Commitment and differentiation of hematopoietic stem cells are associated with the progressive restriction of cellular proliferation and the progressive expression of a subset of genes encoding the markers of mature cells. These two processes are genetically regulated and, in this paper, I review the expression and function of the GATA family of transcription factors as an example of this genetic regulation. GATA cis-acting elements are found in most of the regulatory regions of T-lymphoid, erythrocytic and megakaryocytic restricted genes. These GATA motifs are recognized by the members of a family of transcriptional regulators: the GATA family. Three members of this family, GATA-1, 2 and 3 are expressed in hematopoietic cells. They are necessary for the erythrocytic and megakaryocytic lineages (GATA-1), for the T-lymphoid lineage (GATA-3), and for the proliferation of uncommitted hematopoietic precursors (GATA-2). GATA-1 displays at least four functions: activation of the erythrocytic and megakaryocytic specific genes, regulation of the epsilon-->gamma globin switch and control of the cell cycle. These two last functions will be discussed to show the multiple facets of GATA-1 in the genetic regulation of hematopoiesis.

The recent observations that osteoblasts develop from a stem cell found in the medullary stroma suggest that, as already suspected in classical histological studies, many consolidation mechanisms are based on bone marrow. Since cells characteristics can now be studied in tissue culture, it has become possible to investigate the activity of the bone marrow in non union. The working hypothesis for this study was: if the bone marrow plays a part in bony callus formation, bone marrow from non union site should manifest anomalous activity whatever the origin of the focus sampled. Therefore, the aim of this study was to seek in vitro, using cell cloning techniques, anomalies of bone marrow from non union site.

The first studies on intensive chemotherapy for metastatic breast cancer conducted in the 80s were disappointing. Despite good response rates, the duration of remission was short and long-term survivals exceptional. Nevertheless, these phase I and II trials helped to develop a better understanding of the potential indications of this new therapeutic approach and apprehend its technical aspects. Over the last 5 years, considerable progress has been made in grafting techniques and hematopoietic support greatly improving the safety of the method. Notwithstanding the financial considerations involved, it must be noted that the efficacy autologous stem cell support, in terms of recurrence-free overall survival, has not yet been demonstrated although the (controversial) results of two randomized controlled trials have recently been published. In France, the PEGASE programs for the study of autologous stem cell support in breast cancer have been developed in an attempt to elucidate the question.

Pulmonary blastoma is a rare malignant tumor. A new case is reported in a 3 years 6 month-old girl. An apparent clinical remission was first obtained after a surgical treatment followed by a conventional chemotherapy during six months. Afterwards the persistence of a microscopic residual pulmonary disease lead us to deliver successfully an intensive chemotherapy followed by autologous peripheral blood stem cells reinjection. The child remains disease free 12 months after graft. Problems set by the histogenesis of this tumor, its unspecific clinical and paraclinical features and the role of conventional and intensive chemotherapy followed by autologous bone marrow transplantation are discussed on the basis of a review of 50 cases in the literature.

The decisions of health authorities concerning adverse effects of drugs are usually notified following clinical observations, but are rarely associated to experimental data. The haematopoietic tissue is one of the most sensitive to these effects. In order to anticipate and to explain adverse effects, it becomes necessary to carry out in vitro assays on normal human haematopoietic progenitors. We had the opportunity to use human cord blood progenitors which are able to repopulate allogeneic aplastic bone marrow. Many advantages are associated with this model: numerous samples, non-invasive, absence of species bias, possibilities of mechanistic approach. The clonogenic potential of progenitors in soft agar, as well as their ability to expand in liquid medium after stimulation with specific growth factors, have been used. Evidence of dose-related toxicity by inhibition of colony formation or proliferation was analysed in the presence of reference molecules. Results were reproducible despite an intrinsic variability of progenitor density between samples. They were comparable to assays on bone marrow progenitors reported by us and others. Comparison of toxicity thresholds with plasma therapeutic ranges showed the potential risk for some molecules tested.

