Maintenance therapy in childhood acute myeloid leukemia.

PURPOSE: To determine whether, after very intensive induction and consolidation therapy in childhood AML, further maintenance therapy (MT) confers any advantage. PATIENTS AND METHODS: Three hundred-nine children with previously untreated AML were registered in the LAME 89/91 protocol. This three-cycle intensive regimen included an induction phase (mitoxantrone plus cytarabine) and, for non-allografted patients, two consolidation courses, one containing timed-sequential high-dose cytarabine, asparaginase and amsacrine. In the LAME 89 study, patients were given an additional MT consisting of mercaptopurine and cytarabine for 18 months. In the LAME 91 trial, patients were randomized to be given or not MT after consolidation therapy. RESULTS: Out of 309 patients, 276 (90%) achieved a complete remission. The overall survival (OS) and event-free survival at 6 years for all patients were 60% +/- 6% and 48% +/- 6%, respectively. For the complete responders after consolidation therapy, the 5-year OS was significantly better in patients randomized for no further treatment than in patients randomized for MT (81% +/- 13% vs 58% +/- 15%; p = 0.04) whilst the 5-year disease-free survival was not significantly different (60% +/- 19% vs 50% +/- 15%; p = 0.25). The improvement of OS in MT-patients appeared to be related to a higher salvage rate after relapse. CONCLUSION: Over 50% of patients can be cured of AML in childhood. In the context of a very short and drug-intensive regimen, low-dose MT, owing to the lack of improvement in disease control and the worsening of survival, should not be recommended. Over the past 20 years, the outcome of acute myeloid leukemia (AML) in children has improved substantially. In the eighties, complete remission (CR) was achieved in nearly 90% of patients but event-free survival (EFS) was poor. Myeloablative therapy followed by allogenic bone-marrow transplantation (allo BMT) from an HLA-identical sibling was demonstrated, in our experience, to be the treatment of choice for improving DFS in children with AML in first remission. The major issue was how best to maintain complete remission for patients without an HLA sibling donor. Whereas several groups continued to include low-dose MT and others decided to omit it, in 1991, our group undertook a prospective randomized trial (LAME 91 protocol), the main aim of which was to assess the efficacy of MT in addition to an intensive induction and consolidation chemotherapy. The main results have been published previously and are now updated and described in a higher number of patients.

All trans retinoic acid abrogates spontaneous monocytic growth in juvenile chronic myelomonocytic leukaemia.

INTRODUCTION: All trans retinoic acid, the active metabolite of vitamin A, exerts profound effects on cell differentiation. On normal myeloid progenitors, retinoids switch the differentiation program of granulo-macrophagic progenitors towards the granulocytic lineage and consequently reduce CFU-M colony formation. Bone marrow and peripheral blood mononuclear cells from children with Juvenile Chronic Myelomonocytic Leukaemia show typical spontaneous monocytic growth. We questioned whether in this disease, retinoids could switch myelomonocytic growth and inhibit the abnormal CFU-M colony proliferation. METHODS: Ten JCML samples were studied in the presence of ATRA in methyl cellulose colony assay, before (CFU-C) or after (pre-CFU) liquid suspension culture. RESULTS: In vitro characteristics of JCML such as spontaneous monocytic growth in the absence of growth factor was noted in all patients. In the presence of leucocyte-conditioned medium, nine samples showed only CFU-M growth and one sample CFU-GM growth. Incubation with ATRA inhibited CFU-M colony formation in nine cases. Enhancement of granulocytic differentiation (CFU-G) was noted in nine cases. ATRA also inhibited CD34+ JCML monocytic growth and GM-CSF hypersensitivity. CONCLUSION: These data suggest that, in JCML progenitors, retinoid pathways are functional and inhibition of immature monocytic progenitors cells may be achieved with retinoids, without impeding granulocytic cell growth.

Early secondary acute myelogenous leukemia in breast cancer patients after treatment with mitoxantrone, cyclophosphamide, fluorouracil and radiation therapy.

