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We have previously shown that total T cells derived from lymph nodes (LN) involved by Hodgkin's disease (HD) secrete higher levels of colony-stimulating activity than total T cells present within benign hyperplastic (BH) LN and B-non-Hodgkin's lymphoma (B-NHL) LN, suggesting that T cells with particular properties accumulate in HD LN. To further characterize this T-cell population, we have quantified production of both granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) production in a total of 98 T-cell clones (TCC) derived from CD25+ activated T cells present in HD LN; TCC derived from CD25+ T cells obtained from B-NHL LN(101 TCC), BH LN(95 TCC), and peripheral blood (PBL; 38 TCC) of healthy donors were used as controls. HD LN were characterized by the presence of an elevated number (44%) of TCC producing particularly high titers of both GM-CSF and M-CSF, whereas only a minority of such TCC was found in control groups (10% in B-NHL, 16% in BH, 8% in PBL). These observations support the hypothesis of a selection of T-cell families with particular properties occurring in contact with Reed-Sternberg (RS) cells. According to the biological properties of GM-CSF and M-CSF, it seems reasonable to suggest the involvement of this particular subset of T cells in the granulomatous process, the peripheral blood polynucleosis, and in the paracrine growth of RS cells.

The murine myeloproliferative syndrome induced by the myeloproliferative sarcoma virus (MPSV) has numerous similarities to human primary myelofibrosis. We have shown that medium conditioned by spleen cells of MPSV-infected mice has the capacity to support the growth of primitive blast cell colonies. The detection of this activity associated with MPSV infection stimulated us to characterize the hematopoietins responsible for this activity. Northern blot analysis showed a large increase, or induction, of interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage-CSF (CSF-1), and granulocyte-CSF (G-CSF) transcripts in the hematopoietic organs of MPSV-infected mice; however, no IL-3 transcript could be detected in either MPSV-infected or normal mice. Significant levels of IL-1 alpha, IL-6, G-CSF, and CSF-1 bioactivities were found in the serum of MPSV-infected mice, but not in controls. Additionally, analysis of medium conditioned by spleen cells of MPSV-infected mice showed the presence of tumor necrosis factor alpha bioactivity. The increased production of cytokines that are able to stimulate pluripotent hematopoietic stem cells corroborates the hypothesis of a possible involvement of hematopoietic growth factors in the development of some myeloproliferative disorders.

Colony-stimulating factor 1 (CSF-1) is a cytokine involved in hematopoiesis and perhaps more importantly in the early stages of immunological defense mechanisms. Although numerous studies of in vitro CSF-1-producing cells have been published, in vivo data is totally lacking. According, we performed immunohistochemical detection of CSF-1-positive cells on frozen sections of reactive lymphadenitis (three cases) and Hodgkin's disease (13 cases) lymph node biopsies, using as antibody a highly specific polyclonal rabbit antiserum prepared in our laboratory. Endothelial cells from high endothelial venules and most fibroblasts were positive in all cases (reactive lymphadenitis and Hodgkin's samples), and most lymphocytes in interfollicular T cell areas showed faint granular positivity in reactive lymphadenitis lymph nodes. Hodgkin and Reed-Sternberg cells were positive in all cases tested, although staining intensity was highly variable and the percentage of positive cells differed from case to case. These data from in vivo biopsies confirm previous results for in vitro CSF-1 production by endothelial cells, fibroblasts, T lymphocytes, and Hodgkin cell lines. They are consistent with the role of this cytokine in immune response and raise the question of its significance in Hodgkin's disease.

Macrophage colony stimulating factor (CSF-1) is one of several cytokines that control the differentiation, survival, and proliferation of monocytes and macrophages. A set of 11 human T-cell clones, chosen for their phenotypic diversity, were tested for their ability to express CSF-1 mRNA. After 5 hours of stimulation with phorbol myristate acetate (PMA) + calcium ionophore (Cal), all T-cell clones expressed a major 4-kb transcript, a less abundant 2-kb transcript, and several other minor species. This pattern of expression is typical for CSF-1 mRNAs. Furthermore, of the two alloreactive T-cell clones analyzed, only one showed a definitive message for CSF-1 on specific antigenic stimulation, but with delayed kinetics and less efficiency. Both conditions of stimulation induced the release of CSF-1 protein by T cells in the culture medium. Together, these findings demonstrate for the first time that normal T cells are able to produce CSF-1, previous reports being limited to two cases of tumoral cells of the T-cell lineage.

