Autologous blood stem cell transplantation (ABSCT) is a new technique which has been increasingly used in recent years. It is now well established that ABSCT can be performed as safely as autologous bone marrow transplantation (ABMT) when high numbers of hemopoietic precursors are infused. Multiple leukophoreses are performed during marrow regeneration following chemotherapy-induced aplasia. Hemopoietic recovery (predominantly the granulocytic series) is probably faster after ABSCT than after ABMT. Among other advantages there may be minimal contamination by residual tumor cells in buffy-coats; however, this has not been fully investigated.

Interleukin-3 induces an increase in histamine synthesis, in the murine hematopoietic system. Evidence is given here that this biological activity also exists in the human hematopoietic system (fetal liver, bone marrow and cord blood), and is already detectable after 3 days of culture in the presence of interleukin-3.

Microinjections of antibodies directed against the protein encoded by the c-myc protooncogene strongly inhibit or arrest the early cell cleavage stage of Xenopus laevis embryos. Injections in one blastomere of a two cell stage embryo inhibit the segmentation of this blastomere. The cleavage of the uninjected blastomere behaves normally. Injections of control rabbit immunoglobulins do not alter the embryonic development.

Cytokinins are biological proteins which permit the transmission of signals from one cell to another. These proteins are secreted by groups of specialized cells and are fixed on specific receptors on the surface of responding cells. However, since receptors may be widely distributed, and since the activation of a cell usually permits the release of other cytokinins and a succession of reactions, cytokinins have pleiotropic effects. Cloning of the genes encoding for these cytokinins and their obtention on a large scale by genetic recombination techniques have allowed a better understanding of their biological characteristics and their use in therapy. This cytokinin network is particularly wide in the hematopoietic and in the immune systems. In the present study, we describe the biological properties of the main interleukins and hematopoietic cell growth factors, together with their therapeutic applications, particularly in hemato-oncology.

The hematologic immediate toxicity during radiotherapy for Hodgkin's disease was studied from a series of 72 patients with stage IIB or III who received 3 courses or more of chemotherapy before radiotherapy. The toxicity in the group of 36 of them who received total nodal irradiation (TNI) was the most important. Sixteen of the 28 TNI had irradiation interrupted, 12 of them began with inverted Y type. The blood cells count at the beginning of the treatment was crucial; only 16% of the patients had interruption of irradiation when the blood cells count was normal; on the other side, 63% had interruption when the blood cells count was abnormal (P less than 0.05). Toxicity was due to the daily destruction of the dividing bone marrow stem cells located in the irradiated area, from the first day of treatment; there was a progressive decrease in the pool of these stem cells within a late resaturation. The absence of resaturation of this pool after initial chemotherapy and after the first part of irradiation explained the immediate and durable toxicity; in the same way, inverted Y irradiation destroyed a great part of active bone marrow (40%) and the pool of remaining stem cells with high mitotic index would be located in areas irradiated subsequently. So, waiting for the absolute normalisation of blood cells count before beginning irradiation and start irradiation by mantle field (rather than inverted Y) seem to be the 2 measures able to reduce the number of interruptions of irradiation due to hematotoxicity.

Six patients with acute non-lymphocytic leukemia underwent autologous transplantation of circulating stem cells collected during remission. They were given cyclophosphamide (120 mg/kg) and total body irradiation (1,000-1,200 rads) (five patients) or busulfan (16 mg/kg) and melphalan (140 mg/m2) before the transfusion of 6.7 X 10(8) nucleated cells/kg corresponding to 19.7 X 10(4) CFU-GM/kg. Granulopoietic engraftment was observed in every case and was influenced by the number of CFU-GM injected. Megakaryocytic recovery was obtained in four cases.

A 48 year-old patient with a myelosclerosis was operated from a cauda equina compression which had been revealed by bilateral sciatica. The epidural space was filled with extra-medullary hematopoietic tissue. The mechanism of epidural hematopoiesis is discussed.