BACKGROUND: The topoisomerase II-targeted drugs, epipodophyllotoxins and anthracyclines, have been shown to induce therapy-related AML (t-AML) characterized by a short latency period after chemotherapy, the absence of prior myelodysplastic syndrome and stereotyped chromosome aberrations. Few reports have been published on patients treated with the anthracenedione mitoxantrone which also targets topoisomerase II. We observed 10 cases of such t-AML over a 7-year-period in breast cancer patients treated with mitoxantrone combined with fluorouracil, cyclophosphamide and regional radiotherapy, and in three cases with vindesine. PATIENTS AND METHODS: We retrospectively analyzed patients referred to our hospital for AML with a past history of polychemotherapy for breast cancer, including mitoxantrone, either as adjuvant (8 patients)/neoadjuvant (1 patient) therapy or for metastatic disease (1 patient). We studied the probability of developing t-AML in a prospective series of 350 patients treated with an adjuvant FNC regimen (mitoxantrone, fluorouracil, cyclophosphamide) and radiation therapy. RESULTS: The median age was 45 years (range 35-67). t-AML developed 13-36 months (median 16) after beginning chemotherapy for breast cancer, and 4-28 months (median 10.5) after ending treatment. As described in t-AML following treatment with epipodophyllotoxins or anthracyclines, we found a majority of FAB M4, M5 and M3 phenotypes (7 of 10), and characteristic karyotype abnormalities that also can be found in de novo AML: breakpoint on chromosome 11q23 (3 patients), inv(16)(p13q22) (2 patients), t(15;17)(q22;q11) (1 patient), t(8;21)(q22;q22) (1 patient) and del(20q)(q11) (1 patient). The prognosis was poor. All patients died of AML shortly after diagnosis. Since two patients had been enrolled in a prospective trial for the treatment of breast cancer which included 350 patients, the probability of developing t-AML was calculated to be 0.7% from 25-40 months, using the Kaplan-Meier method (95%, confidence interval (95% CI): 0.1-4.5). CONCLUSIONS: The combination of mitoxantrone with cyclophosphamide, fluorouracil, and radiation therapy can induce t-AML, as with other topoisomerase II-targeted drugs. Despite a low incidence, the prognosis appears to be poor.

Use of recombinant human granulocyte colony-stimulating factor to increase chemotherapy dose-intensity: a randomized trial in very high-risk childhood acute lymphoblastic leukemia.

PURPOSE: To determine whether the use of a recombinant human granulocyte colony-stimulating factor ([G-CSF] lenogastrim) can increase the chemotherapy dose-intensity (CDI) delivered during consolidation chemotherapy of childhood acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Sixty-seven children with very high-risk ALL were randomized (slow early response to therapy, 55 patients; translocation t(9;22) or t(4;11), 12 patients). Consolidation consisted of six courses of chemotherapy; the first, third, and fifth courses were a combination of high-dose cytarabine, etoposide, and dexamethasone (R3), whereas the second, fourth, and sixth courses included vincristine, prednisone, cyclophosphamide, doxorubicin, and methotrexate (COPADM). G-CSF was given after each course, and the next scheduled course was started as soon as neutrophil count was > 1 x 10(9)/L and platelet count was > 100 x 10(9)/L. CDI was calculated using the interval from day 1 of the first course to hematologic recovery after the fifth course (100% CDI = 105-day interval). RESULTS: CDI was significantly increased in the G-CSF group compared with the non-G-CSF group (mean +/- 95% confidence interval, 105 +/- 5% v 91 +/- 4%; P <.001). This higher intensity was a result of shorter post-R3 intervals in the G-CSF group, whereas the post-COPADM intervals were not statistically reduced. After the R3 courses, the number of days with fever and intravenous antibiotics and duration of hospitalization were significantly decreased by G-CSF, whereas reductions observed after COPADM were not statistically significant. Duration of granulocytopenia was reduced in the G-CSF group, but thrombocytopenia was prolonged, and the number of platelet transfusions was increased. Finally, the 3-year probability of event-free survival was not different between the two groups. CONCLUSION: G-CSF can increase CDI in high-risk childhood ALL. Its effects depend on the chemotherapy regimen given before G-CSF administration. In our study, a higher CDI did not improve disease control.

