Abstract: Bone marrow aplasia observed following ionizing radiation exposure (Total Body Irradiation; gamma dose range: 2-10 Gy) is a result, in particular, of the radiation-induced (RI) apoptosis in hematopoietic stem and progenitor cells (HSPC). We have previously shown in a baboon model of mobilized peripheral blood CD34+ cell irradiation in vitro that RI apoptosis in HSPC was an early event, mostly occurring within the first 24 hours, which involves the CD95 Fas pathway. Apoptosis may be significantly reduced with a combination of 4 cytokines (4F): Stem Cell Factor (SCF), FLT-3 Ligand (FL), thrombopoietin (TPO), and interleukin-3 (IL-3), each at 50 ng x mL(-1) (15% survival versus <3% untreated cells, 24 h post-irradiation at 2.5 Gy). In this study we show that addition of TNF-alpha(800 IU/ml) induces an increase in 4F efficacy in terms of cell survival 24 h after incubation (26% survival after 24 h irradiation exposure at 2.5 Gy) and amplification (k) of CD34+ cells after 6 days in a serum free culture medium (SFM) (kCD34+ = 4.3 and 6.3 respectively for 4F and successive 4F + TNF-a/ 4F treatments). In addition, the 4F combination allows culture on pre-established allogenic irradiated stromal cells in vitro at 4 Gy (kCD34+ = 4.5). Overall this study suggests (i) the potential therapeutic interest for an early administration of anti-apoptotic cytokines with or without hematopoiesis inhibitors (emergency cytokine therapy) and (ii) the feasibility in the accidentally irradiated individual, of autologous cell therapy based on ex vivo expansion in order to perform autograft of residual HSPC collected after the accident.

Bone marrow grafting following accidental irradiation exposure should be viewed in the perspective of a severe myeloablative syndrome linked to high medullary damage for a dose range higher than 6-8 Gy, resulting in very late or no recovery. Prognosis will depend on the presence or absence of radio-combined injuries, the toxicity of the transplant procedure, and the risk of rejection induced by insufficient percritical immunosuppression. It is in this context that new cell therapy modalities, which combine enhanced peripheral hematopoietic cell engraftment and high immunosuppressive conditioning regimen with low extrahematological toxicity, inducing early and stable mixed lymphomyeloid chimerism with minimal morbidity, can be considered. Such an approach is being evaluated in the treatment of patients with hematological malignancies at high risk of transplant-related mortality using conventional bone marrow methods.

Transplantation of autologous skeletal muscle cells (myoblasts) into post-infarction scars is intended to restore some functionality in these akinetic areas. This concept is now validated by a large number of experimental studies and the preliminary results of a phase 1 human trial. Several issues however still need to be addressed: critical analysis of myoblasts in comparison with other cell types, in particular bone marrow stem cells; optimization of delivery techniques and cell survival following engraftment; mechanisms by which transplanted cells may affect overall cardiac function and possible extension of the indications to non ischemic cardiomyopathies. Only carefully controlled clinical studies, based on sound experimental data, will allow to address these questions and to define the place cell therapy may have within our armamentarium of techniques designed to ameliorate the prognosis of patients with severe heart failure.

In the adult mammalian brain, neuroblasts are continuously produced within the subgranular zone of the hippocampus and the subventricular zone (SVZ) of the forebrain. In this review we describe how some physiological and environmental factors play important roles in regulating neurogenesis in the hippocampus. Neuroblasts in the SVZ network migrate rostrally into the olfactory bulb where they differentiate into local interneurons. We focus on the production, survival and functional consequences of these newly generated interneurons. We show that enriched odor-exposure enhances the number of newborn neurons in the adult olfactory bulb but not in the hippocampus. This effect did not result from changes in cell proliferation but rather was due to greater neuronal survival. Furthermore, the enriched condition was found to dramatically extend the olfactory memory. By maintaining a constitutive turnover of interneurons subjected to regulation by bulbar activity, ongoing neurogenesis plays a key role in olfactory memory.

