Prevention of potential delayed hemolytic transfusion reaction in two sickle cell patients using intravenous immunoglobulins and steroids before and after red blood cell exchange with antigen positive units and review literature

Emergent Red Blood Cell (RBC) exchange is indicated in sickle cell disease (SCD) patients with severe acute chest syndrome. However, fully matched RBC units may not be available for patients with multiple RBC antibodies. Intravenous immunoglobulin (IVIG) and steroids were reported for preventing potential delayed hemolytic transfusion reaction (HTR) in simple transfusion of antigen-positive RBCs. We investigated the efficacy and safety of IVIG and steroids in two SCD patients presented with acute chest syndrome receiving RBC exchange with multiple incompatible units. The first patient had multiple historical alloantibodies, including anti-Jsb, although none of them were reactive. IVIG (1 g/kg) was given before and after RBC exchange with methylprednisolone (500 mg IV) one hour before exchange. Her sickle hemoglobin (HbS) was reduced from 89.4% to 17.4% after the exchange with five Jsb-positive units. The patient improved clinically without acute or delayed hemolysis. The second patient had reactive anti-Jsb on two different admissions 18 months apart. Only one of the sixteen units used in the exchanges was Jsb negative. He received the same IVIG regimen during both admissions but 100 mg IV hydrocortisone instead of methylprednisolone. His HbS was reduced from 63.4% to 22.4% after the first exchange. Significant clinical improvements were achieved after both exchanges. No delayed HTR was observed. Our experience of these two patients suggested that IVIG and steroids may be used in preventing potential delayed HTR in some SCD patients with rare antibodies receiving large amounts of antigen-positive RBC products.

Sickle Cell Health Awareness, Perspectives, and Experiences (SHAPE) survey: Perspectives of adolescent and adult patients, caregivers, and healthcare professionals on the burden of sickle cell disease

OBJECTIVES

Sickle cell disease (SCD) is an inherited disorder that causes lifelong complications, substantially impacting the physical and emotional well-being of patients and their caregivers. Studies investigating the effects of SCD on quality of life (QOL) are often limited to individual countries, lack SCD-specific QOL questionnaires, and exclude the caregiver experience. The SHAPE survey aimed to broaden the understanding of the global burden of SCD on patients and their caregivers and to capture the viewpoint of healthcare providers (HCPs).

METHODS

A total of 919 patients, 207 caregivers, and 219 HCPs from 10, 9, and 8 countries, respectively, answered a series of closed-ended questions about their experiences with SCD.

RESULTS

The symptoms most frequently reported by patients were fatigue/tiredness (84%) and pain/vaso-occlusive crises (71%). Patients' fatigue/tiredness had one of the greatest impacts on both patients' and caregivers' QOL. On average, patients and caregivers reported missing 7.5 days and 5.0 days per month, respectively, of school or work. HCPs reported a need for effective tools to treat fatigue/tiredness and a desire for more support to educate patients on long-term SCD-related health risks.

CONCLUSIONS

The multifaceted challenges identified using the SHAPE survey highlight the global need to improve both patient and caregiver QOL.

Transfusion of blood components in pediatric age groups: an evidence-based clinical practice guideline adapted for the use in Egypt using 'Adapted ADAPTE'

Pediatric transfusion is a complex area of medicine covering a wide age range, from neonates to young adults. Compared to adult practice, there is a relative lack of high-quality research to inform evidence-based guidelines. We aimed to adapt the pre-existing high-quality practice guidelines for the transfusion of blood components in different pediatric age groups to be available for national use by general practitioners, pediatricians, and other health care professionals. The guideline panel included 17 key leaders from different Egyptian institutions. The panel used the Adapted ADAPTE methodology. The panel prioritized the health questions and recommendations according to their importance for clinicians and patients. The procedure included searching for existing guidelines, quality appraisal, and adaptation of the recommendations to the target context of use. The guideline covered all important aspects of the indications, dosing, and administration of packed red cells, platelets, and fresh frozen plasma. It also included transfusion in special situations, e.g., chronic hemolytic anemia and aplastic anemia, management of massive blood loss, malignancies, surgery, recommendations for safe transfusion practices, and recommendations for modifications of cellular blood components. The final version of the adapted clinical practice guideline (CPG) has been made after a thorough review by an external review panel and was guided by their official recommendations and modifications. A set of implementation tools included algorithms, tables, and flow charts to aid decision-making in practice. This adapted guideline serves as a tool for safe transfusion practices in different pediatric age groups.

