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Purpose: The purpose of this study was to evaluate ophthalmological findings in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) in a Latin American population., Materials and Methods: This was a single-center, retrospective study. The observational analysis was conducted in AML and ALL patients seen as a routine examination at the department of ophthalmology of tertiary care center in Argentina between March 1, 2017, and February 28, 2018., Results: Overall, 137 patients with acute leukemia were included. The mean age was 7.9 ± 5.2 years (0-18), and 55% were male ( n = 75) and 45% female ( n = 45). At least one-fifth ( n = 31) of the patients presented some type of ocular manifestation (23%). The most frequently observed manifestation was retinal hemorrhages ( n = 14), followed by papilledema ( n = 9) and ocular surface involvement ( n = 5). The eye involvement was more frequently identified in the AML group (24%), compared to the ALL group (22%), especially papilledema with central nervous system compromise ALL (5%) and AML (11%), P < 0.01. The presence of hemorrhages was similar in both groups. In patients with retinal hemorrhage ( n = 14), the mean hematological findings were hemoglobin 7.4 ± 0.4 g/dL (6.5-8.0), erythrocytes 2.5M ± 0.3/mm 3 (confidence interval [CI], 2.0-3.1), and platelets 76,000 ± 32,000/mm 3 (CI, 8000-384,000). Patients without retinal findings ( n = 123), the mean hematological findings were hemoglobin 9.1 ± 0.6 g/dL (8.0-10.2), erythrocytes 3.2M ± 0.6/mm 3 (CI, 2.5-3.5), and platelets 92,000 ± 44,000/mm 3 (CI, 42.000-390.000). Multivariable analysis found that hemoglobin levels were the most reliable predictive factor for retinal findings. It was observed that the risk diminishes in patients with levels higher than 8.5 g/dL, and that it increased in patients with levels ranging between 6.5 and 7.5 g/dL at least twice ( P < 0.01)., Conclusions: Our results show that ocular involvement occurs in a high percentage of patients with leukemia with a clear clinical, humoral, and sometimes prognostic correlation, suggesting routine ophthalmologic evaluation in these patients., Competing Interests: There are no conflicts of interest., (Copyright: © 2022 Oman Ophthalmic Society.)

The Spectrometer/Telescope for Imaging X-rays (STIX) is one of six remote sensing instruments on-board Solar Orbiter. The telescope applies an indirect imaging technique that uses the measurement of 30 visibilities, i.e., angular Fourier components of the solar flare X-ray source. Hence, the imaging problem for STIX consists of the Fourier inversion of the data measured by the instrument. In this work, we show that the visibility amplitude and phase calibration of 24 out of 30 STIX sub-collimators has reached a satisfactory level for scientific data exploitation and that a set of imaging methods is able to provide the first hard X-ray images of solar flares from Solar Orbiter. Four visibility-based image reconstruction methods and one count-based are applied to calibrated STIX observations of six events with GOES class between C4 and M4 that occurred in May 2021. The resulting reconstructions are compared to those provided by an optimization algorithm used for fitting the amplitudes of STIX visibilities. We show that the five imaging methods produce results morphologically consistent with the ones provided by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory (SDO/AIA) in UV wavelengths. The χ 2 values and the parameters of the reconstructed sources are comparable between methods, thus confirming their robustness., Competing Interests: Conflict of InterestThe authors declare that they have no conflicts of interest., (© The Author(s) 2022.)

Colorectal cancer (CRC) is one of the most deadly and commonly diagnosed tumors worldwide. Several genes are involved in its development and progression. The most frequent mutations concern APC, KRAS, SMAD4, and TP53 genes, suggesting that CRC relies on the concomitant alteration of the related pathways. However, with classic molecular approaches, it is not easy to simultaneously analyze the interconnections between these pathways. To overcome this limitation, recently these pathways have been included in a huge chemical reaction network (CRN) describing how information sensed from the environment by growth factors is processed by healthy colorectal cells. Starting from this CRN, we propose a computational model which simulates the effects induced by single or multiple concurrent mutations on the global signaling network. The model has been tested in three scenarios. First, we have quantified the changes induced on the concentration of the proteins of the network by a mutation in APC, KRAS, SMAD4, or TP53. Second, we have computed the changes in the concentration of p53 induced by up to two concurrent mutations affecting proteins upstreams in the network. Third, we have considered a mutated cell affected by a gain of function of KRAS, and we have simulated the action of Dabrafenib, showing that the proposed model can be used to determine the most effective amount of drug to be delivered to the cell. In general, the proposed approach displays several advantages, in that it allows to quantify the alteration in the concentration of the proteins resulting from a single or multiple given mutations. Moreover, simulations of the global signaling network of CRC may be used to identify new therapeutic targets, or to disclose unexpected interactions between the involved pathways., (© 2021. The Author(s).)

Background: In East Asia, face masks are commonly worn to reduce viral spread. In Euope and North America, however, their use has been stigmatised for a long time, although this view has radically changed during the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Notwithstanding this, it is still unclear whether face masks worn by COVID-19 carriers may indeed prevent viral transmission and environmental contamination. The objective of this study was to evaluate the effectiveness of surgical face masks in filtering SARS-CoV-2., Methods: Four male patients with COVID-19 were recruited for the study. Two patients wore a surgical mask for 5 h, while two others did not. The spread of the virus in the environment was evaluated through the approved Allplex 2019-nCoV assay., Results: In the room with the two patients without surgical masks, the swab performed on the headboard and sides of the beds was positive for SARS-CoV-2 contamination. In the other room, where two patients were wearing surgical masks, all of the swabs obtained after 5 h tested negative., Conclusions: The results of the current study add to the growing body of literature supporting the use of face masks as a measure to contain the spread of SARS-CoV-2 by retaining potentially contagious droplets that can infect other people and/or contaminate surfaces. Based on the current evidence, face masks should therefore be considered a useful and low-cost device in addition to social distancing and hand hygiene during the postlockdown phase., (© The Author(s) 2020. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: As an emerging infectious disease, the clinical and virologic course of COVID-19 requires better investigation. The aim of this study is to identify the potential risk factors associated with persistent positive nasopharyngeal swab real-time reverse transcription‒polymerase chain reaction tests in a large sample of patients who recovered from COVID-19., Methods: After the acute phase of SARS-CoV-2 epidemic infection, the Fondazione Policlinico A. Gemelli IRCSS of Rome established a post-acute care service for patients discharged from the hospital and recovered from COVID-19. Between April 21 and May 21, 2020, a total of 137 individuals who officially recovered from COVID-19 were enrolled in this study. All patients were tested for the SARS-CoV-2 virus with nucleic acid RT-PCR tests. Analysis was conducted in June 2020., Results: Of the 131 patients who repeated the nasopharyngeal swab, 22 patients (16.7%) tested positive again. Some symptoms such as fatigue (51%), dyspnea (44%), and coughing (17%) were still present in a significant percentage of the patients, with no difference between patients with a negative test and those who tested positive. The likelihood of testing positive for SARS-CoV-2 infection was significantly higher among participants with persistent sore throat (prevalence ratio=6.50, 95% CI=1.38, 30.6) and symptoms of rhinitis (prevalence ratio=3.72, 95% CI=1.10, 12.5)., Conclusions: This study is the first to provide a given rate of patients (16.7%) who test positive on RT-PCR test for SARS-CoV-2 nucleic acid after recovering from COVID-19. These findings suggest that a significant proportion of patients who have recovered from COVID-19 still could be potential carriers of the virus. In particular, if patients continue to have symptoms related to COVID-19, such as sore throat and rhinitis, it is reasonable to be cautious by avoiding close contact, wearing a face mask, and possibly repeating a nasopharyngeal swab., (Copyright © 2020 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: Vasospasm is a severe complication in patients with aneurysmal subarachnoid hemorrhage (aSAH) and cannot be reliably predicted. Its pathophysiology remains elusive with the current body of evidence suggesting inflammation as one of the main driving forces. We here aimed to analyze circulating immune cell subsets over time in patients with aSAH with or without vasospasm. Methods: We performed a prospective observational study recruiting patients with spontaneous aSAH. Peripheral blood withdrawn at pre-specified time-points after aSAH, day 0, days 3-4, 6-8, 10-11, 13-15, and 18-21. Flow cytometry analysis, cell blood counts, and laboratory and diagnostic parameters were performed. Patients were monitored by transcranial Doppler for vasospasm as well as by advanced imaging and divided into a group with (VS) and without vasospasm VS (NVS). Results: We included 42 patients for study analysis, 21 VS and 21 NVS. An early significant increase at day 0 in platelet, leukocyte, neutrophil, lymphocyte, NK lymphocyte, monocyte, and CD 14 ++ CD16 - DR + monocyte counts was found in patients with later ensuing vasospasm. The early differences in platelets, leukocytes, lymphocytes, and NK lymphocytes remained significant on multivariate analysis. Conclusions: An early increase of immune cellular subsets in aSAH may contribute to predict VS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Bacigaluppi, Ivaldi, Bragazzi, Benvenuto, Gallo, D'Andrea, Severi, Uccelli and Zona.)

