Severity and burden of sickle cell disease in France: a nationwide real-world study

The burden of sickle cell disease (SCD) in France has been difficult to apprehend due to the paucity of reliable nationwide epidemiological data. We aimed to describe the epidemiology of SCD and evaluate its burden and costs. Patients with SCD and most severely affected patients were identified between 2012 and 2018 from the French National Health Data System database (SNDS, Système national des données de santé). Outcomes of interest included rates of acute and chronic complications, healthcare resource utilization and associated costs, and were compared in subpopulations of patients before and after hematopoietic stem cell transplantation, initiating hydroxyurea or a chronic transfusion program. Between 2012 and 2018, 22,619 patients with SCD were identified, among which 4,270 patients were defined as most severely affected. Rates of vaso-occlusion episodes and acute chest syndrome were 86.29 (95% confidence interval [CI]: 85.75-86.83] and 12.90 (95% CI: 12.69-13.11) per 100 person years in the study population and 166.9 (95% CI: 165.4- 168.4) and 22.71 (95% CI: 22.16-23.27) per 100 person years in most severely affected patients. Median (Q1-Q3) annualized total costs were €5,073.63 (range, €1,633.74-14,000.94) and €13,295.67 (range, €5,754.67-26,385.23) in the study population and most severely affected patients. Median annualized costs were ten times lower after treatment intensification for hematopoietic stem cell transplantation (€29,011.75 vs. €2,465.98; P<0.001), they slightly decreased after hydroxyurea initiation (€13,057.79 vs. €12,752.44; P=0.003) and were five times higher after chronic transfusion program initiation (€4,643.11 vs. €22,715.85; P<0.001). SCD still places a significant demand on health resources, even after therapeutic intensification

Stroke without cerebral arteriopathy in sickle cell disease children: causes and treatment

Cerebral arteriopathy (CA) in children with sickle cell disease (SCD) is classically described as chronic stenosis of arteries in the anterior brain circulation, leading to ischemic stroke. Some studies have however reported strokes in children with SCD but without CA. In order to better understand the etiology and risk factors of these strokes, we retrospectively analyzed ischemic strokes occurring in a large cohort of children over a 13 year-period. Between 2007 and 2020, 25/1500 children with SCD had an ischemic stroke in our center. Among them, 13 (52%) had CA, described as anatomical arterial stenosis, while 12 (48%) did not. Patients with stroke without CA were older than patients with stroke attributed to SCD-CA (9.0 years old vs 3.6 years old, p=0.008), and had more frequently a SC genotype (25% vs 0% respectively). Their stroke involved posterior circulation more frequently, with cerebellar involvement in 42%. Retained stroke etiologies in patients without typical SCD-related CA were reversible cerebral vasoconstriction syndrome, cerebral fat embolism, arterial thrombosis or thromboembolism, hyperviscosity, vasculitis in a context of infectious meningoencephalitis, and severe hemodynamic failure. No recurrence was observed in the 24 months following stroke, even though 67% of the patients were no longer receiving exchange transfusions in this group. In conclusion, in a cohort of pediatric SCD patients with efficient stroke screening strategy, half of occurring ischemic strokes were related to causes other than CA. They affected a different population of SCD children and systematic long-term transfusion programs may not be necessary in these cases

Early splenectomy in a large cohort of children with sickle cell anemia: risks and consequences

In children with sickle cell anemia (SCA), early splenic complications can require splenectomy, but the benefit-to-risk ratio and the age at which splenectomy may be safely performed remain unclear. To address this question, we analyzed the rate of post-splenectomy events in children with SCA splenectomized between 2000-2018 at the Robert Debré University Hospital, Paris, France. A total of 188 children underwent splenectomy, including 101 (11.9%) from our newborn cohort and 87 referred to our center. Median (Q1-Q3) age at splenectomy was 4.1 years (range 2.5-7.3 years), with 123 (65.4%) and 65 (34.6%) children splenectomized at ≥3 years of age or <3 years of age, respectively. Median postsplenectomy follow-up was 5.9 years (range 2.7-9.2 years) yielding 1192.6 patient-years (PY) of observation. Indications for splenectomy were mainly acute splenic sequestration (101 [53.7%]) and hypersplenism (75 [39.9%]). All patients received penicillin prophylaxis; 98.3% received 23-valent polysaccharic pneumococcal (PPV-23) vaccination, and 91.9% a median number of 4 (range 3-4) pneumococcal conjugate vaccine shots prior to splenectomy. Overall incidence of invasive bacterial infection and thrombo-embolic events were 0.005 / PY (no pneumococcal infections) and 0.003 / PY, respectively, regardless of age at splenectomy. There was an increased proportion of children with cerebral vasculopathy in children splenectomized <3 years of age (0.037 / PY vs. 0.011 / PY; P<0.01). A significantly greater proportion of splenectomized than non-splenectomized children were treated with hydroxycarbamide (77.2% vs. 50.1%; P<0.01), suggesting a more severe phenotype in children who present spleen complications. If indicated, splenectomy should not be delayed in children, provided recommended pneumococcal prophylaxis is available. Spleen complications in childhood may serve as a marker of severity

A micro-bead device to explore Plasmodium falciparum-infected, spherocytic or aged red blood cells prone to mechanical retention by spleen endothelial slits

Présentation oraleInternational audiencen.