Red Blood Cell Exchange as a Valid Therapeutic Approach for Pregnancy Management in Sickle Cell Disease: Three Explicative Cases and Systematic Review of Literature

Pregnancy in women with sickle cell disease (SCD) is a high-risk situation, especially during the third trimester of gestation and in the post-partum period, due to chronic hypoxia and vaso-occlusive phenomena occurring in the maternal-fetal microcirculation: as a result, unfavorable outcomes, such as intra-uterine growth restriction, prematurity or fetal loss are more frequent in SCD pregnancies. Therefore, there is a consensus on the need for a strict and multidisciplinary follow-up within specialized structures. Transfusion support remains the mainstay of treatment of SCD pregnancies, whereas more targeted modalities are still controversial: the benefit of prophylactic management, either by simple transfusions or by automated red blood cell exchange (aRBCX), is not unanimously recognized. We illustrate the cases of three SCD pregnant patients who underwent aRBCX procedures at our institution in different clinical scenarios. Moreover, we carried out a careful literature revision to investigate the management of pregnancy in SCD, with a particular focus on the viability of aRBCX. Our experience and the current literature support the use of aRBCX in pregnancy as a feasible and safe procedure, provided that specialized equipment and an experienced apheresis team is available. However, further research in this high-risk population, with appropriately powered prospective trials, is desirable to refine the indications and timing of aRBCX and to confirm the advantages of this approach on other transfusion modalities.

Impact of Sickle Cell Disease on Academic Performance: A Cross Sectional Study

Purpose

Sickle cell disease (SCD) is a multisystemic disease that results in diverse clinical manifestations in the form of acute and chronic complications. This study aims to assess the academic achievements of patients with SCD.

Methods and Materials

A cross-sectional study was a study conducted among adult patients with SCD from the eastern province of Saudi Arabia, where SCD is more widespread than in other regions.

Results

A total of ninety patients with SCD, whose median age was 32.33 ± 11.84, were retrospectively evaluated. Of the total number, 32 (35.5%) did not obtain a secondary higher education certificate, and five (3.3%) were illiterate. Sixty-three (70%) of the patients were female, indicating no significant association between gender and education level (p-value > 0.05). The patients' mean annual hospitalizations and emergency visits totaling 4.7 and 8.43, respectively, were not significantly associated with education (p-value > 0.05). Throughout the patients' lives, mean blood transfusions and ICU admissions occurred 6.29 and 2.75 times, respectively, which were not significantly associated with education level (p-value > 0.05). However, education was inversely proportional to a history of splenectomy and cholecystectomy (p < 0.05). Laboratory parameters (hemoglobin level, WBC, platelets, and hemoglobin F) showed no significant associations with education level (p-value > 0.05). Patients with sickle-thalassemia exhibited a trend of being better-educated than those without the diseases, but the difference did not reach statistical significance (p-value > 0.05). A linear regression analysis revealed no significant associations among clinical and laboratory parameters.

Conclusion

SCD is a multisystemic disease that impacts socioeconomic status, learning ability, and academic achievements. More research is needed to identify factors that predict poor performance. Additionally, intelligence quotient (IQ) and cognitive assessment should be incorporated into early screening programs for SCD in order to implement preventive measures and a thorough investigation of underlying causes.

A retrospective study for association between post-transfusion hemoglobin S level and pre-transfusion hemoglobin S level at the next scheduled transfusion

BACKGROUND

Patients with sickle cell disease (SCD) frequently undergo prophylactic red blood cell (RBC) exchange transfusion and simple transfusion (RCE/T) to prevent complications of disease, such as stroke. These treatment procedures are performed with a target hemoglobin S (HbS) of ≤30%, or a goal of maintaining an HbS level of <30% immediately prior to the next transfusion. However, there is a lack of evidence-based instructions for how to perform RCE/T in a way that will result in an HbS value <30% between treatments.

PRINCIPAL OBJECTIVE

To determine whether targets for post-treatment HbS (post-HbS) or post-treatment HCT (post-HCT) can help to maintain an HbS <30% or <40% between treatments.

MATERIALS AND METHODS

We performed a retrospective study of patients with SCD treated with RCE/T at Montefiore Medical Center from June 2014 to June 2016. The analysis included patients of all ages, and data including 3 documented parameters for each RCE/T event: post-HbS, post-HCT, and follow-up HbS (F/u-HbS), which is the pre-treatment HbS prior to the next RCE/T. Generalized linear mixed model was used for estimating the association between post-HbS or post-HCT levels and F/u-HbS <30%.

RESULTS

Based on our results, targeting post-HbS ≤10% was associated with higher odds of having events of F/u-HbS <30% between monthly treatments. Targeting post-HbS ≤15% was associated with higher odds of events of F/u-HbS < 40%. As compared to post-HCT ≤30%, a post-HCT >30%-36% did not contribute to more F/u-HbS <30% or HbS <40% events.