On February 20, 2020, a man living in the north of Italy was admitted to the emergency room with an atypical pneumonia that later proved to be COVID-19. This was the trigger of one of the most serious clusters of COVID-19 in the world, outside of China. Despite aggressive restraint and inhibition efforts, COVID-19 continues to increase, and the total number of infected patients in Italy is growing daily. After 6 weeks, the total number of patients reached 128,948 cases (April 5, 2020), with the higher case-fatality rate (15,887 deaths) dominated by old and very old patients. This sudden health emergency severely challenged the Italian Health System, in particular acute care hospitals and intensive care units. In 1 hospital, geriatric observation units were created, the experience of which can be extremely useful for European countries, the United States, and all countries that in the coming days will face a similar situation., (Copyright © 2020 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

Study Design: A cross-sectional study., Objective: The aim of this study is to describe the profile of patients with acute low back pain (LBP) who sought emergency departments (EDs) in Brazilian public hospitals. We also described the profile of these patients according to the STarT Back Screening Tool (SBST)., Summary of Background Data: LBP is the most common musculoskeletal condition worldwide and is one of the main complaints in EDs. There is a lack of evidence describing the profile of these patients from low- to middle-income countries., Methods: This is a cross-sectional study involving patients with a new episode of nonspecific acute LBP that was conducted between August 2014 and August 2016. Variables related to clinical, psychological, sociodemographic and work status characteristics were investigated through structured, in-person oral questionnaire., Results: A total of 600 patients were included in the study. The majority of the patients were women (58%), with a median of eight points on pain intensity (measured on an 11-point scale) and 17 points on disability (measured on a 24-item questionnaire). With regards to the SBST evaluation, 295 (49.2%) patients were classified as being at high risk of developing an unfavorable prognosis with a median pain intensity of nine points on pain intensity, 20 points on disability, and seven points on depression (measured on an 11-point scale). Despite this, the majority of the patients (74%) continued working normally without interference from LBP., Conclusion: Identifying the profile of patients seeking care in EDs can help to define effective management for LBP in low- and middle-income countries. Patients with nonspecific acute LBP who seek EDs in Brazil present high levels of pain intensity and disability. Most patients were classified as having a high risk of developing an unfavorable prognosis., Level of Evidence: 2.

Competing Interests: None

Objective: To study the immunomodulatory effect of teriflunomide on innate and adaptive immune cell populations through a pilot, open-label, observational study in a cohort of patients with relapsing-remitting MS., Methods: Blood lymphocytes were isolated from 10 patients with MS before and after 3 or 12 months of treatment. Adaptive and innate immune cell subsets were analyzed by flow cytometry as follows: B cells (memory, regulatory, and mature subsets), T cells (effector and regulatory subsets), and natural killer (NK) cells (CD56 dim and CD56 bright subsets)., Results: Our results show that teriflunomide significantly reduces absolute counts of total CD19 + B cells and mature and regulatory B-cell subsets. T cells were affected to a lesser extent, with a trend in reduction of absolute counts for both T effector CD4 + cells (Th1, Th17 and Th1/17) and T regulatory CD8 + and CD4 + cells. Teriflunomide had no detectable effect on NK-cell numbers., Conclusions: In our small cohort, teriflunomide treatment affects mainly and significantly on B-cell numbers, while having a milder effect on T-cell numbers. Larger cohorts are necessary to confirm these findings and understand the effect of teriflunomide on the functionality of these cells.

Introduction: Systemic delivery of bone marrow-derived mesenchymal stem cells (MSC) seems to be of benefit in the treatment of multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS) sustained by migration of T cells across the brain blood barrier (BBB) and subsequent induction of inflammatory lesions into CNS. MSC have been found to modulate several effector functions of T cells. In this study, we investigated the effects of MSC on adhesion molecules and receptors on T cell surface that sustain their transendothelial migration., Methods: We used different co-culture methods combined with real-time PCR and flow cytometry to evaluate the expression both at the mRNA and at the plasma-membrane level of α4 integrin, β2 integrin, ICAM-1 and CXCR3. In parallel, we assessed if MSC are able to modulate expression of adhesion molecules on the endothelial cells that interact with T cells during their transendothelial migration., Results: Our in vitro analyses revealed that MSC: (i) inhibit proliferation and activation of both peripheral blood mononuclear cells (PBMC) and CD3(+)-selected lymphocytes through the release of soluble factors; (ii) exert suppressive effects on those surface molecules highly expressed by activated lymphocytes and involved in transendothelial migration; (iii) inhibit CXCL10-driven chemotaxis of CD3(+) cells; (iv) down-regulated expression of adhesion molecules on endothelial cells., Conclusions: Taken together, these data demonstrate that the immunosuppressive effect of MSC does not exclusively depends on their anti-proliferative activity on T cells, but also on the impairment of leukocyte migratory potential through the inhibition of the adhesion molecules and receptors that are responsible for T cell trafficking across BBB. This could suggest a new mechanism through which MSC modulate T cell responses.

Five cases of sporotrichosis occurring in pregnant women in a zoonotic epidemic in Rio de Janeiro, Brazil, are described. The main clinical features, as well as the challenging therapeutic choices for this specific group of patients, are discussed.