A number of years ago several groups reported that Interleukin 10 (IL10) was vigorously overproduced in disseminated lupus erythematosus (reviewed in Llorente et al., 2000). This hyperproduction obeys two different patterns. In one pattern, IL10 serum concentrations become elevated during disease and evolve in parallel with them. In the other, the patients' blood mononucleated cells spontaneously release increased IL10 quantities; contrary to serum variations in the first pattern, this increased output is not correlated with disease spurts. Interestingly an increase of this type is frequently found in disease-free parents of these patients (Llorente et al., 1997; Gröndal et al., 1999). Some studies relate this IL10 hyperproduction to a genetic origin (Mehrian et al., 1998; Mok et al., 1998), while others seem to indicate an environmental cause (Gröndal et al., 1999). Together these findings suggest two different possible origins for lupus IL10 overproduction. The first would be due to intrinsic anomalous IL10 production by some immune cells, the second would result from high IL10 output by tissues damaged by the inflammatory process. Considering the properties of IL10, which activates B lymphocytes and inhibits T lymphocytes, overproduction in lupus could explain the immune anomalies of this disease, which is characterized by anti-self antibodies production and by deficient T responses. Interestingly several of these anomalies are found independently from disease outbreaks and, in the case of some, in relatives of patients. The part played by IL10 in lupus has been inferred from the murine NZB-W model, in which an anti-IL10 monoclonal antibody prevents development of the disease (Ishida et al., 1994); this antibody also prevents the appearance of human anti-ADN autoantibodies in immune-deficient mice restored with patients' lymphocytes. A direct demonstration of the role of IL10 in the etiology of lupus symptoms has recently been adduced in a pilot study bearing on six lupus patients, refractory to anti-inflammatory and immuno-suppressive treatments, who were treated for 3 weeks with a murine anti-IL10 monoclonal antibody (Llorente et al., 2000). This treatment brought about a rapid amelioration of the clinical picture, in particular of the cutaneous and articular symptoms, which was maintained for six months after this trial. This symptomatic amelioration was accompanied by a decrease of the biological signs of immune system hyperactivity and a partial amelioration of T lymphocyte function. The better clinical control of the disease allowed a significant decrease of corticotherapy. While this was an open study, without a control group and without randomisation, the rapid and important evolution of clinical and biological parameters towards normal strongly pleads for a favorable effect of the treatment. While confirming previous hypotheses about the rote of IL10 in lupus, this study leaves several points unexplained. First the clinical and biological amelioration in these patients treated with anti-IL10 monoclonal antibody occurred independently of circulating anti-ADN auto-antibodies, indicating that the role of this interleukin in the disease is more complex than could be thought from the initial experiments in mouse. This unexpected result does not exclude that the beneficial effect of the antibody could be mediated by its action on B lymphocytes, since it is well known that these cells play important parts in development auto-immune processes other than only the production of auto-antibodies. It is also possible that the negative effect of IL10 in this disease exerts on other targets than B lymphocytes, in particular on fibroblasts and endothelial cells. Indeed it should be recalled that, while IL10 has often been held as an anti-inflammatory cytokine, its biological properties are more ambiguous, since it can immuno-stimulate some cell types. Among other remaining unknowns, the reason why some IL10 overproducing individuals, belonging to the family of lupus patients, do not develop lupus, is not understood. This fact underlines the multi-factorial origin of this disease, which must stem from associated genetic and environmental causes. IL10 overproduction, while it apparently promotes the symptoms, is certainly not sufficient. The efficiency of anti-IL 10 monoclonal antibodies during lupus, which are well tolerated, points to their usefulness in the therapeutic arsenal, especially in forms that are refractory to conventional anti-inflammatory and immunosuppressive treatments. In order to be validated, this hypothesis must be submitted to more in depth, randomized, studies. Moreover humanized antibodies should be developed, which would make it possible to reiterate the treatment during further outbreaks. Once all these conditions are fulfilled, the place of anti-IL10 treatment in lupus and the benefice-risk ratio should be compared to these of therapeutic approaches currently used in refractory forms. If further studies confirm the efficiency of- and tolerance to- IL10 neutralizing antibodies in lupus, it is well possible that these antibodies will eventually equate, for this disease, the recent use of TNF antagonists in the treatment of rheumatoid arthritis.