CONCLUSIONS

For patients with SCD undergoing regular RCE/T for stroke prevention, a post-HbS ≤10% can be used as a goal to help maintain an HbS <30% for 1 month, and a post-HbS ≤15% allowed patients to maintain HbS <40%.

A case report and review of literature on the role of automated red cell exchange in managing sickle cell crisis in India

Red cell exchanges (RCE) help in the treatment of complications of sickle cell anemia (SCA) by reducing the viscosity of blood and improving the oxygen-carrying capacity. We present a case of sickle cell crisis (SCC) managed with automated RCE and also reviewed the literature to assess the utilization and clinical efficiency of this therapy in India. A 19-year-old gentleman diagnosed with SCA presented with acute chest syndrome. Hemoglobin (Hb) was 8.8 g%, hematocrit (HCT) was 24%, and HbS was 90%. As there was worsening of symptoms with conventional management, the patient underwent two procedures of automated RCE. The clinical condition of the patient was improved, HbS was reduced to 16% and HCT was remained at 21% postprocedure. Articles on automated RCE in SCA conducted in India were reviewed and four articles were analyzed based on the search strategy. All the included articles concluded automated RCE as an effective procedure for complications of SCA. Common indication in India was SCA patients undergoing surgery as a prophylactic measure. Automated RCEs are promising as an acute treatment for indicated sickle cell complications. This therapy is underutilized in the Indian scenario, especially in patients with SCC.

Sickle cell disease in Ontario, Canada: an epidemiologic profile based on health administrative data

BACKGROUND

The number of patients with sickle cell disease in Ontario, Canada, is unknown. In the absence of a formal registry, we performed a study to determine an approximate census via analysis of health administrative databases.

METHODS

We identified Ontario patients with a diagnosis of sickle cell disease through queries of the Discharge Abstract Database, National Ambulatory Care Reporting System and Newborn Screening Ontario database. The period of inquiry was Apr. 1, 2007, through Mar. 31, 2017. We identified repeat interactions by the same patient by cross-referencing provincial health insurance plan numbers.

RESULTS

We documented health care system interactions for 3418 unique patients (1912 [55.9%] female, median age at the time of identification 24 yr). Over the 10-year study period, patients visited the emergency department a median of 2 (interquartile range [IQR] 1-7) times and an average of 6.69 (standard deviation [SD] 26.71) times, and were admitted to hospital a median of 1 (IQR 1-5) time and an average of 4.38 (SD 8.53) times for treatment related to sickle cell disease. A total of 229 patients (6.7%) died during the study period, with an average age at death of 55 years. Even without accounting for the effects of immigration, the rate of natural increase slowed slightly over the study period owing to a decrease in the annual number of affected births.

INTERPRETATION

The estimated prevalence of patients with sickle cell disease in Ontario in 2007/08-2016/17 was 1 in 4200, and affected patients' need for hospital-based care was substantial, although highly variable. Similar queries of health administrative databases may be feasible in other Canadian provinces.

Timing matters: An analysis of the relationship between red cell transfusion timing and hospitalization outcomes in sickle cell crisis patients using the National Inpatient Sample database

Vaso-occlusive pain crisis is a debilitating complication of sickle cell disease (SCD) and it is the most common cause of hospitalization among these individuals. We studied the inpatient outcomes among patients admitted with sickle cell crisis based on the timing of red blood cell transfusion. In this retrospective study, we used the United States National Inpatient Sample (NIS) data for the year 2019, to identify adult patients hospitalized with the principal diagnosis of sickle cell crisis who received simple red blood cell transfusion during their hospitalization. Patients were divided into two groups. Those who received simple red cell transfusion within 24 hours of admission were classified as early transfusion. After adjusting for confounders, the mean adjusted length of stay for patients with early transfusion was significantly lower than those who received a late blood transfusion by 3.51 days (p-value < 0.001) along with a decrease in mean adjusted hospitalization charges and cost, by 25,487 and 4,505 United States Dollar (USD) respectively. The early red cell transfusion was also associated with a decrease in inpatient mortality, demonstrated by an adjusted odds ratio (aOR) of 0.19 (p-value 0.036), and a reduction in in-hospital sepsis, with an aOR of 0.28 (p-value < 0.001), however, no statistically significant difference was found between the two groups regarding acute respiratory failure requiring intubation, vasopressors requirement, acute kidney injury requiring dialysis and intensive care unit (ICU) admission. We recommend timely triage and reassessment to identify sickle cell crisis patients requiring blood transfusion. This intervention can notably affect the inpatient length of stay, resource utilization, and hospitalization outcomes.

