[Neonatal Fc receptor : role and implications in maternal fetal medicine]. / Récepteur Fc néonatal : rôle et ­implications en médecine ­fœto-maternelle.

During pregnancy, the mother's IgG immunoglobulins cross the -placenta via the neonatal Fc receptor (FcRn), enabling the fetus to acquire passive immunity. In the presence of maternal allo- or auto-antibodies, placental transfer of these pathogenic antibodies mediated by FcRn can cause diseases in the fetus and/or the newborn. FcRn blockade therefore appears to be a therapeutic strategy in these high-risk pregnancies, firstly by reducing IgG recycling, -thereby reducing its concentration in the maternal circulation, and secondly by blocking placental transfer. The promising results of a recent trial testing nipocalimab, a monoclonal antibody targeting FcRn, in very severe erythrocyte alloimmunisation, has opened the way to new targeted therapeutic approaches for perinatal diseases mediated by maternal IgG.

Durant la grossesse, les immunoglobulines de type G (IgG) de la mère franchissent le placenta via le récepteur Fc néonatal (FcRn), permettant au fœtus d'acquérir une immunité passive. En présence d'allo ou d'autoanticorps maternels, ce passage peut entraîner des pathologies fœtales et/ou néonatales. Ainsi, le blocage du FcRn apparaît comme une stratégie thérapeutique dans ces grossesses à risque, d'une part en diminuant le recyclage des IgG, réduisant ainsi leur concentration dans la circulation maternelle, et d'autre part en bloquant leur transfert placentaire. Les résultats prometteurs d'un essai récent testant le nipocalimab, anticorps monoclonal ciblant le FcRn, dans les allo-immunisations érythrocytaires très sévères, a ouvert la voie à de nouvelles approches thérapeutiques ciblées pour les pathologies périnatales médiées par des IgG maternelles.

[Hematological workup in cases of recurrent early miscarriages: what evidences?] / Bilan hématologique en cas de fausses couches précoces à répétition : quelles évidences ?

Recurrent miscarriages have a major psychological and somatic impact, as well as a significant economic burden. An etiological work-up should be offered after two or three miscarriages, the threshold varying from one scientific society to another. However, the proposed biological work-up must be justified by scientific evidence. A simple blood count, basic coagulation tests including fibrinogen assay and anti-phospholipid antibodies testing should be performed initially. Hereditary thrombophilia testing should only be carried out if there is a history of maternal thrombosis. In the event of an abnormality, management should be multidisciplinary, and the prescription of medication should follow recommended guidelines. Prophylactic treatment is not justified in the absence of a known etiology.

Les fausses couches précoces (FCP) à répétition ont un impact psychologique et somatique important, ainsi qu'un poids économique non négligeable. Un bilan étiologique devrait être proposé à partir de deux ou trois fausses couches, le seuil variant selon les sociétés savantes. Cependant, le bilan biologique doit être justifié par des évidences scientifiques. Une formule sanguine simple, des tests de coagulation de base avec le dosage du fibrinogène et une recherche d'anticorps anti-phospholipides devraient être réalisés en première intention. Une recherche de thrombophilie héréditaire ne devrait être effectuée qu'en cas d'antécédent thrombotique maternel. En cas d'anomalie, la prise en charge doit être multidisciplinaire et la prescription de médicaments doit suivre les recommandations. Un traitement prophylactique n'est pas justifié en l'absence d'étiologie retrouvée.

Haematological changes from conception to childbirth: An indicator of major pregnancy complications.

BACKGROUND: About 800 women die every day worldwide from pregnancy-related complications, including excessive blood loss, infections and high-blood pressure (World Health Organization, 2019). To improve screening for high-risk pregnancies, we set out to identify patterns of maternal hematological changes associated with future pregnancy complications. METHODS: Using mixed effects models, we established changes in 14 complete blood count (CBC) parameters for 1710 healthy pregnancies and compared them to measurements from 98 pregnancy-induced hypertension, 106 gestational diabetes and 339 postpartum hemorrhage cases. RESULTS: Results show interindividual variations, but good individual repeatability in CBC values during physiological pregnancies, allowing the identification of specific alterations in women with obstetric complications. For example, in women with uncomplicated pregnancies, haemoglobin count decreases of 0.12 g/L (95% CI -0.16, -0.09) significantly per gestation week (p value <.001). Interestingly, this decrease is three times more pronounced in women who will develop pregnancy-induced hypertension, with an additional decrease of 0.39 g/L (95% CI -0.51, -0.26). We also confirm that obstetric complications and white CBC predict the likelihood of giving birth earlier during pregnancy. CONCLUSION: We provide a comprehensive description of the associations between haematological changes through pregnancy and three major obstetric complications to support strategies for prevention, early-diagnosis and maternal care.

