Dynamic Interplay in Tumor Ecosystems: Communication between Hepatoma Cells and Fibroblasts

Tumors are intricate ecosystems where cancer cells and non-malignant stromal cells, including cancer-associated fibroblasts (CAFs), engage in complex communication. In this study, we investigated the interaction between poorly (HLE) and well-differentiated (HuH7) hepatoma cells and LX2 fibroblasts. We explored various communication channels, including soluble factors, metabolites, extracellular vesicles (EVs), and miRNAs. Co-culture with HLE cells induced LX2 to produce higher levels of laminin β1, type IV collagen, and CD44, with pronounced syndecan-1 shedding. Conversely, in HuH7/LX2 co-culture, fibronectin, thrombospondin-1, type IV collagen, and cell surface syndecan-1 were dominant matrix components. Integrins α6β4 and α6β1 were upregulated in HLE, while α5β1 and αVβ1 were increased in HuH7. HLE-stimulated LX2 produced excess MMP-2 and 9, whereas HuH7-stimulated LX2 produced excess MMP-1. LX2 activated MAPK and Wnt signaling in hepatoma cells, and conversely, hepatoma-derived EVs upregulated MAPK and Wnt in LX2 cells. LX2-derived EVs induced over tenfold upregulation of SPOCK1/testican-1 in hepatoma EV cargo. We also identified liver cancer-specific miRNAs in hepatoma EVs, with potential implications for early diagnosis. In summary, our study reveals tumor type-dependent communication between hepatoma cells and fibroblasts, shedding light on potential implications for tumor progression. However, the clinical relevance of liver cancer-specific miRNAs requires further investigation.

Differential impact of exportin-1-mediated nuclear export of RNAs on the RNA content of extracellular vesicle subpopulations

Extracellular vesicles (EVs) are membrane-enclosed subcellular structures released by all cell types. EVs have important roles in both cellular homeostasis and intercellular communication. Recent progress in the field revealed substantial heterogeneity of EVs even within the size-based EV categories. Here we addressed the question whether the exportin-1 (XPO1)-mediated nuclear export of RNAs contributed to the EV heterogeneity. Size-based populations were separated from the conditioned media of three cell lines (U937, THP-1 and 5/4E8) in steady-state condition. The effects of activation and leptomycin B treatment (to inhibit the XPO1-mediated nuclear export of RNAs) were also tested in the case of the two monocytic cell lines. Agilent Pico and Small chips were used to characterize RNAs, fragment analysis was performed, and EV-associated miRNAs were tested by Taqman assays. As expected, we found the highest small RNA/total RNA ratio and the lowest rRNA/total RNA proportion in small EVs (~ 50-150 nm). Profiles of the small RNAs within different size-based EV categories significantly differed based on the activation status of the EV releasing cells. Leptomycin B had a differential inhibition on the tested small RNAs in EVs, even within the same EV size category. A similar heterogeneity of the EV miRNA content was observed upon cellular activation and nuclear export inhibition. Here we complement the already existing knowledge on EV heterogeneity by providing evidence that the RNA cargo varies depending on the EV size-based category, the releasing cell type, the functional status of the releasing cells and the exportin-1-mediated nuclear export of RNAs.

Circulating cardiomyocyte-derived extracellular vesicles reflect cardiac injury during systemic inflammatory response syndrome in mice

The release of extracellular vesicles (EVs) is increased under cellular stress and cardiomyocyte damaging conditions. However, whether the cardiomyocyte-derived EVs eventually reach the systemic circulation and whether their number in the bloodstream reflects cardiac injury, remains unknown. Wild type C57B/6 and conditional transgenic mice expressing green fluorescent protein (GFP) by cardiomyocytes were studied in lipopolysaccharide (LPS)-induced systemic inflammatory response syndrome (SIRS). EVs were separated both from platelet-free plasma and from the conditioned medium of isolated cardiomyocytes of the left ventricular wall. Size distribution and concentration of the released particles were determined by Nanoparticle Tracking Analysis. The presence of GFP + cardiomyocyte-derived circulating EVs was monitored by flow cytometry and cardiac function was assessed by echocardiography. In LPS-treated mice, systemic inflammation and the consequent cardiomyopathy were verified by elevated plasma levels of TNFα, GDF-15, and cardiac troponin I, and by a decrease in the ejection fraction. Furthermore, we demonstrated elevated levels of circulating small- and medium-sized EVs in the LPS-injected mice. Importantly, we detected GFP+ cardiomyocyte-derived EVs in the circulation of control mice, and the number of these circulating GFP+ vesicles increased significantly upon intraperitoneal LPS administration (P = 0.029). The cardiomyocyte-derived GFP+ EVs were also positive for intravesicular troponin I (cTnI) and muscle-associated glycogen phosphorylase (PYGM). This is the first direct demonstration that cardiomyocyte-derived EVs are present in the circulation and that the increased number of cardiac-derived EVs in the blood reflects cardiac injury in LPS-induced systemic inflammation (SIRS).

An implanted device enables in vivo monitoring of extracellular vesicle-mediated spread of pro-inflammatory mast cell response in mice

Mast cells have been shown to release extracellular vesicles (EVs) in vitro. However, EV-mediated mast cell communication in vivo remains unexplored. Primary mast cells from GFP-transgenic and wild type mice, were grown in the presence or absence of lipopolysaccharide (LPS), and the secreted EVs were separated from the conditioned media. Mast cell-derived EVs were next cultured with LPS-naïve mast cells, and the induction of TNF-α expression was monitored. In addition, primary mast cells were seeded in diffusion chambers that were implanted into the peritoneal cavities of mice. Diffusion chambers enabled the release of GFP+ mast cell-derived EVs in vivo into the peritoneal cavity. Peritoneal lavage cells were assessed for the uptake of GFP+ EVs and for TNF-α production. In vitro, LPS-stimulated mast cell-derived EVs were efficiently taken up by non-stimulated mast cells, and induced TNF-α expression in a TLR4, JNK and P38 MAPK dependent manner. In vivo, using implanted diffusion chambers, we confirmed the release and transmission of mast cell-derived EVs to other mast cells with subsequent induction of TNF-α expression. These data show an EV-mediated spreading of pro-inflammatory response between mast cells, and provide the first in vivo evidence for the biological role of mast cell-derived EVs.

Extracellular vesicles transmit epithelial growth factor activity in the intestinal stem cell niche

Extracellular vesicles (EV) are membrane-surrounded vesicles that represent a novel way of intercellular communication by carrying biologically important molecules in a concentrated and protected form. The intestinal epithelium is continuously renewed by a small proliferating intestinal stem cell (ISC) population, residing at the bottom of the intestinal crypts in a specific microenvironment, the stem cell niche. By using 3D mouse and human intestinal organoids, we show that intestinal fibroblast-derived EVs are involved in forming the ISC niche by transmitting Wnt and epidermal growth factor (EGF) activity. With a mouse model that expresses EGFP in the Lgr5+ ISCs, we prove that loss in ISC number in the absence of EGF is prevented by fibroblast-derived EVs. Furthermore, we demonstrate that intestinal fibroblast-derived EVs carry EGF family members, such as amphiregulin. Mechanistically, blocking EV-bound amphiregulin inhibited the EV-induced survival of organoids. In contrast, EVs have no role in transporting R-Spondin, a critical niche factor amplifying Wnt signaling. Collectively, we prove the important role of fibroblast-derived EVs as a novel transmission mechanism of factors in the normal ISC niche.

