Is There any Relationship Between the Repeated Complications of Sickle Cell Disease and the Potential Development of Acute Leukemia?

Sickle cell disease (SCD) is a severe monogenic hereditary hemoglobinopathy that is characterized by repeated clinical and biological manifestations able to generate stress erythopoiesis. A clonal hematopoiesis involving mainly variants of TP53, DNMT3A, ASXL1, and/or TET2 may be more prevalent in patients with SCD, suggesting that mutations in these genes may lead to an increased risk of leukemia. An increased prevalence of leukemia in patients with SCD has been confirmed by an increasing number of acute myeloid leukemia cases with myelodysplastic features reported in this patient population even in the absence of disease-modifying treatments. This leads to the hypothesis of a mechanism involving multifactorial causes through the pathophysiologic manifestations of SCD, in which cells are undergoing constant hematopoietic hyperplasia, inducing genomic damage and somatic mutations.

Hydroxyurea is associated with later onset of acute splenic sequestration crisis in sickle cell disease: Lessons from the European Sickle Cell Disease Cohort-Hydroxyurea (ESCORT-HU) study.

Acute splenic sequestration crisis (ASSC) is a potentially life-threatening complication of sickle cell disease (SCD), typically occurring in young patients under 5 years of age, with a median age at first episode of less than 2 years. Because a beneficial effect of hydroxyurea (HU) on spleen perfusion and splenic function has been suspected, we hypothesized that HU treatment might be associated with later onset of ASSC in patients with SCD. To investigate this hypothesis, we analyzed data from the ESCORT-HU study on a large cohort of patients with SCD receiving HU, enrolled between January 2009 and June 2017 with a follow-up of 7309 patient-years of observation. The median age at ASSC of the 14 patients who experienced a first episode of ASSC during the study period was 8.0 [IQR: 5.0-24.1] years. The median age at HU initiation was significantly lower in these 14 patients (4.8 [IQR: 3.3-18.7] years) compared to the 1664 patients without ASSC (19.9 [8.8-33.4] years, p = .0008). These findings suggest that ASSC may occur at an unusually late age in patients receiving HU, possibly reflecting longer preservation of spleen perfusion and function secondary to early initiation of HU. Further studies are needed to better characterize the effects of HU on spleen perfusion/function and on the occurrence of ASSC in patients with SCD (ClinicalTrials.gov identifier: NCT02516579; European registry ENCEPP/SDPP/10565).

Prevalence of bone complications in young patients with sickle cell disease presenting low bone mineral density.

PURPOSE: Bone fragility in sickle cell disease (SCD) has been previously reported even in young patients, but the clinical consequences and specific management remain unclear. The objective of this study was to assess the prevalence of bone fragility in sickle cell patients and to evaluate the potential risk factors and associated complications. METHODS: We conducted a single-center cross-sectional study. Bone mineral densitometry (BMD) at the lumbar spine and the hip, Vertebral Fracture Assessment (VFA) and biological measurements were performed in patients aged between 20 and 40 years. RESULTS: One hundred and thirty-eight patients with sickle cell disease were included between June 2020 and December 2021. One hundred and one patients (73.2 %) were from Sub-Saharan Africa, 13 from North Africa (9.4 %), 11 from the Caribbean (7.9 %), 6 from the Indian Ocean. A Z-score < -2 was found in 43 patients (31.2 %) at the lumbar spine, in 4 patients (3 %) at the total hip, and in 5 patients (3.7 %) at the femoral neck. 59 patients (46.8 %) had vertebral deformities. Fragility fractures were recorded in 9 patients (10.8 %). Patients with low BMD had lower BMI (21.3 (19.0, 24.0) versus 24.0 (20.7, 26.1) Kg/m2, p = 0.003), lower osteonecrosis history (7 % versus 25.3 %, p = 0.011) and lower hemoglobin levels (9.0 (8.0, 10.0) versus 10.0 (9.0, 11.0) g/dL, p < 0.01). No association was found between history of fracture and low BMD. CONCLUSION: Young patients with SCD commonly have low BMD at the lumbar spine, but the prevalence of fragility fracture was low. Low BMD - specifically at the spine - may not be tantamount to bone fragility.

