Homozygous Sickle Cell Disease Research Articles

Electrocardiographic Abnormalities in Adult Homozygous Sickle Cell Disease Patients in Nnamdi Azikiwe University Teaching Hospital, Nnewi, South-Eastern Nigeria

Background; Sickle cell anaemia is the most common monogenic hematologic disorder in Nigeria. Cardiovascular pathology, resulting in electrocardiographic abnormalities are a common finding in adult sickle cell patients.
 Objective; This study investigated the pattern of electrocardiographic (ECG) abnormalities in steady state adult sickle cell anaemia (HbSS) patients and compared the findings with that of age and sex matched Haemoglobin AA(HbAA) controls.
 Methodology; Fifty steady state adult HbSS participants were recruited from the haematology clinic at Nnamdi Azikiwe University Teaching Hospital while fifty age and sex matched HbAA controls were recruited from the hospital community. Participants underwent resting 12 lead ECG using a Schiller CARDIOVIT AT-1 ECG machine. Data was analyzed using Statistical Package for Social Sciences version 21.
 Results; The prevalence of ECG abnormalities amongst the adult sickle cell participants and controls was 70% and 10% respectively. ECG abnormalities were more common amongst male sickle cell participants and left ventricle hypertrophy was the most frequent ECG abnormality detected.
 Conclusion; There is a high prevalence of ECG abnormalities amongst adult sickle cell anaemia patients. Regular Electrocardiography is recommended for early detection of these abnormalities for early treatment and improved quality of life.
 Keywords: Electrocardiographic Abnormalities, Sickle Cell Disease Patients, Nnamdi Azikiwe University, Haemoglobin AA

Homozygous Sickle Cell Disease after Age of 40: Follow-Up of a Cohort of 209 Patients in Senegal, West Africa.

The aim of this study was to describe the morbidity and mortality of homozygous sickle cell disease after the age of 40. This was a cohort study of 209 patients followed from 1994 to 2022. All hemoglobin electrophoresis-confirmed SS sickle cell patients over 40 years were included. A descriptive study of epidemiological, diagnostic, therapeutic, and evolutionary data was used to assess morbidity and mortality. Sex ratio (M/F) was 0.6. Median age was 47 (41-75). According to morbidity, 95.1% had less than 3 vaso-occlusive crises/year. Acute anemia was the most frequent complication (52.63%). Chronic complications were noted in 32.5%. At diagnosis, mean hemoglobin was 8.1 g/dl ± 1.9, HbS was 86.5 ± 10, and HbF was 9.4 ± 7.6. Number of patients transfused was 66%. We noted that 8.1% of patients died, 29.2% were lost to follow-up, and 62.7% were still being followed up. The risk factors identified for death were geographical origin, comorbidity, high HbS, low HbF, and thrombocytosis. This study shows that homozygous SCD is increasingly becoming an adult disease and that it can be carried into old age in Africa. Advanced age over 40 is marked by an upsurge in chronic complications, making it essential to set up a screening program and to organize multidisciplinary follow-up.

Extraordinary cause of abdominal pain in sickle-cell disease patient: a case report

Background: The coexistence of extrahepatic portal vein thrombosis (EHPVT) and sickle-cell disease (SCD) was documented in a young adult patient who was presented with vague gastrointestinal symptoms, including right upper quadrant abdominal pain associated with fever and jaundice. Diagnosing EHPVT in children can be challenging due to ambiguous presentation and the lack of sufficient literature, particularly in those with SCD. Case Presentation: A five-year-old boy with homozygous sickle-cell (SS) disease presented to the emergency department with subjective fever and abdominal pain. The patient was managed conservatively with intravenous (IV) fluids, antibiotics, and analgesics. After admission, the patient was found to have hypoalbuminemia, anemia, and thrombocytopenia. Abdominal ultrasound showed moderate ascites with bowel loop thickness and preserved vasculature. Later, the boy developed increased abdominal pain. Abdominal computed tomography (CT) with contrast showed hepatic, portal, superior mesenteric and splenic veins thrombosis. Conclusion: Venous thrombosis is rare in SS disease, and its occurrence in this disease raises the possibility of a common pathogenesis and adds another pathology to the causes of abdominal pain in sickle-cell disease.

Performance evaluation of the Hemotype SCTM rapid test for the diagnosis of sickle cell disease

Introduction: The use of Rapid Orientation Diagnostic Tests ("RODTs") could play an important role in the mass screening of certain diseases. It saves a great deal of time while managing the flow of samples and the difficulties associated with their storage. This study aimed to identify the impact of the delay between sampling and analysis on the analytical performance of the Hemotype RODT SCTM. Methods: This was a descriptive cross-sectional study conducted over one month. The Immunology-Hematology Department of the CHU de Cocody served as the study setting. The study population consisted of sickle cell patients and hemoglobin C carriers of all ages and sexes. We performed hemoglobin electrophoresis on all samples on the day of collection (D0) and the Hemotype SCTM rapid test on D0, D2, D4, and D6. Sensitivity and specificity were used to determine analytical performance, and the chi2 test was used to compare qualitative variables. Results: The study involved 102 patients with a median age of 16 years (IQR: 9-24). Half of the participants (56.96%) were SSFA2 homozygous sickle cell disease major. On average, 87.1% of RODT results were valid from D0 to D6. At D0, the RODT had a sensitivity of 75% and a specificity of 81.40% for Hb A; Hb S had a sensitivity of 79.80% and a specificity of 100%; Hb C had a sensitivity of 35.71% and a specificity of 98.65%. The sensitivity of Hb C and the specificity of Hb A had increased statistically significantly over time. Cross-referencing the RODT results from D0 to D6 with those of electrophoresis showed a concordance of 86.95% for the AA phenotype, 79.52% for AS; 88.52% for SS; and 95.45% for SC. Conclusion: The HemoTypeSC™ test, with a sensitivity of 75% and specificity of 98% is suitable in certain areas where access to electrophoresis is limited. This performance is not impaired on samples stored for 6 days