Radio-detoxified LPS alters bone marrow-derived extracellular vesicles and endothelial progenitor cells

Stem cell-based therapies raise hope for cell replacement and provide opportunity for cardiac regenerative medicine and tumor therapy. Extracellular vesicles are a membrane-enclosed intercellular delivery system with the potential to improve the therapeutic efficacy of the treatment of a variety of disorders. As the incidence of breast cancer continues to rise, radiotherapy has emerged as a leading treatment modality. Radiotherapy also increases the risk of coronary heart disease and cardiac mortality. In a chest-irradiated mouse model of cardiac injury, we investigated the effects of local irradiation. We found an increased lethality after 16 Gy irradiation. Importantly, radio-detoxified LPS (RD-LPS) treatment prolonged the survival significantly. By flow cytometry, we demonstrated that upon administration of RD-LPS, the number of bone marrow-derived endothelial progenitor cells increased in the bone marrow and, in particular, in the circulation. Furthermore, mass spectrometry analysis showed that RD-LPS altered the proteomic composition of bone marrow cell-derived small extracellular vesicles (sEVs). RD-LPS treatment increased interferon-induced transmembrane protein-3 (IFITM3) expression markedly both in bone marrow cells and in bone marrow cell-derived small extracellular vesicles. This is the first study to demonstrate that radio-detoxified LPS treatment induces an increase of circulating endothelial progenitor cells (EPCs) in parallel with a reduced radiotherapy-related mortality. While the total number of bone marrow-derived extracellular vesicles was significantly increased 24 h after treatment in the RD-LPS groups, the number of endothelial progenitor cells was reduced in animals injected with GW4896 (a chemical inhibitor of exosome biogenesis) as compared with controls. In contrast to these in vivo results, in vitro experiments did not support the effect of sEVs on EPCs. Our data raise the intriguing possibility that IFITM3 may serve as a marker of the radio-detoxified LPS treatment.

Extracellular vesicle release from intestinal organoids is modulated by Apc mutation and other colorectal cancer progression factors

Extracellular vesicles (EVs) are membrane-surrounded structures that transmit biologically important molecules from the releasing to target cells, thus providing a novel intercellular communication mechanism. Since EVs carry their cargo in a protected form and their secretion is generally increased in tumorigenesis, EVs hold a great potential for early cancer diagnosis. By 3D culturing, we provide evidence that colorectal cancer (CRC) patient-derived organoids, representing a state-of-the-art established and essential approach for studying human CRC, is a suitable model for EV analysis. When testing the effects of major factors promoting CRC progression on EV release in the organoid model, we observed that Apc mutation, leading to uncontrolled Wnt activation and thus to tumorigenesis in the vast majority in CRC patients, critically induces EV release by activating the Wnt pathway. Furthermore, the extracellular matrix component collagen, known to accumulate in tumorigenesis, enhances EV secretion as well. Importantly, we show that fibroblast-derived EVs induce colony formation of CRC organoid cells under hypoxia. In contrast, there was no major effect of tumor cell-derived EVs on the activation of fibroblasts. Collectively, our results with CRC and Apc-mutant adenoma organoids identify Apc mutation and collagen deposition as critical factors for increasing EV release from tumors. Furthermore, we provide evidence that stromal fibroblast-derived EVs contribute to tumorigenesis under unfavorable conditions in CRC.

En bloc release of MVB-like small extracellular vesicle clusters by colorectal carcinoma cells

Small extracellular vesicles (EVs) are membrane enclosed structures that are usually released from cells upon exocytosis of multivesicular bodies (MVBs) as a collection of separate, free EVs. In this study, we analysed paraffin embedded sections of archived human colorectal cancer samples. We studied 3D reconstructions of confocal microscopic images complemented by HyVolution and STED imaging. Unexpectedly, we found evidence that large, MVB-like aggregates of ALIX/CD63 positive EV clusters were released en bloc by migrating tumour cells. These structures were often captured with partial or complete extra-cytoplasmic localization at the interface of the plasma membrane of the tumour cell and the stroma. Their diameter ranged between 0.62 and 1.94 μm (mean±S.D.: 1.17 ± 0.34 μm). High-resolution 3D reconstruction showed that these extracellular MVB-like EV clusters were composed of distinguishable internal particles of small EV size (mean±S.D.: 128.96 ± 16.73 nm). In vitro, HT29 colorectal cancer cells also showed the release of similar structures as confirmed by immunohistochemistry and immune electron microscopy. Our results provide evidence for an en bloc transmission of MVB-like EV clusters through the plasma membrane. Immunofluorescent-based detection of the MVB like small EV clusters in archived pathological samples may represent a novel and unique opportunity which enables analysis of EV release in situ in human tissues.

Detection and proteomic characterization of extracellular vesicles in human pancreatic juice

AIMS

The prognosis of patients with pancreatic cancer has remained virtually unchanged with a high mortality rate compared to other types of cancers. An earlier detection would provide a time window of opportunity for treatment and prevention of deaths. In the present study we investigated extracellular vesicle (EV)-associated potential biomarkers for pancreatic cancer by directly assessing EV size-based subpopulations in pancreatic juice samples of patients with chronic pancreatitis or pancreatic cancer. In addition, we also studied blood plasma and pancreatic cancer cell line-derived EVs.

METHODS

Comparative proteomic analysis was performed of 102 EV preparations from human pancreatic juices, blood, and pancreatic cancer cell lines Capan-1 and MIA PaCa-2. EV preparations were also characterized by electron microscopy, tunable resistive pulse sensing, and flow cytometry.

RESULTS

Here we describe the presence of EVs in human pancreatic juice samples. Pancreatic juice EV-associated proteins that we identified as possible candidate markers for pancreatic cancer included mucins, such as MUC1, MUC4, MUC5AC, MUC6 and MUC16, CFTR, and MDR1 proteins. These candidate biomarkers could also be detected by flow cytometry in EVs found in pancreatic juice and those secreted by pancreatic cancer cell lines.

CONCLUSIONS

Together our data show that detection and characterization of EVs directly in pancreatic juice is feasible and may prove to be a valuable source of potential biomarkers of pancreatic cancer.

Monocyte activation drives preservation of membrane thiols by promoting release of oxidised membrane moieties via extracellular vesicles

The redox state of cellular exofacial molecules is reflected by the amount of available thiols. Furthermore, surface thiols can be considered as indicators of immune cell activation. One group of thiol containing proteins, peroxiredoxins, in particular, have been associated with inflammation. In this study, we assessed surface thiols of the U937 and Thp1 monocyte cell lines and primary monocytes in vitro upon inflammatory stimulation by irreversibly labelling the cells with a fluorescent derivative of maleimide. We also investigated exofacial thiols on circulating blood mononuclear cells in patients with rheumatoid arthritis and healthy controls. When analysing extracellular vesicles, we combined thiol labelling with the use of antibodies to specific CD markers to exclude extracellular vesicle mimicking signals from thiol containing protein aggregates. Furthermore, differential detergent lysis was applied to confirm the vesicular nature of the detected extracellular events in blood plasma. We found an increase in exofacial thiols on monocytes upon in vitro stimulation by LPS or TNF, both in primary monocytes and monocytic cell lines (p<0.0005). At the same time, newly released extracellular vesicles showed a decrease in their exofacial thiols compared with those from unstimulated cells (p<0.05). We also found a significant elevation of surface thiols on circulating monocytes in rheumatoid arthritis patients (p<0.05) and newly released extracellular vesicles of isolated CD14⁺ cells from rheumatoid arthritis patients had decreased thiol levels compared with healthy subjects (p<0.01). Exofacial peroxiredoxin 1 was demonstrated on the surface of primary and cultured monocytes, and the number of peroxiredoxin 1 positive extracellular vesicles was increased in rheumatoid arthritis blood plasma (p<0.05). Furthermore, an overoxidised form of peroxiredoxin was detected in extracellular vesicle-enriched preparations from blood plasma. Our data show that cell surface thiols play a protective role and reflect oxidative stress resistance state in activated immune cells. Furthermore, they support a role of extracellular vesicles in the redox regulation of human monocytes, possibly representing an antioxidant mechanism.