On one hand, self-renewal of mouse embryonic stem (ES) cells rely exclusively upon the LIFR beta/gp130-signaling pathway and the subsequent activation of the STAT3 transcription factor. On the other hand, the much-studied cellular machinery, that is organized to collect extracellular signals, transduce them via tyrosine kinase receptors and the SOS-RAS-RAF-MEK-MAPK pathway, ultimately leading to regulation of D-type cyclin expression, while regulation of the retinoblastoma (RB) protein phosphorylation is likely not to be operative in ES cells. We hypothetize that ES cells are blinkered by the lack of RB-dependent control of the G1/S transition, and that commitment into differentiation triggers the birth of a regulatable G1 phase. We discuss how the LIFR beta/gp130-signaling pathway and the ES cell-cycle machinery may functionally interact to promote self-renewal.

Myelodysplastic syndromes are clonal diseases of the hematopoietic stem cell with normal or increased bone marrow cellularity and peripheral cytopenias. Pathophysiology of these diseases is complex with frequent ras mutations, a growth defect of immature progenitors mainly erythroid progenitors, and increased apoptosis of differentiated cells. This growth defect could be linked to (1) a resistance to hematopoietic cytokine stimulation although, erythropoietin receptor expression and functionality are normal and/or (2) increased susceptibility to apoptosis due to overexpression of the death domain receptor Fas on CD34+, CD33+ and GPA+ cells. Stromal cells are thought to produce increased quantities of inhibitory cytokines such as TNF-alpha, TGF-beta, IFN gamma et IL-1. Better understanding of MDS pathophysiology is required for applying adequate therapy either blocking apoptosis or stimulating hematopoiesis.

It is essential to approach the question of protection of human life from a legal point of view, because the developments in reproductive biology and the new research fields on the embryo and the so called 'stem' cells, imply the establishment of new laws. This is a real challenge, since to infer rights to the onset of life means that the embryo or the foetus has to have a status. The European Ethics Group has to provide propositions concerning the ethical aspects of embryo research, related to research on the 'stem' cells. In fact, Europe is confronted with several problems related to the cultural, legal and religious pluralism and the market regulations. Reflections on embryos must no longer be based on the search of means to improve reproduction techniques, but on their use as simple cell producers. Some suggestions can be made in favour of a mutual European approach to bioethics: research and medicine devoted to the onset of life must be submitted to strict public control; the status of the embryo must be clarified; recommendations have to be drawn-up regarding so-called 'therapeutic' cloning; and International laws concerning bioethics must be established.

Over a period of 2 months, a 60-year-old man, a chicken breeder, experienced low back pain, lower limb weakness predominant on the right side, and urinary difficulties, leading progressively to a flaccid paraplegia with sphincter impairment. Concomitant poor cognitive performances were noted. MRI showed enlargement of the conus terminalis, with a low-intensity signal on T1-weighted images, high-intensity signal on T2-weighted images, and areas of intramedullar contrast enhancement. A biopsy of the lesion showed macrophages containing yeast cells, with PAS and Grocott staining aspects compatible with the presence of Histoplasma capsulatum (Hc). A brain MRI showed multiple localizations in the brain stem and in both hemispheres with associated edema. Disseminated histoplasmosis was confirmed by a biopsy of a sub-maxillary ganglion demonstrating a necrotic tuberculoid lymphadenitis containing yeast cells resembling Hc. Immune tests disclosed the presence of HTLV1 anti-bodies without immunodeficiency nor HIV co-infection. An anti-micotic treatment was started 2 weeks after surgery, with intra-venous amphotericin B, for 21 days, followed by itraconazole, orally for 90 days. Cognitive functions improved significantly in 5 weeks while paraplegia and sphincter impairment remained unchanged. Seven months later, cerebral MR aspects dramatically improved while the conus medullaris lesion diminished, and the edematous component disappeared in all areas. Even though histoplasmosis is endemic in our region, CNS localization is rare, generally in disseminated forms associated with immunodeficiency. Brain granulomas are well-known, but spinal cord histoplasmomas are exceptional: only four cases have been evaluated by MRI. Unlike our case, spinal cord forms generally improve, due to surgery associated with antifungus medication, or sometimes due to specific medical treatment alone but with sufficient dosage.