A new serologic index for low-grade non-Hodgkin's lymphoma based on initial CA125 and LDH serum levels.

BACKGROUND: Serum CA125 (sCA125) was recently reported to be of clinical value in the staging and follow-up of patients with non-Hodgkin's lymphoma (NHL). This report aims to investigate the prognostic value of a new serologic index combining sCA125 and LDH serum levels. PATIENTS AND METHODS: One hundred thirty-seven patients were studied, sixty-three with histologically proven low-grade NHL, and seventy-four with a high-grade subtype. RESULTS: sCA125 and LDH levels were elevated in more than one third of patients. sCA125 was more frequently increased than LDH in low-grade NHL. In this group, complete remission (CR) was achieved in 87, 45, and 0% (P = <2 x 10(-6)) of patients with normal sCA125 and LDH serum levels (Low-risk group), one parameter increased (Intermediate-risk group), and increased sCA125 and LDH serum levels (high-risk group), respectively. The estimated five-year overall survival was 97%, 67% and 22% for low, intermediate, and high-risk groups, respectively. This combination was the only parameter predictive of RFS and OS in multivariate analysis (P < 0.0001). CONCLUSIONS: In this study the combination of s-LDH and sCA125 levels (normal vs. abnormal) was found to be an important prognostic factor in low-grade lymphoma and may be used in the selection of appropriate therapeutic approaches for individual patients.

Prediction of methotrexate elimination after high dose infusion in children with acute lymphoblastic leukaemia using a population pharmacokinetic approach.

High-dose methotrexate (HD-MTX) with leucovorin rescue is a component of therapy in children with acute lymphoblastic leukaemia. Since MTX toxicity is related to drug exposure, a monitoring of serum MTX concentrations at H24, H48, H72 and until the concentration is less than 0.2 micromol/L is commonly performed. However, a number of patients may reach concentrations of less than 0.2 micromol/L long before the next sampling is scheduled. The aim of our study was to develop a Bayesian method predicting the time at which MTX concentration reaches 0.2 micromol/L in order to decrease the number of samples drawn and to allow for a more rapid patient discharge. Methotrexate population parameters were estimated from a retrospective analysis of 60 infusions in 23 children and MTX concentrations were predicted from an independent set of 20 courses in 14 children with a Bayesian approach using either one (H48) or two (H24 and H48) samples. The following population parameters were obtained using a two-compartment model: CL = 3.51 L/h (inter-individual variability: 66%), Vd = 8.67 L (58%), k12 = 0.0044 h(-1)(105%), k21 = 0.039 h(-1)(25%). Clearance and Vd were found to increase with weight and age respectively. Both sampling schedules tested for the Bayesian estimation enabled accurate prediction of concentrations and provided satisfactory precision despite a small bias. When considering the ability to predict the time at which the threshold was reached, the one-sample (H48) schedule gave the best results. We conclude that a sampling schedule involving only one sample and Bayesian parameter estimation may be able to predict the delay necessary to reach 0.2 micromol/L in each individual.

Intensive therapy with autologous stem cell transplantation as first-line therapy in poor-risk Hodgkin's disease and analysis of predictive factors of outcome.