Variation in Hemoglobin A1c Linked to Hemoglobin S: Comparison of Analysis Results from ion Exchange Chromatography and an Immunoturbidimetric Method

Hemoglobin S can interfere with the measurement of glycated hemoglobin, an essential tool for diagnosing and monitoring diabetes. The objective of this study is to evaluate the analytical performance of  2 glycated haemoglobin assay methods.
 A prospective cross-sectional study was conducted where 186 patients (61 homozygous sickle cell disease, 61 AA type subjects and 64 AS type subjects) were recruited. Glycated hemoglobin was measured by immunoturbidimetry method and ion exchange chromatography.
 The coefficient of variation (CV) of the repeatability is 2.34% and 1.13% (normal rate) ; 2.32% and 1.65% (high rate) respectively for the immunoturbidimetric method and ion exchange chromatography. In reproducibility, the CV obtained are 3.23% and 2.64% (normal rate) and 3.27% and 2.22% (high rate), respectively for the immunoturbidimetric method and the ion exchange chromatography. Linearity is satisfactory for both methods. Mean glycated hemoglobin values ​​show no significant difference (the P-value is equal to 0.09, 0.17 and 0.70 respectively in subjects AA, AS and SS) in the 2 methods for patients with the same hemoglobin electrophoretic profile.
 The analytical performances of the 2 methods are good but their use is not recommended in the biological diagnosis of diabetes and pre-diabetes due to interference from hemoglobin S, especially in the case of homozygous sickle cell disease or in the case of composite heterozygosity.

Use of Conventional Transfusion Thresholds Contributes to Ongoing Iron Overload Issues in Patients with Homozygous (SS) Sickle Cell Disease

Introduction: Homozygous sickle cell disease is characterized by chronic anemia which contributes to a clinical course characterized by recurrent pain crisis episodes. These episodes are usually managed with the use of packed red blood cell products. Randomized data is currently available that supports lower transfusion thresholds in non-sickle cell related conditions including but not limited to patients undergoing orthopedic procedures, cardio-vascular interventions and those needing intensive care. Due to lack of similar randomized trials in patients with sickle cell disease, recommendations from other trials are applied to patients with sickle cell diseases as well. However, this has the potential of worsening iron overload states that patients with sickle cell disease usually suffer from. Methods: Patients with homozygous SS sickle cell disease were evaluated with regarding to transfusion support given during hospitalization for vaso-occlusive pain crisis episodes. The hemoglobin threshold that was used for deciding whether or not to give packed red cell transfusion was studied in patients who were previously getting periodic red blood cell exchange procedures for chronic sickle cell related pain. Serum ferritin levels during the period of exchange transfusion support was compared with levels during simple transfusions. 8 patients were selected from the cohort of patients with homozygous sickle cell disease who had been receiving elective packed red blood cell exchanges. Patients with ferritin levels persistently remaining above 1000 ng/ml were then evaluated with regard to transfusion thresholds used for simple transfusion support during hospitalization for pain crisis episodes. Results: Six patients had persistently high ferritin levels. Thresholds for simple transfusion in this group were studied. A total of 30 units of packed red blood cells were found to be transfused over a 6-month period. During this period only one patient required an exchange transfusion session. 2 out of 30 units were given for a Hgb level above 7 g/dl. The majority, representing 24 out of the total 30 pack red blood cell units were given above a Hgb threshold of 6.0 g/dl. Only 4 units were given using a Hgb threshold less than 6 g/dl. Mean ferritin level before and after the period of simple transfusion support was 6097 ng/ml and 6076 ng/ml respectively. Mean Hgb level in while on exchange transfusion was 7.4 g/dl and it was 6.9 g/dl in those receiving a simple transfusion protocol. Conclusions: Transfusion threshold used in patients with homozygous SS sickle cell disease appears to be similar to patients without sickle cell disease. Current practice based on studies including TRICC and TRISS is to keep the Hgb level above 7 g/dl. This has been shown to be safe and in fact even improves patient outcomes. However, in patients with sickle cell disease this may not be appropriate since their baseline Hgb levels are lower to begin with. Also, transfusions don't appear to improve Hgb levels considerably. These patients also tend to have iron overload at baseline which likely will not improve unless all transfusions are limited. Therefore, applying a lower transfusion threshold would be recommended to avoid acute transfusion related issues and long-term iron overload problems in patients with SS disease.