Impact of COVID-19 on incidence, clinical presentation, and prognosis of acute chest syndrome in patients with sickle cell disease.

Acute chest syndrome (ACS) is a frequent complication of sickle cell disease (SCD). Because coronavirus disease 2019 (COVID-19) increases mortality and morbidity in many diseases, we retrospectively analyzed the impact of SARS-CoV-2 infection on the incidence, the clinical presentation, and the prognosis of ACS in patients with SCD by comparing ACS episode before and during COVID-19 pandemic. Ninety-nine episodes of ACS were registered over 24 months before pandemic versus 81 episodes over 24 months during the pandemic period. The number of ACS episodes varies among children regarding the two period of time: 26 episodes (26%) for the pre-pandemic period versus 11 episodes (13%) for the pandemic period (p = 0.03). Comparisons between adults and children showed a higher incidence of initial VOC (45% vs. 24%; p = 0.04) in adults, and a higher incidence of initial pneumonia (35% vs. 15%; p = 0.01) and documented infection (35% vs. 7%; p < 0.001) in children. One patient died during the pandemic period but without any relationship with ACS or COVID-19. During this pandemic period, 13 episodes of ACS (16%) were found related to coronavirus infection. These ACS episodes did not show any significant differences in terms of outcome when compared to the other ACS episodes observed during this period. Overall, coronavirus infection did not demonstrate a negative impact on incidence, clinical presentation, and outcome of ACS in patients with SCD. Early management, chronic treatment with HU, and exchange transfusions could likely explain the low morbidity and mortality rates.

Sickle cell disease and acute leukemia: one case report and an extensive review.

Population-based studies and case reports suggest that there may be an increased risk of acute leukemia associated with sickle cell disease (SCD). Following the description of a new case report, an extensive review of the literature identified 51 previously described cases. Most cases study showed myelodysplastic features confirmed, when available, by genetic markers such as chromosome 5 and/or chromosome 7 abnormalities and TP53 gene mutations. The increased risk of leukemogenesis is certainly multifactorial and related to the pathophysiologic mechanisms of the clinical manifestations of SCD. Chronic hemolysis and secondary hemochromatosis may cause increased chronic inflammation, resulting in persistent marrow stress, which could potentially compromise the genomic stability of the hematopoietic stem cells generating genomic damage and somatic mutations over the course of SCD and its treatment, resulting in a clone that led to acute myeloid leukemia.

Impact of prenatal corticosteroid therapy on sickle cell disease in pregnant women.

OBJECTIVE: To evaluate safety of prenatal corticosteroids in pregnancies of women with sickle cell disease. METHODS: A multicenter observational study of patients with sickle cell disease, comparing vaso-occlusive crises (VOC) requiring hospital care between pregnancies with versus without prenatal corticosteroids. RESULTS: In 40 pregnancies exposed to prenatal corticosteroids, compared with 370 unexposed pregnancies, VOC were not more frequent (62.5% vs 57.9%, P = 0.578) but they were more severe, with more intensive care hospitalizations (25.0% vs 12.9%, P = 0.039), emergency transfusions (44.7% vs 22.7%, P = 0.006), and acute chest syndromes (22.5% vs 8.9%, P = 0.010). These differences persisted after adjustment for severity and type of sickle cell syndrome (for intensive care admission adjusted odds ratio [aOR] 2.73, 95% confidence interval [CI] 1.10-6.79, P = 0.031 and for acute chest syndrome aOR 4.15, 95% CI 1.57-14.4, P = 0.008). VOC occurred on average 1.2 days following steroid administration. When comparing 36 patients receiving corticosteroids for fetal maturation with 58 patients who were hospitalized for obstetrical complications before 34 weeks of pregnancy but that did not receive corticosteroids, VOC incidence was not significantly higher (41.7% vs 31.5%, P = 0.323). CONCLUSION: The present study was the first to study the impact of prenatal corticosteroids on sickle cell disease. They were associated with more severe VOC, suggesting that steroids should be avoided in these women.