Radiolabeling of Extracellular Vesicles with (99m)Tc for Quantitative In Vivo Imaging Studies

The biodistribution of extracellular vesicles (EVs) is a fundamental question in the field of circulating biomarkers, which has recently gained attention. Despite the capabilities of nuclear imaging methods, such as single-photon emission computed tomography, radioisotope labeling of EVs and the use of the aforementioned methods for in vivo studies hardly can be found in the literature. In this article, the authors describe a novel method for the radioisotope labeling of erythrocyte-derived EVs using the (99m)Tc-tricarbonyl complex. Moreover, the capability of the developed labeling method for in vivo biodistribution studies is demonstrated in a mouse model. The authors found that the intravenously administered (99m)Tc-labeled EVs mostly accumulated in the liver and spleen. The in vivo stability of the labeled EVs was assessed by the comparison of the obtained biodistribution of EVs with that of the free (99m)Tc-tricarbonyl. According to the authors' data, only a minor fraction of the radioactive label became detached from the EVs.

[Extracellular vesicles and their role in hematological malignancies]

Extracellular vesicles are produced in all organisms. The most intensively investigated categories of extracellular vesicles include apoptotic bodies, microvesicles and exosomes. Among a very wide range of areas, their role has been confirmed in intercellular communication, immune response and angiogenesis (in both physiological and pathological conditions). Their alterations suggest the potential use of them as biomarkers. In this paper the authors give an insight into the research of extracellular vesicles in general, and then focus on published findings in hematological malignancies. Quantitative and qualitative changes of microvesicles and exosomes may have value in diagnostics, prognostics and minimal residual disease monitoring of hematological malignancies. The function of extracellular vesicles in downregulation of natural killer cells' activity has been demonstrated in acute myeloid leukemia. In chronic lymphocytic leukemia, microvesicles seem to play a role in drug resistance. Orv. Hetil., 2016, 157(35), 1379-1384.

Improved characterization of EV preparations based on protein to lipid ratio and lipid properties

In recent years the study of extracellular vesicles has gathered much scientific and clinical interest. As the field is expanding, it is becoming clear that better methods for characterization and quantification of extracellular vesicles as well as better standards to compare studies are warranted. The goal of the present work was to find improved parameters to characterize extracellular vesicle preparations. Here we introduce a simple 96 well plate-based total lipid assay for determination of lipid content and protein to lipid ratios of extracellular vesicle preparations from various myeloid and lymphoid cell lines as well as blood plasma. These preparations included apoptotic bodies, microvesicles/microparticles, and exosomes isolated by size-based fractionation. We also investigated lipid bilayer order of extracellular vesicle subpopulations using Di-4-ANEPPDHQ lipid probe, and lipid composition using affinity reagents to clustered cholesterol (monoclonal anti-cholesterol antibody) and ganglioside GM1 (cholera toxin subunit B). We have consistently found different protein to lipid ratios characteristic for the investigated extracellular vesicle subpopulations which were substantially altered in the case of vesicular damage or protein contamination. Spectral ratiometric imaging and flow cytometric analysis also revealed marked differences between the various vesicle populations in their lipid order and their clustered membrane cholesterol and GM1 content. Our study introduces for the first time a simple and readily available lipid assay to complement the widely used protein assays in order to better characterize extracellular vesicle preparations. Besides differentiating extracellular vesicle subpopulations, the novel parameters introduced in this work (protein to lipid ratio, lipid bilayer order, and lipid composition), may prove useful for quality control of extracellular vesicle related basic and clinical studies.

Differential detergent sensitivity of extracellular vesicle subpopulations

This work shows for the first time that exosomes are more resistant to detergents than microvesicles and apoptotic bodies.

Cardioprotection by remote ischemic preconditioning of the rat heart is mediated by extracellular vesicles

Remote ischemic preconditioning (RIPC) of the heart is exerted by brief ischemic insults affected on a remote organ or a remote area of the heart before a sustained cardiac ischemia. To date, little is known about the inter-organ transfer mechanisms of cardioprotection by RIPC. Exosomes and microvesicles/microparticles are vesicles of 30-100 nm and 100-1000 nm in diameter, respectively (collectively termed extracellular vesicles [EVs]). Their content of proteins, mRNAs and microRNAs, renders EV ideal conveyors of inter-organ communication. However, whether EVs are involved in RIPC, is unknown. Therefore, here we investigated whether (1) IPC induces release of EVs from the heart, and (2) EVs are necessary for cardioprotection by RIPC. Hearts of male Wistar rats were isolated and perfused in Langendorff mode. A group of donor hearts was exposed to 3 × 5-5 min global ischemia and reperfusion (IPC) or 30 min aerobic perfusion, while coronary perfusates were collected. Coronary perfusates of these hearts were given to another set of recipient isolated hearts. A group of recipient hearts received IPC effluent depleted of EVs by differential ultracentrifugation. Infarct size was determined after 30 min global ischemia and 120 min reperfusion. The presence or absence of EVs in perfusates was confirmed by dynamic light scattering, the EV marker HSP60 Western blot, and electron microscopy. IPC markedly increased EV release from the heart as assessed by HSP60. Administration of coronary perfusate from IPC donor hearts attenuated infarct size in non-preconditioned recipient hearts (12.9 ± 1.6% vs. 25.0 ± 2.7%), similarly to cardioprotection afforded by IPC (7.3 ± 2.7% vs. 22.1 ± 2.9%) on the donor hearts. Perfusates of IPC hearts depleted of EVs failed to exert cardioprotection in recipient hearts (22.0 ± 2.3%). This is the first demonstration that EVs released from the heart after IPC are necessary for cardioprotection by RIPC, evidencing the importance of vesicular transfer mechanisms in remote cardioprotection.

Improved circulating microparticle analysis in acid-citrate dextrose (ACD) anticoagulant tube

INTRODUCTION

Recently extracellular vesicles (exosomes, microparticles also referred to as microvesicles and apoptotic bodies) have attracted substantial interest as potential biomarkers and therapeutic vehicles. However, analysis of microparticles in biological fluids is confounded by many factors such as the activation of cells in the blood collection tube that leads to in vitro vesiculation. In this study we aimed at identifying an anticoagulant that prevents in vitro vesiculation in blood plasma samples.

