Multicycle high-dose chemotherapy and filgrastim-mobilized peripheral-blood progenitor cells in women with high-risk stage II or III breast cancer: five-year follow-up.

PURPOSE: To determine the safety and efficacy of multiple cycles of dose-intensive, nonablative chemotherapy in women with poor-prognosis breast cancer. PATIENTS AND METHODS: Women with stage II breast cancer and 10 or more involved nodes or four or more involved nodes and estrogen receptor-negative tumors and women with stage III disease received three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2, with progenitor cell and filgrastim support every 28 days (n = 79) or 21 days (n = 20). Patients were reviewed at least twice yearly thereafter. Twenty-six patients had bone marrow and apheresis collections assessed for the presence of micrometastatic tumor cells. RESULTS: Ninety-nine women (median age, 43 years; range, 24 to 60 years) were treated. Ninety-two completed all three cycles of chemotherapy. The major toxicity was severe, reversible myelosuppression that was more prolonged with successive cycles, and this did not differ between patients given treatment every 28 days and those treated every 21 days. Febrile neutropenia occurred in 176 (61%) of 287 cycles. Severe mucositis (grade 3 or 4) occurred in 23% of cycles but tended to be short-lived and was reversible. The cardiac ejection fraction fell by a median of 4% during treatment, and three patients developed evidence of cardiac failure after chemotherapy. Two patients (2%) died of acute toxicity. Three of 26 patients had evidence of circulating micrometastatic tumor cells. The actuarial distant disease-free and overall survival rates at 60-month follow-up were 64% (95% confidence interval [CI], 53% to 75%) and 67% (95% CI, 56% to 78%), respectively. CONCLUSION: Multiple cycles of dose-intensive, nonablative chemotherapy is a feasible and safe approach. Disease control and survival are similar to those in other studies of myeloablative chemotherapy in poor-prognosis breast cancer. The regimen is being evaluated in a randomized trial of the International Breast Cancer Study Group.

Rapid hematopoietic recovery after multicycle high-dose chemotherapy: enhancement of filgrastim-induced progenitor-cell mobilization by recombinant human stem-cell factor.

PURPOSE: To assess the mobilization potential and safety of recombinant human stem-cell factor (SCF) when coadministered with filgrastim to untreated women with poor-prognosis breast cancer. PATIENTS AND METHODS: Eligible women had breast cancer with 10 or more positive axillary nodes, or estrogen receptor-negative tumor with 4 positive nodes, or stage III disease. Patients were randomized to receive SCF plus filgrastim or filgrastim alone. Filgrastim 12 microg/kg daily was administered for 6 days by continuous subcutaneous infusion. SCF was administered by daily subcutaneous injection at 5, 10, or 15 microg/kg concurrent with filgrastim for 7 days, or 10 microg/kg daily starting 3 days before filgrastim for a total of 10 days (SCF pretreatment). Apheresis was performed on days 5, 6, and 7 of filgrastim administration. Patients then had three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2 every 28 days, each supported by one third of the apheresis product. RESULTS: Sixty-two women were treated. Greater yields occurred in patients who received SCF 10 microg/kg daily plus filgastim than those who received filgrastim alone (P=.013 for CD34+ cells; P=.07 for granulocyte-macrophage colony-forming cells [GM-CFCs]). The difference was more marked with SCF-pretreatment than concurrent SCF. Fewer aphereses were required to reach the predetermined target of peripheral-blood progenitor/stem cells (PBPCs) in women who received SCF. SCF was generally well tolerated. Hematologic recovery was rapid after each of the three cycles of chemotherapy. There was no difference in recovery between the different treatment groups. CONCLUSION: Mobilization of PBPCs by filgrastim is significantly enhanced by coadministration of SCF, and commencing SCF before filgrastim can optimize this effect. SCF has the potential to reduce the number of aphereses required to collect a target number of PBPCs.

The detection of Philadelphia chromosome negative metaphases in long-term bone marrow cultures of the peripheral blood from patients with chronic myeloid leukemia predicts response to interferon-alpha 2a.