Outcomes of Pregnancy in Sickle Cell Disease Patients: Results from the Prospective ESCORT-HU Cohort Study.

Sickle cell disease (SCD) refers to a group of inherited hemoglobin disorders in which sickle red blood cells display altered deformability, leading to a significant burden of acute and chronic complications, such as vaso-occlusive pain crises (VOCs). Hydroxyurea is a major therapeutic agent in adult and pediatric sickle cell patients. This treatment is an alternative to transfusion in some complications. Indeed, it increases hemoglobin F and has an action on the endothelial adhesion of red blood cells, leukocytes, and platelets. Although the safety profile of hydroxyurea (HU) in patients with sickle cell disease has been well established, the existing literature on HU exposure during pregnancy is limited and incomplete. Pregnancy in women with SCD has been identified as a high risk for the mother and fetus due to the increased incidence of maternal and non-fetal complications in various studies and reports. For women on hydroxyurea at the time of pregnancy, transfusion therapy should probably be initiated after pregnancy. In addition, there is still a significant lack of knowledge about the incidence of pregnancy, fetal and maternal outcomes, and management of pregnant women with SCD, making it difficult to advise women or clinicians on outcomes and best practices. Therefore, the objective of this study was to describe pregnancy outcomes (n = 128) reported in the noninterventional European Sickle Cell Disease COhoRT-HydroxyUrea (ES-CORT-HU) study. We believe that our results are important and relevant enough to be shared with the scientific community.

Sublingual Microcirculation Specificity of Sickle Cell Patients: Morphology of the Microvascular Bed, Blood Rheology, and Local Hemodynamics.

Patients with sickle cell disease (SCD) have poorly deformable red blood cells (RBC) that may impede blood flow into microcirculation. Very few studies have been able to directly visualize microcirculation in humans with SCD. Sublingual video microscopy was performed in eight healthy (HbAA genotype) and four sickle cell individuals (HbSS genotype). Their hematocrit, blood viscosity, red blood cell deformability, and aggregation were individually determined through blood sample collections. Their microcirculation morphology (vessel density and diameter) and microcirculation hemodynamics (local velocity, local viscosity, and local red blood cell deformability) were investigated. The De Backer score was higher (15.9 mm-1) in HbSS individuals compared to HbAA individuals (11.1 mm-1). RBC deformability, derived from their local hemodynamic condition, was lower in HbSS individuals compared to HbAA individuals for vessels < 20 µm. Despite the presence of more rigid RBCs in HbSS individuals, their lower hematocrit caused their viscosity to be lower in microcirculation compared to that of HbAA individuals. The shear stress for all the vessel diameters was not different between HbSS and HbAA individuals. The local velocity and shear rates tended to be higher in HbSS individuals than in HbAA individuals, notably so in the smallest vessels, which could limit RBC entrapment into microcirculation. Our study offered a novel approach to studying the pathophysiological mechanisms of SCD with new biological/physiological markers that could be useful for characterizing the disease activity.

Case Report of Myelodysplastic Syndrome in a Sickle-Cell Disease Patient Treated with Hydroxyurea and Literature Review.

The safety profile of hydroxyurea (HU) in patients with sickle-cell disease (SCD) is relatively well known. However, despite the suspected association of HU with myeloid neoplasms in myeloproliferative neoplasms (MPN), and the publication of sporadic reports of myeloid malignancies in SCD patients treated with HU, the possible excess risk imparted by HU in this population having an increasing life expectancy has failed to be demonstrated. Herein, we report one case of myelodysplastic syndrome emanating from the results on safety and effectiveness of HU on the largest European cohort of 1903 HU-treated adults and children who were followed-up prospectively in an observational setting over 10 years, accounting for a total exposure of 7309.5 patient-years. A comparison of this single case with previously published similar cases did not allow us to draw any significant conclusions due to the paucity of these events.

Pediatric-Adult Care Transition: Perceptions of Adolescent and Young Adult Patients with Sickle Cell Disease and Their Healthcare Providers.