Bone marrow (BM) derived mesenchymal stem cells (MSC) differentiate into cells of the mesodermal lineage but also, under certain experimental circumstances, into cells of the neuronal and glial lineage. Their therapeutic translation has been significantly boosted by the demonstration that MSC display significant also anti-proliferative, anti-inflammatory and anti-apoptotic features. These properties have been exploited in the effective treatment of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis where the inhibition of the autoimmune response resulted in a significant neuroprotection. A significant rescue of neural cells has been achieved also when MSC were administered in experimental brain ischemia and in animals undergoing brain or spinal cord injury. In these experimental conditions BM-MSC therapeutic effects are likely to depend on paracrine mechanisms mediated by the release of growth factors, anti-apoptotic molecules and anti-inflammatory cytokines creating a favorable environment for the regeneration of neurons, remyelination and improvement of cerebral flow. For potential clinical application BM-MSC offer significant practical advantages over other types of stem cells since they can be obtained from the adult BM and can be easily cultured and expanded in vitro under GMP conditions displaying a very low risk of malignant transformation. This review discusses the targets and mechanisms of BM-MSC mediated neuroprotection., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To document the specificity and the mechanism of induction of a novel class II major histocompatibility complex (MHC) antigen by mitogenic growth factors in human mesenchymal stem cells (MSCs) expanded in vitro for translational applications., Methods: Expression of class II MHC molecules was measured in human MSCs and differentiated cells expanded in the presence of fibroblast growth factor 2 (FGF-2), platelet-derived growth factor BB (PDGF-BB), human platelet lysate, or interferon-γ (IFNγ). The roles of cell proliferation and growth factor-induced signaling pathways were investigated as well as the class II MHC assembly machinery and functional capacity., Results: FGF-2 and, to a lesser extent, PDGF-BB induced in adult human MSCs the expression of HLA-DR (normally induced by inflammatory cytokines), which was able to stimulate CD4+ T cells via superantigen binding. In contrast to IFNγ, FGF induced HLA-DR expression only in human MSCs proliferating under its mitogenic effect and not in mouse MSCs or in differentiated human cells. Although it induced cell proliferation, human platelet lysate did not cause HLA-DR expression in human MSCs. HLA-DR expression occurred following FGF-specific binding to its receptor(s), mainly FGF receptor 1, without inducing IFNγ or tumor necrosis factor α expression. Both MAPK/ERK-1/2 and phosphatidylinositol 3-kinase/Akt controlled cell proliferation and HLA-DR expression, but only MAPK/ERK-1/2 controlled the induction of the class II MHC transcription activator protein CIITA, the major determinant of HLA-DR transcription., Conclusion: The induction of functional HLA-DR in proliferating progenitor MSCs is a property of human MSCs that have been expanded with mitogenic growth factors. This has potential biologic significance in the regulation and/or protection of progenitor cell subpopulations under sustained mitogenic proliferation and needs to be taken into account when expanding MSCs for use in in vivo applications., (Copyright © 2010 by the American College of Rheumatology.)

This work describes the optimization, validation and application of an ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the quantification and confirmation of 11 compounds (atrazine, simazine, terbuthylazine, terbumeton, terbutryn and their main transformation products) in surface and wastewater samples. Several of these analytes are included in the list of priority substances in the framework on European Water Policy. The application of this method to water samples reveals that the most relevant transformation products (TPs) should be incorporated into current analytical methods to obtain a more realistic knowledge of water quality regarding pesticide contamination. TPs are generally more polar and mobile than parents and can be transported to the aquatic environment more easily than their precursors. This can explain their concentrations found in water, which in many cases are much higher than intact triazines. To efficiently combine UHPLC with MS/MS, a fast-acquisition triple quadrupole mass analyser was used. Working in selected reaction monitoring mode, up to three simultaneous transitions per compound were acquired, allowing a reliable quantification and confirmation at nanogram per litre levels. The method developed includes a pre-concentration step based on solid-phase extraction (OASIS HLB cartridges). Satisfactory recoveries (70-120%) and relative standard deviations (<20%) were obtained for all compounds in different water sample types spiked at two concentrations (0.025 and 0.1 microg/L in surface water; 0.25 and 1.0 microg/L in effluent wastewater; 0.5 and 2.0 microg/L in influent wastewater). The optimized method was found to have excellent sensitivity with instrumental detection limits as low as 0.03 pg. In addition, the influence of the matrix constituents on the ionization efficiency and the extraction recovery was studied in different types of Italian and Spanish surface and urban wastewater. Signal suppressions were observed for all compounds, especially for influent wastewater. The use of isotope-labelled internal standards was found to be the best approach to assure an accurate quantification in all matrix samples.

A previous work showed that an antigenic fraction of Sporothrix schenckii, SsCBF, was specifically recognized by IgG antibodies present in patients' clinical specimens. The objective of this investigation was to compare the reactivity of this antigen recovered from three S. schenckii strains. ROC curve analysis revealed a variation in the sensitivity and specificity of the antigen derived from each of the strains, with a higher AUC for strain 1099-18. Moreover, the presence of the main O-glycosidically-linked epitopes described in the SsCBF fraction was ascertained. A significant reduction in SsCBF reactivity of all the strains was observed after beta-elimination confirming the presence of O-glycan epitopes. The antigen isolated from strain 1099-18 proved to be a more accurate diagnostic tool for serodiagnosis of sporotrichosis.

Nicotinamide phosphoribosyltransferase (Nampt) inhibitors such as FK866 are potent inhibitors of NAD(+) synthesis that show promise for the treatment of different forms of cancer. Based on Nampt upregulation in activated T lymphocytes and on preliminary reports of lymphopenia in FK866 treated patients, we have investigated FK866 for its capacity to interfere with T lymphocyte function and survival. Intracellular pyridine nucleotides, ATP, mitochondrial function, viability, proliferation, activation markers and cytokine secretion were assessed in resting and in activated human T lymphocytes. In addition, we used experimental autoimmune encephalomyelitis (EAE) as a model of T-cell mediated autoimmune disease to assess FK866 efficacy in vivo. We show that activated, but not resting, T lymphocytes undergo massive NAD(+) depletion upon FK866-mediated Nampt inhibition. As a consequence, impaired proliferation, reduced IFN-gamma and TNF-alpha production, and finally autophagic cell demise result. We demonstrate that upregulation of the NAD(+)-degrading enzyme poly-(ADP-ribose)-polymerase (PARP) by activated T cells enhances their susceptibility to NAD(+) depletion. In addition, we relate defective IFN-gamma and TNF-alpha production in response to FK866 to impaired Sirt6 activity. Finally, we show that FK866 strikingly reduces the neurological damage and the clinical manifestations of EAE. In conclusion, Nampt inhibitors (and possibly Sirt6 inhibitors) could be used to modulate T cell-mediated immune responses and thereby be beneficial in immune-mediated disorders.

Interleukin 17-producing T helper cells (T(H)-17 cells) are important in experimental autoimmune encephalomyelitis, but their route of entry into the central nervous system (CNS) and their contribution relative to that of other effector T cells remain to be determined. Here we found that mice lacking CCR6, a chemokine receptor characteristic of T(H)-17 cells, developed T(H)-17 responses but were highly resistant to the induction of experimental autoimmune encephalomyelitis. Disease susceptibility was reconstituted by transfer of wild-type T cells that entered into the CNS before disease onset and triggered massive CCR6-independent recruitment of effector T cells across activated parenchymal vessels. The CCR6 ligand CCL20 was constitutively expressed in epithelial cells of choroid plexus in mice and humans. Our results identify distinct molecular requirements and ports of lymphocyte entry into uninflamed versus inflamed CNS and suggest that the CCR6-CCL20 axis in the choroid plexus controls immune surveillance of the CNS.

The immunomodulatory activities of human mesenchymal stem cells (MSCs) provide a rational basis for their application in the treatment of immune-mediated diseases, such as graft versus host disease and multiple sclerosis. The effects of MSCs on invariant natural killer T (iNKT) and gammadelta T cells, both involved in the pathogenesis of autoimmune diseases, are unknown. Here, we investigated the effects of MSCs on in vitro expansion of these unconventional T-cell populations. MSCs inhibited iNKT (Valpha24(+)Vbeta11(+)) and gammadelta T (Vdelta2(+)) cell expansion from peripheral blood mononuclear cells in both cell-to-cell contact and transwell systems. Such inhibition was partially counteracted by indomethacin, a prostaglandin E(2) inhibitor. Block of indoleamine 2,3-deoxygenase and transforming growth factor beta1 did not affect Valpha24(+)Vbeta11(+) and Vdelta2(+) cell expansion. MSCs inhibited interferon-gamma production by activated Valpha24(+)Vbeta11(+) and impaired CD3-mediated proliferation of activated Valpha24(+)Vbeta11(+) and Vdelta2(+) T cells, without affecting their cytotoxic potential. MSCs did not inhibit antigen processing/presentation by activated Vdelta2(+) T cells to CD4(+) T cells. In contrast, MSCs were lysed by activated Vdelta2(+) T cells through a T-cell receptor-dependent mechanism. These results are translationally relevant in view of the increasing interest in MSC-based therapy of autoimmune diseases.