Health Related Quality of Life Outcomes Among Patients with Sickle Cell Disease during the Transition Period from Pediatric to Adult Care in Newark, NJ

Background: Sickle Cell Disease (SCD) is a genetic condition associated with painful vaso-occlusion episodes (VOE), chronic pain, and organ damage. Painful VOE and chronic pain can hinder daily activities and thus affect Quality of Life (QoL). The transition period of SCD patients from pediatric to adult care is often marked by frequent hospitalizations, complications and higher mortality. Our study evaluated patient reported health related QoL outcomes in SCD patients who transitioned from pediatric to adult care. Methods: This is a descriptive study of SCD patients receiving medical care at Newark Beth Israel Medical Center. The informed consent and assent were obtained from patients and/or legal guardians. Enrolled patients filled out a questionnaire using seven domains from the Adult Sickle Cell Quality of Life Measurement Information System (ASCQ-Me): pain episodes, medical history, pain impact, sleep impact, social functioning, stiffness, and emotional impacts. Eligible patients were aged 16-25 years, presenting to the pediatric or adult hematology clinic for their well visit. Recruitment took place from December 2021 to April 2023. Results: Seventy-six individuals were enrolled and questionnaire was administered. Most were aged 16-21 years with homozygous sickle cell disease. Pain episodes: 10-18% of 16-20 year-olds reported pain attacks in the previous year, while 43-100% of 21-25 year-olds reported pain attacks. Among 22-25 year-olds, 25-50% could not do most things that they usually did or relied on family or friends compared to 40-83% of 16-21 year-olds. Pain impact: 50-100% of 22-24 year-olds struggled all day due to pain, while most younger patients were unaffected. About 25-60% of 20-25 year-olds were occasionally, rarely, or never pain-free. In the sleep impact domain, 29-60% of 20-25 year-olds did not get enough sleep, and 20-60% of all ages stayed up most of the night due to difficulty falling asleep. Medical history: 17-36% of 16-20 year-olds and 40-100% of 21-25 year-olds used daily pain medicine. Sickle cell complications affected 8-40% of patients in all age groups. Social functioning domain: 25-60% of 20-25 year-olds often or always had their health that kept them away from doing something fun. Also, 16-17 year-olds (21%) and 20-22 year-olds (25-60%) reported that their family felt that they were a burden. No significant findings were noted in stiffness impact across all age ranges. Emotional impact: 25-83% of all patients were often or always sad about their health (70% of 16 year-olds and 83% of 21 year-olds). Nine % (19 year olds) to 83% (21 year olds) were depressed about their health problems and 21 year olds seemed most affected by emotional impact of their disease. Conclusion: Our cross-sectional study revealed a significant impact of SCD on HRQoL during the transition years from childhood to adulthood. Therefore, screening for mental health in patients aged 16-25 years is crucial, offering support to those at risk. Disease-modifying therapy adherence should be emphasized. Limitations of our study include a small sample size, especially in the older age group. Further studies may be needed to assess age and genotype stratified HRQoL outcomes for 16-25-year-old SCD patients and potential improvement measures.

Successful Use of Therapeutic Plasma Exchange Following Red Blood Cell Exchange for Severe Acute Chest Syndrome: A Single Institution Experience

Introduction: Severe acute chest syndrome (ACS) is a potentially fatal complication of sickle cell disease (SCD) that can progress to multiorgan failure. Treatment includes red blood cell (RBC) exchange to improve oxygenation and reduce vaso-occlusion by decreasing the proportion of hemoglobin (Hb) S. Patients with poor response to RBC exchange are at high risk for mortality. Therapeutic plasma exchange (TPE) may be beneficial in cases of severe organ dysfunction refractory to RBC exchange. TPE is postulated to remove pro-inflammatory cytokines, reduce circulating free hemoglobin, and decrease complement products that contributes to vaso-occlusion and inflammation. The use of TPE for severe ACS and multiorgan failure has been rarely described in adult patients and is even less commonly described for pediatric patients. Aim: To describe use of TPE for the management of severe ACS with multiorgan failure in two pediatric patients and one young-adult patient who did not respond to standard medical management with RBC exchange transfusion. Methods: Case reports Case 1: A six-year-old male with homozygous SCD (HbSS) and moderate persistent asthma was admitted for ACS. His course was complicated by hypoxemia requiring intubation, oliguria, and hypotension. On hospital day 3, he underwent RBC exchange with four units of RBCs. Despite decrease of Hb S to 15%, he remained hypoxic on high ventilatory support and developed acute respiratory distress syndrome. After multidisciplinary discussion, TPE was trialed in hopes of improving oxygenation and reversing multiorgan dysfunction. He underwent 3 TPEs, each with 1.5 total plasma volume (TPV) using 5% albumin (days 4, 5 and 7). After a single session of TPE, his oxygenation saturations improved to the 90s, and his ventilator support was weaned. He was extubated on day 8 and was discharged on day 13 in stable condition. Case 2: A sixteen-year-old male with HbSS, recurrent hyper-hemolytic syndrome, and sickle cell hepatopathy was admitted for medical optimization before scheduled cholecystectomy. His Hb was raised pre-operatively with erythropoietin, in lieu of RBC transfusion, due to history of severe refractory hyper-hemolysis with transfusions. He underwent uncomplicated cholecystectomy on hospital day 2. On day 3, he developed ACS, septic shock, and an exacerbation of known hepatopathy. He was intubated and underwent RBC exchange with 8 units of RBCs. His Hb S decreased to 20% but he had no improvement in clinical status. High-dose steroids and TPE were then trialed. The use of TPE was dual purposed to reduce inflammatory cytokines contributing to systemic dysfunction and to prevent hyper-hemolysis following exchange transfusion. He underwent 3 TPEs each with 1.5 TPV using 5% albumin for three days (days 5, 6, and 7). Throughout his course of TPE, he was extubated (day 6), weaned off pressor support (day 6), and his liver dysfunction began to improve (day 7). He was discharged home on day 16. Case 3: A thirty-five-year-old female with HbSS without chronic complications was transferred from an outside hospital where she presented 3 days prior with ACS and progressive neurologic deterioration with minimal responsiveness. Imaging revealed diffuse pulmonary infiltrates and extensive cerebral micro emboli consistent with fat embolism syndrome. She underwent RBC exchange on the day of arrival to our facility (hospital day 4) with 5 units of RBCs. Her Hb S decreased to 20% but she had no improvement in neurologic function. After multidisciplinary evaluation, TPE was trialed alongside high-dose steroids. She underwent 5 TPEs each with 1.0 TPV using 5% albumin (days 5, 6, 8, 9, and 12). Shortly after initiating TPE, she began recovering neurologically with eye-opening, response to noxious stimuli, and tracking (day 6). After 3 days of TPE, CRP fell from 21 to 5 and ESR from 49 to 23 (day 8). She followed commands on day 10 and was taken off oxygen on day 15. She was discharged to a rehabilitation facility on day 30 with significant improvements in mental status, cognition, and functional abilities. Conclusions: TPE for three to five days should be considered in patients with severe ACS and multiorgan failure with high risk of mortality when standard management fails. The early initiation of TPE likely contributed to the successful recoveries of these three cases. Further studies are needed to delineate the role of TPE in the management of acute complications of SCD.

