophage colony-forming unit cells do not contribute to posttransplant hematopoietic recovery following intensive systemic therapy

“…Marrow cells (in ovarian cancer patients) and peripheral blood hematopoietic cells (in breast cancer patients) were collected when the white cell count reached 2000 cells per mm 3 during the early phase of graunolcyte colony-stimulating factor-driven recovery from conventional dose chemotherapy-induced myelosuppression, and then processed through a CS3000 Cobe Laboratories (Lakewood, CO) Continuous Flow Cell Separator as described (11)(12)(13). The cells were then CD34 selected using the CellPro Ceprate SC Selector, and then subjected to one of the two following transduction protocols: (i) Suspension protocol: the CD34 selected cells were placed in 150-ml DuPont Cell Culture air-porous bags and suspended in the MDR-1 retroviral supernatant at a multiplicity of infection of at least 0.25 in the presence of protamine sulfate (4 g͞ml).…”