The value of high-dose therapy with autologous stem cell transplantation as first-line therapy in poor prognosis Hodgkin's disease is controversial and we report the results of evaluation of twenty-six patients who were selected for this procedure from February 1989 to July 1994. They were all patients with stage IV at diagnosis with at least two other unfavourable characteristics, i.e. B symptoms, mediastinal mass greater than 0.45 of the thoracic diameter, two or more extranodal sites, bone marrow involvement, inguinal node involvement, serum lactic dehydrogenase greater than 400 IU/L, or low hematocrit. At the time of transplantation, 19 patients were in complete remission and 10 were in partial remission > or = 50%. Procedure-related mortality in the first 90 days post-graft was 7% overall. Of the 24 evaluable patients, 22 (92%) were assessed as complete responders, and 2 (8%) had progression of disease at 6 months. The actuarial overall survival (OS), disease-free survival (DFS) and event-free survival (EFS) at 5 years were 69%, 79% and 58%, respectively. The Cox proportional hazards model was used to assess prognostic factors. In univariate analysis only one prognostic factor was found to be significantly associated with improved DFS, i.e. low serum lactic dehydrogenase (LDH) (DFS at 5 years: 92% if LDH < 400 IU/L vs 44% if LDH 400 IU/L, P = 0.007). DFS rates between first complete remission and first partial remission groups were not significantly different (DFS at 5 years: 87% vs 66%, p = 0.15). These first results are encouraging but randomized studies are needed.

CD5 negative B-cell chronic lymphocytic leukemia: clinical and biological features of 42 cases.

Chronic lymphocytic leukemia cell (CLL) usually (95%) express B-phenotype and the CD5 antigen which is usually present on the surface of normal T cells. However, among B CLL, 7 to 20% do not express CD5. The significance of the lack of CD5 expression remains unclear. We reviewed 42 consecutive CD5- B CLL seen in three French medical centers from 1985 to 1991 and compared them with 79 CD5+ B CLL. Immunophenotype studies were performed using indirect immunofluorescence under light microscopy as well as flow cytometry after 1988. B CLL was considered to be CD5 negative when less than 5% of mononuclear cells expressed CD5 after subtraction of the number of T-cells. Cases with CD5- B CLL had isolated splenomegaly more frequently (p = 2.10(-7)). They frequently expressed a higher level of surface immunoglobulin (S-Ig) or the switch mu/delta phenotype (p = 4.7 10(-2)). The median survival time was not reached but no significant difference between CD5 negative and positive B CLL was observed at the time of our data analysis (p = 0.97). Clinical presentation of CD5- B CLL seems to be different from other forms of B CLL. Although, no conclusion can be reached in terms of prognosis, CLL with low expression of CD5 should be regarded as a subtype of CLL with a different clinical presentation than CD5+ CLL.

Mediastinal large-cell lymphoma with sclerosis refractory to conventional chemotherapy can respond after daily oral cyclophosphamide.

Mediastinal large-cell lymphoma with sclerosis (MLCLS) is a distinctive subtype of non-Hodgkin's lymphoma (NHL) with unique clinicopathology aspects and aggressive behavior. Prompt diagnosis and aggressive chemotherapy followed by consolidation radiotherapy may result in long-term survival in the majority of cases. However, a subset of patients do not respond to first-line or salvage treatment and have a poor prognosis. We report here a 27-year-old man with MLCLS resistant to several conventional chemotherapies and to radiotherapy who achieved a very good partial remission after one year's treatment with daily oral cyclophosphamide (100 mg/day). This is the first report of refractory MLCLS with good response to daily oral cyclophosphamide. This case suggests that daily oral monochemotherapy might be beneficial for some patients with mediastinal large-cell lymphoma with sclerosis refractory to conventional intravenous chemotherapies and radiotherapy.

Granulocyte-macrophage colony-stimulating factor accelerates hematopoietic recovery after autologous bone marrow or peripheral blood progenitor cell transplantation and high-dose chemotherapy for lymphoma.