Acquired haemophilia A in the postpartum and risk of relapse in subsequent pregnancies: A systematic literature review.

BACKGROUND: About 1%-5% of acquired haemophilia A cases affect mothers in the postpartum setting. AIMS: This study delineates the characteristics of this disease, specific to the postpartum setting, notably relapse in subsequent pregnancies. METHODS: Report of two cases and literature study (1946-2019), yielding 73 articles describing 174 cases (total 176 cases). RESULTS: Patients were aged 29.9 years (17-41) and 69% primigravidae. Diagnosis was made at a median of 60 days after delivery (range 0-308). Bleeding types were obstetrical (43.4%), cutaneous (41.3%), and muscular (36.7%). In >90% of the cases, FVIII at diagnosis was <1% (range 0%-8%). FVIII inhibitor was documented in 75.4% cases (median titre of 20 BU/ml, range 1-621). Haemostatic treatment was necessary in 57.1% using fresh frozen plasma (16%), factor concentrate (27.6%) and/or bypassing agents (37.4%). Immunosuppressive treatment was administered in 90.8%, mostly steroids (85.3%), alone or combined with immunosuppressants (27%). Rituximab was used mostly as a second line treatment. Only 24 patients (13.6%) had documented subsequent pregnancies and 6 (22.2%) suffered haemophilia recurrence during pregnancy. CONCLUSION: This study allows better definition of: (1) clinical and laboratory characteristics of postpartum acquired haemophilia, (2) response to therapy, and (3) the risk of relapse for subsequent pregnancies.

[Venous thromboembolic disease during pregnancy : diagnosis, treatment and follow-up]. / Maladie thromboembolique veineuse et grossesse : diagnostic, traitement et suivi.

Venous thromboembolism is a leading cause of maternal morbidity and mortality with an overall incidence of 1-2 cases per 1000 pregnancies. The purpose of this article is to summarize more recent recommendations for the management of venous thromboembolism during pregnancy and post-partum period.

La maladie thromboembolique veineuse est l'une des principales causes de morbidité et mortalité maternelles avec une incidence globale de 1 à 2 cas pour 1000 grossesses. Le but de cet article est de résumer les recommandations les plus récentes concernant la prise en charge de la maladie thromboembolique veineuse pendant la grossesse et dans le post-partum.

[Vitamin B12 in practice: When to test ? How to test ? And who should be treated?] / Vitamine B12 en pratique : quand tester ? Comment tester ? Et qui substituer ?

Vitamin B12 deficiency is common in outpatients and inpatient populations, with potentially severe neuropsychiatric and hematological impact, which requires timely diagnosis and treatment. The different diagnostic tests all have their limitations but can be combined, sequentially. We propose to review the treatment options according to the different etiologies of the deficiency, highlighting the costs of the therapies and their coverage by the health insurance.

La carence en vitamine B12 est fréquente en médecine ambulatoire et hospitalière, avec des conséquences neuropsychiatriques et hématologiques potentiellement sévères, nécessitant un diagnostic et un traitement adéquat. Les différents tests diagnostiques ont tous leurs limitations mais peuvent être utilisés de manière complémentaire. Nous proposons de refaire un point sur les possibilités de traitement en fonction des différentes étiologies de la carence, en mettant notamment en exergue les différents coûts des thérapies et leur prise en charge par l'assurance de base.

Pregnancy with Chuvash Polycythaemia and Other Congenital Erythrocytosis.

This original report describes the management of a pregnant woman with congenital erythrocytosis (Chuvash polycythaemia) and reviews the scarce data available in the literature. Therapy consisted of low-dose aspirin and phlebotomies to maintain haematocrit <50% while monitoring iron stores to avoid severe deficiency detrimental to the foetus. Despite normal initial foetal growth, the pregnancy was complicated by preterm birth due to chorioamnionitis. The placenta showed no signs of thrombotic events. The published reports cover 13 pregnancies in 8 patients, showing 1 first-trimester miscarriage, 5 infants with intrauterine growth restriction and/or preterm birth and 1 maternal thrombotic event. These cases were managed with phlebotomies, low-dose aspirin and/or low-molecular-weight heparin, although inconsistently.

[Hematology in the time of COVID-19]. / L'hématologie au temps du COVID-19.