The cytogenetic response of 10 patients with chronic myeloid leukaemia (CML) to human recombinant interferon-alpha 2a (rhIFN alpha 2a) was compared to the Philadelphia chromosome (Ph) status of the pre-treatment peripheral blood cells after in vitro culture under long-term bone marrow culture (LTBMC) conditions. Pre-treatment light density peripheral blood cells were cultured in LTBMC on sex-mismatched irradiated allogeneic stromal layers with weekly cytogenic examination of metaphases in the non-adherent cell fraction. This was correlated with the patients' response to rhIFN alpha. Two groups of patients, five showing a cytogenetic response (responsive) and five who failed to achieve a cytogenetic response (nonresponsive) were studied. At the initiation of the LTBMCs the Ph' was found to be present in 100% of the cells analysed for nine patients and 97% for one patient. Pretreatment peripheral blood from four responsive patients demonstrated a decline in the proportion of Ph'-positive cells (Ph+) after 1 to 2 weeks in LTBMC. In contrast, peripheral blood from all the non-responsive subjects showed persistence of the Ph+ clone in 100% of the cells analysed out to a maximum of 3 to 5 weeks in LTBMC. A significant difference was observed (Fisher exact test, p = 0.023) between the two patient groups in respect to the appearance of normal clones in the nonadherent population. The presence of Ph- metaphases in LTBMC of peripheral blood cells of CML patients may predict their cytogenetic response to rhIFN alpha 2a.

Adjuvant treatment of high-risk breast cancer using multicycle high-dose chemotherapy and filgrastim-mobilized peripheral blood progenitor cells.

Women with primary breast cancer associated with extensive axillary node involvement or large primary tumors have a very poor prognosis despite treatment with standard-dose adjuvant chemotherapy. In an attempt to improve the outlook of these patients, we investigated the safety and feasibility of delivering three cycles of high-dose epirubicin and cyclophosphamide supported with filgrastim-mobilized peripheral blood progenitor cells (PBPC). Fifteen previously untreated women, median age 50 (range, 30-58) years, with poor prognosis early stage breast cancer received filgrastim (12 microgram/kg daily for 6 days) prior to chemotherapy to mobilize progenitor cells. Patients were then given three cycles of epirubicin (200 mg/m2) and cyclophosphamide (4 g/m2) at planned 28-day intervals, each followed by infusion of one third of the PBPC collected and daily administration of filgrastim (5 microgram/kg s.c.). Three leukaphereses collected a median of 114.9 (range, 22.7-273.5) x 10(4) granulocyte-macrophage-colony-forming cells/kg body weight. Hemopoietic recovery was rapid after each cycle, and there was no correlation between the rate of recovery and the number of granulocyte-macrophage-colony-forming cells infused. There was a small but significant progressive delay in recovery from hematological and nonhematological toxicities across the three cycles. Left ventricular ejection fraction fell to below 50% in eight (53%) patients, but none developed congestive cardiac failure. Two patients did not complete three cycles because of insufficient PBPC for a third cycle (n = 1) and 2-mercaptoethane sodium sulfonate- related drug reaction during the second cycle (n = 1). There were no deaths during the study or during the follow-up period (median, 70 weeks; range, 50-85 weeks), and no late toxicities occurred. Therefore, we concluded that the delivery of multiple cycles of nonmyeloablative, dose-intensive chemotherapy supported by PBPC and filgrastim is safe, and may be widely applicable to a variety of common chemosensitive cancers with a poor prognosis. The efficacy of three cycles of high-dose epirubicin and cyclophosphamide is to be compared with standard-dose chemotherapy in a randomized trial in patients with high-risk, operable stage II and III breast cancer.

c-kit is expressed by primitive human hematopoietic cells that give rise to colony-forming cells in stroma-dependent or cytokine-supplemented culture.

Using monoclonal antibody (MAB) YB5.B8, we have examined the expression of the c-kit protein, the receptor for the hematopoietic cytokine stem cell factor (SCF), on primitive hematopoietic cells. Bone marrow mononuclear cells (BMMNC) enriched for immature cells by differential agglutination using the lectin soybean agglutinin (SBA) were subjected to multiparameter fluorescence activated cell sorting (FACS) based on light-scattering properties, the expression of the c-kit protein and the CD34 antigen, and the retention of the vital fluorescent dye, Rhodamine 123 (Rh123). Sorted populations were assayed for their content of directly clonogenic progenitor cells (colony-forming units-granulocyte/macrophage [CFU-GM], burst-forming units-erythroid [BFU-E], and multipotential colony-forming units [CFU-Mix]) and for the presence of more primitive progenitor cells ("pre-CFU"). The latter were assayed by (1) their ability to initiate and sustain hematopoiesis in a standard stromal cell-dependent culture system and (2) their capacity for de novo generation of clonogenic progenitors in response to a combination of six recombinant hematopoietic cytokines in a stroma-independent suspension culture assay. A mean of 76% of CD34+ cells were found to coexpress c-kit. The majority of directly clonogenic cells (98% of CFU-GM, 98% of CFU-Mix, and 85% of BFU-E) were found in the CD34+c-kit+ fraction. Similarly, all pre-CFU were recovered in the CD34+c-kit+Rh123dull fraction, irrespective of whether the cells were maintained on marrow stromal cells or in cytokine-supplemented liquid culture. A mean of 87% (range 70-100%) of the CD34+Rh123dull cells also expressed c-kit. Since SCF has been reported to act as a growth factor for early lymphoid cells as well as myeloid cells, we looked for coexpression of c-kit and early lymphoid markers in the CD34+ population by multiparameter flow cytometry. Coexpression of c-kit on a minority of cells with markers of B or T lineages was observed. The majority of early lymphoid cells, however, appeared to lack c-kit expression. This was confirmed by the finding that only 4% of c-kit+CD34+ cells showed terminal deoxynucleotidyl transferase (TdT) activity, compared with 25% of the c-kit-CD34+ cells.