Characterizing the process of urgent referrals and transfers to a large tertiary care apheresis centre in Ontario: A retrospective database review

BACKGROUND

Therapeutic plasma exchange (TPE) and red blood cell exchange (RBCX) are life-saving apheresis procedures offered in 7 Ontario hospitals. Most referrals are directed by CritiCall Ontario (CritiCall), a 24/7 service funded by the Ontario Ministry of Health and Long-Term Care. We used CritiCall data to examine referral requests, acceptances, and transfers for urgent apheresis to our centre.

METHODS

Retrospective CritiCall referral and transfer data for urgent apheresis between October 2013 and December 2018 were included. Continuous variables were analyzed by linear regression. Categorical variables were analyzed using nonparametric tests.

RESULTS

Eighty-five cases (52 TPE, 33 RBCX) were identified. Median patient age was 52 years (interquartile range [IQR] 32) for TPE, 29 years (IQR 18) for RBCX. Most patients (58%) were female. Total time from referral to arrival at our centre was 243 (IQR 166) minutes. The greatest proportion of this total was from patient acceptance to arrival (169 [IQR 112] minutes). Median distance between referring and accepting centres was 39 (IQR 30) kilometres, with ground transportation used most often. Multiple linear regression examining factors that contribute to total time demonstrated that the number of physicians contacted prior to patient acceptance and inter-hospital distance were independently associated (p = 0.007 and p = 0.048, respectively).

INTERPRETATION

Addressing modifiable factors to reduce time is important given that time to initiate treatment is associated with better outcomes. Quality improvement strategies should be aimed at coordinated provincial resource sharing, pairing referrals with nearest available apheresis centres, and creating efficiency in the interval between patient acceptance and arrival.

Red blood cell alloantibodies in paediatric transfusion in sub-Saharan Africa: A new cohort and literature review

Blood transfusion support predisposes transfused children to the risk of erythrocyte alloimmunization in Sub-Saharan Africa. A cohort of 100 children receiving one to five blood transfusions were recruited for screening and identification of irregular antibodies using gel filtration technique. The mean age was 8 years and the sex-ratio at 1.2. The retrieved pathologies were: major sickle cell anaemia (46%), severe malaria (20%), haemolytic anaemia (4%), severe acute malnutrition (6%), acute gastroenteritis (5%), chronic infectious syndrome (12%) and congenital heart disease (7%). The children presented with haemoglobin levels ≤6 g/dl, and 16% of them presented positive irregular antibodies directed against the Rhesus (30.76%) and Kell (69.24%) blood group systems. A literature review shows that irregular antibody screenings vary from 17% to 30% of transfused paediatric patients in Sub-Saharan Africa. These alloantibodies are in particular directed against the Rhesus, Kell, Duffy, Kidd and MNS blood group and generally found in sickle cell disease and malaria. This study highlights the urgent need of extended red blood cell phenotyping including typing for C/c, E/e, K/k, and Fya/Fyb, and if possible Jka/Jkb, M/N, and S/s for children before transfusion in Sub-Saharan Africa.

Hydroxyurea with dose escalation for primary stroke risk reduction in children with sickle cell anaemia in Tanzania (SPHERE): an open-label, phase 2 trial

BACKGROUND

Transcranial Doppler screening with chronic transfusions reduces stroke risk in children with sickle cell anaemia but is not feasible in low-resource settings. Hydroxyurea is an alternative treatment to decrease stroke risk. We aimed to estimate stroke risk in children with sickle cell anaemia in Tanzania and to determine the efficacy of hydroxyurea to decrease and prevent stroke.

METHODS

We did an open-label, phase 2 trial (SPHERE) at Bugando Medical Centre, Mwanza, Tanzania. Children aged 2-16 years with a diagnosis of sickle cell anaemia confirmed by haemoglobin electrophoresis were eligible for enrolment. Participants had transcranial Doppler ultrasound screening by a local examiner. Participants with elevated Doppler velocities, either conditional (170-199 cm/s) or abnormal (≥200 cm/s), received oral hydroxyurea starting at 20 mg/kg once daily and escalated every 8 weeks by 5 mg/kg per day to the maximum tolerated dose. Participants with normal Doppler velocities (<170 cm/s) received usual care from the sickle cell anaemia clinic and were rescreened after 12 months to determine whether they qualified for treatment on trial. The primary endpoint was change in transcranial Doppler velocity from the baseline visit to after 12 months of hydroxyurea treatment, analysed in all patients who had paired baseline and follow-up measurements collected after 12 months of treatment. Safety was analysed in the per-protocol population (all participants who received study treatment). This study is registered with ClinicalTrials.gov, NCT03948867.