Introduction: The pediatric-adult care transition, which takes place during adolescence, is a high-risk period for medical care adherence in chronic diseases, this encompasses treatment adherence, attending medical consultations and following healthcare advice. Studying perceptions is needed to get a more comprehensive picture of this care transition and to propose interventions to address the gaps. The authors analyzed perceptions from patients and caregivers in adolescents with sickle cell disease. Although this is the first step to improving the actual care management, to our knowledge, no study has explored perceptions from healthcare providers and compared it to patients' perceptions. The purpose of this study was to provide an insight on the experience of adolescent and adult patients, pediatric and adult healthcare providers in the context of pediatric to adult care transition, and analyze those concerns in order to better understand medical care adherence and improve patient care. Material and Methods: Semi-structured interviews were conducted with adolescent and adult patients, as well as healthcare professionals (HCPs) in pediatric and adult departments. These interviews were audiotaped and transcribed before manual inductive content analysis. Results: A total of 15 adolescent patients, 10 adult patients, 9 pediatric HCPs and 13 adult HCPs - including 12 nurses - were interviewed. Patients and healthcare providers all agreed that the pediatric-adult care transition was poorly experienced. This was mainly due to various changes in habits, physicians, and care organization. Anticipating this transition and acquiring new skills both for patients and HCPs are essential steps for improving medical care adherence during this challenging pediatric-adult care transition. Conclusion: Propositions emerged from patients and healthcare providers to improve care and subsequently to improve medical care adherence in patients with sickle cell disease during and after the pediatric to adult care transition.

Exploration of barriers and facilitators to the implementation of the DREPADO randomized controlled trial: A qualitative study.

PURPOSE: DREPADO is a randomized controlled trial (RCT) assessing the impact of a pediatric-adult transition program, on the health status of adolescents with sickle cell disease. Using a biopsychosocial approach with three main facets (educational, psychological and social interactions), it constitutes a complex transition program, which is quite difficult to implement. To facilitate the implementation of this complex program, the aim of this ancillary study is to explore barriers and facilitators at the early stages of this implementation. METHODS: A qualitative study with semi-structured interviews was conducted, according to COREQ quality criteria, in patients with sickle cell disease who had already experienced the transition to adult care before DREPADO, and healthcare professionals working on the DREPADO RCT. RESULTS: Semi-structured interviews were conducted with patients (n = 12) and healthcare professionals (n = 12) from November 2019 to May 2020. The main barriers identified by patients were time and implication required by this transition program. Healthcare professionals involved in the coordinating center mentioned changes in their working habits and also elements about the RCT regulatory procedures. Main facilitators reported by both patients and healthcare professionals were the positive perception of the transition program design, and especially the home setting for therapeutic education sessions. CONCLUSION: This study led to the identification of main barriers and facilitators to the implementation of both the DREPADO intervention and RCT. These propositions could also be used to promote other complex public health interventions or/and other randomized controlled trials.

Shear-Stress-Gradient and Oxygen-Gradient Ektacytometry in Sickle Cell Patients at Steady State and during Vaso-Occlusive Crises.

Oxygen gradient ektacytometry (oxygenscan) measures the changes in red blood cell (RBC) deformability in normoxia and during deoxygenation. We investigated the changes in RBC deformability, measured by both oxygenscan and classical shear-stress-gradient ektacytometry, in 10 patients with sickle cell disease (SCD) during vaso-occlusive crisis (VOC) versus steady state. Oxygenscan and shear-stress-gradient ektacytometry parameters were also measured in 38 SCD patients at steady state on two different occasions. Shear-stress-gradient ektacytometry parameters, maximal RBC deformability at normoxia and the minimum RBC deformability during deoxygenation were lower during VOC compared to steady state. The oxygen partial pressure at which RBCs started to sickle (PoS) was not significantly affected by VOC, but the results were very heterogeneous: the PoS increased in 5 in 10 patients and decreased in 4 in 10 patients. Both oxygenscan and shear-stress-gradient ektacytometry parameters remained unchanged in patients at steady state between two sets of measurements, performed at 17 ± 8 months intervals. In conclusion, the present study showed that both oxygen gradient ektacytometry and shear-stress-gradient ektacytometry are sensitive to disease activity in SCD, and that both techniques give comparable results; however, the oxygen-dependent propensity of RBCs to sickle was highly variable during VOC.

