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...

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