Mesenchymal stem cells (MSC) are part of the bone marrow that provides signals supporting survival and growth of bystander hematopoietic stem cells (HSC). MSC modulate also the immune response, as they inhibit proliferation of lymphocytes. In order to investigate whether MSC can support survival of T cells, we investigated MSC capacity of rescuing T lymphocytes from cell death induced by different mechanisms. We observed that MSC prolong survival of unstimulated T cells and apoptosis-prone thymocytes cultured under starving conditions. MSC rescued T cells from activation induced cell death (AICD) by downregulation of Fas receptor and Fas ligand on T cell surface and inhibition of endogenous proteases involved in cell death. MSC dampened also Fas receptor mediated apoptosis of CD95 expressing Jurkat leukemic T cells. In contrast, rescue from AICD was not associated with a significant change of Bcl-2, an inhibitor of apoptosis induced by cell stress. Accordingly, MSC exhibited a minimal capacity of rescuing Jurkat cells from chemically induced apoptosis, a process disrupting the mitochondrial membrane potential regulated by Bcl-2. These results suggest that MSC interfere with the Fas receptor regulated process of programmed cell death. Overall, MSC can inhibit proliferation of activated T cells while supporting their survival in a quiescent state, providing a model of their activity inside the HSC niche. Disclosure of potential conflicts of interest is found at the end of this article.

Background: The hematopoietic stem cells (HSCs) niche of the bone marrow is comprised of HSCs, osteoblasts, endothelial cells and a stromal component of non-hematopoietic multipotent cells of mesenchymal origin named "mesenchymal stem cells" (MSCs)., Results: Here we studied the global transcriptional profile of murine MSCs with immuno-therapeutic potential and compared it with that of 486 publicly available microarray datasets from 12 other mouse tissues or cell types. Principal component analysis and hierarchical clustering identified a unique pattern of gene expression capable of distinctively classifying MSCs from other tissues and cells. We then performed an analysis aimed to identify absolute and relative abundance of transcripts in all cell types. We found that the set of transcripts uniquely expressed by MSCs is enriched in transcription factors and components of the Wnt signaling pathway. The analysis of differentially expressed genes also identified a set of genes specifically involved in the HSC niche and is complemented by functional studies that confirm the findings. Interestingly, some of these genes play a role in the maintenance of HSCs in a quiescent state supporting their survival and preventing them from proliferating and differentiating. We also show that MSCs modulate T cell functions in vitro and, upon in vivo administration, ameliorate experimental autoimmune encephalomyelitis (EAE)., Conclusion: Altogether, these findings provide novel and important insights on the mechanisms of T cell function regulation by MSCs and help to cement the rationale for their application in the treatment of autoimmune diseases.

In this review we will discuss the unique features that make the central nervous system (CNS) a specialized microenvironment where immune responses are tightly regulated in order to properly face pathogens without damaging the neural cells. We will show how every paradigm of this theoretical model has been addressed by the scientific literature over the past decades providing new insights on the immune response within the CNS. In particular, new light has been shed on the trafficking of the immune cells inside and outside the CNS. Dendritic cells (DCs) have been described in the context of structures in direct contact with the cerebrospinal fluid (CSF) and their migration, upon antigen encounter, outside the CNS into deep cervical lymph nodes (DCLNs) has been further clarified. T-cells, B-cells, and antibody-secreting cells (ASCs) have been found in the CSF and CNS parenchymal lesions of inflammatory disorders and their phenotype depicted. Moreover, in chronically inflamed CNS, ectopic lymphoid structures have been observed and a germinal center reaction similar to the one found in peripheral lymph nodes has been described. These structures may play a role in the maintenance and expansion of the local autoimmune response. Although the complex interactions between immune and neural cells still remain far to be elucidated, the data discussed here suggest that the physiopathology of the adaptive immune response inside the CNS mimics, although in a mitigated fashion, what occurs in other organs and tissues.

Human mesenchymal stem cells (hMSCs) suppress T-cell and dendritic-cell function and represent a promising strategy for cell therapy of autoimmune diseases. Nevertheless, no information is currently available on the effects of hMSCs on B cells, which may have a large impact on the clinical use of these cells. hMSCs isolated from the bone marrow and B cells purified from the peripheral blood of healthy donors were cocultured with different B-cell tropic stimuli. B-cell proliferation was inhibited by hMSCs through an arrest in the G0/G1 phase of the cell cycle and not through the induction of apoptosis. A major mechanism of B-cell suppression was hMSC production of soluble factors, as indicated by transwell experiments. hMSCs inhibited B-cell differentiation because IgM, IgG, and IgA production was significantly impaired. CXCR4, CXCR5, and CCR7 B-cell expression, as well as chemotaxis to CXCL12, the CXCR4 ligand, and CXCL13, the CXCR5 ligand, were significantly down-regulated by hMSCs, suggesting that these cells affect chemotactic properties of B cells. B-cell costimulatory molecule expression and cytokine production were unaffected by hMSCs. These results further support the potential therapeutic use of hMSCs in immune-mediated disorders, including those in which B cells play a major role.

In recent years much excitement has been generated over the possibility that adult stem cells may attempt repair of the injured central nervous system (CNS), thus setting the stage for their utilisation in the treatment of neurodegenerative disorders. Recent studies have shown that some subsets of stem cells can also modulate the (auto)immune response, thus providing a rationale for their use as therapy for experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). This article reviews the scientific evidence supporting the possible use of neural stem cells (NSCs) and mesenchymal stem cells (MSCs) for the treatment of MS. In addition, possible mechanisms sustaining the beneficial mode of action of haematopoietic stem cells (HSCs) following transplantation in MS individuals are discussed. Overall, it is proposed that limited subsets of adult stem cells may have a dual function that may be effective for the treatment of MS, an autoimmune disease of the CNS where degeneration of neural cells follows inflammation.

Ron, the tyrosine kinase receptor for the Macrophage-stimulating protein, is involved in cell dissociation, motility, and matrix invasion. DeltaRon, a constitutively active isoform that confers increased motility to expressing cells, is generated through the skipping of exon 11. We show that abnormal accumulation of DeltaRon mRNA occurs in breast and colon tumors. Skipping of exon 11 is controlled by a silencer and an enhancer of splicing located in the constitutive exon 12. The strength of the enhancer parallels the relative abundance of DeltaRon mRNA and depends on a sequence directly bound by splicing factor SF2/ASF. Overexpression and RNAi experiments demonstrate that SF2/ASF, by controlling the production of DeltaRon, activates epithelial to mesenchymal transition leading to cell locomotion. The effect of SF2/ASF overexpression is reverted by specific knockdown of DeltaRon mRNA. This demonstrates a direct link between SF2/ASF-regulated splicing and cell motility, an activity important for embryogenesis, tissue formation, and tumor metastasis.

We studied the immunoregulatory features of murine mesenchymal stem cells (MSCs) in vitro and in vivo. MSCs inhibited T-cell receptor (TCR)-dependent and -independent proliferation but did not induce apoptosis on T cells. Such inhibition was paired with a decreased interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha production and was partially reversed by interleukin-2 (IL-2). Thus, we used MSCs to treat myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis (EAE) in C57BL/6J mice. We injected intravenously 1 x 10(6) MSCs before disease onset (preventive protocol) and at different time points after disease occurrence (therapeutic protocol). MSC administration before disease onset strikingly ameliorated EAE. The therapeutic scheme was effective when MSCs were administered at disease onset and at the peak of disease but not after disease stabilization. Central nervous system (CNS) pathology showed decreased inflammatory infiltrates and demyelination in mice that received transplants of MSCs. T-cell response to MOG and mitogens from MSC-treated mice was inhibited and restored by IL-2 administration. Upon MSC transfection with the enhanced green fluorescent protein (eGFP), eGFP(+) cells were detected in the lymphoid organs of treated mice. These data suggest that the immunoregulatory properties of MSCs effectively interfere with the autoimmune attack in the course of EAE inducing an in vivo state of T-cell unresponsiveness occurring within secondary lymphoid organs.