CFU-mix are no better than CFU-GM in predicting hemopoietic reconstitutive capacity of peripheral blood stem cells collected in the very early remission phase of acute nonlymphoblastic leukemia.

High levels of circulating myeloid progenitor cells (CFU-GM) occur during the very early remission phase of acute nonlymphoblastic leukemia (ANLL). Autologous stem cell rescue using blood cells collected during this phase has shown that successful hemopoietic reconstitution can be achieved, but a higher CFU-GM dose appears to be required than when bone marrow cells are used. This suggests that during very early remission, the level of marrow repopulating pluripotent stem cells (PSC) in blood does not undergo the same amount of increase as does the CFU-GM. This study set out to determine whether the levels of the multilineage progenitor cell (CFU-Mix) would be better indicators of the PSC in these cells than the CFU-GM. Serial peripheral blood CFU-Mix and CFU-GM measurements were carried out in six ANLL patients during very early remission. The levels of peripheral blood CFU-Mix showed a mean 12-fold increase, as compared to a mean 20-fold increase in the CFU-GM. The timing of the increase in the CFU-Mix paralleled that of the CFU-GM. These findings suggest that the CFU-Mix is no better than the CFU-GM in predicting PSC levels during very early remission of ANLL, and is closer to the CFU-GM than to the PSC in ontogeny.

Transplantation with selected autologous peripheral blood CD34+Thy1+ hematopoietic stem cells (HSCs) in multiple myeloma: impact of HSC dose on engraftment, safety, and immune reconstitution.

OBJECTIVE: The aims of our study performed in myeloma were to evaluate the performance and the safety of Systemix's high-speed clinical cell sorter, to assess the safety and efficacy of deescalating cell dose cohorts of CD34+Thyl+ hematopoietic stem cells (HSCs) as autologous grafts by determining engraftment, and to assess the residual tumor cell contamination using polymerase chain reaction (PCR) amplification assays of patient-specific complementarity determining region III (CDR III) analysis for residual myeloma cells. MATERIALS AND METHODS: The clinical trial was performed in 31 multiple myeloma patients, using purified human CD34+Thyl+ HSCs mobilized from peripheral blood with cyclosphosphamide and granulocyte-macrophage colony-stimulating factor to support a single transplant after high-dose melphalan 140 mg/m2 alone (cohort 1) and with total body irradiation (TBI) (cohorts 2-5) after an HSC transplant cell dose de-escalation/escalation design. RESULTS: Twenty-three patients were transplanted. Engraftment data in the melphalan + TBI cohorts confirmed that HSC doses above the threshold dose of 0.8 x 10(6) CD34+Thy1+ HSCs/ kg provided prompt engraftment (absolute neutrophil count >0.5 x 10(9)/L day 10; platelet count >50 x 10(9)/L day 13). A higher rate of infections was observed in the early and late follow-up phases than usually reported after CD34+ selected or unselected autologous transplantation, which did not correlate with the CD34+Thy1+ HSC dose infused. Successful PCR for CDR III could only be performed in five patients on initial apheresis product and final CD34+Thy1+ HSC product and showed a median tumor log reduction >3.12. CONCLUSIONS: CD34+Thy1+ HSCs are markedly depleted or free of detectable tumor cells in multiple myeloma and are capable of producing fast and durable hematopoietic reconstitution at cell doses >0.8 x 10(6) CD34+Thy1+ HSCs/kg. The delayed immune reconstitution observed is not different from that described in unselected autologous bone marrow and peripheral blood mononucleated cells transplants in multiple myeloma and may be corrected by addition of T cells either to the graft or to the patient in the posttransplant phase.