FINDINGS

Between April 24, 2019, and April 9, 2020, 202 children were enrolled and had transcranial Doppler screening. Sickle cell anaemia was confirmed by DNA-based testing in 196 participants (mean age 6·8 years [SD 3·5], 103 [53%] were female, and 93 [47%] were male). At the baseline screening, 47 (24%) of 196 participants had elevated transcranial Doppler velocities (43 [22%] conditional, four [2%] abnormal); 45 initiated hydroxyurea at a mean dose of 20·2 mg/kg per day (SD 1·4) with escalation to a mean dose of 27·4 mg/kg per day (5·1) after 12 months. Treatment response was analysed after 12 months (± 1 month; median 11 months, IQR 11-12) and 24 months (±3 months; median 22 months, 22-22). Transcranial Doppler velocities decreased to a mean of 149 cm/s (SD 27) compared with 182 cm/s (12) at baseline, which was significantly lower than baseline (p<0·0001), with an average decline of 35 cm/s (SD 23) after 12 months of treatment in 42 participants with paired results available at baseline and 12 months. No clinical strokes occurred, and 35 (83%) of 42 participants reverted to normal transcranial Doppler velocities. Clinical adverse events were mild, and dose-limiting toxicities were uncommon. The most common grade 3 adverse events were malaria (12 [29%] episodes in 45 patients) and sepsis (13 [32%] episodes). There were three serious adverse events, none of which were treatment-related, and no treatment-related deaths occurred.

INTERPRETATION

Children with sickle cell anaemia in Tanzania have a high baseline stroke risk. Hydroxyurea at the maximum tolerated dose significantly lowers transcranial Doppler velocities and reduces primary stroke risk. Transcranial Doppler screening plus hydroxyurea at the maximum tolerated dose is an effective stroke prevention strategy, supporting wider hydroxyurea access for patients with sickle cell anaemia across sub-Saharan Africa.

FUNDING

American Society of Hematology, National Institutes of Health, Cincinnati Children's Research Foundation.

Emergency red cell exchange for the management of acute complications in sickle cell disease: Automated versus manual

BACKGROUND

Red blood cell exchange is the cornerstone of the management for acute complications of sickle cell disease. It improves anaemia and improvesperipheral tissue oxygen delivery while at the same time reduces the proportion of circulating sickle erythrocytes. Even though automated red cell exchange is very effective in rapidly lowering the Hb S level, 24-h availability is currently not feasible for most specialist centres including our own.

OBJECTIVE

Here, we describe our experience using both automated and manual red cell exchange for the management of acute sickle cell complications.

METHODS

Eighty-six such episodes have been recorded between June 2011 and June 2022 comprising of 68 episodes of automated and 18 episodes of manual red cell exchange.

RESULTS

The post procedure Hb S/S + C level was 18% after automated and 36% after manual red cell exchange. The platelet count dropped by 41% and 21% after automated and manual red cell exchange respectively. The clinical outcomes including need for organ support, duration of stay in the intensive care unit and overall length of hospitalisation was comparable between the two groups.

CONCLUSION

In our experience, manual red cell exchange is a safe and effective alternative to an automated procedure that can be used while specialist centres are building up their capacity to offer automated red cell exchange for all patients requiring the intervention.

Reconsidering sickle cell trait testing of red blood cell units allocated to children with sickle cell disease

BACKGROUND

Sickle cell trait (SCT) testing of red blood cell (RBC) units is sometimes performed to identify and divert units containing hemoglobin S (HbS). Recipients strategically guarded against this exposure include fetuses, neonates, and children with sickle cell disease (SCD). The clinical necessity of this practice is unclear.

STUDY DESIGN AND METHODS

A one-year audit (2018) was performed at a pediatric tertiary care hospital that tests for SCT in RBC units prescribed to children with SCD and neonates. The impact of incorporating varying numbers of SCT RBC units in a single-unit top-up, partial-manual red cell exchange, and automated erythrocytapheresis was modeled in four typical-parameter age scenarios (2, 5, 10, and 18 years) sharing a high baseline HbS. Additionally, a survey assessing SCT testing practices was administered to Canadian pediatric hospital transfusion laboratories serving hemoglobinopathy programs.

RESULTS

Of 2268 donor RBC units tested, one was positive for SCT (0.04% [95% CI: 0.01%-0.24%]), at a cost of $19,384.56 CAD. The impact of SCT unit incorporation on lost HbS reduction was modest (Δ1%-3% [automated erythrocytapheresis] and Δ4%-15% [top-up/partial manual exchange]). The survey (with all 13 sites responding) showed variable SCT testing practice; four (31%) do not test, four (31%) test for children with SCD, and six (46%) test for neonates.