The COVID-19 pandemic impacts the hematology practice. Intensive chemotherapies for high-grade lymphomas and acute leukemias, multiple myeloma treatments and most hematopoietic stem cell transplantations should be performed as usual. Low-grade lymphomas should only be treated when strictly indicated, maintenance can be postponed. Other myeloid neoplasia and their therapies cause imunosupression; dose adjustment is recommended but no brisk stopping. Sickle cell anemia patients are highly succeptible to severe COVID-19 course. Thrombocytopenia and procoagulant state are associated with severe courses of COVID-19, requiring an individualized therapy. No data indicate a risk of SARS-CoV-2 transmission through blood product transfusion.

La pandémie de COVID-19 affecte la prise en charge hématologique. Les chimiothérapies intensives pour les lymphomes agressifs et les leucémies aiguës, les traitements du myélome multiple, ainsi que la plupart des greffes de cellules souches hématopoïétiques doivent continuer à être pratiquées. Les lymphomes de bas grade seront traités uniquement avec des indications claires ; et la maintenance repoussée. Les autres néoplasies myéloïdes et leurs traitements causent une immunosuppression ; on recommande une adaptation des doses, mais pas d'arrêt brusque. La drépanocytose rend les patients très vulnérables au COVID-19. La thrombopénie signe un état procoagulant et la sévérité du COVID-19, nécessitant un traitement individualisé. Aucune donnée n'indique de risque d'une transmission du SARS-CoV-2 par transfusion de produits sanguins.

A key role for Rac and Pak signaling in neutrophil extracellular traps (NETs) formation defines a new potential therapeutic target.

NET formation in mice (NETosis) is supported by reactive oxygen species (ROS) production by NADPH oxidase and histone hypercitrullination by peptidylarginine deiminase 4 (PAD4). Rac1 and Rac2, expressed in polymorphonuclear neutrophils (PMNs), regulate the cytoskeleton, cell shape, adhesion, and migration and are also essential components of the NADPH oxidase complex. We aimed to explore the role of the Rac signaling pathway including the upstream guanosine exchange factor (GEF) activator, Vav, and a downstream effector, the p21-activated kinase, Pak, on NETosis in PMNs using a previously described flow-cytometry-based assay. Rac2-/- PMNs showed reduced levels of citrullinated histone H3 (H3Cit)-positive cells and defective NETosis. Rac1Δ/Δ ; Rac2-/- PMNs demonstrated a further reduction in PMA-induced H3Cit levels and a more profound impairment of NETosis than deletion of Rac2 alone, suggesting an overlapping role of these two highly related proteins. Genetic knockouts of Vav1, or Vav2, did not impair H3Cit response to phorbol myristate ester (PMA) or NETosis. Combined, Vav1 and Vav3 deletions decreased H3Cit response and caused a modest but significant impairment of NETosis. Pharmacologic inhibition of Pak by two inhibitors with distinct mechanisms of action, led to reduced H3Cit levels after PMA stimulation, as well as significant inhibition of NETosis. We validated the importance of Pak using Pak2Δ/Δ PMNs, which demonstrated significantly impaired histone H3 citrullination and NETosis. These data confirm and more comprehensively define the key role of the Rac signaling pathway in PMN NETosis. The Rac signaling cascade may represent a valuable target for inhibition of NETosis and related pathological processes.

[Diagnostic and treatment of mesenteric ischemia]. / Diagnostic et traitement des ischémies mésentériques.

Mesenteric ischemia results from acute or chronic blood flow reduction in the mesenteric arterial or venous vascular supply. This is usually due to an embolus, thrombosis or intestinal hypoperfusion. Radiologic and / or endoscopic imaging and histology allow for diagnosis in high-risk patients with suggestive clinical symptoms and signs. Treatment aims at preventing multi-organ failure through medical treatment, saving intestinal integrity and resecting necrotic bowel segments. Rapid and multidisciplinary management is key in order to optimize treatment and avoid long-term debilitating consequences.

L'ischémie mésentérique est provoquée par l'interruption aiguë ou chronique du flux sanguin splanchno-mésentérique par des mécanismes comme l'embolie, la thrombose ou l'hypoperfusion intestinale. Le diagnostic est posé par imagerie et / ou endoscopie face à un tableau clinique évocateur dans un contexte à risque. La prise en charge vise la prévention d'une défaillance multiviscérale par un traitement médical, la préservation de l'intestin par une revascularisation et la résection des segments nécrotiques. Une prise en charge rapide et multidisciplinaire est cardinale afin d'optimiser le traitement et éviter des séquelles fonctionnelles graves à long terme.

Flow cytometric assay for direct quantification of neutrophil extracellular traps in blood samples.