The use of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) as an adjunct to autologous bone marrow transplantation (ABMT) or peripheral blood progenitor cell (PBPC) transplantation was evaluated in 59 lymphoma patients. Patients were divided into three groups. In group I (n = 21) patients received rhGM-CSF (5 micrograms/kg daily) at the time of PBPC collection and during the recovery phase post-infusion. In group II (n = 12) patients received rhGM-CSF as an adjunct to ABMT. In group III (n = 26) they were grafted with bone marrow without rhGM-CSF. Administration of rhGM-CSF (groups I and II) significantly reduced the time to myeloid engraftment, the number of febrile days and the median duration of antibiotics administration and of hospital stay when compared with the group in which patients did not receive rhGM-CSF. The only difference between ABMT and PBPC, given with rhGM-CSF support, was observed in the duration of hospitalization (group I > group II, P < 0.05). These data show that rhGM-CSF is highly effective in reducing the duration of aplasia following BMT and PBPC transfusion, and there appears to be little difference in efficacy between these techniques, provided that patients also receive rhGM-CSF.

Induction chemotherapy followed by allogeneic bone marrow transplantation or aggressive consolidation chemotherapy in childhood acute myeloblastic leukemia. A prospective study from the French Society of Pediatric Hematology and Immunology (SHIP).

In the LAME89/91 protocol, children with acute myeloid leukemia (AML) who achieved complete remission (CR) after induction chemotherapy, were treated either with allogeneic bone marrow transplantation (BMT) if they had an HLA-compatible related donor or with chemotherapy including high-dose cytarabine. The objectives of this study were to describe the overall results of this strategy and to compare the two post-remission arms. Two hundred and thirty-one children were enrolled in the protocol. Induction chemotherapy consisted of a combination of cytarabine and mitoxantrone. A CR was achieved in 204 children (88%).

High-dose therapy and autologous bone marrow transplantation in first complete or partial remission for poor prognosis Hodgkin's disease.

We report the experience of three French centres which evaluated high-dose therapy (HDT) as consolidation therapy for poor prognosis Hodgkin's disease (HD). From March 1986 to April 1990, 23 consecutive patients with poor prognosis stage IV HD underwent HDT followed by autologous bone marrow transplantation (ABMT) after achieving either complete remission (CR1) or good partial response (GPR1) (reduction mass> 75%). The median age was 31 years (range 18 to 55 years), 14 were male. All patients except one initially had at least 2 poor prognosis factors such as: systemic symptoms (n = 19), bulky tumor (n = 16), more than one extranodal site (n = 9), bone marrow involvement (n = 5), lymphocyte count < or = 1.10(9)/1 (n = 8) and biological stage B (n = 21). All patients had previously been treated with alternating MOPP/ABVD. Ten patients were in GPR1 and 13 in CR1 before transplant. The conditioning regimens were: CBV (n = 17), BEAM (n = 5), BEAC (n = 1) followed by bone marrow rescue. Radiotherapy was introduced just before the conditioning regimen for 6 patients or after ABMT for 5 patients. Nine of 10 patients in GPR1 achieved CR after ABMT but one died early of treatment-related toxicity. Five of 22 patients who were in CR posttransplant, relapsed (3, 4, 4, 18, 36 months). Seventeen patients remain alive in continuous CR with a median follow-up of 60 months (range: 30-100 months). The overall survival (OS) and disease-free survival (DFS) projected at 5 years are 92% and 77% respectively. Consolidation by HDT and ABMT proved to be well tolerated. An international trial is currently underway to attempt to demonstrate a clear benefit on survival for this subset of poor prognosis HD patients.

Tolerance evaluation of L-asparaginase loaded in red blood cells.

OBJECTIVE: A pilot clinical study was conducted to evaluate the toxicity of a single dose of L-asparaginase loaded in red blood cells (RBCs). METHODS: Thirteen patients received a single dose of L-asparaginase in the range 30-200 i.u.kg-1. The enzyme was loaded in one autologous blood unit using a lysis-resealing process. A control population of 33 patients receiving L-asparaginase intravenously were tested in parallel. IgG, IgM and IgE class anti-L-asparaginase antibodies were detected using specific radioimmunoassays. RESULTS: L-Asparaginase pharmacodynamic parameters may be greatly improved by administration of the drug after internalisation in RBCs as compared to intravenous injection of free drug. The drug elimination was prolonged and similar to that of circulating carrier. After one injection of 30 i.u.kg-1, plasma L-asparagine was eliminated in 10 days and this was extended to 50 days for 150-200 i.u.kg-1. The drug was well tolerated and only transient variations were observed for some of the biological parameters measured. We did not reach the maximum tolerable dose (MTD) of L-asparaginase loaded in RBCs. No significant clinical toxicity was detected. In particular, no immune adverse effects were observed. CONCLUSION: This study opens new perspectives for the clinical utilisation of L-asparaginase. This mode of administration of the drug is able to improve pharmacodynamic parameters and enzymic efficacy and to increase the general tolerance of the treatment.