Use of IV Hydration Instead of Exchange Transfusion for Prophylactic Management of Pain Crisis in Homozygous (SS) Sickle Cell Disease Helps Maintain Hgb Levels and Prevents Further Escalation of Iron Overload

Introduction: Indications for exchange transfusion in the management of sickle cell disease and its complications are over time becoming limited. Currently accepted indications include acute chest syndrome and cerebrovascular accidents only. However, there is often consideration of using exchange transfusions for management of sickle cell pain crisis episodes resistant to opioid-based pain management. This is, however, of questionable efficacy due to concerns of iron overload as well as alloimmunization. The excessive utilization of blood products also presents a significant challenge. Therefore, it is important to explore alternatives to exchange transfusion in the management of pain crisis in sickle cell disease. Method: This study aimed at investigating the effects of transitioning patients with homozygous SS disease from routine exchange transfusions to IV hydration protocols. The main objective was to examine the changes in Hgb levels and the status of iron overload in these patients. A cohort of 16 patients with a Ferritin level above 1000 ng/ml, who were already receiving regular exchange transfusions, were included in the study. Their Hgb levels and Ferritin levels were measured periodically. This group was then given IV hydration twice a week, regardless of whether they were experiencing pain issues. We then compared the Hgb and Ferritin levels during a 6-month period of active exchange transfusions and 6-month period of being on IV hydration protocols. Both periods were a year apart, allowing for adequate homeostatic changes to take place. Additionally, we compared the number of simple transfusions during both these periods. Result: The mean ferritin level in patients getting exchange transfusions was 6097 ng/mL with the mean Hgb level maintained at 7.48 g/dL. During the initial study period, there were 14 exchange transfusion sessions involving 96 units of packed red blood cells (PRBCs). Additionally, 8 units of simple transfusion units were administered during the same period. Interestingly, as this cohort transitioned away from exchange transfusions, the number of simple transfusions increased to 30. Only one exchange transfusion occurred during the second 6-month observation period. During this time, ferritin level stopped increasing, and the mean was measured at 6076 ng/ml. The Hgb levels did show a slight decrease, with the mean being 6.90 g/dL, but the difference was not statistically significant. Conclusion: The findings of this study suggest that the use of IV hydration protocol is effective in managing iron overload issues and maintaining an adequate Hgb level in patients who were previously undergoing routine exchange transfusions to prevent or manage pain crisis episodes. The results indicate that IV hydration should be initiated when ferritin levels increase beyond 1000 ng/ml, rather than waiting for more advanced stages. Moreover, the study shows that even when IV hydration is started at a later stage of iron overload, it still appears to limit further iron accumulation, as evidenced by the stabilization of ferritin levels. Overall, the use of IV hydration as an alternative to routine exchange transfusions holds promise in managing pain crisis and iron overload in sickle cell disease.