Neutrophil extracellular traps (NETs) contribute to innate immunity as well as numerous diseases processes such as deep vein thrombosis, myocardial ischemia, and autoimmune disease. To date, most knowledge on NETs formation has been gathered via the qualitative microscopic examination of individual neutrophils in vitro, or aggregate structures in vivo. Here we describe a novel flow cytometry (FLOW)-based assay to identify and quantify NETs using antibodies against key NETs constituents, specifically DNA, modified histones, and granular enzymes. This method is applicable to both murine and human samples for the assessment of induced NETs in vitro, or detection of NETosis in vivo in blood samples. This FLOW-based method was validated by comparison with the well-established microscopy assay using two genetic mouse models previously demonstrated to show defective NETosis. It was then used on healthy human neutrophils for detection of ex vivo induced NETs and on blood samples from patients with sepsis for direct assessment of in vivo NET-forming neutrophils. This new methodology allows rapid and robust assessment of several thousand cells per sample and is independent of potential observer-bias, the two main limitations of the microscopic quantification. Using this new technology facilitates the direct detection of in vivo circulating NETs in blood samples and purification of NETting neutrophils by fluorescence-activated cell sorting (FACS) for further analysis.

Targeted management of coexistent severe thrombophilias-A case report of a successful pregnancy despite paroxysmal nocturnal hemoglobinuria and hereditary protein C deficiency.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder characterized by the absence of complement regulatory proteins on the surface of erythrocytes, leading to intravascular hemolysis and thrombosis. Managing PNH during pregnancy poses significant challenges due to increased risks of morbidity and mortality. This case report describes the detailed obstetric course of a 44-year-old woman with PNH and additional hereditary protein C deficiency who had previously experienced multiple thrombotic events and adverse pregnancy outcomes (two early miscarriages and one stillbirth at 25 weeks gestation [WG]), treated with eculizumab (terminal C5 inhibitor) and optimal anticoagulation management. Close monitoring of hemolysis and hemostasis parameters was conducted throughout the gestation period together with increased obstetrical surveillance. The pregnancy progressed without thrombotic complications or breakthrough hemolysis, and the patient delivered a healthy newborn at 36 WG after induction of labor due to restricted fetal growth. To the best of our knowledge, this is the first reported case of a positive pregnancy outcome despite PNH in conjunction with hereditary thrombophilia. This case report highlights the importance of a multidisciplinary approach involving hematologists and obstetricians in the management of pregnant women with PNH. Tailored therapy, close monitoring, and comprehensive care are crucial to minimize risks and optimize outcomes.

Swiss Survey on current practices and opinions on clinical constellations triggering the search for PNH clones.

This national survey investigated the current practice in Switzerland by collecting participants' opinions on paroxysmal nocturnal hemoglobinuria (PNH) clone assessment and clinical practice. Aim: This study aimed to investigate clinical indications prompting PNH clones' assessment and physician's accessibility of a flow cytometry facility, and also to understand clinical attitudes on the follow-up (FU) of patients with PNH clones. Methods: The survey includes 16 multiple-choice questions related to PNH and targets physicians with a definite level of experience in the topic using two screener questions. Opinion on clinical management was collected using hypothetical clinical situations. Each participant had the option of being contacted to further discuss the survey results. This was an online survey, and 264 physicians were contacted through email once a week for 5 weeks from September 2020. Results: In total, 64 physicians (24.2%) from 23 institutions participated (81.3% hematologists and 67.2% from university hospitals). All had access to flow cytometry for PNH clone testing, with 76.6% having access within their own institution. The main reasons to assess for PNH clones were unexplained thrombosis and/or hemolysis, and/or aplastic anemia (AA). Patients in FU for PNH clones were more likely to be aplastic anemia (AA) and symptomatic PNH. In total, 61% of the participants investigated PNH clones repetitively during FU in AA/myelodysplastic syndromes patients, even when there was no PNH clone found at diagnosis, and 75% of the participants tested at least once a year during FU. Opinions related to clinical management were scattered. Conclusion: The need to adhere to guidelines for the assessment, interpretation, and reporting of PNH clones emerges as the most important finding, as well as consensus for the management of less well-defined clinical situations. Even though there are several international guidelines, clear information addressing specific topics such as the type of anticoagulant to use and its duration, as well as the indication for treatment with complement inhibitors in some borderline situations are needed. The analysis and the discussion of this survey provide the basis for understanding the unmet needs of PNH clone assessment and clinical practice in Switzerland.

Amyloid-beta aggregates cause alterations of astrocytic metabolic phenotype: impact on neuronal viability.