Pregnancy outcome in women with transfused beta-thalassemia in France.

Because of chronic anemia, hypogonadotropic hypogonadism, and iron chelation, pregnancy in homozygous and heterozygous compound beta-thalassemia patients stays a challenge. Pregnancies of transfused beta-thalassemia women registered in the French National Registry, conducted between 1995 and 2015, are described. These pregnancies were compared with pregnancies in healthy women and to data previously published in the literature. Fifty-six pregnancies of 37 women were studied. There were 5 twin pregnancies. Assisted reproductive technologies (ART) were used in 9 pregnancies. Median term at delivery was 39 amenorrhea weeks, and median weight at birth was 2780 g. Cesarean section was performed in 53.6% of the pregnancies. There were 6 thromboembolic events, 6 serious infections, 6 pregnancy-induced hypertensions (PIH), 6 intrauterine growth retardations (IUGR), 5 severe hemorrhages, 4 gestational diabetes, 3 alloimmunizations, 2 heart diseases, and 1 pre-eclampsia. There were 5 infections and 4 osteoporosis in the first year of post-partum. ART and cesarean sections were more often used in the beta-thalassemia group, compared to control subjects. Thromboembolic events, PIH, hemorrhage at delivery, and IUGR were more frequent in the beta-thalassemia group. Time to delivery was not different, but infant weight at birth was significantly smaller in the beta-thalassemia group. In the post-partum period, global maternal complications were more frequent in the beta-thalassemia group. Pregnancy in transfused beta-thalassemia women is safe with rare obstetrical and fetal complications. Cesarean section remains often chosen, and infant weight at birth remains smaller than that in the general population, despite delivery at full term.

Nocturnal Hypoxemia Rather Than Obstructive Sleep Apnea Is Associated With Decreased Red Blood Cell Deformability and Enhanced Hemolysis in Patients With Sickle Cell Disease.

Background: Although obstructive sleep apnea (OSA) could act as a modulator of clinical severity in sickle cell disease (SCD), few studies focused on the associations between the two diseases. Research Question: The aims of this study were: (1) to explore the associations between OSA, nocturnal oxyhemoglobin saturation (SpO2) and the history of several acute/chronic complications, (2) to investigate the impact of OSA and nocturnal SpO2 on several biomarkers (hematological, blood rheological, and coagulation) in patients with SCD. Study Design and Methods: Forty-three homozygous SCD patients underwent a complete polysomnography recording followed by blood sampling. Results: The proportion of patients suffering from nocturnal hypoxemia did not differ between those with and those without OSA. No association between OSA and clinical severity was found. Nocturnal hypoxemia was associated with a higher proportion of patients with hemolytic complications (glomerulopathy, leg ulcer, priapism, or pulmonary hypertension). In addition, nocturnal hypoxemia was accompanied by a decrease in RBC deformability, enhanced hemolysis and more severe anemia. Interpretation: Nocturnal hypoxemia in SCD patients could be responsible for changes in RBC deformability resulting in enhanced hemolysis leading to the development of complications such as leg ulcers, priapism, pulmonary hypertension or glomerulopathy. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03753854.

Comparisons of oxygen gradient ektacytometry parameters between sickle cell patients with or without α-thalassaemia.

The present study tested the impact of α-thalassaemia on oxygen gradient ektacytometry in sickle cell anaemia (SCA). Three SCA groups were compared: (i) no α-thalassaemia (four α-genes, n = 62), (ii) silent α-thalassaemia (three α-genes, n = 35) and (iii) homozygous α-thalassaemia (two α-genes, n = 12). Red blood cell (RBC) deformability measured in normoxia was not different between the three groups. The lowest RBC deformability reached at low oxygen partial pressure (pO2 ) was greater and the pO2 at which RBC started to sickle was lower in the two α-genes group compared to the other groups. Our present study showed an effect of α-thalassaemia on oxygen gradient ektacytometry in SCA.