CONCLUSION

RBC SCT testing may be more costly than beneficial or necessary in children with SCD. As of 2019, our transfusion service has ceased SCT testing for this population. Further research in the fetal/neonatal populations is needed to overturn this entrenched practice.

Prevalence and Risk Factors for Pulmonary Embolism in Pediatric Sickle Cell Disease: A National Administrative Database Study

Patients with sickle cell disease (SCD) have a high risk for venous thromboembolism which is associated with increased risk of mortality. Studies examining risk of pulmonary embolism (PE) in children with SCD are lacking. This study was conducted in children with SCD between 0-21 years of age using a nationwide administrative database in the United States- Pediatric Health Information System (PHIS) from January 2010 to June 2021. Diagnostic codes and imaging, procedure, and pharmaceutical billing codes were used to identify PE and potential clinical, demographic, and utilization risk factors. Logistic regression analyses were performed to assess association between risk factors and PE. We identified 22,631 unique patients with SCD with a median age of 10.8 years (range: <0.1-20.9). A total of 120 (0.53%) patients developed a PE with median age of 17.4 years (range: 6.6-20.9) at PE diagnosis. Patients with PE had longer hospitalization and more frequent ICU admissions than patients without PE (p < 0.001). Risk factors significantly associated with PE on multivariable analysis included older age, prior history of central venous line (CVL), acute chest syndrome, and apheresis. Mortality was not significantly different between those with and without PE. The prevalence of PE in hospitalized children with SCD was estimated to be 0.53%. Patients with PE had higher healthcare utilization characteristics. Factors significantly associated with PE suggest that the risk for PE in SCD may be related to the severity of disease state. Future trials are needed for risk stratification and PE prevention strategies in children with SCD.

Acute Hospital Management of Pediatric Stroke

The field of pediatric stroke has historically been hampered by limited evidence and small patient cohorts. However the landscape of childhood stroke is rapidly changing due in part to increasing awareness of the importance of pediatric stroke and the emergence of dedicated pediatric stroke centers, care pathways, and alert systems. Acute pediatric stroke management hinges on timely diagnosis confirmed by neuroimaging, appropriate consideration of recanalization therapies, implementation of neuroprotective measures, and attention to secondary prevention. Because pediatric stroke is highly heterogenous in etiology, management strategies must be individualized. Determining a child's underlying stroke etiology is essential to appropriately tailoring hyperacute stroke management and determining best approach to secondary prevention. Herein, we review the methods of recognition, diagnosis, management, current knowledge gaps and promising research for pediatric stroke.

Fifteen-minute consultation: Recognition of sickle cell crises in the paediatric emergency department

Children with sickle cell disease can develop life-threatening and painful crises that require prompt assessment and efficient management by healthcare professionals in the emergency or acute care setting. Due to migration patterns and improved survival rates in high-prevalence countries, there is an increased tendency to encounter these patients across the UK. These factors warrant regular revisions in sickle cell crisis management, along with education for medical personnel and patients to improve clinical care and patient management. The focus of this article is on the initial assessment and management of acute paediatric sickle cell complications in the emergency setting. Specific case studies, including acute pain crises, trauma, splenic sequestration, aplastic crises, acute chest syndrome, infection, avascular necrosis, osteomyelitis and stroke, are discussed. Due to the current COVID-19 pandemic, we have also reviewed specific concerns around this patient group.

Haemoglobin S testing using HEA BeadChip™ technology: Lifeblood comparison with clinical diagnosis

BACKGROUND AND OBJECTIVES

Red cell antigen genotyping is commonly performed on patients requiring chronic transfusion support, such as sickle cell disease and thalassaemia. The Immucor HEA BeadChip™ test, in addition to assessing red cell antigen expression, can also detect the haemoglobin S (HbS) mutation. Our aim was to compare HbS results using HEA BeadChip™ performed at the Australian Red Cross Lifeblood with conventional haemoglobin studies.

MATERIALS AND METHODS

Patients with thalassaemia and sickle cell trait (SCT) or disease (SCD) referred for red cell genotyping between 2017 and 2019 were assessed. The HbS result obtained from HEA BeadChip™ was compared with that obtained from high-performance liquid chromatography (HPLC) performed by the referring pathology provider.

RESULTS

One-hundred and nineteen cases had comparable HPLC and HEA BeadChip™ results. On HEA BeadChip™ testing, 40 cases showed a negative HbS result, 31 cases showed HbS+ and 47 cases showed HbS++. There was one case with 'low signal' result. Of the negative HbS cases, there was none with SCT. The HbS+ group comprised a mixture of SCT and SCD due to compound heterozygosity for HbS and β-thalassaemia mutations. The HbS++ group comprised predominantly SCD due to homozygosity for HbS.