MATERIALS AND METHODS

We compared the levels of platelet microparticles and non-platelet-derived microparticles in platelet-free plasma samples of healthy donors. Platelet-free plasma samples were isolated using different anticoagulant tubes, and were analyzed by flow cytometry and Zymuphen assay. The extent of in vitro vesiculation was compared in citrate and acid-citrate-dextrose (ACD) tubes.

RESULTS

Agitation and storage of blood samples at 37 °C for 1 hour induced a strong release of both platelet microparticles and non-platelet-derived microparticles. Strikingly, in vitro vesiculation related to blood sample handling and storage was prevented in samples in ACD tubes. Importantly, microparticle levels elevated in vivo remained detectable in ACD tubes.

CONCLUSIONS

We propose the general use of the ACD tube instead of other conventional anticoagulant tubes for the assessment of plasma microparticles since it gives a more realistic picture of the in vivo levels of circulating microparticles and does not interfere with downstream protein or RNA analyses.

The role of citrullination of an immunodominant proteoglycan (PG) aggrecan T cell epitope in BALB/c mice with PG-induced arthritis

The P70-84 peptide (also called 5/4E8 epitope) of the human cartilage proteoglycan (PG) aggrecan is the dominant/arthritogenic epitope in both humans and arthritis-prone BALB/c mice (PG-induced arthritis, PGIA). An elevated T cell reactivity was demonstrated to a citrullinated version of the P70-84 epitope in most of the patients with rheumatoid arthritis (RA). The goal of this study was to understand better how a T cell epitope, if citrullinated, may affect antigenicity/arthritogenicity in PGIA, a murine model of RA. T cell reactivity to differentially citrullinated versions of either the human PG aggrecan P70-84 peptide or the corresponding mouse sequence was assessed in peptide or aggrecan-immunized and arthritic BALB/c mice as well as in T cell receptor transgenic mice specific for peptide P70-84 sequence. Peripheral T cell responses were induced by priming BALB/c mice with either the human wild-type or its citrullinated versions. Unexpectedly, priming with the citrullinated self-peptide induced a higher T cell response compared to the wild-type sequence (p<0.001), and the citrullination of the human peptide abolished T cell reactivity in PGIA. Our data suggest that T cells reactive to the citrullinated P70-84 peptide escaped thymic selection and are present in the peripheral T cell repertoire. Results of this study provide evidence that citrullination of an immunodominant T cell epitope may substantially alter, either increase or abolish, T cell recognition at the periphery in an experimental model of arthritis.

The recently identified hexosaminidase D enzyme substantially contributes to the elevated hexosaminidase activity in rheumatoid arthritis

Since the 1970s, numerous reports have described elevated hexosaminidase activities in rheumatoid arthritis. However, due to the overlapping substrate specificities of different hexosaminidases, identification of the exact enzyme(s) responsible for the elevated activity remains incomplete. In this work we tested if the recently described enzyme, hexosaminidase D was expressed in human arthritic joints, and could contribute to the elevated hexosaminidase activity in rheumatoid arthritis. Thermostable β-d-N-acetyl-galactosaminidase (hexosaminidase D) activities were determined in synovial fluid samples, synovial membranes, synovial fibroblast cell strains and synovial fibroblast-derived extracellular vesicles of patients with rheumatoid arthritis and osteoarthritis using chromogenic substrates. Expression of the HEXDC gene was detected both in steady state and in TGF-β treated synovial fibroblasts by real time PCR. Strikingly, hexosaminidase D accounted for approximately 50% of the total β-N-acetyl-galactosaminidase activity in synovial membranes and synovial fibroblasts, and it was responsible for the vast majority of the β-d-N-acetyl-galactosaminidase activity in synovial fluid samples. TGF-β downregulated the expression of hexosaminidase D in synovial fibroblasts dose-dependently. Of note, significant activity of hexosaminidase D was also found in association with extracellular vesicles released by synovial fibroblasts. This first study that describes the expression and disease relevance of the HEXDC gene in humans demonstrates the expression of this novel enzyme within the joints, and suggests that its activity may significantly contribute to the overall local exoglycosidase activity.

Proteomic characterization of thymocyte-derived microvesicles and apoptotic bodies in BALB/c mice

Several studies have characterized exosomes derived from different cell sources. In this work we set the goal of proteomic characterization of two less studied populations of membrane vesicles, microvesicles (100-800 nm) and apoptotic bodies (> 800 nm) released by thymus cells of BALB/c mice. The vesicles were isolated by the combination of differential centrifugation and gravity driven multistep filtration of the supernatant of thymus cell cultures. The size distribution of vesicle preparations was determined by transmission electron microscopy. Proteins were released from the vesicles, digested in solution, and analyzed using nano-HPLC/MS(MS). Ingenuity pathway analysis was used to identify functions related to membrane vesicle proteins. In apoptotic bodies and microvesicles we have identified 142 and 195 proteins, respectively. A striking overlap was detected between the proteomic compositions of the two subcellular structures as 108 proteins were detected in both preparations. Identified proteins included autoantigens implicated in human autoimmune diseases, key regulators of T-cell activation, molecules involved in known immune functions or in leukocyte rolling and transendothelial transmigration. The presence and abundance of proteins with high immunological relevance within thymocyte-derived apoptotic bodies and microvesicles raise the possibility that these subcellular structures may substantially modulate T-cell maturation processes within the thymus.

Remarkably reduced transplant-related complications by dibromomannitol non-myeloablative conditioning before allogeneic bone marrow transplantation in chronic myeloid leukemia

A non-myeloablative conditioning protocol containing dibromomannitol (DBM/cytosine arabinoside/cyclophosphamide) has been applied to 36 chronic myeloid leukemia (CML) patients followed by bone marrow transplantation (BMT) from sibling donors. Risk factors include: accelerated phase (10 patients), older age (17 patients over >40 years) and long interval between diagnosis and BMT (27 months on average). Severe mucositis did not occur. Venoocclusive liver disease was absent. Infectious complications were rare. Although grade II-IV acute graft-versus-host disease (GVHD) was present in 9 (25%) cases, there were only 2 serious (III-IV) ones. Chronic GVHD occurred in 25 (69%) cases, preceded by acute GVHD in 9 of the 25 affected patients. Early hematological relapse, 7-29 weeks after BMT, developed in 6 patients (17.6%). No relapse was noted in the completely chimeric patients, however molecular genetic residual disease was observed in 6 patients, in most of them after transient short-term mixed chimeric state. Overall actual survival rate is 83.3% for the 36 cases, and leukemia-free survival is 72.2% for the 34 engrafted patients.

[Role of molecular genetic investigations in the diagnosis of acute leukemias and in the detection of minimal residual disease]

Chimera gene products, the molecular hallmark of acute leukemias were detected and quantified for diagnostic purposes and for follow up of therapy and characterization of minimal residual disease. In acute lymphoid leukemia mainly the bcr-abl, and in acute myeloid leukemias, depending on the morphological classification, the aml-eto, bcr-abl, pml-rara, plzf-rara, and cbfb-myh chimeras were investigated. The determinations were based on reverse transcriptase-polymerase chain reaction. The results were used in diagnosis of 315 new leukemic patients, and in follow up of 70 ones. In the present paper the usefulness of the applied methods is illustrated by presentation of data of 38 (27, acute myeloid leukemias and 11 acute lymphoid ones) patients out of the 139 treated in the National Institute during the last years.