Long-term effects of cancer treatment and consequences of cure: cancer survivors enjoy quality of life similar to their neighbours.

To assess the long-term effects of cancer treatment and consequences of cure, 102 index cancer cases were compared with 95 neighbourhood controls of similar age and sex and with 78 cardiac controls. The quality of life experienced by these three groups was examined using multiple instruments with proven psychometric properties. All the major quality of life domains (physical, psychological and social) were covered. The findings revealed that the index cases were similar to their neighbours in areas of subjective well-being. However, the index cases exhibited more sexual dysfunction, were more conscientious, determined and emotionally disciplined, and applied the defence mechanisms of displacement and reaction formation more often than the neighbourhood controls. The cardiac controls were older, more anxious, more conventional/less imaginative and used suppression as a defence mechanism to a greater degree than the index cases. In conclusion, young adult cancer survivors enjoy a quality of life similar to their neighbours, whereas coronary bypass survivors adjust less well psychosocially.

Residual leukemia cannot be detected in very early remission peripheral blood stem cell collections in acute non-lymphoblastic leukemia.

We have used a combined cell culture and cytogenetic approach to study the level of residual leukemia during the very early remission (VER) phase of acute non-lymphoblastic leukemia. Clonogenic leukemic cells were induced to proliferate by phytohemagglutinin-stimulated leucocyte conditioned medium and identified by a leukemia-associated karyotype t(8;21) and a morphological marker (Auer rod). When leukemic blasts were cultured, the leukemic karyotype and Auer rods were most readily detected after 3-9 days. When VER blood cells were cultured, no leukemia-associated karyotype or Auer rods could be detected. Based on the number of VER blood cell derived metaphases analysed, the incidence of leukemic blasts among dividing cells is less than 2%.

A differential sensitivity to recombinant human interferon-alpha 2a between normal and chronic myeloid leukaemic peripheral blood granulocyte-macrophage colony-forming units.

The sensitivity to recombinant human interferon-alpha 2a (IFN) of peripheral blood granulocyte-macrophage colony-forming units (PB CFU-GM) from patients with chronic myeloid leukaemia (CML) was studied in a semi-solid clonogenic assay, and compared with normal PB CFU-GM. Like normal PB CFU-GM, the growth of CML PB CFU-GM in vitro was found to be dependent on the plating concentration used. The optimal CFU-GM growth occurred when CML PB mononuclear cells (MNC) were plated at low concentrations in the range of 0.01-0.1 x 10(5)/ml, compared to the range of 0.3-3.0 x 10(5)/ml optimal for CFU-GM growth in normal subjects. The optimal plating concentration for CML PB CFU-GM was similar to that observed in PB collected from patients with ovarian carcinoma during haematological recovery following chemotherapy-induced myelosuppression (recovery phase). The recovery phase PB was used as a source of non-leukaemic cells with a higher incidence of CFU-GM similar to that of CML. IFN produced a dose-related inhibition of CFU-GM growth in normal, recovery phase ovarian carcinoma and CML, PB MNC. The IFN concentration required to inhibit 50% of the CFU-GM in culture (LD50) was found to be significantly influenced by the plating concentration. When cells were cultured at 1.0 x 10(5) MNC/ml the mean LD50 for 7 CML patients was similar to that in normal (n = 5) or recovery phase (n = 5) peripheral blood, 273 i.u./ml, 1047 i.u./ml and 795 i.u./ml, respectively. In contrast when CML cells were cultured at 0.03 x 10(5) MNC/ml the concentration for optimal CML CFU-GM growth, the mean LD50 was significantly lower than that in normal PB and recovery phase PB, 4 i.u./ml, 251 i.u./ml and 78 i.u./ml, respectively (p less than 0.05). This is the first report of a differential sensitivity to IFN between CML and non-CML progenitors using an optimized PB CFU-GM assay system and proposes that further study of the in vitro culture of CML progenitors may increase our understanding of the clinical effects of IFN.

Bone marrow biopsy during induction chemotherapy for acute myeloid leukaemia identifies only 50% of patients with resistant disease.