Improved pharmacodynamics of L-asparaginase-loaded in human red blood cells.

To evaluate the modification of pharmacodynamic parameters induced by the administration of L-asparaginase loaded into red blood cells, 13 patients received a single dose of L-asparaginase internalised into the carrier. The enzyme was loaded using a reversible lysis-resealing process. The dose per patient ranged from 30 to 200 i.u. kg-1. Considerable heterogeneity occurred between patients. the level of L-asparaginase circulating after 24 h represented 47% of the total injected dose as compared to 74.8% for red blood cells (RBCs). However, the half-life of the enzyme remaining in the circulation was very similar to that of the RBC carrier, i.e. 29 days and 27 days, respectively, compared with 8-24 h for the free enzyme. Sustained elimination of plasma L-asparagine occurred, the duration of which was dependent on the injected dose. A single injection of 30.i.u.kg-1 was sufficient to eliminate plasma L-asparagine over 10 days. With 150-200 IU.kg-1 the elimination period was extended to 50 days. These data show that the use of RBCs as carriers of L-asparaginase greatly improves the pharmacodynamic parameters of the drug.

Long-term cultures to evaluate engraftment potential of CD34+ cells from peripheral blood after mobilization by chemotherapy with and without GM-CSF.

In this study we used a long-term culture system to evaluate engraftment potential of human peripheral blood (PB) cells mobilized by chemotherapy (CT) associated or not with granulocyte-macrophage colony-stimulating factor (GM-CSF). In six patients who underwent blood cell transplantation, PB CD34+ cells were cultured after mobilization and were compared to CD34+ cells in steady state from PB and bone marrow (BM). Qualitative differences were shown between PBC samples obtained after CT with and without GM-CSF. Despite similar CFU-GM counts at culture initiation, GM-CSF-mobilized CD34+ cells might contain a lower proportion of primitive stem cells, as suggested by the significant decrease in CFU-GM numbers produced beyond week 5 compared to CT-mobilized CD34+ cells (p = 0.033). Likewise, the percentage of CFU-GM produced beyond week 5 in relation to initial input was significantly lower than steady-state PB (p = 0.039) and than CT-mobilized CD34+ cells (p = 0.033). However, this CFU-GM production with GM-CSF-mobilized PB CD34+ cells was not different from cultures with BMC CD34+ cells. These results suggest that GM-CSF can mobilize CFU-GM in the blood mainly by differentiation at the expense of the primitive stem cell compartment. It appears valuable to define clearly for each mobilizing procedure a particular threshold of CFU-GM which reflects sufficient numbers of primitive stem cells to ensure long-term engraftment.

VAD-PECC regimen in the treatment of advanced-stage multiple myeloma.