Developing an expert system for immunophenotypical diagnosis in immunodeficiency. Age-related reference values of peripheral blood lymphocyte subpopulations in Hungary

In the process of developing a decision support system based on flow cytometric data for the diagnosis of immunodeficiency, assessment of lymphocyte subpopulations in human peripheral blood provides the key for further analysis. Samples from 273 'healthy' Hungarian subjects were measured between 1998 and 1999. Immunophenotypic data are compared here (unadjusted for gender) by different age groups: I 0-6 years (n=45); II 7-18 years (n=71); III 19-35 years (n=72); IV 36-55 years (n=48); and V 56-99 years (n=37). Two-color flow cytometric analysis was performed using the Becton Dickinson Simultest IMK Plus kit (CD45/CD14, isotype control, CD3/CD19, CD4/CD8, CD3/HLA-DR, CD3/CD16+56). All lymphocyte subpopulations were measured in all blood samples identically. The quality criteria involved at least 95% of total lymphocytes in the analysis gate, homogenous CD45+ lymphocyte population (minimum of 2000 events in the gate, CD45+ >95%). The frequency of B lymphocytes was the highest, significantly, in the youngest Hungarian subjects, but there were no significant changes with age comparing the data of other II-V age groups. On the other hand, some T subpopulations changed with aging; both CD4 and CD8 subsets varied over time including the elevation of the fraction of activated T cells as well as LGL-NK cells. Some of these changes were significant by statistical tests. Interpretation of flow cytometric data is time-consuming and requires human knowledge of an expert laboratory staff. To facilitate the diagnosis of immunodeficiency, a pilot study aiming at the development of a diagnostic algorithm has been initiated. Algorithm nodes compare the frequency of each lymphocyte subpopulations to the generated reference values. This knowledge-based system describes a short summary report as a result of the comparison, and points to some values requiring further human examination to reach a final conclusion. These reference values and the expert system appear to be a recommended basis for comparing and combining results from different laboratories.

Mouse plasmacytoma: an experimental model of human multiple myeloma

BACKGROUND AND OBJECTIVES

There is no ideal animal model for human multiple myeloma (MM). All the models resemble the human disease in some respect, but none of them fulfils all the criteria of a perfect animal model.

EVIDENCE AND INFORMATION SOURCES

The pristane oil (2,6,10,12-tetramethylpentadecane)-induced mouse plasmacytoma (MPC) model is the most widely used and accepted model and has provided the most data on plasmacytomagenesis so far. This model gives the opportunity to study the role of c-myc dysregulations, the mechanisms leading to cytogenetic changes involving Ig genes, the role of chronic inflammatory factors, the role of interleukin-6 (IL-6), insulin-like growth factor-I, prostaglandins, as well as signal transduction pathways in the neoplastic process. Therapeutic agents have been successfully tested. Although MPC growth is usually restricted to the peritoneal environment, intraperitoneal injection of MPC cell suspensions can reproduce the disseminated characteristics of the human disease in recipients. The IL-6 transgene and knockout models are important tools for clarifying the role of IL-6 in the pathogenesis of MM. Transgenic mice and retroviral gene transfer facilitate the study of oncogenes in neoplastic transformation. Spontaneous development of plasmacytomas in C57BL/ KaLwRij aging mice has several advantages, mainly because the disseminated growth, the typical bone lesions and renal involvement resemble, in part, the human disease. Furthermore, this model has already proved useful in studies on the effect of bisphosphonate in the treatment of bone disease in MM. The severe combined immunodeficiency (SCID) mouse model is also very attractive. A disseminated-like disease can be reproduced in this model. Multiple osteolytic bone lesions and bone marrow involvement are generated, and conventional drugs applied in the treatment of human multiple myeloma have proven to be effective. Nevertheless, the immune system of SCID mice basically differs from that of a MM patient.

PERSPECTIVES

Taken together, all these models have contributed to our understanding of MM, but demonstrate the opportuness of developing a more appropriate model of the human disease.

[Restricted antibody diversity after bone marrow transplantation--homogeneous immunoglobulins]

After bone marrow transplantation, a prolonged dysregulation of humoral immunity, including restricted electrophoretic heterogeneity of serum immunoglobulins and the appearance of homogeneous immunoglobulin components, can be observed. The current study was undertaken to characterize further and define the posttransplantational incidence of monoclonal and oligoclonal immunoglobulins, as well as the clinical and laboratory correlations of these phenomena. For this purpose, serial serum protein (IgM, IgG, IgA and CRP) quantification, electrophoresis and immunofixation were performed on 29 patients undergoing allogeneic bone marrow transplantation for chronic myeloid leukemia. 23 out of the 29 patients developed transient oligoclonal and/or monoclonal gammopathies that appeared between 20 and 1750 posttransplantational days. No correlation, however, between the development of graft versus host disease, EBV or CMV infections, or any other symptoms and development of homogeneous immunoglobulin components was seen. Therefore, the development of oligoclonal and monoclonal gammopathies after bone marrow transplantation may be an ubiquitous finding reflecting the inadequacy, i.e. oligoclonality of the recovering B-cell system.

[B-cell content after bone marrow transplantation--molecular basis of the limited antibody diversity]

Despite B-cell counts and serum immunoglobulin levels usually normalized by one year, humoral immunity and the incidence of bacterial infections continue to be abnormal even after years following bone marrow transplantation. This immunodeficiency could be partially caused by B-cell repertoire restriction similar to that observed early in ontogeny. Immune reconstitution after haematopoietic stem cell transplantation really follows many established ontogenetic patterns relating to the appearance of particular membrane markers, immunoglobulin classes and subclasses, and onset of antigen receptor rearrangements. The sequence of events that occur during successful bone marrow transplantation can be regarded as a blueprint for immune reconstitution in other clinical settings as well. However, the repertoire does not resemble a fetal one, because it displays adult-size IgH CDR3s, adult-type immunoglobulin gene utilization and no evidence of bias towards any particular VH-gen family. Therefore, in the description and interpretation of these events, it is important to realize that immune reconstitution does not appear to recapitulate human fetal ontogeny. In terms of B lymphocyte diversity, the inadequacy of the recovering immune system is more likely to be explained by a combination of other factors--such as clonal dominance and the delayed occurrence of somatic hypermutation.

[Regeneration of the immune system after bone marrow transplantation]

After haematopoietic stem cell transplantation, reconstitution of bone marrow consists of two distinct phenomena, numerical recovery of bone marrow cellular elements on the one hand and functional recovery of cellular interactions on the other. Immune reactivity during the first month postgrafting is extremely low. Cytotoxic and phagocytic functions usually recover by day 100, while more specialized and cooperative functions of T and B cells remain impaired up to one year or more postgrafting. Regeneration of total CD4+ T cell number in adult (and especially in elderly) transplant recipients is severely limited and occurs largely by peripheral expansion of mature CD4+ T cells. While restoration of total CD8+ T cell number is commonly seen in adults, potentially important alterations in the subset composition of CD8+ populations remain. Contracted T cell repertoires for CD4+ and CD8+ T cells are consistently found in adults after T cell regeneration. This suggests that thymic function is frequently limiting in adults and that thymic-independent pathways are insufficient for restoring host immunocompetence. Although there are similarities in immune reconstitution after alllo- and autologous haematopoietic stem cell transplantations, allogeneic transplantation involves graft versus host disease and the use of immunosuppressive therapy to control it, both of which further interfere in the early developmental stages of immune reconstitution.