A study was carried out to determine whether bone marrow biopsy performed on day 6 of induction therapy for acute myeloid leukaemia (AML) can identify those patients with resistant disease who would need an intensification of the first course of induction. Bone marrow biopsies were performed on day 6 of induction chemotherapy in 44 patients with AML treated with daunorubicin, cytosine arabinoside and thioguanine. Biopsies were assessed for blast count, trephine cellularity and leukaemic index. Discrimination between patients who went on to achieve remission and those with resistant disease was best achieved using the reduction in bone marrow cellularity from pretreatment marrow to day-6 marrow. However, this discriminator identified only 50% of the patients with resistant disease and included 13% of patients who achieved remission with the first course of chemotherapy. The other parameters of response were even less effective at discriminating between chemotherapy-resistant and chemotherapy-responsive disease.

Expression of a 150-kD cell surface antigen identified by monoclonal antibody YB5.B8 is associated with poor prognosis in acute non-lymphoblastic leukaemia.

Peripheral blood specimens, obtained from 71 patients with newly-diagnosed acute non-lymphoblastic leukaemia (ANLL) prior to the initiation of therapy, were assayed for the presence of a myeloid leukaemia-associated cell surface antigen identified by monoclonal antibody YB5.B8. The antibody bound to cells from 22 patients, and these patients had a poorer overall survival rate than those whose cells failed to bind the antibody (p less than 0.025). Fifty patients were treated with daunorubicin/cytosine arabinoside/6-thioguanine (DAT) according to a standard protocol and survived at least to the end of the induction phase (7 days). Of the 34 patients whose cells were YB5.B8 negative, 28 obtained a complete remission. In contrast, only four of the 16 patients whose cells expressed YB5.B8 antigen obtained complete remission (p less than 0.001). Expression of the YB5.B8 antigen in ANLL appears to be a strong prognostic indicator which is independent of other known prognostic factors such as patient age, leucocyte count and pre-existing hematopoietic abnormality.

Human interleukin 4 regulates the phenotype of lymphocytes generated during mixed lymphocyte culture and inhibits the IL-2-induced development of LAK function in normal and leukaemic cells.

This study examined the immunoregulatory role of recombinant interleukin 4 (IL-4), also known as B-cell stimulating factor 1, on the generation of cytotoxic effector cells from normal and leukaemic human blood mononuclear cells. When tested on cells from normal individuals, the addition of IL-4 to mixed lymphocyte cultures led to a dose-dependent proliferation of T-helper cells (CD3, 4 positive) with a concomitant decrease in phenotypic and functional cytotoxic T cells and natural killer (NK) cells. IL-4 also inhibited the interleukin-2 (IL-2)-induced generation of lymphokine-activated killer (LAK) activity when added at the beginning of mixed lymphocyte culture. When tested on mature leukaemic NK cells, IL-4 also inhibited the ability of IL-2 to induce LAK function using a short-term culture system. These results show that IL-4 acts on both normal and leukaemic cells and suggests that it acts at more than one level during the development of LAK function.

What's new in blood progenitor cell autotransplants?

Autotransplants of blood progenitor cells are increasingly used in persons with cancer, sometimes added to bone marrow cells but increasingly in their stead. Clearly, transplants of blood progenitor cells accelerate hematopoietic recovery after high-dose therapy. However, because some residual recipient-derived hematopoiesis typically persist even after the most intensive therapy, it is not certain that long-term hematopoiesis is from the blood progenitor cell autograft. However, this issue may be unimportant since the immediate goal is short-term recovery of bone marrow function regardless of which cells are responsible for long-term recovery. This issue is, however, of considerable import were more intensive treatment to be used or where blood progenitor cells were to be used for allografts. There are some reasons to think that transplants of blood-derived cells might have a lower likelihood of returning cancer cells to the recipient, at least in some lymphomas and solid tumors, than an autotransplant of bone marrow cells. This notion is as yet unproven and may be important only when and if more effective anti-cancer pretransplant regimens are developed. The potential role of transplants of blood progenitor cells depends on how useful autotransplants prove. Whether use of blood progenitor cells rather than bone marrow cells offers any advantage requires considerable additional data and controlled trials.

Blood stem cell transplants come of age.

In this report we review meeting highlights. Clearly there has been substantial progress in the laboratory and clinic with regard to blood stem cells. Having proven that these transplants work, it is now time to investigate biologic features in greater detail. Also needed are randomized trials evaluating several of the issues we raise such as whether the better results of blood cell autotransplants are due to more effective treatment or subject selection and whether in vitro removal of tumor cells is necessary or effective.

Blood cell transplantation: report from an International Consensus Meeting.

