[Is hematological cytology outdated at the age of molecular biology and flow cytometry ? Report of a VEXAS syndrome clinical case]. / Cas clinique. La cytologie hématologique désuète à l'heure de la biologie moléculaire et de la cytométrie en flux ? Illustration au travers d'un syndrome de VEXAS.

VEXAS syndrome is a new entity, described as the first one of a new class of hemato-inflammatory diseases. Through this article and based on the first case highlighted at the CHU of Liege, we offer you a review of the literature as well as an overview of different laboratory techniques used for the diagnosis of this syndrome.

Le syndrome de VEXAS est une nouvelle entité, décrite comme pionnière d'une nouvelle classe de maladies hémato-inflammatoires. Au travers de cet article et sur base du premier cas mis en évidence au CHU de Liège, nous vous proposons une revue de la littérature ainsi qu'un aperçu des différentes techniques de laboratoire permettant le diagnostic de ce syndrome.

[Contribution of hematology analyzers (Sysmex XN-Series) in the rapid diagnosis of malaria: case reports]. / Apport des automates d'hématologie (Sysmex XN-Series) dans le diagnostic rapide du paludisme : à propos de deux cas.

Malaria is a potentially severe disease, particularly in Africa. In Europe, the majority of malaria cases come from travelers returning from endemic areas. The non-specific symptomatology may not alert the clinician if this notion of travel is not addressed. However, diagnosis and rapid initiation of treatment prevent the evolution of severe forms of the disease, especially in the case of Plasmodium falciparum infection, which can be life-threatening within 24 hours. Thin and thick blood smears microscopy is the main tools for diagnosis, but some automated hematology analyzers have demonstrated their ability to participate in early diagnosis. We describe two cases illustrating the contribution of the Sysmex XN-9100 automated system for the diagnosis of malaria. The first clinical case described a young man infected with numerous Plasmodium falciparum gametocytes. WNR (white blood cell count) and WDF (white blood cell differenciation) scattergrams showed an additional population, corresponding to gametocytes. The second case focused on a man with neuromalaria and high Plasmodium falciparum parasitaemia. Parasitized red blood cells form an inconspicuous double population on the reticulocyte scattergram, located at the discrimination limit between mature red blood cells and reticulocytes. Scattergram abnormalities, which can be visualized in a few minutes, offer an anticipation of the diagnosis of malaria in comparison to thin and thick smears microscopy, that requiring considerable time and expertise.

P2X1 ion channel deficiency causes massive bleeding in inflamed intestine and increases thrombosis.

BACKGROUND: Intestinal inflammation is associated with bleeding and thrombosis, two processes that may involve both platelets and neutrophils. However, the mechanisms and the respective contribution of these cells to intestinal bleeding and extra-intestinal thrombosis remain largely unknown. OBJECTIVE: Our study aimed at investigating the mechanisms underlying the maintenance of vascular integrity and thrombosis in intestinal inflammation. METHODS: We used a mouse model of acute colitis induced by oral administration of dextran sodium sulfate (DSS) for 7 days. Bleeding was assessed after depletion of platelets, neutrophils, or glycoprotein VI (GPVI); treatment with aspirin or clopidogrel; or in P2X1-deficient mice. Extra-intestinal thrombosis was analyzed using a laser-induced injury model of thrombosis in cremaster muscle arterioles. RESULTS: Platelet depletion or P2X1 deficiency led to macrocytic regenerative anemia due to intestinal hemorrhage. In contrast, GPVI, P2Y12, and thromboxane A2 were dispensable. Platelet P-selectin expression and regulated on activation, normal T-cell expressed and secreted (RANTES) plasma levels were lower in DSS-treated P2X1-deficient mice as compared to wild-type mice, indicative of a platelet secretion defect. Circulating neutrophils had a more activated phenotype, and neutrophil infiltration in the colon was increased. P2X1-deficient mice also had elevated plasma granulocyte-colony stimulating factor (G-CSF) levels. Neutrophil depletion limited blood loss in these mice, whereas exogenous administration of G-CSF in colitic wild-type mice caused macrocytic anemia. Anemic colitic P2X1-deficient mice formed atypical neutrophil- and fibrin-rich, and platelet-poor thrombi upon arteriolar endothelial injury. CONCLUSIONS: Platelets and P2X1 ion channels are mandatory to preserve vascular integrity in inflamed intestine. Upon P2X1 deficiency, neutrophils contribute to bleeding and they may also be responsible for enhanced thrombosis.

[Monoclonal B-cell lymphocytosis: from literature to laboratory practice]. / Lymphocytoses B monoclonales: de la revue de la littérature à la pratique de laboratoire.