A new growth factor, provisionally named vasculotropin (VAS), with a unique specificity for vascular endothelial cells has been purified to homogeneity. VAS is a 45 kDa glycosylated homodimeric protein. Cloning of the VAS gene has evidenced a sequence homology with A and B chains of Platelet-Derived Growth Factor. The receptor on vascular endothelial cells has been shown to be a 180 kDa protein. A 110 kDa receptor has been found on cells that do not respond to the mitogenic effect of vasculotropin, such as lens epithelial cells or corneal endothelial cells.

Angiogenesis is a key step in organ development and remodeling during embryogenesis or tissue regeneration. Some pathological events such as tumor growth or diabetic retinopathy also lead to angiogenesis formation. Several molecules have already been identified as promoting angiogenesis in vivo. Whether their bioactivity is mediated by other angiogenic growth factors or not is still unclear. We identified and purified recently a new angiogenic growth factor. Its unique specificity for vascular endothelial cells led us to provisionally name it vasculotropin (VAS). We describe the biochemical properties of VAS and its biological functions. Structural data showed that VAS is related to the SIS family. In vivo VAS was recognized as an inducer of angiogenesis and vascular permeability. In vitro, despite a moderate action on proliferation, VAS strongly stimulates the cell migration. The screening of the presence of cellular receptors and VAS production showed that the cells which bind VAS do not synthesize it, whereas the cells which synthesize VAS do not bind it. Thus, VAS seems to act through a paracrine pathway. We also present data suggesting that VAS has a lymphokine activity.

Vasculotropin is a growth factor with a unique specificity for vascular derived endothelial cells. We report that normal human peripheral lymphocytes represent another target for vasculotropin. The mitogenic activity of the medium conditioned by these cells cultured in the presence of Concanavalin A is potentiated by vasculotropin. This effect is exerted more likely through interactions with the soluble mediators rather than through the VAS receptors since VAS binds equally to Concanavalin A stimulated and to unstimulated lymphocytes.

CSF-1 or M-CSF is a homodimeric glycosylated protein purified to homogeneity through its hematopoietic growth factor properties. It has recently been cloned and sequenced as a unique gene encoding several m-RNAs and peptidic species. Its receptor has been identified as the c-fms protooncogene product expressed at the surface of all CSF-1 responsive cells as a transmembrane tyrosine kinase responsible for CSF-1 induced signal transduction. CSF-1 is permanently present in serum and several biological fluids at stable concentrations and can thus be considered as a hormone. In vivo concentrations are mainly regulated by binding, internalization and degradation of the CSF-1 molecule by hepatic and splenic macrophage receptors. Very little is known about the organs and cell types responsible for in vivo CSF-1 synthesis. In vitro, CSF-1 regulates the survival, proliferation and differentiation of the monocyte-macrophage lineage from progenitors to mature cells and activates several important functions of mature tissular macrophages. Recent results obtained with injections of recombinant CSF-1 show that interesting activities, e.g., as ADCC, NK or antiinfectious effects, that had been initially observed in vitro can also be induced in vivo. All these in vitro and in vivo data and the recent availability of large amounts of pure recombinant human CSF-1 point to the diagnostic value of CSF-1 concentration measurements in biological fluids and suggest a therapeutic role for CSF-1 infusion in cancer and infection therapy.

During the course of an acute graft-vs-host reaction in the mouse we observed a progressive increase in the concentration of CSF-1 in serum and liver, peaking at day 14. In contrast, there was a progressive decrease in the splenic CSF-1 concentration. In vivo studies of 125I-CSF-1 uptake and degradation and in vitro studies of 125I-CSF-1 binding by splenic cells demonstrated that within 24 h of the reaction the number of CSF-1 receptor+ cells had increased by 2-fold and their capacity to express the CSF-1 receptor by approximately 3-fold, resulting in a approximately 2.5-fold increase in the splenic clearance of CSF-1 from the circulation. Inasmuch as at 24 h, serum CSF-1 was not significantly altered, these results are suggestive of an increased rate of release of CSF-1 into the circulation early in the response. The splenic CSF-1-receptor bearing cells were in a Mac-1+ fraction that is consistent with a role for CSF-1 in the generation of host-derived splenic macrophages in acute graft-vs-host reaction.

