Myeloid Sarcoma of the Uterine Cervix as Presentation of Acute Myeloid Leukaemia after Treatment with Low-Dose Radioiodine for Thyroid Cancer: A Case Report and Review of the Literature

The development of acute myeloid leukaemia after low-dose radioiodine therapy and its presentation as a myeloid sarcoma of the uterine cervix are both rare events. We report a case of acute myeloid leukaemia revealed by a myeloid sarcoma of the uterine cervix in a 48-year-old woman, 17 months after receiving a total dose of 100 mCi 131I for papillary thyroid cancer. A strict hematological follow-up of patients treated with any dose of 131I is recommended to accurately detect any hematological complications which might have been underestimated. Unusual presentations, such as chloroma of the uterine cervix, may reveal myeloid malignancy and should be kept in mind

CDX2 expression in the hematopoietic lineage promotes leukemogenesis via TGFβ inhibition

The intestine-specific caudal-related homeobox gene-2 (CDX2) homeobox gene, while being a tumor suppressor in the gut, is ectopically expressed in a large proportion of acute leukemia and is associated with poor prognosis. Here, we report that turning on human CDX2 expression in the hematopoietic lineage of mice induces acute monoblastic leukemia, characterized by the decrease in erythroid and lymphoid cells at the benefit of immature monocytic and granulocytic cells. One of the highly stimulated genes in leukemic bone marrow cells was BMP and activin membrane-bound inhibitor (Bambi), an inhibitor of transforming growth factor-β (TGF-β) signaling. The CDX2 protein was shown to bind to and activate the transcription of the human BAMBI promoter. Moreover, in a leukemic cell line established from CDX2-expressing mice, reducing the levels of CDX2 or Bambi stimulated the TGF-β-dependent expression of Cd11b, a marker of monocyte maturation. Taken together, this work demonstrates the strong oncogenic potential of the homeobox gene CDX2 in the hematopoietic lineage, in contrast with its physiological tumor suppressor activity exerted in the gut. It also reveals, through BAMBI and TGF-β signaling, the involvement of CDX2 in the perturbation of the interactions between leukemia cells and their microenvironment

BCR-associated factors driving chronic lymphocytic leukemia cells proliferation ex vivo

International audienceA chronic antigenic stimulation is believed to sustain the leukemogenic development of chronic lymphocytic leukemia (CLL) and most of lymphoproliferative malignancies developed from mature B cells. Reproducing a proliferative stimulation ex vivo is critical to decipher the mechanisms of leukemogenesis in these malignancies. However, functional studies of CLL cells remains limited since current ex vivo B cell receptor (BCR) stimulation protocols are not sufficient to induce the proliferation of these cells, pointing out the need of mandatory BCR co-factors in this process. Here, we investigated benefits of several BCR co-stimulatory molecules (IL-2, IL-4, IL-15, IL-21 and CD40 ligand) in multiple culture conditions. Our results demonstrated that BCR engagement (anti-IgM ligation) concomitant to CD40 ligand, IL-4 and IL-21 stimulation allowed CLL cells proliferation ex vivo. In addition, we established a proliferative advantage for ZAP70 positive CLL cells, associated to an increased phosphorylation of ZAP70/SYK and STAT6. Moreover, the use of a tri-dimensional matrix of methylcellulose and the addition of TLR9 agonists further increased this proliferative response. This ex vivo model of BCR stimulation with T-derived cytokines is a relevant and efficient model for functional studies of CLL as well as lymphoproliferative malignancies. Like in most mature lymphoproliferative malignancies, an antigenic stimulation is believed to drive the leukemo-genic process in chronic lymphocytic leukemia (CLL) 1-3. A restricted use of IGHV genes and the existence of ste-reotypic B cell receptor (BCR) on CLL cells 4-6 provides evidence in favor of antigenic stimulation where different microbial antigens, as well as auto-antigens, have been suspected as actors of this chronic stimulation 7. In addition , a chronic BCR self-activation has been shown in subtypes of CLL cells 8. Moreover, several signaling aberrations have been described downstream of the BCR, notably in aggressive CLL with unmutated IGHV (UM-CLL), in which the expression of ZAP70 reinforces BCR responsiveness 9-12. BCR activation, which is essential for the physiological development of lymphocytes 13 would also be indispensable for the survival and proliferation of CLL cells in vivo 2. Accordingly, withdrawal of this stimulation is believed to be responsible for the rapid spontaneous apoptosis of CLL cells ex vivo 14. The cellular consequences of this BCR activation has been extensively studied an

Les leucémies aiguës lymphoblastiques T (Aspects cytogénétiques, immunophénotypiques, moléculaires et morphologiques.)