Monoclonal B-cell lymphocytosis (MBL) is defined as an asymptomatic condition characterized by the presence of less than 5,000 monoclonal B-cells per microliter and the absence of clinical signs or symptoms of a B-cell lymphoproliferative disorder. Most MBL cases involve B cells presenting an identical phenotype to CLL (CLL-like MBL) with a Catovsky-Matutes score of 3 to 5 and share the same chromosomal abnormalities than CLL. Depending on the absolute B cell count, one may distinguish low-count CLL-like MBL (<500 B cells/µL) which have no evidence of progression, no reduction in overall survival, no increase in infection risk and do not require any specific follow-up. Patients with clinical CLL-like MBL (>500 B cells/µL) have a 1% to 2% per year risk of progression to CLL requiring therapy, a higher risk of infectious complications and mortality implicating an annual follow-up by hematologist. MBL may also express other less common phenotypes and are named atypical MBL in case of CD5 antigen expression (Catovsky-Matutes score: 1-2) and non-CLL-like MBL for CD5 negative cases (Catovsky-Matutes score: 0-2). Their poorer prognosis implicates imaging studies, bone marrow biopsy and cytogenetic analysis in addition to physical examination in order to rule out non-hodgkinien lymphoma, and require a more frequent follow-up. This review focuses on key concepts in the classification, diagnosis, monitoring and biology of MBL in laboratory practice.

Fatal alveolar echinococcosis of the lumbar spine.

For the last 10 years, the southern part of Belgium has been recognized as a low-risk area of endemicity for alveolar echinococcosis. This infection, caused by Echinococcus multilocularis, usually induces a severe liver condition and can sometimes spread to other organs. However, alveolar echinococcosis involving bones has been described only very rarely. Here, a fatal case of spondylodiscitis due to E. multilocularis contracted in southern Belgium is reported.

BCL-3 degradation involves its polyubiquitination through a FBW7-independent pathway and its binding to the proteasome subunit PSMB1.

The oncogenic protein BCL-3 activates or represses gene transcription through binding with the NF-kappaB proteins p50 and p52 and is degraded through a phospho- and GSK3-dependent pathway. However, the mechanisms underlying its degradation remain poorly understood. Yeast two-hybrid analysis led to the identification of the proteasome subunit PSMB1 as a BCL-3-associated protein. The binding of BCL-3 to PSMB1 is required for its degradation through the proteasome. Indeed, PSMB1-depleted cells are defective in degrading polyubiquitinated BCL-3. The N-terminal part of BCL-3 includes lysines 13 and 26 required for the Lys(48)-linked polyubiquitination of BCL-3. Moreover, the E3 ligase FBW7, known to polyubiquitinate a variety of substrates phosphorylated by GSK3, is dispensable for BCL-3 degradation. Thus, our data defined a unique motif of BCL-3 that is needed for its recruitment to the proteasome and identified PSMB1 as a key protein required for the proteasome-mediated degradation of a nuclear and oncogenic IkappaB protein.

The repressing function of the oncoprotein BCL-3 requires CtBP, while its polyubiquitination and degradation involve the E3 ligase TBLR1.

The nuclear and oncogenic BCL-3 protein activates or represses gene transcription when bound to NF-kappaB proteins p50 and p52, yet the molecules that specifically interact with BCL-3 and drive BCL-3-mediated effects on gene expression remain largely uncharacterized. Moreover, GSK3-mediated phosphorylation of BCL-3 triggers its degradation through the proteasome, but the proteins involved in this degradative pathway are poorly characterized. Biochemical purification of interacting partners of BCL-3 led to the identification of CtBP as a molecule required for the ability of BCL-3 to repress gene transcription. CtBP is also required for the oncogenic potential of BCL-3 and for its ability to inhibit UV-mediated cell apoptosis in keratinocytes. We also defined the E3 ligase TBLR1 as a protein involved in BCL-3 degradation through a GSK3-independent pathway. Thus, our data demonstrate that the LSD1/CtBP complex is required for the repressing abilities of an oncogenic I kappaB protein, and they establish a functional link between the E3 ligase TBLR1 and NF-kappaB.

Deregulated NF-kappaB activity in haematological malignancies.

The NF-kappaB family of transcription factors plays key roles in the control of cell proliferation and apoptosis. Constitutive NF-kappaB activation is a common feature for most haematological malignancies and is therefore believed to be a crucial event for enhanced proliferation and survival of these malignant cells. In this review, we will describe the molecular mechanisms underlying NF-kappaB deregulation in haematological malignancies and will highlight what is still unclear in this field, 20 years after the discovery of this transcription factor.