Cyclic ADP-ribose (cADPR) is an intracellular calcium mobilizer generated from NAD(+) by the ADP-ribosyl cyclases CD38 and BST-1. cADPR, both exogenously added and paracrinally produced by a CD38(+) feeder layer, has recently been demonstrated to stimulate the in vitro proliferation of human hemopoietic progenitors (HP) and also the in vivo expansion of hemopoietic stem cells. The low density of BST-1 expression on bone marrow (BM) stromal cells and the low specific activity of the enzyme made it unclear whether cADPR generation by a BST-1(+) stroma could stimulate HP proliferation in the BM microenvironment. We developed and characterized two BST-1(+) stromal cell lines, expressing an ectocellular cyclase activity similar to that of BST-1(+) human mesenchymal stem cells, the precursors of BM stromal cells. Long term co-culture of cord blood-derived HP over these BST-1(+) feeders determined their expansion. Influx of paracrinally generated cADPR into clonogenic HP was mediated by a concentrative, nitrobenzylthioinosine- and dipyridamole-inhibitable nucleoside transporter, this providing a possible explanation to the effectiveness of the hormone-like concentrations of the cyclic nucleotide measured in the medium conditioned by BST-1(+) feeders. These results suggest that the BST-1-catalyzed generation of extracellular cADPR, followed by the concentrative uptake of the cyclic nucleotide by HP, may be physiologically relevant in normal hemopoiesis.

Vitiligo patients possess high frequencies of circulating CD8+ T lymphocytes specific for the melanocyte differentiation antigen Melan-A/MART-1. These self-specific T cells exhibit intact functional properties and their T cell receptors are selected for a narrow range of high affinities of antigen recognition, suggesting their important role in the pathogenesis of vitiligo. In order to understand the molecular base for this unexpected, optimal T cell receptor recognition of a self-antigen, a tetramer-guided ex vivo analysis of the T cell receptor repertoire specific for the Melan-A antigen in a patient affected by vitiligo is reported. All T cell receptors sequenced corresponded to different clonotypes, excluding extensive clonal expansions and revealing a large repertoire of circulating Melan-A-specific T lymphocytes. A certain degree of T cell receptor structural conservation was noticed, however, as a single AV segment contributed to the alpha chain rearrangement in 100% of clones and a conserved amino acid sequence was found in the beta chain complementarity determining region 3 of various high affinity cells. We suggest that the conserved alpha chain confers self-antigen recognition, necessary for intrathymic selection and peripheral homeostasis, to many synonymous T cell receptors, whereas the beta chain fine tunes the T cell receptor affinity of the specific cells. In addition, we demonstrate that many high avidity T cell clones from this patient were capable of specifically lysing normal, HLA-matched melanocytes. These autoreactive clones persisted for more than 3 y in the patient's peripheral blood. These data, together with the skin-homing potential of the clones, directly point to the in vivo pathogenic role of melanocyte-specific cytotoxic T lymphocytes in vitiligo.

TCR-alpha and -beta chains are composed of somatically rearranged V, D, and J germline-encoded gene segments that confer Ag specificity. Recent crystallographic analyses revealed that TCR-alpha has more contacts with peptide than TCR-beta, suggesting the possibility that peptide recognition predominantly relies on TCR-alpha. T cells specific for the self Ag Melan-A/MART-1 possess an exceptionally high precursor frequency in human histocompatibility leukocyte Ag-A2 individuals. This provided a unique situation for assessment of the structural relationship between TCR and peptide/MHC ligand at both the pre- and postimmune levels. Molecular and phenotypic analysis of many different Melan-A-specific T cell populations revealed that a structural constraint is imposed on the TCR for engagement with Melan-A peptides presented by HLA-A2, namely the highly preferential use of a particular TCRAV segment, AV2. Examination of CD8 single-positive thymocytes indicated that this preferential use in forming the Melan-A-specific TCR is mainly imposed by intrathymic positive selection. Our data demonstrate a dominant function of TCRAV2 segment in forming the TCR repertoire specific for the human self Ag Melan-A/MART-1 and support the view that Ag recognition is mediated predominantly by TCR-alpha.

Objectives: Mitochondrial toxicity is a serious side-effect of antiretroviral drugs, especially nucleoside reverse transcriptase inhibitors (NRTI). An in vitro assay to predict mitochondrial toxicity of in-use and developmental NRTI would be invaluable. To test the ability of a cytofluorimetric technique to predict the mitochondrial-dependent pancreatic and hepatic toxicity we used didanosine (ddI) alone or in combination with hydroxyurea (HU)., Methods: The technique is based on the ability of the lipophilic cation JC-1 to enter selectively into mitochondria and change its colour as the membrane potential changes due to toxicity. Mitochondrial toxicity by HU and ddI was evaluated in pancreatic and hepatic human cell lines. The results were expressed as mitochondrial toxicity index (MTI), ranging from 0 to 100: the negative control was 0, and 100 indicating maximal toxicity., Results: Dose-dependent pancreatic toxicity of ddI was evident after 14 days of culture (MTI 34 +/- 4 at 100 microM, 10 +/- 4 at 10 microM, 2 +/- 3 at 1 microM ddI). HU alone was not toxic (MTI 7 +/- 10 at 100 microM, 2 +/- 2 at 50 microM and 2 +/- 4 at 10 microM HU); however, HU increased the toxicity of high, but not low, concentrations of ddI. For example, the MTI of 10 microM ddI plus 50 microM HU was 54 +/- 9. Negligible mitochondrial toxicity was observed in the hepatic cell line exposed to ddI alone or in combination with HU., Conclusions: This in vitro assay might have in vivo relevance. First, ddI-related pancreatitis is dose dependent, and is reported more frequently than hepatic failure, consistent with our in vitro results. Second, patients who developed pancreatitis during randomized, controlled trials were treated with HU in combination with 400 mg ddI once daily (high peak concentration of ddI in the blood). In contrast, no pancreatitis was observed when HU was combined with 200 mg ddI twice daily (low peak concentration of ddI). These in vivo results are consistent with our in vitro observation that HU increases pancreatic cell toxicity in the presence of high concentrations of ddI. The in vitro assay described here might be used to predict the mitochondrial toxicity of other NRTI, alone or in combination.

Introduction: Limited information is available on the natural killer cell reconstitution after bone marrow transplantation and on the possible role of these cells in graft-versus-host-disease., Materials and Methods: Blood samples were collected at different time intervals after transplantation. Lymphocytes were analyzed for informative markers by immunocytofluorimetric analysis. Natural killer cells derived from patients undergoing matched unrelated donor transplant were cloned by limiting dilution in the presence of phytohemoagglutinin and IL2. The natural killer cell clones were analyzed for cytolytic activity., Results: In the nine patients analyzed undergoing transplantation from sibling donors, the majority of peripheral blood lymphocytes during the first 80 d after BMT were represented by T lymphocytes, while in the 15 patients undergoing matched unrelated donor transplant natural killer cells consistently outnumbered T lymphocytes. During the early phases after transplantation, most CD56+CD3- natural killer cells did not express CD16 which was expressed at later intervals. Analysis of the inhibitory receptors specific for HLA-class I molecules showed that CD94/NKG2A, specific for HLA-E, unlike normal donors, was expressed by all natural killer cells including the early appearing CD16-negative ones. Killer inhibitory receptors of the Ig superfamily were expressed late and in low percentages after transplantation and were always coexpressed with CD94/NKG2A. Natural killer-cell clones efficiently lysed the HLA-class I-negative cell lines K562 and 721-221. Natural killer-cell populations or clones isolated from patients with graft-versus-host-disease, failed to lyse donor or recipient derived phytohemoagglutinin-induced lymphoblasts., Conclusion: Our analysis shows that (1) recipients of matched unrelated donors transplants exhibit a high proportion of NK cells (2) all NK cells express CD94/NKG2A while the HLA-class I-specific inhibitory receptors of Ig superfamily appear at later stages and (3) donor NK cells do not lysed donor or recipient target cells.