Improvements in the chemotherapeutic and transplant regimens have had a significant impact in improving survival rates for pediatric leukemia. However, there are still major problems to address including what options are available for patients with chemoresistant disease and what strategies are available to avoid toxicity associated with highly cytotoxic treatment regimens. Gene and immunotherapy protocols hold great promise. Using gene transfer of a marker gene, a number of biologic issues in the therapy of leukemia have been addressed. For example, by gene marking autologous bone marrow grafts it has been possible to demonstrate that infused marrow contributes to relapse in acute and chronic myeloid leukemias. In the allogeneic transplant setting, genetically modified T-cells have proven valuable for the prophylaxis and treatment of viral diseases and may have an important role in preventing or treating disease relapse. Gene transfer is also being used to modify tumor function, enhance immunogenicity, and confer drug-resistance to normal hematopoietic stem cells. With the continued scientific advancements in this field, gene therapy will almost certainly have a major impact on the treatment of pediatric leukemia in the future.

Amniotic membrane's unique combination of properties including the facilitation of migration of epithelial cells, the reinforcement of basal cellular adhesion and the encouragement of epithelial differentiation [6] together with its ability to modulate stromal scarring and its anti-inflammatory and anti-bacterial activity has led to its use in the treatment of ocular surface pathology as well as an adjunct to stem cell grafts of the corneal limbus [6-4]. We report a prospective study of 30 patients so treated.

In a 70 year old man with primary glomerulonephritis, severe anemia occurred after 4 years on hemodialysis and rHu-EPO. The usual mechanisms of EPO-resistance were excluded. A bone marrow sample showed red all aplasia. No circulating EPO could be detected; the serum inhibited the growth of erythroid precursors in bone marrow cultures. Immunoprecipitation identified an IgG anti-EPO, still active against deglycosylated EPO, i.e. directed against the peptidic matrix. Its high neutralising capacity and the absence of any immune abnormality rule out an auto-antibody. Anti-rHu EPO immunisation is a very rare occurrence, made severe by transfusion-dependence and the risk of hemosiderosis. An immuno-modulating treatment can therefore be justified.

Allogeneic stem cell transplantation is able to cure many hematologic malignancies, through, at least partially, a graft versus disease effect of the donor's immune system transfer. However, the toxicity of this technique limits its use to selected patients. The aim of non-myeloablative stem cell transplantation is to reduce the toxicity of the conditioning regimen while allowing the engrafement of donor's stem cells and the immunological antitumoral activity of the donor's immune system. Several reports have already demonstrated the validity of this concept. This new multi-step therapeutic strategy is complex, raises many questions and deserves further studies to be fully applicable to a greater number of patients.

The beginning of this century was marked, in our specialty as in other, by two revolutions: the routine use of molecular biology tools for a better prognosis of the disease (flt3 receptor duplication in AML, mutational profile of Ig genes in CLL, gene expression profile with ARN chips in aggressive lymphomas.), and the discovery of "intelligent" molecules, targeting the tumoral cell. In this category, the most appealing is the STI571 (Gleevec , Novartis), targeting the molecular abnormality of the cells expressing bcr-abl protein: CML, ALL Ph1(+). Other molecules targeting signal transduction proteins (ras farnesylation inhibitors for example) are already in clinical trials. The increasing therapeutic use of monoclonal antibodies is also to be cited, with a special mention concerning the rituximab, used in several B lymphoid pathologies, from lymphoma to autoimmune diseases. His very good tolerance permits his use in ambulatory patients, and his combination with chemotherapy or his linkage with radioactive elements render this molecule indispensable. The other side of these molecules is their incredibly high cost, explaining the uncontrolled expenses in 2001 of hospitals hosting hematology as well as oncology activities.