Availability and Cost of Basic Drugs for Sickle Cell Disease in 13 African Countries

Background Sub-Saharan African countries are the hardest hit by sickle cell disease (SCD). Several studies have demonstrated the remarkable efficacy of hydroxyurea (HU) in African sickle-cell populations. As a result, many specialists recommend widespread use of this drug in Africa to reduce the disease's high morbidity/mortality. Nevertheless, in those countries health insurance mechanisms do not exist or and many families affected by SCD do not have enough income to pay for the care. In addition to cost, frequent supply chain disruptions lead to low drugs availability. The cost of basic treatments for SCD and their actual availability in different African countries is not yet known. Yet this information is essential for guiding health policies or the action of non-governmental organizations, and for planning the cost of assistance that could be provided to these patients. The aim of this study was to determine the availability, frequency of supply disruptions and cost of basic treatments for SCDin sub-Saharan African countries. Methods A cross-sectional online international survey was carried out from 24 March to 08 May 2023 among health professionals from French-speaking sub-Saharan African countries following SCD patients and registered in the database of the non-governmental organisation (NGO) Drep-Afrique. Participants completed questions covering the availability (on a scale from 0 (drug not available) to 10 (no availability concern) and the cost of basic drugs in their centres: HU, penicillin V, folic acid, morphine and vaccines. Results 120 health professionals, mainly physicians (91%), from 13 French-speaking Sub-Saharan African countries took part in this study. 58% of the participants worked in SCD referral centres and 36% in university hospitals. 91,000 homozygous SCD patients were reported as being followed in their centres. The median availability score for hydroxyurea and morphine were respectively 5 (IQR 3-8) and 5 (IQR 2-7), compared with 10 (IQR 10-10) for folic acid, 8 (IQR 4-10) for penicillin V, 3 (IQR 1-8) for anti-pneumococcal and 5 (IQR 2-8) for anti-meningococcal vaccines. Frequent supply chain disruptions were declared: 78% for HU, 77% for anti-pneumococcal vaccine, 66% for morphine, 45 % for Penicillin V, while they were rare for folic acid (8%). The median price of HU for one month's treatment of a 30 kg child (mean dose 20 mg/kg/day) was $19.3 (IQR 13.5- 25.3) and varied greatly from country to country (from $38 in Guinea to $10.1 in Togo (p=0.0002) (figure 1). The median price of pneumococcal vaccine was $35.3 (IQR 16.9- 58.7), and thant of meningococcal vaccine $31.4 (IQR 11- 57.5), also with significant differences between countries. The cost of pneumococcal vaccine was 1.6 times higher in centres where the supply chain disrupted than when there is no disruption (p=0.02). Conclusion This study shows that the cost of HU varies from one country to another in French-speaking Africa. Although not very high, it remains unaffordable for the most patients' families. For example, in 2023, the median monthly salary is 238 $ in the Democratic Republic of Congo (the country with the highest prevalence of SCD in the world with Nigeria), compared with a median monthly cost of HU of 25 $ in this country for a child in our study. The high cost of vaccines, beyond the first years of life when a free national program is available in most of African countries, is also a problem. In addition to cost, availability and frequent supply disruptions prevent regular intake of hydroxyurea and, to a lesser extent, of penicillin V. International solidarity and the governments of these countries should work to bring down the cost of hydroxyurea and improve the distribution circuit for these essential medicines.

Fetal Hemoglobin Decrease during Voxelotor Treatment

Sickle cell disease (SCD) is an inherited disorder caused by a point mutation in the β-globin gene leading to the formation of hemoglobin S (HbS). The polymerization of deoxygenated HbS is the first event in the molecular pathogenesis of SCD resulting in sickling of red blood cells (RBC), and hemolytic anemia which has been shown to be associated with organ damage and early death. Hemolytic anemia is defined by an accelerated rate of destruction RBC resulting in a lowered Hb level and a reduced gas transport capacity. Because Hb S in its oxy (R) conformation do not polymerize, drugs modifying hemoglobin (Hb) to increase the proportion of oxy-HbS have been propose to inhibit HbS polymerization. Voxelotor is such a molecule, which allosterically modifies Hb-oxygen affinity improving anemia and reducing hemolysis. However, the impact of Voxelotor on HbF levels is unknown. We describe here variations of %HbF and Mean corpuscular HbF (MCHbF) in a cohort of homozygous SCD patients treated with Voxelotor in our Sickle Cell Referral center. We conducted a prospective register study to analyze clinical and biological evolution of SCD patients treated with Voxelotor at 1500mg taken orally once daily. From December 2021 through December 2022, 25 SCD adult patients were followed during a median of 7 months [1-12]. Among them, HbF values were analyzable for 15 patients (SS gentype n=14; women in 73%; median age of 50 years [24-61]) who completed 6 months of Voxelotor with no transfusion during the same period; and with a stable dose of hydroxyurea (HU), for at least 3 months before inclusion and during the study in case of patients treated by HU (n=10). The dose of Voxelotor was stable for 13/15 patients and was decreased in 2 patients due to skin allergy (n=1) and moderate digestive intolerance. One patient died after 6 months of treatment in a context of end-stage renal failure and severe pulmonary hypertension not related to Voxelotor treatment. Mean corpuscular HbF (MCHbF) was calculated (MCHbF (pg) = MCH x %HbF). HbF percentage was measured by high performance liquid chromatography (Biorad, Variant II, beta-thal dual program). All participants provided written informed consent (CPP Erythropedie). From baseline to 6 months of follow up mean Hb (g/dL) concentration increased from 7.4 [5.4-8.5] to 8 [5-11.9] (p=0,0003; Figure A); absolute reticulocyte count (ARC ; Giga/L) decreased from 158 to 145 (p=0,005), %HbF decreased by 63% in all patients from 7,1% to 3,3% (p=0,008; Figure B) and MCHbF (pg) decreased from 3,36 to 1,03 (p=0,001; Figure D). A decrease in % HbF was observed from the first 15 days of treatment in both groups of patients treated or not with HU (Figure C) ; no changes in mean corpuscular volume (p=0.15) was observed in patients treated with HU during follow up. The HbF decrease in SCD patients treated with Voxelotor could be explained by different mechanisms: - Reduction of stress erythropoiesis which is due to an increase in erythroid output in response to anemic stress associated with a reduced expression of BCL11A, a transcriptional repressor that inhibits adult-stage HbF expression. This hypothesis is supported by the reduction in reticulocytes in patients treated with Voxelotor - The loss of an HbF-related survival advantage for SCD RBCs, while the normal RBC lifespan is approximatively 120 days, in SCD RBCs it is only a sixth of it. HbF is a major modulator of SCD and prolonge SCD RBCs survival. Its protective effect relies on its quantity and distribution among the RBC population, which is often heterogeneous in SCD patients. Protection against polymerisation of Voxelotor is probably more homogeneous among RBCs. As a result, RBCs containing low levels of HbF, which would normally disappear, have a prolonged lifespan. Similarly, it was presumed that sickling of erythroblasts could lead to ineffective terminal erythroid differentiation with an anti-apoptotic role for HbF during the terminal stages of erythroid differentiation. However we found no significant difference for index of ineffective erythropoiesis (soluble transferrin receptor / absolute reticulocyte count) before and after 6 months of treatment. The question raised is therefore that of the risk of a rebound effect upon discontinuation of Voxelotor, which has a short half-life, during the time it takes for HbF to increase. To better study this hypothesis, distribution of HbF/RBC will be studied in the HEMOPROVE trial (NCT05199766) currently in progress.

