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Background: In neonates, antibody-mediated destruction of neutrophils may occur as a consequence of auto- or isoimmune disorders. There are few studies on this topic, and particularly on neonatal alloimmune neutropenia (NAN)., Materials and Methods: We retrospectively evaluated the clinical and molecular/serological findings of 83 neutropenic infants referred to our Reference Laboratory for diagnostic evaluation of NAN, from 2008 to 2021. We also genotyped 260 Italian healthy subjects for the four principal human neutrophil antigens (HNA)., Results: The diagnosis of NAN was confirmed in 31 cases. The other 52 cases were autoimmune neutropenia (n=21), neutropenia caused by maternal neutrophil autoantibodies (n=8), neutropenia of non-immune origin (n=17), and cases in which a diagnosis could not be reached (n=6). The median age at neutropenia onset and absolute neutrophil count (ANC) were significantly lower in NAN than in non-NAN cases (1 vs 30 days, p<0.005; 330 vs 580/μL, p=0.003, respectively). About 74% of NAN cases developed neutropenia within the first week of life and laboratory investigations were required within 2 weeks. In five patients the neutropenia was discovered at the end of the first month of life and they were referred to our laboratory 1-2 months later when neutropenia had already resolved. Infections were seen in 19% of NAN cases. The median time to resolution of NAN was 31 days. About 50% of NAN cases were due to alloantibodies against HNA-1b, the most frequent allele of HNA-1 in the Italian population (allele frequency 0.63). In five cases of NAN the mothers had an HNA-1 null phenotype, a frequency higher than that observed in our Italian cohort., Discussion: NAN should be considered by clinicians in infants with neutropenia onset within 5-7 days of life, even though there can be other reasons for a low ANC. If neutropenia is detected later, benign neutropenia seems more likely, although persistence of maternal alloantibodies cannot be ruled out.

SARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6-56.1, Welch's t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.

Background: Severe acute respiratory syndrome coronavirus 2 is a recently discovered pathogen responsible of coronavirus disease 2019 (COVID-19). The immunological changes associated with this infection are largely unknown., Methods: We evaluated the peripheral blood mononuclear cells profile of 63 patients with COVID-19 at diagnosis. We also assessed the presence of association with inflammatory biomarkers and the 28-day mortality., Results: Lymphocytopenia was present in 51 of 63 (80.9%) patients, with a median value of 720 lymphocytes/µl (IQR 520-1,135). This reduction was mirrored also on CD8+ (128 cells/µl, IQR 55-215), natural killer (67 cells/µl, IQR 35-158) and natural killer T (31 cells/µl, IQR 11-78) cells. Monocytes were preserved in total number but displayed among them a subpopulation with a higher forward and side scatter properties, composed mainly of cells with a reduced expression of both CD14 and HLA-DR. Patients who died in the 28 days from admission (N=10, 15.9%), when compared to those who did not, displayed lower mean values of CD3+ (337.4 cells/µl vs 585.9 cells/µl; p=0.028) and CD4+ cells (232.2 cells/µl vs 381.1 cells/µl; p=0.042) and an higher percentage of CD8+/CD38+/HLA-DR+ lymphocytes (13.5% vs 7.6%; p=0.026)., Discussion: The early phases of COVID-19 are characterized by lymphocytopenia, predominance of Th2-like lymphocytes and monocytes with altered immune profile, which include atypical mononuclear cells., 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 Lombardi, Trombetta, Cattaneo, Castelli, Palomba, Tirone, Mangioni, Lamorte, Manunta, Prati, Ceriotti, Gualtierotti, Costantino, Aliberti, Scaravilli, Grasselli, Gori, Porretti and Bandera.)