An International Consensus Meeting on blood cell transplantation took place in Heemskerk, The Netherlands on 27-29 June 1994. The term 'blood cell transplantation' was preferred to peripheral blood stem cell transplantation. The following issues were addressed: stem cell assessment and ex vivo expansion, techniques for stem cell mobilization, applications of blood cell transplantation, malignant cell contamination and allogeneic blood cell transplantation.

Peripheral blood stem cells mobilized from patients with acute myeloid leukaemia have different platelet repopulating abilities compared with those mobilized from patients with other diseases.

Peripheral blood stem cell (PBSC) transplantation gives rapid recovery of neutrophils and platelets and sustained haemopoiesis. However in patients with acute myeloid leukaemia (AML) platelet recovery has a distinctive rapid rise and then secondary fall between 3 to 8 weeks post-transplant. This study compares platelet and neutrophil recovery after PBSC transplantation in 15 patients with AML and 29 patients with other diseases consecutively transplanted in a single unit. PBSC were collected during recovery from consolidation chemotherapy in AML patients and after cyclophosphamide or cytokine administration in the other patient groups. Mononuclear cell numbers collected were similar but CFU-GM numbers were greater from the AML patients. A significant secondary fall occurred only in the platelet count and only in AML patients. Long-term recovery of the platelet count was the same in AML as in the other patients. In AML patients, the fall was the same in the long term remitters as in those who eventually relapsed. Previous studies have not, demonstrated a difference in type of precursors mobilized by differing methods, but have not included AML patients. Megakaryocyte precursors were assayed in this study and showed no consistent differences in number between patient groups however pre-progenitor assays are not yet established especially in the megakaryocytic lineage. The possible explanation for this secondary fall in AML patients is discussed.

Immune reconstitution following peripheral blood stem cell transplantation, autologous bone marrow transplantation and allogeneic bone marrow transplantation.

The rate and pattern of recovery of total lymphocytes, T cell subsets, B cells and NK cells were compared for 12 months following recovery phase peripheral blood stem cell (PBSC) autotransplantation (n = 49), autologous (n = 7) and allogeneic BMT (n = 11). The PBSC group had a significantly faster recovery of total lymphocyte count, total T cells (CD3+ cells), CD8 cells and CD4 cells than the allogeneic BMT group. The pattern of earlier recovery of CD8 cells than CD4 cells was the same for each type of transplant. Reconstitution following autologous BMT was intermediate between PBSC and allogeneic BMT. Multivariate analysis identified type of transplant, number of mononuclear cells transplanted and conditioning regimen as significantly influencing immune recovery.

Evaluation of a monoclonal IgM antibody for purging of bone marrow for autologous transplantation.

A monoclonal antibody of the IgM class, reacting with the CD9 (p24) antigen is described. The antibody (FMC27) is cytotoxic against cells of the common type of acute lymphoblastic leukaemia (c-ALL), giving killing at higher dilutions than an IgG antibody (FMC8) against the same antigen. FMC27 and FMC8 recognise different epitopes, and FMC27 may thus be used in a cocktail together with FMC8 and an antibody against the c-ALL antigen, WM21. Furthermore, the IgM antibody can be coated directly onto magnetic microparticles for magnetic purging, unlike the IgG antibody which must be used in a two-layer procedure.

Peripheral blood stem cells collected in very early remission produce rapid and sustained autologous haemopoietic reconstitution in acute non-lymphoblastic leukaemia.

Haemopoietic reconstitution was achieved in a patient with acute non-lymphoblastic leukaemia (ANLL) in relapse who was autografted with blood-derived stem cells collected during very early remission. The patient received a myeloid progenitor cell dose of 230 x 10(4) CFU-GM/kg body weight. Engraftment was evident in the bone marrow 7 days post-graft. Normal neutrophil and platelet counts were attained by day 14 and blood counts remained normal thereafter. An overshoot in peripheral blood haemopoietic progenitor levels occurred at the end of the second week, presumably the progeny of a family of early progenitor cells. The completeness of haemopoietic reconstitution is further illustrated by the satisfactory nucleated cell and myeloid progenitor cell yield when a bone marrow harvest was performed 4 1/2 months post-graft. Seven months post-graft, the patient remained in complete remission with normal blood counts and bone marrow cellularity, although haemopoietic progenitor levels were slightly reduced. The rapid recovery minimises aplasia-related risks and suggests that such autografting can be carried out safely in first remission. We propose that autografting using very early remission blood cells is a new therapeutic option for patients with acute ANLL.