The Onset of Intussusceptive Angiogenesis in COVID-19 Patients Might Come from the Mobilization of Stem Cell Sub-Populations Expressing the Hemangioblast Marker CD143.

COVID-19 and infectious diseases have been included in strategic development goals (SDG) of United Nations (UN). The SARS-CoV-2 pandemic has unveiled complex pathophysiological mechanisms underpinning COVID-19, notably inducing a systemic acquired vascular hemopathy characterized by endothelial dysfunction and intussusceptive angiogenesis, a rapid vascular remodeling process identified as a hallmark in severe COVID-19 cases affecting pulmonary and cardiac tissues. Stem cell migration have been proposed as significant regulators of this neoangiogenic process. In a monocentric cross-sectional study, through spectral flow cytometry analysis of peripheral blood mononuclear cells, we identified a distinct stem cell subpopulation mobilized in critical COVID-19. Indeed, by an unsupervised analysis generating a UMAP representation we highlighted eleven different clusters in critical and non-critical COVID-19 patients. Only one cluster was significantly associated to critical COVID-19 compared to non-critical patients. This cluster expressed the markers: CD45dim, CD34+, CD117+, CD147+, and CD143+, and were negative for CD133. Higher level of expression of hemangioblast markers CD143 were found in critical COVID-19 patients. This population, indicative of hemangioblast-like cells, suggests a key role in COVID-19-related neoangiogenesis, potentially driving the severe vascular complications observed. Our findings underscore the need for further investigation into the contributions of adult stem cells in COVID-19 pathology, offering new insights into therapeutic targets and interventions.

[Pernicious anemia with false normal vitamin B12 levels caused by intrinsic factor antibodies interference: a case report]. / Maladie de Biermer avec dosage de vitamine B12 faussement normal par interférence avec les anticorps anti-facteur intrinsèque : à propos d'un cas.

We present a case of a 48-year-old woman with a fortuitous discovery of macrocytic anemia and thrombocytopenia. Serum folate and vitamin B12 levels were normal. However, due to the presence of indirect signs of cobalamin deficiency, such as elevated homocysteine and methylmalonic acid, and signs of dyserythropoiesis on the bone marrow aspirate, pernicious anemia was suspected. Vitamin B12 dosage was repeated finding fluctuating but always normal results. Anti-intrinsic factor antibodies were present at a very high level, explaining the fluctuations and the interference found on the assay using competitive binding chemiluminescence (CBLA). Serum vitamin B12 dosage by electrochemiluminescence, a method described as not interfering with intrinsic factor antibodies, showed a collapsed vitamin B12 level. Measurement of vitamin B12 with CBLA after adsorption of immunoglobulins in the sample using protein G SepharoseTM, confirmed the interference of the cobalamin assay with autoantibodies. This case illustrates the difficulties regarding the analysis and standardization of the vitamin B12 assay for the diagnosis of pernicious anemia.

Clinical and biological impact of ATP-binding cassette transporter activity in adult acute myeloid leukemia.

Chemotherapy resistance is the main cause of treatment failure in acute myeloid leukemia (AML) and has been related to ATP-binding cassette (ABC) transporter activity. However, the links between ABC activity, immunophenotype, and molecular AML parameters have been poorly evaluated. Moreover, the prognostic value of ABC activity, when compared to new molecular markers, is unknown. Here we investigated the links between ABC activity, as evaluated by JC-1 +/- cyclosporine A assay, and immunophenotypic, cytogenetic, molecular, and targeted next-generation sequencing features in 361 AML patients. High ABC activity was found in 164 patients and was significantly associated with less proliferating disease, an immature immunophenotype (expression of CD34, HLA-DR, CD117, CD13), and gene mutations defining AML as belonging to secondary-type ontogenic groups. Low ABC activity was associated with more mature myeloid differentiation (CD34-, cyMPO+, CD15+, CD33+) or monocytic commitment (CD64+, CD4+weak, CD14+), with NPM1 mutations, KMT2A rearrangements, and core-binding factor gene fusions, hallmarks of the de novo-type AML ontogeny. ABC activity was one of the major factors we identified using a random forest model for early prediction of AML ontogeny. In the 230 patients evaluated at diagnosis and intensively treated, high ABC activity was a predictive factor for primary resistance, and in multivariate analysis including full molecular data, an independent factor for event-free survival (P=0.0370). JC-1 +/- cyclosporine A assay could be used at diagnosis to predict AML ontogeny and to complete prognosis evaluation in addition to new molecular markers.