Small extracellular vesicles (EVs) are able to pass from the central nervous system (CNS) into peripheral blood and contain molecule markers of their parental origin. The aim of our study was to isolate and characterize total and neural-derived small EVs (NDEVs) and their micro RNA (miRNA) cargo in Alzheimer's disease (AD) patients. Small NDEVs were isolated from plasma in a population consisting of 40 AD patients and 40 healthy subjects (CTRLs) using high throughput Advanced TaqMan miRNA OpenArrays ® , which enables the simultaneous determination of 754 miRNAs. MiR-23a-3p, miR-223-3p, miR-100-3p and miR-190-5p showed a significant dysregulation in small NDEVs from AD patients as compared with controls (1.16 ± 0.49 versus 7.54 ± 2.5, p = 0.026; 9.32 ± 2.27 versus 0.66 ± 0.18, p <0.0001; 0.069 ± 0.01 versus 0.5 ± 0.1, p < 0.0001 and 2.9 ± 1.2 versus 1.93 ± 0.9, p < 0.05, respectively). A further validation analysis confirmed that miR-23a-3p, miR-223-3p and miR-190a-5p levels in small NDEVs from AD patients were significantly upregulated as compared with controls ( p = 0.008; p = 0.016; p = 0.003, respectively) whereas miR-100-3p levels were significantly downregulated ( p = 0.008). This is the first study that carries out the comparison between total plasma small EV population and NDEVs, demonstrating the presence of a specific AD NDEV miRNA signature., Competing Interests: The authors declare no conflict of interest.

Background: Chronic benign neutropenia of infancy includes primary autoimmune neutropenia (pAIN) and chronic idiopathic neutropenia (CIN). A diagnosis of CIN is supported by the absence of free and/or cell-bound neutrophil autoantibodies, which can be detected by flow cytometry with the indirect-granulocyte immunofluorescence test (I-GIFT) and direct-granulocyte immunofluorescence test (D-GIFT), respectively. Conclusive evidence is lacking on the diagnostic value of the D-GIFT, whose performance requires specific laboratory expertise, may be logistically difficult, and hampered by very low neutrophil count in patient samples. This study investigated whether the evaluation of D-GIFT improves the diagnostic accuracy of pediatric neutropenia., Procedure: I-GIFT and D-GIFT were performed in 174 pAIN, 162 CIN, 81 secondary AIN, 51 postinfection neutropenic, and 65 nonautoimmune neutropenic children referred to this laboratory during 2002-2014., Results: Using 90% specific median fluorescence intensity cut-off values calculated by receiver operating characteristic curves, D-GIFT was positive in 49% of CIN patients, who showed similar clinical features as those with pAIN. In 44 (27%) of 162 CIN patients, I-GIFT was repeated two to three times in a year, resulting positive in 12 and two patients at second and third screening, respectively. Interestingly, 10 of the latter 14 patients showed a positive D-GIFT at the first serological screening. False positive D-GIFT was shown by 12% and 22% of nonneutropenic and nonautoimmune neutropenic patients, respectively., Conclusions: D-GIFT evaluation improves the diagnostic accuracy of pediatric neutropenia, but improvement of cell-bound antibody detection is needed to decrease false positive results., (© 2017 Wiley Periodicals, Inc.)

Background: Low-risk myelodysplastic syndromes (MDS) show several immunologic abnormalities, including increased frequency of autoimmune manifestations and/or overt autoimmune diseases, whose prognostic significance still remains controversial., Study Design and Methods: We studied the presence of erythroblast antibodies in mitogen-stimulated bone marrow (BM) cultures of 70 patients with early-stage MDS (refractory anemia and refractory anemia with ringed sideroblasts)., Results: Sixty-six percent of patients showed positive erythroblast antibodies, along with BM erythroid hyperplasia and a hemolytic picture in the peripheral blood. Supernatants from positive cultures induced an increase of overall cellularity, the appearance of erythroblastic clustering, and dyserythropoietic signs in normal BM. We identified CD45(dim) Gly-A(dim) CD71(bright) cells (red blood cell precursors at different maturation stage) as the target of the antibodies. Erythropoietin (EPO) levels were reduced and EPO receptors (EPO-R) increased in BM culture supernatants from positive patients. However, flow cytometric analysis showed that neither EPO nor EPO-R was involved in an abnormal stimulation driven by these autoantibodies. Values of the proapoptotic protein Bax were increased in positive patients and Bcl-2 levels were decreased, although not significantly., Conclusion: MDS patients with anti-erythroblast autoimmunity showed increased BM apoptosis, suggesting that the autoimmune reaction may contribute to an unfavorable BM microenvironment for optimal erythropoiesis., (© 2016 AABB.)