[Clinical and immunopathological significance of chimerism in bone marrow and organ transplantations]

Chimerism is an exceptional immunogenetic state, characterized by the survival and collaboration of cell populations originated from two different individuals. The prerequisites to induce chimerism are immunosuppression, myeloablation or severe immunodeficiency of the recipients on one side and donor originated immuno-hematopoietic cells in the graft on the other. Special immunogenetic conditions to establish chimerism are combined with bone marrow transplantation, transfusion and various kinds of solid organ grafting. There are various methods to detect the type of chimera state depending on the immunogenetic differences between the donor and recipient. The chimera state seems to be one of the leading factors to influence the course of the post-transplant period, the frequency and severity of graft-versus-host disease (GVHD), and the rate of relapse. However, the most important contribution of the chimeric state is the development of graft versus leukemia (GVL) effect. A new conditioning protocol (DBM/Ara-C/Cy) for allogeneic BMT in CML patients and its consequence on chimera state and GVL effect is demonstrated.

[Autologous hematopoietic stem cell transplantation in chronic myeloid leukaemia with different clinical stages]

For most chronic myeloid leukaemia patients the option of a potentially curative allogeneic stem cell transplantation is not available because of age or lack of donor. Alternative therapy with interferon-alpha appears to prolong survival but is probably not curative. The aim of the study is to analyse the clinical results of the first Hungarian autologous transplantations in CML. METHODS: Seven patients were treated with ICE-based regimen plus G-CSF with the aim of mobilising and collecting Ph-negative peripheral stem cells in the setting of autologous transplant program. Five patients had CML in first chronic phase and two in accelerated phase. All patients have been previously treated with interferon-alpha. RESULTS: Median value and ranges for harvested mononuclear cells, CD34(+) cells and CFU-GM were: 5.65x10(8)/kg (2.61-11.38), 1.48x10(6)/kg (0.216-3.5) and 3.43x10(4)/kg (0.243-11.6), respectively. Four out of seven autologous grafts have been transplanted. Busulfan conditioning was used in one case and TBI/Cy conditioning in three patients. All patients are alive and well post-transplant being on interferon-alpha therapy. CONCLUSIONS: Based on the clinical advantages of autologous transplantation including long-term chronic phase, achievement of second chronic phase and improved response to interferon-alpha therapy, the procedure can offer an alternative treatment in CML in lack of HLA-identical donor.

[Therapy of multiple myeloma]

Multiple myeloma (MM) is a haematological malignancy characterised by the clonal expansion of malignant plasma cells within the bone marrow. It accounts for 10% of all haematological malignant diseases and 1% of all malignancies. The median age of patients at the time of the diagnosis is 70 years. The characteristic clinical features of MM are bone marrow failure, susceptibility to infections, bone pain, pathological bone fractures, hypercalcaemia, and renal failure. Though MM is currently incurable, the important progress in chemotherapy has resulted in an improvement in survival from a median of 7 months in the 1950-ies to about 3 years today. Advances in the diagnosis and in supportive treatment of infections, hypercalcaemia, and renal failure also contributed to the prolongation of survival. For decades, the gold standard of treatment had been oral melphalan alone or in combination with prednisolone. Combination chemotherapy has not improved overall survival (OS), but these regimens have led to the prolongation of event-free survival (EFS) and also to a better quality of life. High-dose chemotherapy with haemopoietic stem cell rescue resulted in a great improvement in EFS as well as OS. For those very few who have an HLA-compatible donor and are under 55, allogeneic bone marrow transplantation offers the best hope of survival but comes at a greatly increased risk of toxicity. There are conflicting data in the literature concerning the role of interferon-alpha; it seems to be able to prolong the duration of the plateau phase. Current treatment is moving towards an approach using sequential therapy. This involves induction therapy proceeding to high-dose chemotherapy with some form of stem-cell rescue. Bisphosphonates reduce hypercalcaemia, bone pain and can inhibit bone destruction. They also possess a direct antitumor activity. The better understanding of the pathomechanism of the disease gives the opportunity of the application of new therapeutic modalities such as antagonising the effect of interleukin-6 (IL-6), or idiotypic vaccination.

Elevated levels of serum prolactin in patients with advanced multiple myeloma

BACKGROUND AND OBJECTIVE

The role of prolactin in immunoregulation and normal hemopoiesis is well known. However, prolactin also seems to be involved in the pathomechanism of malignancies and autoimmune diseases. Elevated serum prolactin levels were reported in patients with malignant lymphoma, colon and breast carcinoma, systemic lupus erythematosus and rheumatoid arthritis. Recently we demonstrated prolactin immunostaining in bone marrow cells of patients with multiple myeloma.

DESIGN AND METHODS

Serum prolactin levels of 56 patients with multiple myeloma, as well as serum beta(2)-microglobulin, and interleukin-6 concentrations were determined in this study.

RESULTS

Patients with advanced disease showed a significant increase in serum prolactin concentration, while patients with a clinical stage of I and II, and also control patients had normal values. The concentration of serum beta(2)-microglobulin and interleukin-6 changed in parallel with that of serum prolactin in patients with multiple myeloma. Determining serum prolactin levels several times during the disease process in a given patient clearly showed that the prolactin concentration was increasing during the disease progression.

INTERPRETATION AND CONCLUSIONS

Our results indicate a role of prolactin in disease progression in multiple myeloma.

[Immunophenotyping in acute leukemia: detection of minimal residual disease]

Immunophenotyping improves both accuracy and reproducibility of the acute leukaemia classification and is considered particularly useful for identifying poorly differentiated subtypes of acute myeloid leukaemia and lineage association of acute lymphoid leukaemia. Immunological studies of leukaemic blasts has become critical also identifying biphenotypic leukaemias and acute myeloid leukaemia expressing lymphoid associated markers. At present, while the prognostic value of individual antigen expressions is still controversial, the immunologic detection of minimal residual disease seems to be important in monitoring the acute leukaemia patients in remission. In the present study immunophenotyping of bone marrow samples of 42 patients with acute myeloid leukaemia and 13 patients with acute lymphoid leukaemia was analysed. Patients were assessed both before and after treatment by immunophenotyping, cytogenetics and polymerase chain reaction amplification. The immunophenotyping have allowed more sensitive definition of acute leukaemia relapse, but molecular genetic methods are recommended for detection of elimination of residual disease.

Immunological importance of chimerism in transplantation: new conditioning protocol in BMT and the development of chimeric state

Chimerism is an exceptional immunogenetic state, characterized by the survival and collaboration of cell populations originated from two different individuals. The prerequisits to induce chimerism are immuno-suppression, myeloablation, or severe immunodeficiency of the recipients on the one side and donor originated immuno-hematopoietic cells in the graft on the other. The pathologic or special immunogenetic conditions to establish chimerism are combined with bone marrow transplantation, transfusion, and various kinds of solid organ grafting. Different types of chimerism are known including complete, mixed and mosaic, or split chimerism. There are various methods used to detect the type of chimera state, depending on the immunogenetic differences between the donor and recipient. The induction of complete or mixed chimerism is first determinated by the effect of myeloablative therapy. The chimera state seems to be one of the leading factors to influence the course of the post-transplant period, the frequency and severity of GVHD, and the rate of relapse. However, the most important contribution of the chimeric state is in development of graft versus leukemia effect. A new conditioning protocol (DBM/Ara-C/Cy) for allogeneic BMT in CML patients and its consequence on chimera state and GVL effect is demonstrated.