Background and Objective: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disease of the hemopoietic stem cell (HSC) characterized by intravascular hemolysis and increased risk of venous thrombosis. There are different therapeutic approaches for PNH which do not cure the disease, but can decrease its complications. Allogeneic bone marrow transplantation (BMT) may cure PNH. We reports here our experience of seven PNH patients who underwent allogeneic BMT., Design and Methods: Between January 1991 and January 1999 seven patients with PNH, aged 23 to 37, were transplanted with unmanipulated bone marrow from HLA identical siblings. Median time from diagnosis to BMT was 2.5 years (range: 1-16). All patients were transfusion-dependent and had received various treatments before BMT: steroids, vitamins, cyclosporin A (CyA), growth factors. One patient had also been treated with anti-thymocyte globulin. One patient was HbsAg positive and one anti-HCV positive. At the time of BMT the median value of hemoglobin (Hb) was 9 g/dL (range 6.5-11), white blood cells 5&10(9)/L (range: 2.9-7.7), platelets 97&10(9)/L (range: 31-355), LDH: 2726 U/L. The conditioning regimen was cyclophosphamide (160 mg/kg) and busulfan (10-14 mg/kg), followed by unmanipulated bone marrow (median of 5&10(8) cells/kg) and CyA (+MTX in two patients) for prophylaxis of graft-versus-host disease (GvHD)., Results: All seven patients are alive, full chimeras, with complete hematologic recovery and no evidence of PNH, at a median follow up of 51 months post-BMT (6-103). Time to achieve a granulocyte count of 0.5&10(9)/L, platelets 30&10(9)/L and Hb 10 g/dL was respectively 16, 19 and 22 days. Acute GvHD was limited or mild in six patients, and severe in one. Chronic GvHD was extensive in two patients., Interpretation and Conclusions: This study confirms that HLA identical sibling BMT is an effective therapeutic option for PNH, also in the hemolytic phase of the disease: it also suggests that HBV and HCV infections are not an absolute contraindication.

We report our experience of high-dose cyclophosphamide (HDCY) followed by high-dose therapy (HDT) and peripheral blood progenitor cell (PBPC) autografting in patients with diffuse, intermediate and high-grade non-Hodgkin's lymphomas who have failed conventional treatment. From 1991 to 1996, 54 consecutive patients pre-treated with a median of two chemotherapy lines entered the study. Eighteen patients (33%) were still responders to conventional chemotherapy (sensitive relapse), and 20 patients (37%) were in partial response (PR) after chemotherapy (CT). Sixteen patients (30%) were resistant to conventional CT either at presentation (non responder) or in relapse (resistant relapse). Thirty-nine patients had bone marrow involved by disease and fifteen had an hypoplastic marrow following conventional treatment. Patients received HDCY (7gr/m2) and G-CSF or GM-CSF in order to collect PBPC. Median collected CD34+ cells was 12.3 x 10(6)/Kg (range 0.7-197). After HDT (BEAM or Melphalan + TBI) 50 patients underwent PBPC autografting. According to intention to treat, 44 (81%) of 54 patients achieved complete remission (CR) (50% after HDCY and 31% after HDT). Procedure related death occurred in 6 patients (11%), one after HDCY and 5 after autografting. Twenty-nine (66%) of 44 patients are still in CR, 7 to 63 months (median 27 months) after the procedure. Three-year probability of survival, disease-free survival and progression-free survival are 63%, 64% and 52% respectively. In conclusion, HDCY is an effective procedure not only in mobilizing PBPC, but also in reducing tumour burden. HDT with PBPC support may further improve the outcome in this category of high-risk non-Hodgkin's lymphomas.

Intensive chemotherapy given in early chronic phase of chronic myelogenous leukemia (CML) has resulted in high numbers of circulating Philadelphia (Ph) chromosome-negative hematopoietic progenitor cells (HPC). We have autografted 30 consecutive patients with CML in chronic phase with HPC collected in this way to facilitate restoration of Ph-negative hematopoiesis in bone marrow after high-dose therapy. Hematopoietic recovery to greater than 0.5 x10(9)/L neutrophils and to greater than 25 x 10(9)/L platelets occurred in all patients, a median of 13 (range, 9 to 32) days and 16 (range, 6 to 106) days postautograft, respectively. Regenerating marrow cells were Ph-negative in 16 (53%) patients and greater than 66% Ph-negative in 10 (33%) patients. Twenty-eight patients are alive 6 to 76 months (median, 24 months) after autografting. Three patients have developed blast crisis from which 2 have died. Eight patients are in complete cytogenetic remission at a median of 20 (range, 6 to 44) months with a median ratio BCR-ABL/ABL of 0.002 (range, <0.001 to 0.01). Eight patients are in major cytogenetic remission at a median of 22 (range, 6 to 48) months. No patient died as a consequence of the treatment. All patients had some degree of stomatitis that was severe in 15 (50%) patients. Gastrointestinal and hepatic toxicities were observed in about one fourth of patients. Thus, autografting with Ph-negative mobilized HPC can result in prolonged restoration of Ph-negative hematopoiesis for some patients with CML; moreover, most autograft recipients report normal or near normal activity levels, suggesting that this procedure need not to be associated either with prolonged convalescence or with chronic debility.

We carried out studies to quantify Ph-negative progenitors both in steady state and during regeneration after chemotherapy and G-CSF in 23 newly diagnosed chronic myeloid leukaemia (CML) patients (group A) and in 14 individuals more than a year from diagnosis (nine in chronic and five in accelerated phase, group B). In steady-state bone marrow, Ph-negative long-term culture initiating cells (LTC-IC) and Ph-negative colony-forming-cells (CFC) were detected in 18/23 and 14/23 patients of group A versus 3/14 and 3/14 patients of group B (P<0.001 and P<0.02, respectively). The absolute number of mobilized Ph-negative progenitors was markedly higher in group A versus group B (P<0.02 for LTC-IC, P<0.003 for CFC). 12/16 newly diagnosed patients mobilized Ph-negative LTC-IC only and the yield was in the range of normal allogeneic donors. Overall the frequency of Ph-negative LTC-IC in the bone marrow predicted the yield of Ph-negative LTC-IC mobilized into peripheral blood (P<0.001). The bone marrow frequency of Ph-positive LTC-IC was considerably lower than the normal counterpart. Taken together, these findings suggest that normal progenitors are relatively well preserved in newly diagnosed CML patients, but tend to rapidly decline with time. This observation helps in the understanding of the pathogenesis of CML and has potential implications for autografting. The optimal time for a successful collection of Ph-negative circulating progenitors would appear to be soon after diagnosis.