Authors have selected and presented radiofrequency tissue ablation for primary renal tumors and cellular therapy with dendritic cells or nonmyeloablative allogeneic transplantation as the main results in 2000-2001 on renal cell carcinoma. Furthermore other points are developed as hypertension increasing the risk of renal cell carcinoma, chromosomal events until renal cell carcinoma and prognosis of incidentally detected tumors.

The aim of this work was to quantify by flow cytometry the main adhesion receptors on CD34+ cells. These cells were isolated from bone marrow (BM) or mobilized peripheral blood (PB). The proportions of CD34+/CD49d+ and CD34+/CD49e+ are weaker on PB cells, without quantitative expression variation. This phenotypic variation may induce CD34+ cells exist from BM into circulation, promoting the mobilization. The homing to the BM implicate the CD62L receptor, which expression was found more frequently and stronger on PB cells than on BM. The CD11b, CD18 and CD54 receptors are implicated in CD34+ cells adhesion to BM micro-environment. No significant variation in CD34+/CD11b+ and CD34+/CD18+ cells frequency was noted. Moreover, CD54 receptor was more frequently expressed on PB cells. Quantitative analysis revealed that CD18 was more strongly expressed on BM than on PB cells. This quantitative variation could promote progenitor adhesion by interacting with stromal cells. Finally, quantitative expression of the main receptors on CD34+ cells provides an original option for studying CD34+ cells during the mobilization, the homing or the adhesion to BM micro-environment.

Ovarian carcinoma is the worst gynecologic cancer due to an advanced stage at diagnosis in two thirds of the cases. Advanced stages are usually characterized by a large tumor burden on the ovaries as well as metastatic disease in the peritoneal cavity. Early stages are more common in young women and the surgical treatment should comprise the tumor excision and a comprehensive abdominal staging to be sure that there is no extension beyond the ovaries--unilateral oophorectomy can preserve the fertility before childbearing. No treatment is needed after surgery in stage I without poor prognostic factors. Adjuvant chemotherapy should be applied postoperatively in the other cases. The best likelihood of prolonged survival is observed after optimal debulking surgery and chemotherapy in advanced stages. If possible surgery should be performed at first but in most advanced stage with large tumor volume in the upper abdomen according to clinical and CT-scan examination, the concept of chemosurgical debulking should be considered. Interval surgery underwent after three or four courses of front line chemotherapy but this strategy should be further evaluated by clinical trials. Currently paraplatin associated with paclitaxel is the most commonly used regimen due to its effectiveness and lower toxicity. In a near future progress can be expected with new protocols. Thank to aggressive surgery and chemotherapy many patients should be able to reach a complete remission of their disease but most of them will still die of recurrent disease. At this point, two questions should be answered: 1) how to manage the residual abdominal disease in order to prevent the recurrence. No consolidation treatment demonstrated any superiority but the French experience and trial with high dose chemotherapy supported by autologous stem cells transplantation showed recently positive results? 2) How to manage the recurrent disease with sometime indication for secondary surgical debulking and always chemotherapy? This is the field for testing new drugs or new strategies. A large number of patients should enter clinical trials in order to answer these questions and due to the very poor prognosis of this disease large attention should be given to the quality of life of theses patients.

A reliable model, usable in vitro and in vivo, is necessary for analysis of processes engaged during cell death, regeneration and differentiation. The peripheral olfactory system is an attractive model for studying these processes through its dynamic neurogenesis that occurs continually throughout the lifetime.