Stem cell apheresis in patients with acute nonlymphocytic leukemia

Abstract

In patients with acute nonlymphocytic leukemia (ANLL) it has previously been reported that the number of blood-derived hemopoietic stem cells (HSC) is very low during the remission phase. 1,2 However, we and others have recently demonstrated that the concentration of granulocyte-macrophage precursors (CFU-GM cells) in the peripheral blood could be increased to 10- to 40-fold above the mean value in normal subjects during the period of marrow reconstitution following aplasia (or hypoplasia) induced by previous chemotherapy. 1,3 To collect high numbers of circulating HSC, leukocyta-phereses could be performed during this short period of “recirculation” of blood-derived progenitors. However, patients with ANLL may be subjected to different chemotherapy regimens that vary according to the age of the patients, the status of the leukemia, and the therapeutic strategy. The amplitude of the recirculation of CFU-GM cells during remission is influenced mostly by the type of chemotherapy administered to the patient. 1 In order to evaluate this phenomenon, we serially assayed peripheral blood CFU-CM cells in 26 ANLL patients. The mean value of the highest recorded peak (HRP) level was 4370 CFU-GM/mL (1133 to 9066) in 13 patients who achieved complete remission after a single course of induction treatment including cytosine arabinoside (Ara-c) (100 mg/m2 × 10 days) and daunorubicin (DNR) (60 mg/m2 × 3 days). As mentioned in a previous report, HPR levels of CFU-GM cells observed in two patients given a late, intensification treatment (with DNR: 300 mg/m2) were similar to those observed in these latter 13 patients. 1 The recirculation of CFU-GM cells was less marked in seven patients who received two consecutive courses of induction chemotherapy or in four other patients receiving less intensive treatment as consolidation. 1,2 These results confirm the results of our previous report and the data reported by To et al., who studied 13 ANLL patients during the very early remission phase following induction chemotherapy. 3 They found that the mean value of the HRP level of CFU-GM cells was 2796/mL (370 to 14520) and concluded that the early remission period after one single course of chemotherapy could be the best time for collection of circulating HSC in ANLL patients.