Background and Objective: The main objective of this pilot study was to assess the possibility of achieving engraftment of HLA-matched sibling donor mobilized hematopoietic stem cells after immunosuppressive non-myeloablative therapy. The second objective was to verify whether high-dose therapy with autologous stem cells rescue followed by allografting conditioned by only an immunosuppressive regimen, can be combined in order to achieve the reduction of tumor burden after autografting and the control of residual disease with immune-mediated effects after allografting., Design and Methods: To enter the pilot study the patients had to fulfil the following criteria: advanced resistant disease, presence of an HLA matched sibling donor, no general contraindications to stem cell transplantation. Our data refers to 9 patients: Hodgkin's disease (n = 4), non-Hodgkin's lymphoma (n = 2), advanced chronic myelogenous leukemia (n = 2) (one patient with accelerated phase Ph-negative but p190 BCR-ABL gene positive by RT-PCR and one with Ph-positive blastic phase), refractory anemia with excess of blasts t(1;3) (p36;q21) (n = 1). All patients but one received the combined approach. At a median of 40 days (range 30-96), after high-dose therapy and autologous stem cell engraftment, the patients were treated with immunosuppressive therapy consisting of fludarabine and cyclophosphamide (Flu-Cy protocol) and then HLA matched donor mobilized stem cells were infused into the patients. GvHD prophylaxis consisted of cyclosporin and methotrexate., Results: To date, with a median observation period of 4 months (range, 2-10), complete chimerism (100% donor cells) has been achieved in 6 patients. Three patients did not achieve complete chimerism: one patient died of progressive Hodgkin's disease when he reached 55% of donor cells, another patient is now in increasing phase of donor cell engraftment and the last patient (blastic phase-CML) was the only case who appears to have had autologous recovery. Two of the Hodgkin's disease patients, who were in partial remission after autografting, achieved complete remission after allografting and both are disease free 2 and 6 months after. Another Hodgkin's disease patient is alive at 10 months but she has progressive disease. One of the two patients with non-Hodgkin's lymphoma, who achieved partial remission after autografting, obtained complete remission and he is disease free 2 months after allografting. The other patient maintains partial remission obtained after autografting. The accelerated phase-CML patient obtained hematologic and molecular remission; the RAEB patient achieved hematologic and cytogenetic remission. In two patients severe aGVHD (grade II-III) was the single major complication but neither patient died of it. Mild aGVHD was seen in another patient. In only one patient did the ANC decrease to below 1 x 10(9)/L and in no case did platelets decrease below 20 x 10(9)/L. No patients required a sterile room or any red cell or platelet transfusions., Interpretation and Conclusions: Immunosuppressive therapy with a Flu-Cy protocol allowed engraftment of HLA-matched sibling donor stem cells without procedure-related deaths; moreover, we have demonstrated that this combined procedure can be pursued in safety in a serious ill population and some of these patients achieved a complete remission. This procedure is not likely to be curative, but a fascinating step along the path to curing these diseases. Of course, the follow-up is too short to document the incidence of cGvHD.

In vitro priming of T cell with horse antilymphocyte globulin (HALG) results in cytokine release, and this has been associated with its clinical efficacy in patients with severe aplastic anaemia (SAA). Rabbit antithymocyte globulin (RATG) has been studied less extensively. In this study we compare the in vitro priming effect of HALG and RATG on purified normal marrow T cells: end-points of the study were 1) levels of TNF-alpha (TNF-alpha), IFN-gamma (IFN-gamma) GM-CSF in T cell supernatants, and 2) effect of T cell supernatants on colony formation with or without exogenous GM-CSF TNF-alpha, IFN-gamma and GM-CSF levels were comparable for HALG, RATG and phytohaemagglutinin (PHA). T cell supernatants showed comparable enhancement of colony formation in the presence of recombinant human GM-CSF (rhGM-CSF) and supported colony forming unit granulomacrophage (CFU-GM) growth in the absence of growth factor. This study shows that horse and rabbit derived ALG/ATG and PHA have a comparable in vitro priming effect on T cells: both agents should probably be tested for their clinical efficacy in SAA patients.

This trial was designed to test the use of CD34+ selected haemopoietic stem cells (HSC) in HLA-mismatched donor-recipient pairs, following intensive conditioning with thiotepa, antilymphocyte globulin (ALG), cyclophosphamide and single-dose total-body irradiation (sTBI). 10 patients aged 16-50 with advanced malignancies and a two- or three-antigen mismatched family donor entered this study. Donor marrow and G-CSF primed peripheral blood cells were processed separately on CD34 columns (Ceprate). The median number of infused CD34+ cells were 5.66 x 10(6)/ kg, with 0.55 x 10(6)/kg CD3+ cells. Nine patients received cyclosporin for graft-versus-host disease (GvHD) prophylaxis. Median neutrophil counts on day 21 were 2 x 10(9)/l with a median platelet count of 60 x 10(9)/l, but CD4 counts remained extremely depressed throughout the study. Acute GvHD was scored as grade 0-I in two patients, as grade II in seven, and grade III in one. Eight patients died at a median interval of 72 d from HSCT (range 20-144) due to cytomegalovirus (CMV) associated interstitial pneumonitis (IP) (n = 5), renal failure (n = 1). GvHD (n = 1) and Aspergillus meningitis (n = 1). Two patients are alive 365-495 d post transplant, one in remission and one in relapse. This study suggests that large numbers of positively selected mismatched HSC can rapidly engraft after intensive conditioning regimen: however, profound post-transplant immunodeficiency leads to a high risk of lethal infectious complications.

Donor lymphocyte infusions (DLI) were given between June 1990 and March 1996 to 18 patients with chronic myeloid leukemia (CML) for the treatment of cytogenetic (n = 6) or hematologic relapse (n = 12) following an allogeneic bone marrow transplant (BMT). Patients were divided in two groups: patients in group A (n = 8) received a large dose of donor lymphocytes (> or = 1 x 10(8)/kg), whereas patients in group B (n = 10) received escalating numbers of cells (2 x 10(5) up to 2 x 10(8)/kg). The median number of DLI in group A was 2 (range 1-3); the median number of infusions in group B was 7 (range 3-9). Acute GVHD occurred in 12 patients (grades I-III) and was a major cause of death in two. The risk of developing GVHD correlated with the number of cells infused: 37%, 14%, 5% and 0% for DLI with cells > or = 1 x 10(8), 2 x 10(7)/kg, 2 x 10(6)/kg, and 2 x 10(5)/kg, respectively (P = 0.01). Median transaminase levels were found to be significantly increased in patients with, as compared to patients without, acute GVHD (GPT 412 vs 28 IU/l; P = 0.03). Severe aplasia occurred in four and was a contributing cause of death in two patients. Overall, four patients died as a consequence of DLI and all received > 1 x 10(8)/kg cells: the actuarial risk was 38% in group A and 14% in group B (P = 0.1). There were 10 complete and three partial cytogenetic responses: the actuarial probability at 5 years of being Ph negative was 69%: it was 46% for group A and 85% for group B (P = 0.1). The longest patient is now 6 years post-DLI, Ph negative, BCR-ABL negative. The actuarial 3 year survival is 38% in group A and 86% in group B (P = 0.06). The study confirms that DLI post-BMT is not innocuous and that there is a definite long-lasting antileukemic effect in patients with CML. It also suggests that: (1) the risk of developing GVHD correlates with the number of infused cells; (2) that significant elevations of serum GPT levels are associated with GVHD; and (3) that the use of escalating doses of cells may allow the identification of side-effects and discontinuation of infusions before life-threatening GVHD has developed.

Elevated white blood cell counts are frequently found in patients with chronic myeloid leukaemia (CML). Although some studies have disclosed that bone marrow of CML patients may contain some normal Philadelphia-negative early progenitor cells, it has been assumed that the dramatic increase of white blood cells was entirely related to the leukaemic cell expansion. In this study we attempted to quantify the number of normal and leukaemic progenitor cells in the bone marrow and peripheral blood of newly diagnosed CML patients. Bone marrow and peripheral blood cells of eight newly diagnosed CML patients were analysed for clonogenic colony-forming cells (CFC) and very early progenitor cells, i.e. long-term culture initiating cells (LTC-IC). The leukaemic (Ph-positive) or normal (Ph-negative) origin of progenitor cells was revealed by cytogenetic analysis performed on single colonies arising from in-vitro assays. In 6/8 patients the marrow CFC frequency ranged from 400 to 9300/10(6) mononuclear cells (MNC), 0-50% being Philadelphia chromosome negative; the LTC-IC frequency ranged from 0 to 11/10(6) MNC, and were 80-100% Ph-negative. The corresponding absolute values into peripheral blood were: CFC = 1-35.5 x 10(3)/ml, 0-50% Ph-negative, and LTC-IC = 0-2.5 x 10(3)/ml, 0-100% Ph-negative. In one patient, no LTC-IC were detected in either the marrow or the peripheral blood. In conclusion, in the peripheral blood of some CML patients, the number of normal LTC-IC is more than 3 times the number of leukaemic progenitor cells, and is much higher (50 times) than the corresponding value found in normal subjects in steady state (2.5/ml v 124/ml). These data support the concept that leukaemic 'stem cells', with respect to normal ones, may be considerably fewer than previously thought. In addition it is shown that at the beginning of CML high numbers of normal LTC-IC are spontaneously mobilized into the blood. Finally, the presence of Ph-negative early progenitors into the blood may represent a potential source of normal stem cells available for autografting providing they can be separated from leukaemic cells.