CONCLUSION

HEA BeadChip™ is an accurate screening test for the detection of HbS. There were no false positives or false negatives. The identification of donors with the HbS mutation through the targeted genotyping programme would enable early intervention, improved donor management and reduced wastage.

Transfusional Approach in Multi-Ethnic Sickle Cell Patients: Real-World Practice Data From a Multicenter Survey in Italy

Sickle cell disease (SCD) is a worldwide distributed hereditary red cell disorder characterized by recurrent acute vaso-occlusive crises (VOCs and anemia). Gold standard treatments are hydroxycarbamide (HC) and/or different red blood cell (RBC) transfusion regimens to limit disease progression. Here, we report a retrospective study on 1,579 SCD patients (median age 23 years; 802 males/777 females), referring to 34 comprehensive Italian centers for hemoglobinopathies. Although we observed a similar proportion of Caucasian (47.9%) and African (48.7%) patients, Italian SCD patients clustered into two distinct overall groups: children of African descent and adults of Caucasian descent. We found a subset of SCD patients requiring more intensive therapy with a combination of HC plus chronic transfusion regimen, due to partial failure of HC treatment alone in preventing or reducing sickle cell-related acute manifestations. Notably, we observed a higher use of acute transfusion approaches for SCD patients of African descent when compared to Caucasian subjects. This might be related to (i) age of starting HC treatment; (ii) patients' low social status; (iii) patients' limited access to family practitioners; or (iv) discrimination. In our cohort, alloimmunization was documented in 135 patients (8.5%) and was more common in Caucasians (10.3%) than in Africans (6.6%). Alloimmunization was similar in male and female and more frequent in adults than in children. Our study reinforces the importance of donor-recipient exact matching for ABO, Rhesus, and Kell antigen systems for RBC compatibility as a winning strategy to avoid or limit alloimmunization events that negatively impact the clinical management of SCD-related severe complications.

Multifocal Osteonecrosis in a 3-Year-old Child With Sickle Beta Plus Thalassemia

Sickle beta+thalassemia is considered to be a mild form of sickle cell disease. However, some patients with mild disease can present with osteonecrosis. Here, we present a rare 3-year-old male who presented with acute pain, a baseline hemoglobin of 13 g/dL, who acutely developed multifocal osteonecrosis, and improved with partial exchange transfusion and hydroxyurea therapy.

Real-world effectiveness of voxelotor for treating sickle cell disease in the US: a large claims data analysis

BACKGROUND

Sickle cell disease (SCD) is a genetic disease that impacts patients' quality of life, healthcare costs, and life expectancy. Elevated sickle hemoglobin (HbS), which readily polymerizes, causes red blood cell sickling, leading to chronic hemolytic anemia and complications often requiring hospitalization and transfusions. In 2019, voxelotor, which inhibits HbS polymerization, was approved for SCD treatment.

OBJECTIVES

This study uses real-world evidence to assess voxelotor's effectiveness in SCD patients in typical clinical practice from 2019 to 2021 using a national medical claims database (N = 3128).

RESULTS

After initiating voxelotor, 60.8% of patients with available hemoglobin (Hb) laboratory data (n = 74) showed a Hb increase >1 g/dL. Mean transfusion rate per patient-year dropped 52% in patients with ≥1 transfusion before treatment (n = 190). In patients with ≥1 of the corresponding events (n = 1065), decreases were observed in mean vaso-occlusive crisis (VOC) frequency (-23%); mean VOC-related hospitalizations and length of stay (LOS) time (-34% and -30%, respectively); mean all-cause hospitalization and LOS time (-37% and -23%, respectively); outpatient visits (-10%); iron chelation use (-46%); and prescribed opioids (-13%).

CONCLUSION

These data align with randomized controlled trial results showing voxelotor improvements and support that voxelotor may lower transfusion and VOC rates in clinical practice.

Indications for transfusion in the management of sickle cell disease

The transfusion of red blood cells (RBCs) is a crucial treatment for sickle cell disease (SCD). While often beneficial, the frequent use of transfusions is associated with numerous complications. Transfusions should be offered with specific guidelines in mind. Here we present updates to the indications for transfusion of RBCs in SCD. We review recent publications and include expert perspectives from hematology and transfusion medicine. For some clinical indications, such as ischemic stroke, the role of transfusion has been well studied and can be applied almost universally. For many other clinical scenarios, the use of transfusion therapy has less conclusive data and therefore must be tailored to individual needs. We highlight the roles of RBC transfusions in preventing or mitigating neurological disease, in reducing perioperative complications, in managing acute chest syndrome, and in optimizing pregnancy outcomes in SCD. We further highlight various transfusion techniques and when each might be considered. Potential complications of transfusion are also briefly discussed.