The endothelin B receptor plays a crucial role in the adhesion of neutrophils to the endothelium in sickle cell disease

Although the primary origin of sickle cell disease is a hemoglobin disorder, many types of cells contribute considerably to the pathophysiology of the disease. The adhesion of neutrophils to activated endothelium is critical in the pathophysiology of sickle cell disease and targeting neutrophils and their interactions with endothelium represents an important opportunity for the development of new therapeutics. We focused on endothelin-1, a mediator involved in neutrophil activation and recruitment in tissues, and investigated the involvement of the endothelin receptors in the interaction of neutrophils with endothelial cells. We used fluorescence intravital microscopy analyses of the microcirculation in sickle mice and quantitative microfluidic fluorescence microscopy of human blood. Both experiments on the mouse model and patients indicate that blocking endothelin receptors, particularly ETB receptor, strongly influences neutrophil recruitment under inflammatory conditions in sickle cell disease. We show that human neutrophils have functional ETB receptors with calcium signaling capability, leading to increased adhesion to the endothelium through effects on both endothelial cells and neutrophils. Intact ETB function was found to be required for tumor necrosis factor α-dependent upregulation of CD11b on neutrophils. Furthermore, we confirmed that human neutrophils synthesize endothelin-1, which may be involved in autocrine and paracrine pathophysiological actions. Thus, the endothelin-ETB axis should be considered as a cytokine-like potent pro-inflammatory pathway in sickle cell disease. Blockade of endothelin receptors, including ETB, may provide major benefits for preventing or treating vaso-occlusive crises in sickle cell patients

Fetal hemoglobin rescues ineffective erythropoiesis in sickle cell disease

While ineffective erythropoiesis has long been recognized as a key contributor to anemia in thalassemia, its role in anemia of sickle cell disease (SCD) has not been critically explored. Using in vitro and in vivo derived human erythroblasts we assessed the extent of ineffective erythropoiesis in SCD. Modeling the bone marrow hypoxic environment, we found that hypoxia induces death of sickle erythroblasts starting at the polychromatic stage, positively selecting cells with high levels of fetal hemoglobin (HbF). Cell death was associated with cytoplasmic sequestration of heat shock protein 70 and was rescued by induction of HbF synthesis. Importantly, we document that in the bone marrow of SCD patients similar cell loss occurs during the final stages of terminal differentiation. Our study provides evidence for ineffective erythropoiesis in SCD and highlights an anti-apoptotic role for HbF during the terminal stages of erythroid differentiation. These findings imply that the beneficial effect on anemia of increased HbF levels is not only due to the increased life span of red cells but also a consequence of decreased ineffective erythropoiesis

Peritoneal Sclerosis in a Patient on Long-term Continuous Ambulatory Peritoneal Dialysis (CAPD). : An Autopsy Case.

若年性ネフロン癆による慢性腎不全でCAPD (continuous ambulatory peritoneal dialysis)導入し, 6年6ヵ月後に死亡した20歳男性の1剖検例を報告した。CAPD導入数カ月後, 腹膜炎による除水能低下を起こしたが, 約5ヵ月後に回復した。CAPD導入1年5ヵ月以降重症な腹膜炎罹患により除水能低下状態が遷延したが, 次第に回復した。しかし, 体液貯留傾向のため, 3年2ヵ月後より高張透析液を使用し除水量の増加を得たが, 3年9ヵ月後に不可逆的な除水能低下状態となった。一方, クレアチニンの透析排液/血漿濃度比(D/P)から見た溶質除去能は, その約半年後まで保たれており, 血清クレアチニン値の上昇は軽度であった。剖検にて腹膜の線維性肥厚と高度の内腔狭窄を伴う動静脈硬化を認め, 腹膜硬化症と診断した。本例の腹膜硬化症は, 頻回の腹膜炎と高張透析液の使用が主な原因と考えられた。腹膜機能を長期に維持するためには, 腹膜炎の予防と高張透析液の使用を最小限にすることが重要と考えられた。A 20-year-old man, treated with continuous ambulatory peritoneal dialysis (CAPD) for 6.5 years because of-end-stage renal disease due to juvenile nephronophthysis, died of ultrafiltration failure, and the morphological examination of peritoneum was carried out at autopsy. Nine episodes of peritonitis developed, and ultrafiltration transiently decreased after each episodes. At 2 years after the start of CAPD, severe peritonitis occurred, and then his body weight and blood pressure gradually increased. At 4 years after the beginning of CAPD, when hyperosmotic dialysate was frequently used, ultrafiltration was irreversively deteriorated. On the other hand, creatinine dialysate/plasma ratio remained within normal limits for about several months, and the increase in the level of serum creatinine was very little. The peritoneum obtained at autopsy revealed marked fibrous thickening as well as the conspicuous luminal narrowing of arteries and veins due to intimal thickening. The development of peritoneal sclerosis seemed to be related with the frequency and severity of peritonitis and the use of hyperosmotic dialysate