Background: Hereditary spherocytosis (HS) is a congenital hemolytic anemia caused by defects in red blood cell (RBC) membrane proteins leading to premature RBC clearance in the spleen. The presence of RBC autoantibodies has never been extensively investigated in HS., Study Design and Methods: RBC antibody-bound immunoglobulin (Ig)G was investigated in 91 consecutive HS patients by mitogen-stimulated direct antiglobulin test (MS-DAT), a sensitive method able to magnify latent RBC antibody autoimmunity and related with hemolytic variables, previous splenectomy, and type of membrane defect., Results: A total of 61% of HS cases had RBC antibodies by MS-DAT (29 Band 3, 17 spectrin deficiency, and nine no defined defect). The amount of RBC-bound IgG was greater in HS compared with controls (236 ± 192 ng/mL vs. 52 ± 29 ng/mL, p < 0.0001), although lower than that observed in autoimmune hemolytic anemia (AIHA; 634 ± 371 ng/mL vs. 236 ± 192 ng/mL, p < 0.0001). Western blot experiments showed that purified IgG fraction from MS-DAT-positive patients bind to α- and β-spectrin, Band 3, and Band 4.9. Positive cases displayed increased reticulocytosis and slightly reduced hemoglobin (Hb) values compared to negative ones. Patients displaying RBC-bound IgG of more than 250 ng/mL (the positive threshold of AIHA) showed increased number of spherocytes and mainly had spectrin deficiency. RBC-bound IgG and free Hb increased over time after storage at 4°C, a surrogate of ex vivo aging, more evidently in HS than controls, and particularly in Band 3 deficiency., Conclusion: RBC autoantibodies were detected by MS-DAT in more than a half of HS patients. Positive cases showed a more evident hemolytic pattern suggesting a pathogenic role of these autoantibodies in RBC opsonization and splenic removal., (© 2015 AABB.)

Background: Accurate estimation of haematopoietic stem cell (HSC) counts by flow cytometry may be difficult in laboratories in which sophisticated equipment and staff with specific expertise are not available. Affordable flow cytometers that can perform basic functions may help to overcome these difficulties. In this study we compared HSC and leucocyte counts determined by volumetric and bead-based protocols performed with the small, low-cost Accuri(®) C6, with those obtained with two gold-standard instruments, the four-colour FACSCalibur(®) and the eight-colour FACSCantoII(®), our reference flow cytometers., Materials and Methods: With the three cytometers we tested, in parallel, 111 consecutive samples from cord blood, peripheral blood from patients with myelofibrosis and myeloproliferative syndromes, fresh and thawed HSC collected by apheresis and bone marrow products. The findings were compared with one-way ANOVA, Bland-Altman analysis and linear regression., Results: The results of HSC and leucocyte enumeration by the three devices were strongly correlated (r(2)>0.99; p<0.0001). ANOVA performed on different subgroups of samples did not reveal significant differences between HSC count determined by the C6 bead-based and reference flow cytometers in any of the subgroups. Regarding the C6 volumetric protocol, a statistically significant difference was observed only in the cord blood subgroup. Time for instrument set-up, calibration and analysis was slightly longer with Accuri(®) C6 (40 min) than with FACSCantoII(®) (30 min)., Discussion: Accuri(®) C6 is a reliable instrument for HSC enumeration in fresh samples, using both volumetric and bead-based approaches, although the volumetric protocol on cord blood samples needs to be improved. The Accuri(®) C6 is easy to use, does not require profound knowledge of flow cytometry and could be employed in an urgent setting. Its performance may be improved by more efficient calibration and shorter analysis time.

The analysis of cellular and molecular profiles represents a powerful tool in many biomedical applications to identify the mechanisms underlying the pathological changes. The improvement of cellular starting material and the maintenance of the physiological status in the sample preparation are very useful. Human umbilical vein endothelial cells (HUVEC) are a model for prediction of endothelial dysfunction. HUVEC are enzymatically removed from the umbilical vein by collagenase. This method provides obtaining a good sample yield. However, the obtained cells are often contaminated with blood cells and fibroblasts. Methods based on negative selection by in vitro passages or on the use of defined marker are currently employed to isolate target cells. However, these approaches cannot reproduce physiological status and they require expensive instrumentation. Here we proposed a new method for an easy, tag-less and direct isolation of HUVEC from raw umbilical cord sample based on the gravitational field-flow fractionation (GrFFF). This is a low-cost, fully biocompatible method with low instrumental and training investments for flow-assisted cell fractionation. The method allows obtaining pure cells without cell culture procedures as starting material for further analysis; for example, a proper amount of RNA can be extracted. The approach can be easily integrated into clinical and biomedical procedures.