We describe a rabbit intralymphnode immunization technique for obtaining a high titer antihuman CSF-1 antiserum with small amounts of antigen. This procedure provided a rapid (42 days after primo-injection), stable maximum immune response with a high titer antiserum precipitating 30% of 125I CSF-1 at a 1:25.000 dilution. The specificity of the immune serum was assessed by competitive binding experiments in RIA and neutralization of the CSF-1 biological activity in culture. The antiserum was also tested for its ability to detect CSF-1 in Western blotting, immunocytochemistry and immunohisto-chemistry. The results show that the immune serum specifically recognizes the biological active domain of human CSF-1 molecules from different origins and only detects dimeric forms. The potential uses of this anti CSF-1 antiserum are discussed.

The CEM-ON malignant T cell line and long-term cultured normal T cells can be induced to release CSF-1 in their culture supernatants. Chemical inducers (PMA + A23187) and, more interestingly, cytokines (tumor necrosis factor alpha (TNF alpha) and interleukin-1 alpha (IL-1 alpha)), as well as physiological (antigen + IL-2) or specific (anti-CD3 + IL-2 or PMA) stimuli, lead to rapid transient colony-stimulating factor-1 (CSF-1) gene expression and production of biologically active CSF-1. These data suggest that CSF-1 may play a role in the early phases of immune response.

The cytokine HILDA (human IL for DA cells)/LIF (leukemia inhibitory factor), previously reported to trigger the proliferation of the DA1.a cell line was purified to homogeneity from the culture supernatant of the 5637 bladder carcinoma cell line by using a four step procedure, including cationic exchange chromatography at pH 6, Con A affinity chromatography, reverse phase HPLC, and gel filtration HPLC. The purified radiolabeled protein was analyzed in SDS-PAGE and a single band with a molecular mass of 43 kDa was revealed. The iodinated material was then tested in a radioreceptor assay using the M1 cell line as a second target cell line. The binding of the natural 125I hormone was abrogated in a dose dependent and specific fashion by either natural and rHILDA. The limit of signal detection of displacement for the radiolabeled ligand by unlabeled sample was found to be 0.05 ng/ml. The proliferative DA1.a assay and the M1 radioreceptor assay were used to analyze the HILDA content of 17 human tumor cell line culture supernatants, and 12 among them were spontaneously secreting a detectable level of LIF. The secreted amount of HILDA was largely enhanced by treating the cell line with 30 to 80 nM PMA; in these conditions a 10 to 20x increase in the detected amount was observed. The specificity of the detected signal was reinforced by analyzing the mRNA expression of HILDA in the tumor cell lines. The secreting cell lines were found to express various forms of LIF transcripts with a major specie at 3.8 kb.

Asta-Z 7557, an in vitro active metabolite of cyclophosphamide, is used for human bone marrow purging in acute leukemias and solid tumors since it is more highly toxic to tumor than normal hematopoietic clonogenic cells. However, doses higher than 80 microM totally inhibit the growth of hematopoietic progenitors in semisolid assays, despite preservation of marrow repopulating ability in vivo. This discrepancy complicates assessment of the functional value of purged grafts. In 11 patients undergoing autologous bone marrow transplantation with 100 microM Asta-Z purged marrow, we investigated the advantages of the collagen gel culture system for detection of spared hematopoietic progenitors. This technique provides a suitable and convenient assay as compared with results with agar. In nine of 11 samples after 14 or 21 days of incubation, up to 100 colonies were observed, (64% monocytic, 27% granulocytic). Day-14 granulocytic colonies were mostly immature, suggesting that they derived from early CFU-GM or pre-CFU-GM. This development of early progenitors could account for the better sensitivity of this technique compared with agar or methylcellulose systems. The mechanism involved as well as the correlation between colony growth in collagen and clinical hematopoietic recovery is also considered.

Photodynamic therapy is a new concept for in vitro evaluation of bone marrow clearance in leukemia. This treatment eliminates 99.9999% of leukemic cells, but under the same conditions over 50% of normal bone marrow cells are damaged. WR-2721, a thiol compound, is reported to except a protective effect for bone marrow against radiation therapy. This study analyzed the protective effect of WR-2721 during photodynamic therapy with hematoporphyrin derivative. Mice hemopoietic cells were exposed to laser light after sensitization by hematoporphyrin, with or without WR-2721 at 3 dose levels (250, 500, 750 mg/kg). The efficacy of protection was evaluated by GM-CFU assay in collagen gel medium. Results showed significant protection at 25 and 50 j/cm2 (p less than 0.05), but at 75 j/cm2 irradiation only the 750 mg/kg dosage remained protective. The protective factor of WR-2721 is 1.65 (95% confidence interval: 1.38-1.99) WR-2721 is protective against photodynamic lesions but this protection is diminished by increased irradiation energy. The best results are obtained with a dose of 750 mg/kg though this appears to be toxic. Further studies are needed to evaluate the action of WR-2721 on leukemic cells before the use of WR-2721 in bone marrow clearance.