Originally developed against the effects of ionizing radiations, amifostine is an organic thiophosphate compound shown able to selectively protect normal tissues against cytotoxic agents in cellular and animal models, without protecting tumor tissues. Amifostine is a prodrug which is dephosphorylated into its active metabolite, a free thiol derivative, by membrane alkaline phosphatase of the target issue. This unique metabolism supports its cellular selectivity and its preferential uptake by normal tissues. In phase II clinical trials, a decreased toxicity has been demonstrated in patients given alkylating agents; however, reduction of the response has not been observed. On the basis of these results, a prospective, randomized, phase III study has been conducted in patients with ovarian carcinoma receiving a combination of cisplatinum and cyclophosphamide. A significant decrease in hematologic, renal and neurologic toxicity was observed in the amifostine-treated patients compared with the control group, and response rates did not significantly differ between the two groups. Insufficient or emerging data are only available for other applications, including either in vitro manipulation of hematopoietic grafts or in vivo treatment of non-Hodgkin's lymphoma, head and neck carcinoma, non-small cell lung cancer and radioprotection. No data are yet available in regard to the potential protective effects of amifostine against mutagenicity and cancerogenicity of both chemo- and radiotherapy.

The purpose of the present study was the detection of tumor cells in aphereses after mobilization of peripheral blood stem cells (PBSCs) with G-CSF from 39 breast cancer patients. Circulating tumor cells were searched using sensitive immunocytochemical technique (APAAP) with three anticytokeratin monoclonal antibodies. Counting of mononuclear cells and CD34 progenitor cells was also performed. Circulating tumor cells were detected in 35% of the patients. Cytokeratin-positive cells were detected in 45% of the patients of the metastatic group compared with 20% of the non metastatic one. Aphereses contamination was not correlated with lymph node involvement. Numbers of mononuclear cells and CD34 cells were not significantly different in positive and negative PBSCs collections. In our study, presence of tumor cells was associated with advanced clinical stage and could not be related to a higher CD34 cells mobilization by G-CSF.

The aim of this study was to determine the value of haematological counts at the 4th day of a chemotherapy cycle, in order to foresee neutro and/or thrombocytopenia during the same chemotherapy cycle. One hundred and ten cycles of chemotherapeutic regimens with carboplatin (400 mg/m2, dl) and 5-fluorouracile (1 g/m2/d, by iv continuous infusion for 96 hours) every 3 weeks, were analyzed for 42 patients with locally advanced but non metastatic squamous cell carcinoma of head and neck, without prior chemotherapy. Lymphocyte counts were significantly decreased at the 4th day but normalized at the 8th day (P < 10(-6)). Decreases of lymphocyte and neutrophil counts at the 4th day were significantly correlated to grade > 2 neutropenia. The positive predictive value of lymphocyte or neutrophil counts is about 50% for some cut-off values but not high enough, with the schedule of chemotherapy in our study, to justify the systematic prophylactic therapy with haematopoietic growth factors.

Since the first radiation accidents which resulted in severe health effects in the workforce or the population, great progress has been made in the fields of diagnosis, prognosis and treatment of accidentally overexposed victims. Since then, progress has also been made in the medical management of diseases such as aplasia. Because of the relative scarcity of radiation accidents, there is a need for complementary researches, in order to take advantage of new techniques and medical approaches. After whole body overexposure, the key issue is the therapeutic decision, ie, the choice between bone marrow transplantation and other strategies. The indications of bone marrow transplantation cover only a short range of doses, provided the exposure is distributed uniformly within the body. The last accidental overexposures which happened in the world have demonstrated the possible efficiency of haematopoietic growth factors, most of them being still under clinical trials. Actions based on these various approaches are summarized, as well as the lessons which have been learned.

Transduction and expression of a transgene in hematopoietic stem cells with retroviral vectors still remain major challenges for gene therapy in blood disorders. Use of an easily detectable gene marker, such as the nlsLacZ, at the laboratory and clinical levels, provides a powerful approach of these two combined problems.

Autologous bone marrow transplantation for the treatment of gynecologic tumors in adults remains an uncommon therapeutic approach. The feasibility of such high-dose therapies is clearly proved, especially with the advent of hematopoietic growth factors and the rescue by the peripheral stem cells to reduce the duration of the chemotherapy-induced myeloid aplasia. The question is to exactly define the place of high-dose therapy in the land of solid tumors. In the treatment of poor prognosis breast cancer, high-dose therapy with autologous bone marrow transplantation or with peripheral stem cells support is able to convert some patients with partial response into complete responders. However, the consequences on overall survival and disease-free survival are not convincing. For metastatic breast cancer and for poor-prognosis tumors (inflammatory breast cancer, axillary metastatic nodes > or = 8), the interest of high-dose therapy has to be determined by randomized studies. These studies are ongoing in USA and in France. For the treatment of poor-prognosis ovarian cancer, the situation is more difficult to appraise. Randomized studies have to be done to precisely define the interest of high-dose therapy in terms of response and disease-free survival for the treatment of ovarian carcinomas.