Background and Objective: We previously reported that patients with acquired severe aplastic anemia (SAA) treated with antilymphocyte globulin (ALG), 6-methylprednisolone, cyclosporin A (CyA) and granulocyte colony-stimulating factor (G-CSF) can mobilize peripheral blood hemopoietic progenitors (PBHP). The aim of the present study was to assess phenotypic and functional properties of these PBHP., Methods: We studied seven patients who underwent 43 leukophereses (median 5) between day +30 and +80 following ALG, while in treatment with CyA and G-CSF. Mobilized peripheral blood hemopoietic progenitors were analyzed using surface markers, conventional assays for clonogenic cells (CFU-GM, BFU-E, CFU-GEMM) as well as the recently developed assay for long-term culture initiating cells (LTC-ICs)., Results: The proportion of CD34+ cells ranged between 0% and 5.4% (median 0.3%), CD34+DR between 0% and 3.5% (median 0.1%) and CD8+ cells between 3.3% and 56% (median 31%). When light density mononuclear cells (MNC) were plated in vitro, we could grow colony-forming units-granulo-macrophage (CFU-GM) (range 0-45/10(5) MNC; normal controls 21-200/10(5) MNC), burst-forming units-erythroid (BFU-E) (range 0-5/10(5) MNC; normal controls 0-6/10(5) MNC), multipotent colonies (CFU-GEMM) (range 0-3/10(5) MNC; normal controls 0-6/10(5) MNC) and high proliferative potential colony-forming cells (HPP-CFC) (range 0-3.4/10(5) MNC). We studied long-term culture-initiating cells (LTC-ICs) in 18 leukophereses from 4 patients; in 7/18 samples LTC-ICs were grown at low frequency (range 0.4-2/10(6) MNC) (normal controls 5-130/10(6) MNC), and in one patient in the absence of CFU-GM growth. The total yield of LTC-ICs in two patients was 7.64 and 10.5 x 10(2)/kg of body weight., Interpretation and Conclusions: This study suggests that cells with the phenotype and in vitro function of early hemopoietic progenitors are found, though in small numbers, in the peripheral blood of patients with SAA after treatment with immunosuppressants and prolonged G-CSF administration. Whether G-CSF-mobilized progenitors contribute to hemopoietic recovery in these patients remains to be determined.

Peripheral blood stems cells (PBSCs) have been used in autologous transplantation as an alternative to bone marrow-derived cells. Recently, PBSCs have been collected from healthy donors after priming with G-CSF and used for allogeneic transplantation. We have a comparatively large experience with PBSC collection in autologous and allogeneic settings. The five cell separators we employ are: the CS3000 plus, AS 104, Excel, Cobe Spectra and MCS 3p. These machines appear to have different efficacies but no studies have been carried out on this topic. In a prospective study we have randomly assigned donors to different cell separators to evaluate their efficiency. Twenty-five donors underwent the procedure and 50 leukaphereses were carried out. Donors were given 5 micrograms kg-1 d-1 of recombinant human G-CSF for 3 days and 10 micrograms kg-1 d-1 for 4 days subcutaneously. Leukaphereses were performed on days 6 and 7 of G-CSF administration. The results of our study show that a total value of CD34+ cells ranging from 48.44 x 10(6) to 270.37 x 10(6) can be collected from donors with a white cell count ranging from 40.50 x 10(3) microL-1 to 51.34 x 10(3) microL-1 and mononuclear cells ranging from 16.42 to 20.37%. The Excel and the MCS 3p seem to differ from the other machines in terms of higher CD34+ cell collection efficiency. The Excel appears to be even more efficient than the MCS 3p, but this may not reflect reality because the Excel processes 12 L of blood while the MCS 3p employs an 8 L procedure. All the machines showed satisfactory results in terms of yield and quality of the harvests.

We have previously reported that mobilization of Philadelphia (Ph) chromosome-negative progenitors is possible in a significant number of Ph1-positive acute lymphoblastic leukaemia (ALL) and chronic myelogenous leukaemia (CML) patients. In this pilot study we employed the same approach for patients with RAEB-t, secondary AML (sAML) and therapy-related AML (t-AML). All patients except one had double or complex cytogenetic abnormalities in marrow cells before mobilization therapy. All patients received an idarubicin-containing regimen (mini-ICE protocol) followed by rh-G-CSF and the first leukapheresis was performed as they were recovering from aplasia. In six out of nine patients the leukapheresis product was entirely karyotypically normal, combined with a significant number of CFU-GM. CD34+ cells and LTC-IC. Recovery time from mobilization therapy was short and no patient died as a result of the procedure. To date, three patients have undergone autografting using their karyotypically normal collections, of which two (sAML) are alive with karyotypically normal marrow a few months after autografting.

Thirty-five aggressive non-Hodgkin's lymphomas (NHL) with marrow involvement received high-dose cyclophosphamide (7 g/m2) and G-CSF in order to collect peripheral blood progenitor cells (PBPC). Fourteen patients were in partial remission, 16 patients were in relapse ('sensitive', 12; 'resistant', 4) and five patients were refractory to conventional treatment. A good yield of PBPC was obtained in 30 patients, while a low number of CD34+ cells and of CFU-GM was seen in two cases. Two patients entered progression and one patient died. Thirty patients underwent PBPC autografting. Twenty-nine out of 35 (83%) patients entered complete remission (CR). Two patients died in CR of infection following marrow aplasia 3 and 6 months after autografting. At 3 years the probability of survival and disease-free survival (DFS) are 62 and 51%, respectively.

The study was devised to evaluate whether it was possible to collect Philadelphia-negative precursor cells in patients with chronic myeloid leukaemia. The approach was based on previous experience showing that complete remission (Ph-negative bone marrow cells) is rarely achieved after chemotherapy and is very short-lasting. We decided to explore whether it was possible to collect Ph-negative precursor cells in peripheral blood during the early phase of haemopoietic recovery. These data show that: the collection of Ph-negative precursor cells occurred in 12/16 (75%) patients mobilized within one year of diagnosis (group A) versus 12/33 (36%) in patients with a history of more than one year of disease (group B). Furthermore the numbers of Ph-negative precursor cells were significantly much higher at diagnosis. Ten patients mobilized at diagnosis were subsequently autografted with such Ph-negative precursor cells. Five of them remain Ph-negative from 4 to 12 months while the other five have percentages of Ph-positive cells in their marrow ranging from 20% to 70%. In this stage of the disease the procedure is safe and associated with a very good compliance. Occasional restoration of Ph-negative haemopoiesis could be observed up to 40 months after autograft, in patients of group B, but most of patients revert to Ph-positive haemopoiesis. in conclusion these data suggest that it is possible to restore Ph-negative haemopoiesis in 70% of patients mobilized at diagnosis. This percentage represent the highest one can obtain without allogeneic BMT, and this includes patients who never would have been cytogenetic responders to IFN-alpha. Whether and how long for Ph-negative status can be maintained is a matter for future observation and study.