Agar culture systems for the clonal growth and differentiation of hemopoietic cells were first described 20 yr ago (1). The progenitor cells that developed into colonies in agar after several days of culture in the presence of a source of hemopoietic growth factor (2,3) were initially called "Colony Forming Units in Culture" (CFU-C). They are found in bone marrow, spleen, blood, fetal liver, and yolk sac. It was subsequently demonstrated that the CFU-C population was heterogeneous and contained progenitors giving rise to granulocyte/macrophage (CFU-GM), granulocyte (CFU-G), and macrophage (CFU-M) colonies. Progenitor cells of other lineages (erythroid and megakaryocytic) have also been similarly demonstrated in hemopoietic organs.

In a patient with plasma cell leukemia and a kappa type Bence Jones protein in serum and urine, the immunofluorescence study of blood plasma cells showed intracellular gamma and kappa chain determinants. Biosynthesis experiments showed the production of abnormally short heavy chains (45,000 daltons) that assembled with normal sized light chains with a partial block. These abnormal heavy chains were secreted at a slow rate and were degraded after secretion.

Repeated analysis of peripheral blood lymphocytes (PBLs) from a patient with large granular lymphocytosis, neutropenia, and rheumatoid arthritis revealed that approximately 45% of PBLs displayed the following phenotype: CD3+, CD4-, CD8-, CD16+, HNK-1-, WT31-. This population was purified for further analysis by depletion with anti-CD4 and anti-CD8 monoclonal antibodies (MoAbs). Southern blot analysis showed preferential rearrangements of the V gamma 9 genes. Northern blot demonstrated the presence of V gamma 9 mRNA transcripts. With MoAbs directed against either the V gamma 9 peptide (Ti gamma A) or the delta chain of the gamma delta T-cell receptor (TCR delta 1), we further demonstrated that those cell surfaces expressed both V gamma 9 and a delta gene product. In addition, analysis of the gamma gene rearrangements on six clones derived from this population demonstrated a unique rearrangement on a single chromosome, strongly suggesting the monoclonality of this T-cell population. Significant cytotoxic activity against K562, U937 was observed only after an in vitro culture period with interleukin-2 (IL-2), whereas no specific inhibitory effect on autologous bone marrow (BM) CFU-G was noted.

Photodynamic therapy represents a new approach for the local control of cancers. It has recently been claimed that photodynamic therapy mediated by hematoporphyrin derivative (HPD) is selectively more efficient for killing leukemic cells than normal progenitors. To improve this effect, we studied the influence of hematoporphyrin dose, temperature during incubation and/or treatment, hematoporphyrin derivative incubation time, and fractionation of the argon laser light (488-514 nm) used for hematoporphyrin stimulation. Plating efficiency calculated after a 7-day period of growth on collagen gel medium showed a dose-dependent phototoxicity of HPD reaching 0.01% for normal hemopoietic progenitors and 0.001% for leukemic cells (dose = 12.5 micrograms/ml). The 10:1 ratio of normal hemopoietic progenitors to leukemic cells was also found to be the same or increased when temperature was 37 degrees C during incubation and 4 degrees C during laser irradiation. Similar results were also found when incubation time was varied from 75-120 min, or when laser irradiation dose was fractionated into 2 or 3 periods. The ratio of normal progenitors to leukemic cells reached 100:1 when 75 J/cm2 were fractionated into 3 periods after an incubation time of 120 min with 10 micrograms/ml HPD. Selectivity in photodynamic treatment seems to occur between normal hemopoietic progenitors and leukemic cells. The mechanism of this selectivity remains unclear, but experiments with the fractionated irradiation dose suggest that as in radiotherapy, better potentially lethal damage repair in normal cells could be a factor for selectivity in photodynamic therapy. Our results obtained with leukemic cells are fully in agreement with data in the literature concerning similar experimental models.

Circulating erythroid progenitors from 14 patients with acute lymphoblastic leukemia (ALL) and from 8 healthy subjects were studied in culture to determine the frequency and size of CFU-E- and BFU-E-derived colonies. Cells were cultured in a plasma clot system, and hemoglobinized colonies identified by diaminobenzidine reaction. The numbers of CFU-E and BFU-E per milliliter of peripheral blood were greatly increased in 10 patients when compared to controls. In 13 patients, the size distribution of BFU-E-derived colonies, analyzed by counting the number of subunits in each colony, was also found to differ significantly from controls, with a large excess of small colonies and a low percentage or a total lack of large colonies. This abnormal BFU-E size distribution was partially corrected, in the 5 patients tested, by the addition to the culture medium of 10% phytohemagglutinin-leukocyte-conditioned medium (PHA-LCM). Bone marrow crowding out of the normal progenitors, as well as disturbances in the cellular interactions involved in their normal development, most likely explain these results and these factors could be implicated in the frequent pancytopenia of ALL.