Increased Circulating CD62E+ Endothelial Extracellular Vesicles Predict Severity and in- Hospital Mortality of COVID-19 Patients.

COVID-19 and infectious diseases have been included in strategic development goals (SDG) of United Nations (UN). Severe form of COVID-19 has been described as an endothelial disease. In order to better evaluate Covid-19 endotheliopathy, we characterized several subsets of circulating endothelial extracellular vesicles (EVs) at hospital admission among a cohort of 60 patients whose severity of COVID-19 was classified at the time of inclusion. Degree of COVID-19 severity was determined upon inclusion and categorized as moderate to severe in 40 patients and critical in 20 patients. We measured citrated plasma EVs expressing endothelial membrane markers. Endothelial EVs were defined as harboring VE-cadherin (CD144+), PECAM-1 (CD31 + CD41-) or E-selectin (CD62E+). An increase in CD62E + EV levels on admission to the hospital was significantly associated with critical disease. Moreover, Kaplan-Meier survival curves for CD62E + EV level showed that level ≥ 88,053 EVs/µL at admission was a significant predictor of in hospital mortality (p = 0.004). Moreover, CD62E + EV level ≥ 88,053 EV/µL was significantly associated with higher in-hospital mortality (OR 6.98, 95% CI 2.1-26.4, p = 0.002) in a univariate logistic regression model, while after adjustment to BMI CD62E + EV level ≥ 88,053 EV/µL was always significantly associated with higher in-hospital mortality (OR 5.1, 95% CI 1.4-20.0, p = 0.01). The present findings highlight the potential interest of detecting EVs expressing E-selectin (CD62) to discriminate Covid-19 patients at the time of hospital admission and identify individuals with higher risk of fatal outcome.

Pain Assessment Using Virtual Reality Facemask During Bone Marrow Aspiration: Prospective Study Including Propensity-Matched Analysis.

BACKGROUND: Bone marrow aspiration (BMA) is a medical procedure necessary to the diagnosis and monitoring of patients with hematological or nonhematological disorders. This procedure is considered painful, and patients are generally anxious before and during BMA. OBJECTIVE: This study assesses the effect of immersive virtual reality on pain during BMA. METHODS: This observational prospective and monocentric study enrolled 105 consecutive patients who underwent sternal BMA with lidocaine anesthesia. The study was carried on during 2 periods. First, virtual reality facemask (VRF) was proposed to all patients in the absence of exclusion criteria. During the second period, BMA was performed without the VRF. For all patients, pain intensity after the procedure was assessed using a 10-point numerical pain rating scale (NPRS). All analyses were performed on propensity score-matched cohort (with or without VRF) to evaluate efficacy on NRPS levels. RESULTS: The final matched cohort included 12 patients in the VRF group and 24 in the control group. No difference in anxiety level before BMA evaluated by the patient and by the operator was observed between groups (P=.71 and .42 respectively). No difference of NPRS was observed using VRF when compared to control group (median NPRS 3.8, IQR 2.0-6.3 vs 3.0, IQR 1.9-3.0, respectively; P=.09). CONCLUSIONS: Our study did not prove the efficacy of VRF to reduce pain during BMA.

Current concepts on endothelial stem cells definition, location, and markers.