[Use of studies on genome polymorphism in follow up after allogenic bone marrow transplantation]

The study of structures polymorphic in size found in the human genom (the VNTR loci) enables us to differentiate two individuals or--after bone marrow transplantation--to detect the simultaneous presence of two genoms in patients' blood or marrow. The existence of mixed chimerism may influence the therapy. The authors have screened 54 patients, transplanted in their Institute, and their donors by determination of four polymorphic loci. Informative marker was found in 43 cases. The bone marrow transplantation immunotherapy of 29 patients could be followed over 2-36 months. To increase the sensitivity of the polymerase chain reaction method used, the authors introduced the blotting/hybridization steps using isotop labeled repetitive sequences. The results are presented in comparison with literature data.

[A new radiation-free conditioning in bone marrow transplantation and dibromo-mannitol therapy in chronic myeloid leukemia]

A new, radiation-free, conditioning protocol, containing the original Hungarian mitobronitol (DBM) (DBM/ cytosine arabinoside/cyclosphosphamide) has been applied to 36 chronic myeloid leukemia (CML) patients followed by bone marrow transplantation (BMT) from HLA identical sibling donors between 1990-1997. In spite of some prognostically disadvantageous factors (half of them were above 40 years, 10 out of 36 patients were in accelerated phase, the disease history was longer than 2 years in average) the overall survival (30/36) and the leukemia free survival rate (26/36) were in accordance with the best international results. Transplantation-related toxicity was remarkably reduced in comparison to bone marrow transplantation performed by total body irradiation/cyclophosphamide (TBI/Cy) or busulphan/cyclophosphamide (Bu/Cy) conditioning protocols. Acute graft versus host disease was present in lower percentage (9/36) and the number of serious cases was only 2/36. Chronic GVH disease, generally known to be associated with antileukemic effect (GVL), occurred in 25 of cases. Early haematological relapse among the 34 patients with functioning graft occurred in 6 patients which rate is slightly higher than reported after TBI/Cy or Bu/Cy conditioning treatment. There was no relapse among patients transplanted within one year post-diagnosis and patients having CML with accelerated phase. The leukemia free post-transplant period was in association with the chronic GVH disease and full chimeric state.

Histidine decarboxylase in peripheral lymphocytes of healthy individuals and chronic lymphoid leukemia patients

Histidine decarboxylase (HDC), the only enzyme capable of synthetizing histamine, has been found in many proliferating cells and tissues suggesting a role of histamine in cellular proliferation. In this study expression of HDC and the significance of histamine in the proliferation of peripheral lymphocytes of five healthy persons and six patients with chronic lymphoid leukemia (CLL) was examined. Expression of HDC mRNA and the protein was proved by reverse transcriptase polymerase chain reaction and by immunoblot, respectively. The role of histamine was studied in proliferation assays in the presence of irreversible inhibitor of the HDC (alpha-fluoromethylhistidine--aFMH) and also by competing for the intracellular binding sites of histamine using N,N-diethyl-2, 4-phenylmethyl-phenoxy-ethanamine-HCl (DPPE). By inhibiting the HDC enzyme activity by FMH and blocking the intracellular action of histamine by DPPE, a significant decrease in cell proliferation was observed in mitogen stimulated lymphocytes of healthy donors. In CLL patients the proliferation of leukemic lymphocytes was significantly inhibited by blocking the binding of histamine to intracellular binding sites by DPPE but not by FMH inhibiting only the de novo histamine formation. The observations suggest that HDC has functional relevance in lymphocytes, since mitogen induced lymphocyte proliferation of healthy donors is mainly enhanced by de novo synthesis and subsequent action of intracellular histamine. Alternatively, in constitutively proliferating chronic lymphoid leukemia cells we suggest that the preformed pool but not the de novo synthesized intracellular histamine interferes with cellular proliferation.

Reduction in the frequency of transplant-related complications in patients with chronic myeloid leukemia undergoing BMT preconditioned with a new, non-myeloablative drug combination

A radiation-free, non-myeloablative, myelosuppressive protocol, containing dibromomannitol and cytosine arabinoside, that remarkably reduced the frequency of transplant-related complications, such as veno-occlusive liver disease (VOLD), severe mucositis, bacterial sepsis, hemorrhagic cystitis, interstitial pneumonitis, has been applied in 19 CML patients, allotransplanted from identical siblings. Five patients were in accelerated phase. Acute GVHD developed in two patients and chronic GVHD occurred in 66% of patients. Follow-up was 3 to 7 1/2 years. Although only eight patients were under 30 years of age, and only two patients had a history of less than 1 year, the leukemia-free survival was 82%. There were four hematological relapses. The reduction in post-BMT complications has greatly enhanced quality of life. The nurses reported significant reduction of work-load. Savings in eliminating the need for irradiation, parenteral nutrition, and several antibiotics are also remarkable. The remarkable reduction of certain transplant-related complications shows some advantage against busulphan-preconditioning.

Comparison of the lymphoid toxicities of mitobronitol and busulphan in mice: reduced B cell toxicity and improved thymic recovery as possible contributors to the reduced risk for complications following BMT with mitobronitol preconditioning

It has previously been reported that the use of mitobronitol (dibromomannitol, DBM) instead of busulphan (BU) for myelosuppression is associated with significantly decreased risk for several complications of allogeneic bone marrow transplantation in accelerated chronic granulocytic leukemia. In exploring the pharmacologic basis for this observation, we have compared the acute and subacute cytotoxicities of DBM and BU on the spleen and thymus of mice. While there was comparable early (day 3) weight loss in both organs following these treatments, splenic B cells exhibited significantly less damage, and thymic regeneration (over weeks) was significantly faster following DBM treatment than with BU. These observations raise the possibility that improved post-BMT immune recovery could contribute to the clinical benefits observed with DBM-preconditioning.

Inhibition of IgE production by epsilon (epsilon) chain-specific antisense oligonucleotides (AOs) studied on human myeloma cell line U266 and peripheral blood mononuclear cells of a patient with hypereosinophilia

Based on cDNA sequence data epsilon chain-specific antisense oligonucleotides were synthesized and checked on in vitro IgE production. Using peripheral blood cells from a hypereosinophilic patient and a human IgE myeloma cell line, U266, marked reduction of in vitro IgE production measured by PRIST was observed. The effect of epsilon antisenses proved to be isotype specific since IgG production by both peripheral blood cells and a lymphoma cell line, CESS, was not affected. Moreover, the expression of other markers on U266 (interleukin-6 receptor and gp130) were not influenced by epsilon-specific antisense oligonucleotides.