Enhanced Expression of Heme Oxygenase-1 (HO-1) Among Children with Sickle Cell Disease: Results of the Sickle Cell Disease Genomics of Africa (SickleGenAfrica) Study

Sickle cell disease (SCD) is characterized by intense and chronic intravascular hemolysis that generates multiple erythroid danger associated molecular pattern (eDAMP) molecules in the extracellular space. Extracellular heme is a prototypical eDAMP that causes tissue injury and is associated with multiple complications of SCD including vaso-occlusive crisis, acute kidney injury and acute chest syndrome (ACS). Heme-oxygenase-1 (HO-1) is the rate-limiting enzyme that degrades heme to neutralize its deleterious effects on organ function. Raised extracellular heme is associated with 2.5 higher odds ratio of developing ACS, while HO-1 gene promoter allelic variants that drive robust HO-1 expression are associated with lower ACS-related hospitalization rates among children. Young transgenic homozygous SCD (SS) mice have higher survival rates than adult SS mice from a heme-induced ACS model due to their ability to rapidly degrade excess extracellular heme. While these data suggest that HO-1 may be involved in the well-established higher ACS survival among children, and potentially other ameliorating features of SCD in early development, no study had previously studied HO-1 expression in this patient population. The SickleGenAfrica Network enrolled over 2,000 children and adults with SCD from three sites in Ghana from 2018 to 2021, with consent for use of samples in future studies. The SCD status of participants was confirmed using automated capillary hemoglobin electrophoresis, and serum HO-1 level measured using ELISA. Patients were grouped based on age, using five-year intervals. The median HO-1 level comparisons across groups were performed using the pairwise Wilcoxon test, with Bonferroni correction for multiple comparisons. All analyses were performed using R version 4.3.1. The study included 1,971 patients with SCD, with a median age of 13 years (range 0 - 78), of which 1,067 participants (55%) were female. The majority of patients (1149 ;58%) had HbSS, 589 (30%) had HbSC, 171 (9%) sickle-hereditary persistence of fetal hemoglobin, and 62 (3%) HbS-beta(+). We observed an approximately 3-fold drop-off in median HO-1 levels between the 11-15-year-old (73.9 ng/ml) and 16-20-year-old (25.1 ng/ml) age groups (adj. p<0.001). Furthermore, males had higher average HO-1 levels (85.5 ng/ml) relative to females (63.1 ng/ml) (p<0.001). Our data show for the first time that children with SCD have significantly elevated HO-1 levels relative to adults, with a sharp decline in HO-1 levels during adolescence. HO-1 may serve as a protective SCD factor, contributing to enhanced ACS survival rates in children versus adults. To the best of our knowledge, this is the first study of HO-1 levels in patients with SCD at different ages. Our future work aims to establish whether baseline blood HO-1 levels can predict ACS incidence and severity, in addition to further investigating genetic and epigenetic mechanisms controlling HO-1 expression.

Acute splenic sequestration in HbSS: observations from the Jamaican birth cohort

ObjectiveTo document the prevalence, clinical features, haematology and outcome of acute splenic sequestration (ASS) in homozygous sickle cell disease (HbSS).Study designA cohort study from birth.SettingThe Medical Research Council Laboratories at...