PURPOSE: This prospective study was undertaken to evaluate the efficacy of combination chemotherapy with alternating cycles of vincristine, doxorubicin, and dexamethasone (VAD) and prednisone, vindesine, carmustine, and cyclophosphamide (PECC) in poor-risk multiple myeloma (MM). PATIENTS AND METHODS: Forty-four patients were previously untreated; 36 had been pretreated with an alkylating agent-containing regimen and had refractory or relapsed MM. All previously untreated patients had a high tumor burden at inclusion (stage III according to the Durie and Salmon classification). Logistic regression and the Cox proportional hazards models were used to assess the association between patient characteristics and response rate and survival, respectively. RESULTS: The overall response rate was 68% for previously untreated patients, compared with 54% for previously treated patients (P = .16). The median survival time for all patients was 28 months: 53 months in previously untreated patients, and 18 months in previously treated patients. Univariate analysis showed that the predictive factors that had a significant affect on survival in the newly diagnosed patients were age, therapeutic response to VAD-PECC, low pretreatment Karnofsky score, high baseline serum beta 2-microglobulin (beta 2M) level, bone marrow impairment, and renal insufficiency at the start of treatment. When these parameters were used as continuous variables in multivariate analysis, three were found to correlate with survival: serum beta 2M, followed by therapeutic response and Karnofsky score. In the previously treated group, only Karnofsky score entered the Cox model. CONCLUSION: These results indicate that combination VAD-PECC chemotherapy is an effective treatment that results in high response rates and long-term survival in advanced MM.

Haemopoiesis of transplanted patients with autologous marrows assessed by long-term marrow culture.

We assessed the effect of antitumoural therapy at intensive doses on the haemopoietic system using long-term marrow cultures (LTMC) established from 33 patients (25 with haematological diseases and eight with solid tumours) after autologous bone marrow transplantation (ABMT). When compared to 42 pre-graft patients, a decreased CFU-GM production and a defect in stromal layer (SL) confluence were found after ABMT on day 90 but also on day 365. However, these abnormalities were observed only in patients with haematological diseases and no differences between pre-graft and post-graft results were found in patients with solid tumours. Among the patients with haematological diseases, on day 90 those with acute lymphoid leukaemias showed lower CFU-GM production whereas patients with non-Hodgkin's lymphomas developed more frequently subconfluent or confluent SL. Other factors studied such as sex, patient age, disease status, marrow purging and post-graft administration of growth factors did not appear to influence post-graft LTMC results. Multivariate analysis including all the patients has shown (a) that solid tumours were associated with higher CFU-GM production, and (b) that conditioning regimens with total body irradiation (TBI) or busulfan led more frequently to non-confluent SL. In conclusion, high-dose therapy followed by ABMT can induce a persistent impairment of the stem cell and stromal cell compartments, particularly in patients with haematological diseases conditioned with TBI, despite the absence of any alloimmune reaction and post-graft immunosuppressive therapy.

Successful blood stem cell collection and transplant in children weighing less than 25 kg.

Peripheral blood stem cells (PBSCs) were collected for autotransplantation in 20 children (median age 4 years, range 0.5-10 years) weighing < 25 kg (median 14.5 kg, range 6.8-24 kg) with various malignant diseases: leukemias and lymphomas (n = 6), solid tumours (n = 14). Cytaphereses were carried out after standard chemotherapy (n = 10), mobilizing high-dose chemotherapy (n = 9) or radiotherapy alone (n = 1). In 13 children PBSCs were harvested after haematopoietic growth factor (HGF) administration. PBSCs were collected using a continuous flow blood separator (Cobe Spectra). In 13 patients access was through a central catheter with peripheral venous return, in 4 patients access was through a central catheter with return through a femoral catheter; one patient had femoral catheter access with peripheral venous return and two patients had both access and return through peripheral veins. For 19 patients the extracorporeal line was primed with red blood cells. The median blood flow rate was 13.8 ml/min (range 7-22 ml/min). Sixty-six procedures (mean 3.3/patient, range 1-4) were performed with a mean total collection time of 8.5 h. The median number of granulocyte-macrophage colony-forming units (CFU-GM) collected was 37.7 x 10(4)/kg (mean 107 x 10(4)/kg, range 1.05-882 x 10(4)/kg). The number of CFU-GM collected per procedure in children with HGF was 7.8-fold higher than in children without HGF (median 20.4 versus 2.6 x 10(4) CFU-GM/kg body weight, respectively). There were no consistent effects on peripheral blood counts except on platelet counts which decreased following each procedure (median decrease in platelet count was 36%).(ABSTRACT TRUNCATED AT 250 WORDS)