Ischemic vascular disease is a major cause of mortality and morbidity worldwide, and regeneration of blood vessels in perfusion-deficient tissues is a worthwhile therapeutic goal. The idea of delivering endothelial stem/progenitor cells to repair damaged vasculature, reperfuse hypoxic tissue, prevent cell death, and consequently diminish tissue inflammation and fibrosis has a strong scientific basis and clinical value. Various labs have proposed endothelial stem/progenitor cell candidates. This has created confusion, as there are profound differences between these cell definitions based on isolation methodology, characterization, and reparative biology. Here, a stricter definition based on stem cell biology principles is proposed. Although preclinical studies have often been promising, results from clinical trials have been highly contradictory and served to highlight multiple challenges associated with disappointing therapeutic benefit. This article reviews recent accomplishments in the field and discusses current difficulties when developing endothelial stem cell therapies. Emerging evidence that disputes the classic view of the bone marrow as the source for these cells and supports the vascular wall as the niche for these tissue-resident endothelial stem cells is considered. In addition, novel markers to identify endothelial stem cells, including CD157, EPCR, and CD31low VEGFR2low IL33+ Sox9+ , are described.

Elevated Circulating Stem Cells Level is Observed One Month After Implantation of Carmat Bioprosthetic Total Artificial Heart.

The Aeson® total artificial heart (A-TAH) has been developed as a total heart replacement for patients at risk of death from biventricular failure. We previously described endothelialization of the hybrid membrane inside A-TAH probably at the origin of acquired hemocompatibility. We aimed to quantify vasculogenic stem cells in peripheral blood of patients with long-term A-TAH implantation. Four male adult patients were included in this study. Peripheral blood mononuclear cells were collected before A-TAH implantation (T0) and after implantation at one month (T1), between two and five months (T2), and then between six and twelve months (T3). Supervised analysis of flow cytometry data confirmed the presence of the previously identified Lin-CD133+CD45- and Lin-CD34+ with different CD45 level intensities. Lin-CD133+CD45-, Lin-CD34+CD45- and Lin-CD34+CD45+ were not modulated after A-TAH implantation. However, we demonstrated a significant mobilization of Lin-CD34+CD45dim (p = 0.01) one month after A-TAH implantation regardless of the expression of CD133 or c-Kit. We then visualized data for the resulting clusters on a uniform manifold approximation and projection (UMAP) plot showing all single cells of the live Lin- and CD34+ events selected from down sampled files concatenated at T0 and T1. The three clusters upregulated at T1 are CD45dim clusters, confirming our results. In conclusion, using a flow cytometry approach, we demonstrated in A-TAH-transplanted patients a significant mobilization of Lin-CD34+CD45dim in peripheral blood one month after A-TAH implantation. Using a flow cytometry approach, we demonstrated in A-TAH transplanted patients a significant mobilization of Lin-CD34+CD45dim in peripheral blood one month after A-TAH implantation. This cell population could be at the origin of newly formed endothelial cells on top of hybrid membrane in Carmat bioprosthetic total artificial heart.

Transcriptomic and genomic heterogeneity in blastic plasmacytoid dendritic cell neoplasms: from ontogeny to oncogenesis.

Oncogenesis and ontogeny of blastic plasmacytoid dendritic cell neoplasm (BPDCN) remain uncertain, between canonical plasmacytoid dendritic cells (pDCs) and AXL+ SIGLEC6+ DCs (AS-DCs). We compared 12 BPDCN to 164 acute leukemia by Affymetrix HG-U133 Plus 2.0 arrays: BPDCN were closer to B-cell acute lymphoblastic leukemia (ALL), with enrichment in pDC, B-cell signatures, vesicular transport, deubiquitination pathways, and AS-DC signatures, but only in some cases. Importantly, 1 T-cell ALL clustered with BPDCN, with compatible morphology, immunophenotype (cCD3+ sCD3- CD123+ cTCL1+ CD304+), and genetics. Many oncogenetic pathways are deregulated in BPDCN compared with normal pDC, such as cell-cycle kinases, and importantly, the transcription factor SOX4, involved in B ontogeny, pDC ontogeny, and cancer cell invasion. High-throughput sequencing (HaloPlex) showed myeloid mutations (TET2, 62%; ASXL1, 46%; ZRSR2, 31%) associated with lymphoid mutations (IKZF1), whereas single-nucleotide polymorphism (SNP) array (Affymetrix SNP array 6.0) revealed frequent losses (mean: 9 per patient) involving key hematological oncogenes (RB1, IKZF1/2/3, ETV6, NR3C1, CDKN2A/B, TP53) and immune response genes (IFNGR, TGFB, CLEC4C, IFNA cluster). Various markers suggest an AS-DC origin, but not in all patients, and some of these abnormalities are related to the leukemogenesis process, such as the 9p deletion, leading to decreased expression of genes encoding type I interferons. In addition, the AS-DC profile is only found in a subgroup of patients. Overall, the cellular ontogenic origin of BPDCN remains to be characterized, and these results highlight the heterogeneity of BPDCN, with a risk of a diagnostic trap.