Rhabdomyolysis aggravates renal iron accumulation and acute kidney injury in a humanized mouse model of sickle cell disease

Individuals with sickle cell disease (SCD) are at greater risk of rhabdomyolysis, a potentially life-threatening condition resulting from the breakdown of skeletal muscle fibers. Acute kidney injury (AKI) is one of the most severe complications of rhabdomyolysis. Chronic kidney and cardiovascular disease, which account for SCD mortality, are long-term consequences of AKI. Although SCD elevates the risks of rhabdomyolysis-induced sudden death, the mechanisms that underlie rhabdomyolysis-induced AKI in SCD are unclear. In the present study, we show that, unlike their control non-sickling (AA) counterparts, transgenic homozygous SCD (SS; Townes model) mice exhibited 100% mortality 8–24 h after intramuscular glycerol injection. Five hours after glycerol injection, SS mice showed a more significant increase in myoglobinuria and plasma creatine kinase levels than AA mice. Basal plasma heme and kidney tissue iron levels were significantly higher in SS than in AA mice. In contrast to AA, glycerol-induced rhabdomyolysis aggravated these parameters in SS mice. Rhabdomyolysis also amplified oxidative stress in SS compared to AA mice. Glycerol-treated SS mice exhibited worse renal function, exemplified by a reduction in GFR with a corresponding increase in plasma and urinary biomarkers of early AKI and renal tubular damage. The free radical scavenger and Fenton chemistry inhibitor, TEMPOL, ameliorated rhabdomyolysis-induced AKI in the SS mice. These findings demonstrate that oxidative stress driven by renal iron accumulation amplifies rhabdomyolysis-induced AKI in SCD mice.

Prevalence of Haemoglobinopathy among Young College Students in Anand-Gujarat: A Premarital Screening Program for Carrier Detection of Hemoglobin Disorders

Background: Hemoglobin disorders are the leading health concern in the World including India. Effective screeningprograms, awareness campaign and proper prenatal diagnosis are the only ways to eradicate the disease. Verysparse data are available on the spectrum of haemoglobinopathies in the central part of Gujarat state. Hence, thisstudy was undertaken to find out the prevalence of haemoglobinopathies among the students of Anand People’sMedicare Society, Anand District, Gujarat, India.Methods: In this prospective study, total 2195 students were screened for haemoglobinopathies after takingclinical and familial history. A complete hemogram report was obtained by an automated hematology counterand hemoglobin variants were quantitated by performing HPLC on Bio-Rad Variant II. The prevalence ofhemoglobinopathies was 7.06%, which includes β-thalassemia trait (2.73 %), sickle cell trait (3.82%), homozygoussickle cell disease (0.09%), Hb D trait (0.22%), Hb E (0.09%) trait and other haemoglobinopathies (0.08%).Conclusion: Population groups with high gene frequency of haemoglobinopathies requires a routine premaritalscreening program, awareness and education for identification, prevention of high-risk marriages and birth ofthalassemic homozygotes.

Acid Elution (Kleihauer-Betke) Test in a Patient with Homozygous Sickle Cell Disease and Elevated Hemoglobin-F Levels.

Acid Elution (Kleihauer-Betke) Test in a Patient with Homozygous Sickle Cell Disease and Elevated Hemoglobin-F Levels.

Dual-energy computed tomography to detect early pulmonary vascular changes in children with sickle cell disease: a pilot study.

Pulmonary hypertension (PH) is a rare but fatal complication of sickle cell disease (SCD) that is possibly reversible if treated early. Dual-energy computed tomography (DECT) is a valuable tool for diagnosing PH. We attempted to determine if DECT can detect early signs of PH in children with SCD. This prospective observational pilot study was conducted at the Geneva University Hospitals and was approved by the local human ethics committee (CCER 2019-01975). A written informed consent was obtained from the patients and/or their legal guardian. Eight children (consisting of five girls and three boys) with homozygous SCD were included in the study. They underwent full cardiological workup using transthoracic echocardiography (TTE) and cardiopulmonary exercise test (CPET), as well as DECT. The median age of the children was 11 years old (range 8-12). All patients exhibited a normal biventricular systo-diastolic function using the TTE. The median tricuspid regurgitant jet velocity value was 2.24 m/s (range 1.96-2.98). Four children were found to have signs of vasculopathy detected on DECT. Of them, two had abnormal screening test results. They both had an increased VE/VCO2 slope during CPET and an increased TVR of >2.5 m/s on TTE. DECT is capable of identifying early signs of pulmonary vascular disease in children with SCD. Further studies are needed to understand the correlation between DECT abnormalities and hemodynamic pulmonary circulation better.

Plasminogen activator inhibitor-2 and impaired fibrinolysis in pregnancy and sickle cell anemia.

This is the first study that aimed to determine antigen levels in plasma and genotypes of PAI-2 in pregnant and non-pregnant homozygous sickle cell anemia (SCA) patients. The study subjects were all Bahraini females in the reproductive age group. The study population included 31 pregnant homozygous SS (SCA) patients. Three control groups were also studied to evaluate the effect of pregnancy and SCA on PAI-2 levels and fibrinolysis: (1) 31 healthy non-pregnant volunteers; (2) 31 cases of normal pregnancy; and (3) 20 non-pregnant SCA patients. Pregnancies were screened in the second (TM2) and third (TM3) trimesters. Global coagulation, fibrinolysis rate (euglobulin clot lysis time, ECLT), PAI-2 antigen (ELISA), and PAI-2 Ser(413)/Cys polymorphism (restriction fragment length polymorphism analysis) were determined. Feto-maternal complications were documented in both pregnancy groups. PAI-2 antigen levels were undetectable in the non-pregnant groups, but was quantifiable in both pregnant groups. Impaired fibrinolysis rate and rising PAI-2 levels with progression of pregnancy were observed in both healthy and SCA subjects. These changes were more prominent in SCA, although the rise in ECLT was less steep and PAI-2 antigen levels were not significantly different compared to normal pregnancy in the third trimester. No correlation was observed between PAI-2 genotypes and plasma antigen levels.Also, no significant difference in feto-maternal complications was found in normal (n = 25) versus SCA pregnant patients (n = 30). These observations suggest that with progression of pregnancy, increasing PAI-2 levels contribute to the hypercoagulable state, particularly in SCA patients.

