Collection and analysis of peripheral blood mononuclear cells during haemopoietic recovery following PBSCT for CML: autografting as an in vivo purging manoeuvre?

Abstract

Summary:A 47-year-old man with a 2-year history of Philadelphia chromosome-positive chronic phase (CP) chronic myeloid leukaemia (CML) underwent autologous PBSCT. During the period of haemopoietic reconstitution he underwent five leucapheretic (LP) harvests yielding a total of 2.6 ؋ 10 6 /kg CD34 + cells. Cytogenetic analyses revealed 94, 83, 83, 96 and 85% Ph negativity respectively for the five harvests. RT-PCR analyses for BCR-ABL performed on randomly picked CFU-GM from the five LP products were negative in all cases. These observations suggest that the majority of harvested cells, including the more primitive clonogenic cells, were BCR-ABL (Ph) negative and presumably were not part of the leukaemic clone. These findings support the notion that autologous PBSCT in CML whilst serving as a therapeutic manoeuvre may also facilitate the collection of non-leukaemic progenitor cells for further transplantation procedures. Keywords: CML; PBSCT; leucapheresis; purging Potentially curative alloSCT is presently unavailable to the majority of CML patients because of patient age and/or the lack of availability of a suitably matched donor.1 Interferon is reported in some multicentre randomised studies to be associated with a prolongation of survival when compared to chemotherapy, 2,3 however, no discernible plateauing of survival curves has been demonstrated, thus suggesting that IFN is unlikely to be curative. Comparison with historical controls suggests that autologous PBSCT may be associated with a prolongation of survival for CP CML patients and in instances can result in prolonged periods of Philadelphia chromosome-negative haemopoiesis.4 Thus, the demonstration that significant numbers of Ph-negative peripheral blood MNC could be obtained by LP after the administration of high-dose chemotherapy 5 has led to the development of numerous therapeutic strategies based on Correspondence: Dr A Spencer, Hunter Haematology Unit, Locked Bag 7, Hunter Region Mail Centre, NSW 2310, Australia Received 8 July 1997; accepted 2 September 1997 this perceived in vivo purging effect. Whether PBSCT following in vivo purging is more beneficial when compared to the use of unmanipulated PBSC is uncertain but theoretically it is a more attractive approach. Based on these observations we chose to examine whether sufficient numbers of PBSC could be obtained during the recovery phase from PBSCT to enable a second autografting procedure, thus combining a potential therapeutic benefit with high-dose chemotherapy in vivo purging and subsequent progenitor cell collection. Case reportIn March 1995, a 47-year-old male was incidentally found to have a total leucocyte count of 97 ϫ 10 9 /l with a normal haemoglobin and platelet count. The peripheral blood features were consistent with CP CML. Bone marrow aspirate confirmed the diagnosis with 100% of metaphases showing t(9;22)(q34;q11). RT-PCR revealed b2a2 BCR-ABL transcripts. Initial disease control was achieved with hydroxyurea. He was then started on daily alpha-interferon (IFN) and received subc...

Leukapheresis after high‐dose chemotherapy and autologous peripheral blood progenitor cell transplantation: a novel approach to harvest a second autograft

“…Two published case reports already question whether sufficient numbers of CD34+ cells can be collected by leukapheresis during the recovery of hematopoiesis after HDCT and autologous PBPC transplantation. 12,13 We reported on two patients (Hodgkin's disease and germ cell cancer) who underwent leukapheresis for PBPC harvesting during hematopoietic reconstitution after HDCT and autografting. Collection attempts were successful in the patient who was autografted with 8.5 ‫ן‬ 10 6 CD34+ cells per kg but were ineffective in the patient who received 1.8 ‫ן‬ 10 6 CD34+ cells per kg.…”

“…We concluded that patients with sufficient mobilization and collection of circulating CD34+ cells after CDCT were potential candidates for the harvesting of a second hematopoietic autograft after HDCT and autologous transplantation. 12 In a second report, Spencer et al 13 described a patient with chronic myelogenous leukemia who underwent successful PBPC separation after high-dose busulfan and autologous transplantation of 12.0 ‫ן‬ 10 6 CD34+ cells per kg. The authors concluded that CD34+ cell collection after autografting could facilitate the use of sequential autologous transplantation procedures in chronic myelogenous leukemia with the initial course of HDCT acting as an in vivo purging manoeuvre.…”

“…The authors concluded that CD34+ cell collection after autografting could facilitate the use of sequential autologous transplantation procedures in chronic myelogenous leukemia with the initial course of HDCT acting as an in vivo purging manoeuvre. 13 In vivo purging would be of special interest for patients undergoing autologous transplantation because it is well known that leukapheresis components collected after mobilization by CDCT plus growth factors can be contaminated with tumor cells. [21][22][23] To our knowledge, the present study is the first report on a series with 30 patients dealing with collection of circulating CD34+ cells during the phase of hematopoietic recovery after autologous PBPC transplantation.…”

“…Based on two published case reports, the collection of circulating CD34+ cells after HDCT and autografting appears to be feasible. 12,13 In the present study, we attempted harvesting of CD34+ cells by leukapheresis during the posttransplantation course of 30 patients with the aim to obtain a further hematopoietic autograft for a second treatment of HDCT. The data of the study are presented after a retrospective analysis.…”

“…These cells may serve as hematopoietic rescue for a second course of HDCT. Based on two published case reports, the collection of circulating CD34+ cells after HDCT and autografting appears to be feasible 12,13 …”