A preliminary study of the culture of leukemic progenitor cells (CFU-L) from acute non-T lymphoblastic leukemia was undertaken for 25 patients (19 were considered in complete remission and 6 in the acute phase of the disease). Two culture systems were tested; a double layer agar-liquid phase and a single layer of methylcellulose. The major problem was the characterization of the colonies: immunological labelling coupled with cytofluorometry, as well as cytomorphology, cytogenetic and more recently molecular biology may allow the characterization of the CFU-L. The culture of CFU-L appears to be an efficient method for detecting residual leukemic cells which can be used to evaluate the quality of both the remission obtained and that of autologous bone marrow after purging.

Limiting dilution analysis, a technique which measures the ability of cells to form colonies in liquid media has been used to quantitative residual cells subsequent to treatment. The reliability of this in vitro test as a tool in the selection of process of bone marrow purging was examined. With conventional methods like release of 51Chrome a 2 log reduction could be evaluated, while a reduction of 4 log was assessed by limiting dilution analysis for a same treatment. However the sensibility of this method depends of several factors which we have been examined in this study.

Limiting dilution culture is a powerful tool for the quantification of residual clonogenic cells in the evaluation of a depletion procedure in bone marrow purging. The definition of suitable numerical indicators and the choice of the statistical technique for data treatment are of crucial importance. Most common techniques are presented and discussed. A standardization for data treatment is proposed.

Immune protection in vertebrates is provided by a dual system: the cellular immune response, mediated by T lymphocytes and the humoral immune response, mediated by B lymphocytes. These lymphocytes develop immunocompetence in the primary lymphoid organs: thymus, for the T lymphocytes and bursa of Fabricius (in birds), on its equivalent (in mammals), for B lymphocytes. The crucial period during which thymus and bursa influence the immunological development is the embryonic and early postnatal life. Hemopoietic stem cells home to these primary lymphoid organs during well-defined periods of colonization. Under the influence of thymic and bursal microenvironments, they become oriented respectively toward the T or B cell differentiation pathway. They acquire various membrane antigens and an antigen receptor. T lymphocytes also learn to recognize self-antigens (antigens encoded by the Major Histocompatibility Complex). T and B lymphocytes then colonize respectively T-dependent and B-dependent areas of secondary lymphoid organs where they become functional. Some immune deficiencies result from a defect in development which can affect selectively T or B lymphocytes or both systems in case of severe combined immunodeficiency disorders.

In a retrospective study, a DNA histogram was established from specimens obtained by cystectomy in 65 carcinomas of the bladder (stages pT1 to pT4, pN0, pN1 and pN2). Flow cytometry and automated photocytometry were systematically compared. Automated photocytometry makes it possible to differentiate between diploid, polyploid and aneuploid tumors. Among aneuploid tumors, the DNA content of tumor stem cells make it possible to identify another subgroup. The analysis of various tumor sections showed that the DNA histogram obtained by photocytometry was a stable and reproducible characteristic of the tumor. The subgroups of carcinoma of the bladder, determined by topology, have markedly different long-term prognoses. In contrast to automated photocytometry, flow cytometry did not allow for reproducible determination of the biologic characteristics of carcinoma of the bladder.

In cultures of normal mouse hematopoietic cells containing Interleukin-3 develop cells with many features of mast cells. These cells seem heterogeneous with respect to morphological and biochemical examination. Nevertheless, most of the cells show many granules and a low ability to self-renew. In the present report we describe the development of a blastic cell population, termed mastoblasts, when normal mouse hematopoietic cells are exposed continuously to retinoic acid (RA: 10(-6) to 10(-5) M/l). Using H*3-thymidine incorporation, cell cycle measurement and protein content by flow cytometry, transmission and scanning electron microscopy, we show that these cells seem to be of mast cell lineage but with a high self-renewing capability. So, RA is able to inhibit mast cell differentiation and to provide us a "mastoblastic" population which could be used as a model to study mast cell differentiation.

Peripheral blood stem cells were collected from 50 patients with different hematological malignancies. Leukaphereses (n = 263) were performed during the marrow regeneration phase following different types of chemotherapy. The mean number of CFU-GM collected per leukapheresis was 486 x 10(4), highest levels of CFU-GM being obtained in patients who received the most intensive chemotherapy and who had not been treated previously. Twenty-five patients underwent autologous blood stem cell transplantation. Hemopoietic recovery was complete and prompt in 24 patients. Only one patient had no megakaryocytic engraftment. These findings indicate that peripheral blood stem cells may be used for autologous transplantation in leukemic patients.