Background: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated mortality. Antibodies against human leucocyte antigens (HLA) and human neutrophil antigens (HNA) are often detected in the implicated donors. We investigated the incidence and aetiology of TRALI in Lombardy. Moreover, we determined the rate of HLA and HNA alloimmunisation and the HNA genotype in a cohort of local blood donors., Materials and Methods: During a 2-year observational study in eight blood transfusion services, suspected TRALI cases were collected and characterised by means of HLA and HNA antibody screening of implicated donors, donor/recipient cross-matching and HLA/HNA molecular typing. In addition, 406 Italian donors were evaluated for alloimmunisation and in 102 of them HNA gene frequencies were determined., Results: Eleven cases were referred to the central laboratory, of whom three were diagnosed as having TRALI, seven as having possible TRALI and one as having transfusion-associated circulatory overload. Seven TRALI cases were immune-mediated whereas in three we did not find either alloantibodies in implicated donors or a positive reaction in the cross-match. The most frequently implicated blood component was red blood cells (in 5 males and in 1 female), whereas four cases of TRALI were associated with transfusion of fresh-frozen plasma (in 3 females and in 1 male). The frequency of reported TRALI/possible TRALI cases was 1:82,000 for red blood cells and 1:22,500 for fresh-frozen plasma. No cases were observed for platelets. Overall, the frequency of HLA or HNA alloimmunisation in blood donors was 29% for females and 7% for males. The latter could be related, at least in part, to natural antibodies. HNA gene frequencies showed that HNA-1b is more frequent than HNA-1a in our sample of donors., Discussion: The recently adopted national policy to prevent TRALI, i.e. using only plasma donated by males, would have had a positive impact in our setting.

Background and Aims: Increasing evidence that a number of malignancies are characterised by tumour cell heterogeneity has recently been published, but there is still a lack of data concerning liver cancers. The aim of this study was to investigate and characterise tumour-propagating cell (TPC) compartments within human hepatocellular carcinoma (HCC)., Methods: After long-term culture, we identified three morphologically different tumour cell populations in a single HCC specimen, and extensively characterised them by means of flow cytometry, fluorescence microscopy, karyotyping and microarray analyses, single cell cloning, and xenotransplantation in NOD/SCID/IL2Rγ/⁻ mice., Results: The primary cell populations (hcc-1, -2 and -3) and two clones generated by means of limiting dilutions from hcc-1 (clone-1/7 and -1/8) differently expressed a number of tumour-associated stem cell markers, including EpCAM, CD49f, CD44, CD133, CD56, Thy-1, ALDH and CK19, and also showed different doubling times, drug resistance and tumorigenic potential. Moreover, we found that ALDH expression, in combination with CD44 or Thy-1 negativity or CD56 positivity identified subpopulations with a higher clonogenic potential within hcc-1, hcc-2 and hcc-3 primary cell populations, respectively. Karyotyping revealed the clonal evolution of the cell populations and clones within the primary tumour. Importantly, the primary tumour cell population with the greatest tumorigenic potential and drug resistance showed more chromosomal alterations than the others and contained clones with epithelial and mesenchymal features., Conclusions: Individual HCCs can harbor different self-renewing tumorigenic cell types expressing a variety of morphological and phenotypical markers, karyotypic evolution and different gene expression profiles. This suggests that the models of hepatic carcinogenesis should take into account TPC heterogeneity due to intratumour clonal evolution.