[The bone-marrow transplantation program in Hungary: report from the period 1990-1995]

The article summarises the statistical data of bone marrow transplantation (BMT) carried out in Hungary between 1990-1995 in yearly distribution. Since the first BMT up to the end of 1995, 168 BMT were performed. The number of transplantations since 1990 to our days was gradually increasing. As a result of this activity in the three transplantation centers (National Institute of Haematology and Immunology, St. László Hospital and County Hospital in Miskolc) 36 allogeneic and 12 autologous BMT were performed in 1995. Out of the allogeneic BMT cases, 14% of them were completed with unrelated, donors in the last three years. The most frequent indications for allogenic BMT are: chronic myeloid leukaemia (CML), acute lymphoid leukaemia (ALL), acute myeloid leukaemia (AML), myelodysplasia, severe aplastic anaemia. Child allogenic BMTs are carried out on pediatric patients in St. László Hospital in leukaemia, severe aplastic anaemia cases and children born with immunodeficiency. Autologous BMTs started in an organised way in 1995 for adult patients in cases of non-Hodgkin lymphoma, Hodgkin lymphoma and for children with solid tumour indication in the Miskolc Centre. BMT activity in Hungary compared with international data, especially within Europe, shows a significant drop behind. To calculate for ten million inhabitants, the optimal BMT activity should be between 100-200 transplantations (allogeneic and autologous BMT together) in 1994. Among the Central European countries Hungary and Poland fall most behind. Autologous BMTs in most countries of Europe are above of allogeneic BMTs in numbers as indication in cases of lymphoma and solid tumours (first of all mamma carcinoma) comes into focus. This summary emphasises the most important difficulties in connection with the development of the National BMT program.

Establishment and characterization of an EBNA-negative human lymphoma cell line (BHL-89)

BACKGROUND

The aim of the work was to establish human malignant lymphomas in culture, in order to study the biological characteristics and drug sensitivity of lymphomas of human lymphoid origin.

MATERIALS AND METHODS

Lymph nodes of patients were explanted and kept in cultures using conventional tissue culture methods. Cytogenetic methods were used for karyotype analysis. Clonogenic assay was applied to test drug sensitivity. The tumorigenic capacity of the cells was determined by inoculating them into immunosuppressed mice. Immunological and other markers were examined with conventional techniques.

RESULTS

A cell line, BHL-89, was established in culture from a patient with B-cell type non-Hodgkin's malignant lymphoma. Cells started to grow after a few days without a feeder layer in stationary suspension. The population doubling time was 48 h. The cells were hyperploid, and non-random aberrations were +1, -15, +14q+. Cloning efficiency in soft agar was found to be as high as 50-60%. The cells expressed markers characteristic of early B cells. The BHL-89 cells were Epstein-Barr nuclear antigen (EBNA) negative. They produced tumors when 10(7) cells were injected into immunosuppressed mice. The cells were sensitive to dibromodulcitol (Elobromol), an alkylating antitumor drug, and resistant to the phorbol ester TPA.

CONCLUSIONS

The established EBNA-negative BHL-89 cell line has a few unique characteristics, e.g. rapid establishment without feeder cells, origin from the lymph node of an adult patient, high clonogenicity in soft agar, and resistance to TPA. The cell line is suitable for studying the nature of B lymphomas and testing compounds against lymphoproliferative disorders.

Low activity of the classical complement pathway predicts short survival of patients with chronic lymphocytic leukaemia

The activities of the classical (CP) and alternative (AP) complement pathways as well as the levels of some complement components and circulating immune complexes were measured in 43 patients with chronic lymphocytic leukaemia (CLL) between 1980 and 1984. Depressed CP activities were frequently found in these patients. Clinical course of the disease in the patients was followed until 1992, and compared with the initial complement values. During the follow-up period 36 patients died, death of 33 patients being related to the underlying disease. A strong positive correlation (P < 0.01) was found between the length of survival of the patients and the initial CP values. Patients were divided into two groups: group A, short-term survivors, i.e patients who died in CLL-related complications within 3 years after the complement measurements; and group B, long-term survivors who died > or = 4 years after the complement measurements due to any cause, or were alive at the end of the follow-up period. Average CP values in Group B were almost twice those in group A (P = 0.002), and a similar but less pronounced difference was found in C3 levels (P = 0.055). These differences were even more marked (P = 0.0006 and P = 0.0015, respectively) when only patients in Rai stage 2 and 3 were considered. Low classical pathway activities predicted short survival time: according to the logrank test, patients in Rai stage 2-3 with low (< mean - 2s.d. of the normal values), and normal CP levels survived for 2.0 +/- 1.1, and 4.6 +/- 3.0 years, respectively. All the nine and 11/13 patients with low CP and C4 levels, respectively, died within 3 years after the complement measurements were made. These findings indicate that complement measurements performed in CLL patients have a clinical value.

Immunologic and molecular biologic characterization of pleural involvement in a case of T-chronic lymphocytic leukemia

Pleural involvement is a rare complication of chronic lymphocytic leukemia (CLL). We report a CLL case of T-cell origin (documented by cell surface marker as well as DNA rearrangement studies) where the lymphoid cells of the pleural fluid were found to belong to the same monoclonal population of T cells as those of the peripheral blood.

[Experience with the molecular genetical detection of the chimera gene of the Philadelphia chromosome]

Molecular genetical techniques could be developed for detection of the chimera gene of Philadelphia chromosome or that of its gene product, due to the relatively conserved structure of the chimera gene. The authors successfully analysed 123 blood/bone marrow samples from 106 patients using these molecular techniques adapted from the literature. Patients were classified by the first diagnosis, 65 CML, 7 AML, 13 ALL patients were studied. 12 patients had the diagnosis of myeloproliferative syndrome, and 9 patients were after bone marrow transplantation. 57% of the total, and by diagnosis, 74% of CML, 28% of AML, 54% of ALL, and 33% of post-transplant samples have shown the chimera gene structure characteristic for Philadelphia chromosome. All patients of myeloproliferative syndrome were negative. In some cases the authors had the opportunity to study simultaneously the peripheral blood and the bone marrow sample of the same patient and of the same date. The ratio of the positivity of the two samples varied from one to infinite. The authors could follow the effect of interferon in one case, the change of clonality of the leukemic cell line in an other case. They had the opportunity to detect two different abnormal gene structures in the sample of an AML patient.

Autoantibody occurrence in hairy cell leukemia

BACKGROUND

Autoimmune syndromes accompanying hairy cell leukemia (HCL) may represent a specific entity in HCL patients. It has been claimed that interferon (IFN)-alpha therapy contributes to the occurrence of autoantibodies in HCL. The study was undertaken to determine the occurrence of autoantibodies in HCL patients prior to IFN-alpha therapy.

PATIENTS AND METHODS

Sera of 24 patients with HCL of B-cell origin (as determined previously by peripheral blood mononuclear cell surface markers and/or DNA rearrangement studies) were investigated. In addition serum from a T-HCL patient was studied. Nineteen of the 25 HCL patients had been splenectomized prior to the study. One patient was found to have IgM lambda monoclonal protein in her serum. Antinuclear antibodies were determined with an indirect IF test using Hep-2 cells. Rheumatoid factors of the IgM and IgA classes were determined by enzyme-linked immunosorbent assay (ELISA). Granulocyte-specific antinuclear antibodies and antineutrophil cytoplasmic antibodies were determined by indirect immunofluorescence.

RESULTS

No clinical syndrome of an autoimmune disease was apparent in any of our HCL-patients. Rheumatoid factors of either IgM or IgA class were found in the sera of six B-HCL patients and antinuclear antibodies in five cases, while anti-cytoplasmic antibodies were identified in only three cases. The occurrence of antibodies seemed to be independent of the clinical stage of the disease as determined according to the functional criteria. Two patients with arthralgias and one with vitiligo had no autoantibodies in their sera.

CONCLUSIONS

Autoantibodies might occur in HCL patients prior to treatment with interferon-alpha and in the absence of the clinical syndrome of an autoimmune disease.