Global, regional, and national prevalence and mortality burden of sickle cell disease, 2000–2021: a systematic analysis from the Global Burden of Disease Study 2021

Previous global analyses, with known underdiagnosis and single cause per death attribution systems, provide only a small insight into the suspected high population health effect of sickle cell disease. Completed as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021, this study delivers a comprehensive global assessment of prevalence of sickle cell disease and mortality burden by age and sex for 204 countries and territories from 2000 to 2021. We estimated cause-specific sickle cell disease mortality using standardised GBD approaches, in which each death is assigned to a single underlying cause, to estimate mortality rates from the International Classification of Diseases (ICD)-coded vital registration, surveillance, and verbal autopsy data. In parallel, our goal was to estimate a more accurate account of sickle cell disease health burden using four types of epidemiological data on sickle cell disease: birth incidence, age-specific prevalence, with-condition mortality (total deaths), and excess mortality (excess deaths). Systematic reviews, supplemented with ICD-coded hospital discharge and insurance claims data, informed this modelling approach. We employed DisMod-MR 2.1 to triangulate between these measures-borrowing strength from predictive covariates and across age, time, and geography-and generated internally consistent estimates of incidence, prevalence, and mortality for three distinct genotypes of sickle cell disease: homozygous sickle cell disease and severe sickle cell β-thalassaemia, sickle-haemoglobin C disease, and mild sickle cell β-thalassaemia. Summing the three models yielded final estimates of incidence at birth, prevalence by age and sex, and total sickle cell disease mortality, the latter of which was compared directly against cause-specific mortality estimates to evaluate differences in mortality burden assessment and implications for the Sustainable Development Goals (SDGs). Between 2000 and 2021, national incidence rates of sickle cell disease were relatively stable, but total births of babies with sickle cell disease increased globally by 13·7% (95% uncertainty interval 11·1-16·5), to 515 000 (425 000-614 000), primarily due to population growth in the Caribbean and western and central sub-Saharan Africa. The number of people living with sickle cell disease globally increased by 41·4% (38·3-44·9), from 5·46 million (4·62-6·45) in 2000 to 7·74 million (6·51-9·2) in 2021. We estimated 34 400 (25 000-45 200) cause-specific all-age deaths globally in 2021, but total sickle cell disease mortality burden was nearly 11-times higher at 376 000 (303 000-467 000). In children younger than 5 years, there were 81 100 (58 800-108 000) deaths, ranking total sickle cell disease mortality as 12th (compared to 40th for cause-specific sickle cell disease mortality) across all causes estimated by the GBD in 2021. Our findings show a strikingly high contribution of sickle cell disease to all-cause mortality that is not apparent when each death is assigned to only a single cause. Sickle cell disease mortality burden is highest in children, especially in countries with the greatest under-5 mortality rates. Without comprehensive strategies to address morbidity and mortality associated with sickle cell disease, attainment of SDG 3.1, 3.2, and 3.4 is uncertain. Widespread data gaps and correspondingly high uncertainty in the estimates highlight the urgent need for routine and sustained surveillance efforts, further research to assess the contribution of conditions associated with sickle cell disease, and widespread deployment of evidence-based prevention and treatment for those with sickle cell disease. Bill & Melinda Gates Foundation.

Alloimmunization in children with sickle cell disease: A tertiary care experience

IntroductionPatients with sickle cell disease (SCD) show a high prevalence of red blood cell (RBC) alloimmunization, however, few studies have focused on children. The present study was undertaken to determine the prevalence of alloimmunization and autoimmunity in children with SCD and to assess any correlation with age, number of transfusions received, and the number and frequency of crisis. Material & methodsSixty children affected with homozygous SCD, aged between five to eighteen years and having received more than one packed red blood cell (PRBC) transfusion were enrolled in the study.The preliminary tests included antiglobulin test (indirect and direct), alloantibody screening by three panel, antibody typing using 11 panel and auto-control test to detect autoantibodies. ResultsDirect antiglobulin test was negative in all the 60 patients, whereas indirect antiglobulin test was positive in 4/60 (6.6%) patients. Specific typing of alloantibodies revealed anti-D and anti-Kell antibodies in 2 (3.3%) each. Patients with alloantibody (4) had a higher mean age at onset of first symptom (7.05 ± 2.12 years) and age at first transfusion (7.5 ± 2.12 years) as compared to those without alloantibody, (4.48 ± 3.09 and 4.91 ± 3.12 years respectively). Patients with alloantibody received more PRBC transfusions, maintained low hemoglobin, required higher doses of hydroxyurea and also had a larger liver and spleen. ConclusionThe present study found a low prevalence of antibodies in patients with SCD. Patients presenting with symptoms of SCD at younger age received hydroxyurea at an earlier age. Starting hydroxyurea at an earlier age may decrease subsequent alloantibodies development. Larger studies to compare groups of patients related to administration of hydroxyurea are required to confirm this hypothesis.