The aim of this study, carried out at the Institut Paoli-Calmettes (Marseille-France), was to compare, in terms of monetary and non monetary costs, alternate procedures for hematopoietic stem cells collection i.e. peripheral blood stem cells collection (PBSCC) and bone marrow collection (BMC) used in cancer therapies. Monetary costs have been evaluated by calculating the direct costs of the two types of procedures and non monetary costs by comparing anxiety, discomfort and pain of cancer patients submitted to PBSCC or BMC. Patients, randomized (7/1993-2/1994), in view of autologous transplantation, to receive the first procedure or the second one received three self-administered questionnaires to complete before, during and after the procedure. Pain was assessed using visual analogical scale and McGill Pain questionnaire. Anxiety was evaluated by means of State-Trait Anxiety Inventory. Results showed that, under some conditions, presently realized in the current practice, direct costs of PBSCC (10,140 to 13,780 FF) were lower than BMC ones (16,509 FF) and that anxiety and pain experienced by patients submitted to PBSCC, with or without femoral catheter, were significantly less severe than in other group patients (State anxiety, before procedure : p < 0.01 ; pain related to the procedure assessed on VAS : p < 0.001 and total McGill score : p < 0.00001). These findings justify the substitution of bone marrow transplantation by peripheral blood stem cells transplantation, provided there is a demonstration of similar medical efficacy for cancer therapy.

Megakaryocytopoiesis concerns the commitment of hematopoietic stem cells towards the megakaryocyte lineage, the proliferation and maturation of megakaryocyte progenitors, leading to platelet formation. Normal megakaryocytopoiesis requires an equilibrium between positive and negative regulators. Thrombopoietin, recently cloned, is the main growth factor for the megakaryocyte lineage, enhancing all the steps of megakaryocyte development: proliferation, maturation, ploidisation, platelet formation. Several other factors have a direct (interleukin 3, 6, 11, 13, GMCSF, erythropoietin) or indirect (interleukin 1, stem cell factor) positive effect. Factors inhibiting megakaryocytopoiesis are synthetized by the megakaryocytes themselves (platelet factor 4, transforming growth factor beta), or have many other effects (alpha-interferon, thrombin) or correspond to a novel molecule (anagrelide). Heparin and other glycosaminoglycans positively modulate megakaryocytopoiesis by acting synergistically with some growth factors and by neutralizing some inhibitors. These progresses in the knowledge of normal and pathological megakaryocytopoiesis should lead to considerable therapeutic advances.

The study analysed the financial benefits of transplantation with peripheral blood stem-cells primed after chemotherapy and growth factor in comparison with bone marrow transplantation. Twenty-three consecutive transplantations were performed during one year: 14 peripheral blood stem-cell (CSC group) and 9 bone marrow transplantations (MO group). No differences in patients characteristics were seen between the two groups except for higher number of "BEAM" conditioning in CSC group. Were analyzed delay in neutrophil and platelet recovery, numbers of days in hospital, with fever, under antibiotics, costs of supportive therapy, stem-cell collection and cryopreservation. Difference was significant for duration of neutropenia with advantages in CSC group, but the number on days in hospital, with fever or under antibiotics were similar. Number of platelet transfusions was reduced in CFC group: this economical advantage was lost with the cost of growth factor used for priming stem-cells stem-cell collections and cryopreservations. In our retrospective study, financial advantages associated to peripheral blood stem-cell transplantation was not verified.

Over the ten past years, we performed 336 apheresis among 51 children who were 19 months to 15 years old (10 to 30 kg body weight). 3 types of apheresis were carried out. 14 red blood cell exchange, 293 plasma exchanges and 29 peripheral blood stem cell collections (CSP). 5 different types of continuous or discontinuous flow machines have been used. Technical adaptations depending on patient blood volume, hematocrit, type of machine used and apheresis performed permitted us to obtain a very good tolerance and acceptability. According us, the apheresis should be used each time this treatment is needed in the child, because of the very low frequency of side effects.

Immunological transfusion reactions more than often lead to an activation of the complement proteins and mononuclear cells, inducing a haemolysis from which stem the observed clinical symptoms. In the case of incompatibility, the alloantibodies can lead to an immediate reaction, taking place in the first few minutes or, in the case of a delayed reaction, arising after 24 hours. A standardized clinical and biological evaluation is necessary in order to confirm the diagnosis and to assess the consequences of the antigen-antibody conflict.