Artemisinins are safely used in the combination therapy for uncomplicated malaria, but their employment during pregnancy is still controversial. In fact, animal studies reported that the active metabolite, dihydroartemisinin (DHA), causes embryonic erythrocytes depletion, when the treatment is performed during a critical period of time. The present study investigates the effect of DHA on human developmental erythropoiesis in order to characterize the target erythroid stage and to predict the window of susceptibility in human pregnancy. As a model for human developmental erythropoiesis, peripheral blood purified, CD34+ cells were committed towards erythrocytes and DHA (0.5 or 2 μM) was added to different erythroid stages during 14 days culture. Erythroid differentiation was investigated by cytofluorimetric analysis of Glycophorin A expression, by morphological analysis and erythroid globin gene expression analysis with real-time PCR. It was found that the effect of DHA was dependent on the maturation stage of erythroid cells. In fact when DHA was added to the pro- and basophilic erythroblasts caused a significant dose-dependent inhibition of cell proliferation and a significant delay of erythroid differentiation, as measured by morphological analysis, expression of Glycophorin A by immunofluorescence and of erythroid globin genes by real-time PCR. In contrast, the inhibition of stem cells and of early progenitors was transient and masked by the subsequent exponential cell growth. No effect was observed on mature erythroid stages. This is the first demonstration that DHA affects human erythropoiesis in vitro, in a dose- and time-dependent manner; the target population seems to be the pro-erythroblast and basophilic erythroblast stage, suggesting that DHA toxicity is limited to primitive human erythropoiesis. These findings outline the relevance of DHA dosage and timing to prevent embryotoxicity and support current WHO recommendations of avoiding malaria treatment with artemisinins during the first trimester of pregnancy., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Ex vivo expansion of hematopoietic stem cells has been explored in the fields of stem cell biology, gene therapy and clinical transplantation. Recently, we demonstrated the existence of a circulating myogenic progenitor expressing the CD133 antigen. The relative inability of circulating CD133+ stem cells to reproduce themselves ex vivo imposes substantial limitations on their use for clinical applications in muscular dystrophies. Here we report that the use of cluster-assembled nanostructured titanium dioxide (ns-TiO(2)) substrates, in combination with cytokine enriched medium, enables high-level expansion of circulating CD133+ stem cells in vitro. Furthermore, we demonstrate that expanded circulating CD133+ stem cells retain their in vitro capacity to differentiate into myogenic cells. The exploitation of cluster-assembled ns-TiO(2) substrates for the expansion of CD133+ stem cells in vitro could therefore make the clinical application of these stem cells for the treatment of muscle diseases practical., (Copyright 2010 Elsevier Ltd. All rights reserved.)

The human liver is a complex tissue consisting of epithelial, endothelial, hematopoietic, and mesenchymal elements that probably derive from multiple lineage-committed progenitors, but no comprehensive study aimed at identifying and characterizing intrahepatic precursors has yet been published. Cell suspensions for this study were obtained by enzymatic digestion of liver specimens taken from 20 patients with chronic liver disease and 13 multiorgan donors. Stem and progenitor cells were first isolated, amplified, and characterized ex vivo according to previously validated methods, and then optimized flow cytometry was used to assess their relative frequencies and characterize their immunophenotypes in the clinical specimens. Stem and progenitor cells committed to hematopoietic, endothelial, epithelial, and mesenchymal lineages were clearly identifiable in livers from both healthy and diseased subjects. Within the mononuclear liver cell compartment, epithelial progenitors [epithelial cell adhesion molecule (EpCAM)(+)/CD49f(+)/CD29(+)/CD45(-)] accounted for 2.7-3.5% whereas hematopoietic (CD34(+)/CD45(+)), endothelial [vascular endothelial growth factor-2 (KDR)(+)/CD146(+)/CD45(-)], and mesenchymal [CD73(+)/CD105(+)/CD90 (Thy-1)(+)/CD45 (-)] stem cells and progenitors accounted for smaller fractions (0.02-0.6%). The patients' livers had higher percentages of hematopoietic and endothelial precursors than those of the donors. In conclusion, we identified and characterized precursors committed to four different lineages in adult human liver. We also optimized a flow cytometry approach that will be useful in exploring the contribution of these cells to the pathogenesis of liver disease.

Background: Various prognostic serum and cellular markers have been identified for many diseases, such as cardiovascular diseases and tumor pathologies. Here we assessed whether the levels of certain stem cells may predict the progression of Duchenne muscular dystrophy (DMD)., Methods and Findings: The levels of several subpopulations of circulating stem cells expressing the CD133 antigen were determined by flow cytometry in 70 DMD patients. The correlation between the levels and clinical status was assessed by statistical analysis. The median (+/-SD) age of the population was 10.66+/-3.81 (range 3 to 20 years). The levels of CD133+CXCR4+CD34- stem cells were significantly higher in DMD patients compared to healthy controls (mean+/-standard deviation: 17.38+/-1.38 vs. 11.0+/-1.70; P = 0.03) with a tendency towards decreased levels in older patients. Moreover, the levels of this subpopulation of cells correlated with the clinical condition. In a subgroup of 19 DMD patients after 24 months of follow-up, increased levels of CD133+CXCR4+CD34- cells was shown to be associated with a phenotype characterised by slower disease progression. The circulating CD133+CXCR4+CD34- cells in patients from different ages did not exhibit significant differences in their myogenic and endothelial in vitro differentiation capacity., Conclusions: Our results suggest that levels of CD133+CXCR4+CD34- could function as a new prognostic clinical marker for the progression of DMD.