High levels of circulating haemopoietic stem cells in very early remission from acute non‐lymphoblastic leukaemia and their collection and cryopreservation

Abstract

Circulating myeloid progenitor cells (PB CFU-GM) were measured in the peripheral blood of 13 patients with acute non-lymphoblastic leukaemia (ANLL) as they entered first remission. The mean of the recorded peak levels was 2796 X 10(3) CFU-GM/l, representing a 25-fold increase above the mean value in normal subjects. These elevated levels of PB CFU-GM occurred regularly during the very early remission phase when platelet counts rose rapidly. Five of the patients had PB mononuclear cells collected by continuous-flow leukapheresis during this early recovery phase. CFU-GM were assayed as a measure of the number of haemopoietic stem cells in each collection. The cells were concentrated and then cryopreserved in liquid nitrogen. Leukapheresis was also performed on five normal subjects for comparison. Low numbers of CFU-GM were harvested from normal subjects, mean 0.33 +/- 0.06 X 10(4) CFU-GM/kg body weight for each leukapheresis. In ANLL patients entering remission, however, very large numbers of CFU-GM were regularly harvested. A mean of 11 +/- 2 X 10(4) CFU-GM/kg body weight were cryopreserved after each leukapheresis, representing 5 times the number of CFU-GM considered necessary for successful autologous haemopoietic reconstitution. Haemopoietic stem cell viability was assessed after varying periods of cryopreservation. There was no significant stem cell loss after up to 24 months storage. Thus, it is possible to collect and cryopreserve large numbers of CFU-GM and by inference pluripotent haemopoietic stem cells from the peripheral blood of patients with ANLL during very early remission. The possible biological and therapeutic implications are discussed.

Prior chemotherapy does not prevent effective mobilisation by G-CSF of peripheral blood progenitor cells

“…The protocol described in this study may be more widely applicable because it is not associated with these problems -the only side effects being mild bone pain during G-CSF administration and thrombocytopenia during leukapheresis (requiring platelet transfusion in two patients of 21) (Sheridan et al, 1992). In addition the yield of PBPC using chemotherapy techniques (without addition of CSF's) is 10-100-fold less than with G-CSF alone (Gabrilove et al, 1988;To et al, 1984). However, based on chemotherapy mobilised PBPC a minimum number of 30 x 104 GM-CFC kg-' is estimated to be required for subsequent engraftment using PBPC transfusion alone .…”

Flow cytometry using annexin V can detect early apoptosis in peripheral blood stem cell harvests from patients with leukaemia and lymphoma

“…5,6 The effects of these chemotherapeutic drugs, given as part of a mobilisation regimen or in previous cycles of chemotherapy, on progenitor cell viability and apoptosis are unknown. In lymphoma patients, who were heavily pretreated, significantly lower numbers of progenitor cells were collected despite the use of G-CSF to improve mobilisation.…”

Dose-intense paclitaxel, etoposide and cyclophosphamide: a safe and active regimen for tumor cytoreduction and stem cell mobilization in metastatic breast cancer

“…7 However, the number of circulating stem cells as determined by assays for CFU-GM, blood mononuclear cells or CD34-stained cells increases up to 20-fold during recovery from pancytopenia following myelosuppresive chemotherapy. 8,9 Numerous strategies have been devised to increase the number of PBSC. [10][11][12][13][14] Chemotherapy alone was utilized initially for PBSC mobilization.…”