STRASBOURG-Medecine (674822101) / SudocSudocFranceF

Direct Visualization of Circulating Neutrophil Extracellular Traps Using Cell Fluorescence during Human Septic Shock-Induced Disseminated Intravascular Coagulation

International audienceSeptic shock is the most severe form of infection, defined as a subset of sepsis in which circulatory, cellular and metabolic abnormalities are profound and responsible for multiple organ failure and a high mortality-rate. Septic shock is characterized by a broad coagulation activation that can lead to uncontrolled thrombin and fibrin generation, which may evolve to disseminated intravascular coagulation (DIC). DIC increases the risk of death, thus representing a therapeutic target of interest. However, the pathophysiological mechanisms of DIC are not fully understood. Polymorphonuclear neutrophils (PMNs) have recently been identified as potential players of the response to infection by releasing their content, including DNA, histones and granules enzymes. These structures, called neutrophils extracellular traps (NETs), form a large net-like structure in which pathogens get trapped. NETs capture invading pathogens, but also represent a pro-coagulant surface at the interface between immunity and thrombosis. During septic shock-induced DIC, neutrophil activation may result in excessive NET formation. In this study, we originally report the presence of circulating NETs in human blood during septic shock-induced DIC using a simple and robust method. Blood samples were obtained from healthy human volunteers (n=3), patients with septic shock without DIC (n=3) and with DIC (n=3). PMNs were immediately purified immediately after sampling using negative immune-magnetic sorting method. 5x104 purified PMNs were subsequently spotted on microscope slides using cytocentrifugation at 35g for 5 minutes, thus preserving cell integrity and morphology. Positive controls for NET formation were obtained using PMNs isolated from healthy volunteers that were stimulated in-vitro with 4 μM ionomycin. PMNs were stained with mouse anti-human FITC anti-myeloperoxidase (MPO) antibody and the blue-fluorescent DAPI nucleic acid stain. NETs were identified as elongated extracellular DAPI stained DNA fibers associated to MPO detected by immunofluorescence microscopy. The degree of NETs formation was blindly quantified into 5 categories according to the proportion of neutrophils forming NETs per microscopic field: absence (0% of neutrophils forming NETs), scarce (1-25%), moderate (26% to 50%), high (50% to 75%) or very high degree of NETS formation (76% to 100%). PMNs from healthy donors stimulated by ionomycin released NETs, evidenced as double-stained DAPI-positive chromatin structures decorated with MPO in the extracellular space using fluorescence microscopy. NET structures similar to those observed after ionomycin stimulation were unambiguously visualized in PMNs from septic shock patients with DIC, but neither in PMNs from septic shock patients without DIC, nor in unstimulated PMNs from healthy donors. DIC patients were stratified into "high" or "very high" degree of NETs formation groups (>75 % of PMNs displaying DNA release), not different from ionomycin-stimulated PMNs (50 to 75%). Conversely, PMNs from patients devoid of DIC as well as unstimulated normal PMNs from healthy volunteers were stratified into "scarce" or "absence" of PMNs forming NET categories. Blind review of May-Giemsa-Grunwald (MGG) stained slides showed the correlation of the detection of NETs with nuclear decondensation and vacuolation of the cytoplasm of PMNs, features that are associated with neutrophil activation. Accordingly, neutrophils' side-fluorescence (NEUT-SFL), a Sysmex™ CBC analyzers parameter previously associated to NETosis (Stiel et al., 2016, Delabranche et al., 2017) was increased during septic shock induced DIC as well as following in-vitro ionomycin stimulation of normal PMNs. In this study, we showed for the first time direct evidence of circulating NETs in peripheral blood of patients with septic shock-induced DIC using immunofluorescence. These NETs are undistinguishable from NETs features observed following in-vitro ionomycin stimulation of normal PMNs. NETs images were furthermore associated with modifications of PMN morphology that could be detected using MGG staining. This observation may be of great interest in order to stratify patients eligible for future treatment protocols with molecules targeting NETs. Figure Disclosures Meziani: STAGO: Research Funding

Concomitant haemorrhagic syndrome and recurrent extensive arterial thrombosis in a patient with COVID‐19 and acute promyelocytic leukaemia

No abstrac