The choice of an automated differential leukocytes counting system depends on a number of criteria including reliability, speed an cost/effectiveness ratio. We have compared the performance of three commercially available instruments, the Hematrak 360 (Geometric data), the ADC 500 (Abbott) and the DIFF 3 (Coultronics). We have voluntarily confined this study to pattern recognition systems and have not investigated other systems based on cell volume determination and cytochemical reactions (Hemalog D, Technicon). Comparison of a new system with an established automated system simplifies the task considerably, provided that the quality and performance of the reference system have been previously well-established, as has been done in our laboratory with the LARC which has been evaluated comparatively to the traditional method (5). A final difficulty is that the conclusions drawn from this type of study cannot be considered as definitive insofar as changes and improvements are continually being proposed for all systems which are still going through a mutation stage as we noticed in the course of this evaluation.

Hematological investigations of two propositus from a family with congenital thrombopathia characterised by a moderate thrombopenia and a specific platelet alpha granule deficiency revealed that the thrombopathia was associated with a constitutive reticulinic myelofibrosis, without any sign of evolutivity. This association led us to present an hypothesis to explain the genesis of this myelofibrosis. This hypothesis is based on the potential role of a mitogenic factor(s) synthetized in megakaryocytes and transported normally by platelets in alpha granules, to induce fibroblastic proliferation and increased synthesis of collagen type III by bone marrow. This myelofibrosis is similar to that found in most of myeloproliferative disorders at some step of evolutivity. In these diseases myelofibrosis is associated with qualitative and quantitative abnormalities of platelets and megakaryocytes. These abnormalities give elements to sustain our hypothesis.

The selectivity of in vitro photodynamic reactions and the in vivo effects induced by PRT, whether the irradiation is applied interstitially or externally, still remains unclear. In vitro studies were performed using leukemic cell lines and syngeneic normal hemopoietic progenitors. For these, cells incubated with hematoporphyrin derivative (HPD) and non-incubated cells were irradiated with an argon laser. Data were obtained as the count of cell colonies found after a 7-day incubation period on semi-solid collagen gel medium. In vivo studies employed the HT 29 tumor model grafted into nude mice. Both animals injected with HPD and non-infected controls were irradiated with a dye laser pumped by an argon laser (Coherent) using a 400 micron optic fiber located either at a distance of 65 mm from the skin or inserted into the tumor. The temperature increase occurring during PRT was measured using non-absorbing thermocouples. In vitro, after HPD treatment and argon irradiation leukemic cells showed a greater phototoxicity (greater than 2 log10) than did the normal cells (0.25 log10). In vivo, when the heat rise is very similar (less than 4 degrees C) in both the tissues irradiated externally and those irradiated interstitially after HPD injection, histological examination of these did not reveal any quantitative differences (90% of tumor mass). These results are discussed.

Myeloproliferative disease (MPD) is heterogeneous in phenotypic expression and may display features consistent with expansion and activation of the monocyte/macrophage population during its course. The role of colony-stimulating factor-1 (CSF-1) in the pathophysiology of MPD was investigated by measuring circulating CSF-1 levels and examining their relationship to disease phenotype. Serum CSF-1 concentrations, measured by radioimmunoassay, were elevated in all MPD phenotypes. CSF-1 levels differed significantly between groups of patients with essential thrombocythemia, polycythemia vera, and postpolycythemic or agnogenic myeloid metaplasia (in ascending order). CSF-1 serum levels were positively correlated with spleen size and the degree of peripheral bone marrow extension, determined by scintigraphy using a macrophage-seeking isotope. There was no correlation between CSF-1 concentration and circulating levels of erythrocytes, neutrophils or platelets, or the presence of bone marrow fibrosis. Elevated serum CSF-1 levels appear to be associated with an expanded monocyte/macrophage population in MPD. In view of the known cooperativity between CSF-1 and other growth factors in regulating hematopoiesis, the finding of increased serum CSF-1 concentrations and its association with myeloid metaplasia and bone marrow extension may indicate a pathophysiologic role for CSF-1 in determining the phenotypic expression of MPD.