Plasmacytoid dendritic cells proliferation associated with acute myeloid leukemia: phenotype profile and mutation landscape

Neoplasms involving plasmacytoid Dendritic Cells (pDCs) include Blastic pDC Neoplasms (BPDCN) and other pDC proliferations, where pDCs are associated with myeloid malignancies: most frequently Chronic MyeloMonocytic Leukemia (CMML) but also Acute Myeloid Leukemia (AML), hereafter named pDC-AML. We aimed to determine the reactive or neoplastic origin of pDCs in pDC-AML, and their link with the CD34+ blasts, monocytes or conventional DCs (cDCs) associated in the same sample, by phenotypic and molecular analyses (targeted NGS, 70 genes). We compared 15 pDC-AML at diagnosis with 21 BPDCN and 11 normal pDCs from healthy donors. CD45low CD34+ blasts were found in all cases (10-80% of medullar cells), associated with pDCs (4-36%), monocytes in 14 cases (1-10%) and cDCs (2 cases, 4.8-19%). pDCs in pDC-AML harbor a clearly different phenotype from BPDCN: CD4+ CD56- in 100% of cases, most frequently CD303+, CD304+ and CD34+; lower expression of cTCL1 and CD123 with isolated lymphoid markers (CD22/CD7/CD5) in some cases, suggesting a pre-pDC stage. In all cases, pDCs, monocytes and cDC are neoplastic since they harbor the same mutations as CD34+ blasts. RUNX1 is the most commonly mutated gene: detected in all AML with minimal differentiation (M0-AML) but not in the other cases. Despite low number of cases, the systematic association between M0-AML, RUNX1 mutations and an excess of pDC is puzzling. Further evaluation in a larger cohort is required to confirm RUNX1 mutations in pDC-AML with minimal differentiation and to investigate whether it represents a proliferation of blasts with macrophage and DC progenitor potential.

How should we diagnose and treat blastic plasmacytoid dendritic cell neoplasm patients?

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive leukemia for which we developed a nationwide network to collect data from new cases diagnosed in France. In a retrospective, observational study of 86 patients (2000-2013), we described clinical and biological data focusing on morphologies and immunophenotype. We found expression of markers associated with plasmacytoid dendritic cell origin (HLA-DRhigh, CD303+, CD304+, and cTCL1+) plus CD4 and CD56 and frequent expression of isolated markers from the myeloid, B-, and T-lymphoid lineages, whereas specific markers (myeloperoxidase, CD14, cCD3, CD19, and cCD22) were not expressed. Fifty-one percent of cytogenetic abnormalities impact chromosomes 13, 12, 9, and 15. Myelemia was associated with an adverse prognosis. We categorized chemotherapeutic regimens into 5 groups: acute myeloid leukemia (AML)-like, acute lymphoid leukemia (ALL)-like, lymphoma (cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP])-like, high-dose methotrexate with asparaginase (Aspa-MTX) chemotherapies, and not otherwise specified (NOS) treatments. Thirty patients received allogeneic hematopoietic cell transplantation (allo-HCT), and 4 patients received autologous hematopoietic cell transplantation. There was no difference in survival between patients receiving AML-like, ALL-like, or Aspa-MTX regimens; survival was longer in patients who received AML-like, ALL-like, or Aspa-MTX regimens than in those who received CHOP-like regimens or NOS. Eleven patients are in persistent complete remission after allo-HCT with a median survival of 49 months vs 8 for other patients. Our series confirms a high response rate with a lower toxicity profile with the Aspa-MTX regimen, offering the best chance of access to hematopoietic cell transplantation and a possible cure.