Amyloid-beta (Abeta) peptides play a key role in the pathogenesis of Alzheimer's disease and exert various toxic effects on neurons; however, relatively little is known about their influence on glial cells. Astrocytes play a pivotal role in brain homeostasis, contributing to the regulation of local energy metabolism and oxidative stress defense, two aspects of importance for neuronal viability and function. In the present study, we explored the effects of Abeta peptides on glucose metabolism in cultured astrocytes. Following Abeta(25-35) exposure, we observed an increase in glucose uptake and its various metabolic fates, i.e., glycolysis (coupled to lactate release), tricarboxylic acid cycle, pentose phosphate pathway, and incorporation into glycogen. Abeta increased hydrogen peroxide production as well as glutathione release into the extracellular space without affecting intracellular glutathione content. A causal link between the effects of Abeta on glucose metabolism and its aggregation and internalization into astrocytes through binding to members of the class A scavenger receptor family could be demonstrated. Using astrocyte-neuron cocultures, we observed that the overall modifications of astrocyte metabolism induced by Abeta impair neuronal viability. The effects of the Abeta(25-35) fragment were reproduced by Abeta(1-42) but not by Abeta(1-40). Finally, the phosphoinositide 3-kinase (PI3-kinase) pathway appears to be crucial in these events since both the changes in glucose utilization and the decrease in neuronal viability are prevented by LY294002, a PI3-kinase inhibitor. This set of observations indicates that Abeta aggregation and internalization into astrocytes profoundly alter their metabolic phenotype with deleterious consequences for neuronal viability.

Complex Modes of Inheritance in Hereditary Red Blood Cell Disorders: A Case Series Study of 155 Patients.

Hereditary erythrocytes disorders include a large group of conditions with heterogeneous molecular bases and phenotypes. We analyzed here a case series of 155 consecutive patients with clinical suspicion of hereditary erythrocyte defects referred to the Medical Genetics Unit from 2018 to 2020. All of the cases followed a diagnostic workflow based on a targeted next-generation sequencing panel of 86 genes causative of hereditary red blood cell defects. We obtained an overall diagnostic yield of 84% of the tested patients. Monogenic inheritance was seen for 69% (107/155), and multi-locus inheritance for 15% (23/155). PIEZO1 and SPTA1 were the most mutated loci. Accordingly, 16/23 patients with multi-locus inheritance showed dual molecular diagnosis of dehydrated hereditary stomatocytosis/xerocytosis and hereditary spherocytosis. These dual inheritance cases were fully characterized and were clinically indistinguishable from patients with hereditary spherocytosis. Additionally, their ektacytometry curves highlighted alterations of dual inheritance patients compared to both dehydrated hereditary stomatocytosis and hereditary spherocytosis. Our findings expand the genotypic spectrum of red blood cell disorders and indicate that multi-locus inheritance should be considered for analysis and counseling of these patients. Of note, the genetic testing was crucial for diagnosis of patients with a complex mode of inheritance.

Modulation of astrocytic metabolic phenotype by proinflammatory cytokines.

Astrocytes play an important role in nervous system homeostasis. In particular, they contribute to the regulation of local energy metabolism and to oxidative stress defence. In previous experiments, we showed that long-term treatment with interleukin 1alpha (IL-1alpha) or tumor necrosis factor-alpha (TNFalpha) alone increases glucose utilization in primary culture of mouse astrocytes. In our study, we report that a combination of IL-1beta and TNFalpha exerts a synergistic effect on glucose utilization and markedly modifies the metabolic phenotype of astrocytes. Thus, IL-1beta+TNFalpha treated astrocytes show a marked decrease in glycogen levels, a slight but not significant decrease in lactate release as well as a massive increase in both the pentose phosphate pathway and TCA cycle activities. Glutamate-stimulated glucose utilization and lactate release, a typical feature of astrocyte energy metabolism, are altered after pretreatment with IL-1beta+TNFalpha. As far as mechanisms for oxidative stress defence are concerned, we observed that treatment with IL-1beta+TNFalpha decreases cellular glutathione content and increases glutathione release into the extracellular space while stimulating superoxide anion and nitric oxide production as well as H(2)O(2) release. Interestingly, stimulation of glucose utilization by IL-1beta+TNFalpha is not affected by the antioxidant N-acetyl-L-cysteine, suggesting that cellular stress does not account for this effect. Finally, the effects of cytokines on glucose utilization appear to involve multiple signaling cascades including the phosphoinositide 3-kinase and mitogen-activated protein kinases. Taken together these results establish that a proinflammatory environment such as observed in several neuropathological conditions including Alzheimer's disease, markedly modifies the metabolic phenotype of astrocytes.