Red cell transfusion and alloimmunization in sickle cell disease

Red cell transfusion remains a critical component of care for acute and chronic complications of sickle cell disease. Randomized clinical trials demonstrated the benefits of transfusion therapy for prevention of primary and secondary strokes and postoperative acute chest syndrome. Transfusion for splenic sequestration, acute chest syndrome, and acute stroke are guided by expert consensus recommendations. Despite overall improvements in blood inventory safety, adverse effects of transfusion are prevalent among patients with sickle cell disease and include alloimmunization, acute and delayed hemolytic transfusion reactions, and iron overload. Judicious use of red cell transfusions, optimization of red cell antigen matching, and the use of erythrocytapheresis and iron chelation can minimize adverse effects. Early recognition and management of hemolytic transfusion reactions can avert poor clinical outcomes. In this review, we discuss transfusion methods, indications, and complications in sickle cell disease with an emphasis on alloimmunization.

Automated Red Cell Exchange in the Management of Sickle Cell Disease

Red cell transfusion represents one of the cornerstones of the chronic management of sickle cell disease, as well as its acute complications. Automated red cell exchange can rapidly lower the number of circulating sickle erythrocytes, without causing iron overload. Here, we describe our experience, having offered this intervention since 2011. A transient reduction in the platelet count by 61% was observed after the procedure. This was not associated with any haemorrhagic complications. Despite exposure to large volumes of blood, the alloimmunisation rate was only 0.027/100 units of red cells. The absence of any iron loading was confirmed by serial Ferriscans, performed over a number of years. However, patients with advanced chronic kidney disease showed evidence of iron loading due to reduced innate haemopoiesis and were subsequently switched to simple transfusions. A total of 59% of patients were on regular automated red cell exchange with a history of recurrent painful crises. A total of 77% responded clinically, as evidenced by at least a 25% reduction in their emergency hospital attendance for pain management. The clinical response was gradual and increased the longer patients stayed on the program. The earliest sign of clinical response was a reduction in the length of stay when these patients were hospitalised, indicating that a reduction in the severity of crises precedes the reduction in their frequency. Automated red cell exchange also appeared to be beneficial for patients with recurrent leg ulcers and severe, drug resistant stuttering priapism, while patients with pulmonary hypertension showed a dramatic improvement in their symptoms as well as echocardiographic parameters.

Guideline on the peri-operative management of patients with sickle cell disease: Guideline from the Association of Anaesthetists

Sickle cell disease is a multisystem disease characterised by chronic haemolytic anaemia, painful vaso-occlusive crises and acute and chronic end-organ damage. It is one of the most common serious inherited single gene conditions worldwide and has a major impact on the health of affected individuals. Peri-operative complications are higher in patients with sickle cell disease compared with the general population and may be sickle or non-sickle-related. Complications may be reduced by meticulous peri-operative care and transfusion, but unnecessary transfusion should be avoided, particularly to reduce the risk of allo-immunisation. Planned surgery and anaesthesia for patients with sickle cell disease should ideally be undertaken in centres with experience in caring for these patients. In an emergency, advice should be sought from specialists with experience in sickle cell disease through the haemoglobinopathy network arrangements. Emerging data suggest that patients with sickle cell disease are at increased risk of COVID-19 infection but may have a relatively mild clinical course. Outcomes are determined by pre-existing comorbidities, as for the general population.

Transfusion and Cellular Therapy in Pediatric Sickle Cell Disease

Red blood cell (RBC) transfusion is critical in managing acute and chronic complications of sickle cell disease. Alloimmunization and iron overload remain significant complications of transfusion therapy and are minimized with prophylactic Rh and K antigen RBC matching and iron chelation. Matched sibling donor hematopoietic stem cell transplant (HSCT) is a curative therapeutic option. Autologous hematopoietic stem cell (HSC)-based gene therapy has recently shown great promise, for which obtaining sufficient HSCs is essential for success. This article discusses RBC transfusion indications and complications, transfusion support during HSCT, and HSC mobilization and collection for autologous HSCT with gene therapy.

Understanding the demand for phenotyped red blood cell units and requests to perform molecular red blood cell typing for Australian patients

BACKGROUND

Australian Red Cross Lifeblood has seen a 50 % increase in demand for phenotyped red blood cell (RBC) units between 2016-2018 and a 30 % increase in demand in 2018 to perform molecular RBC typing on patient samples. Lifeblood conducted a survey to understand transfusion laboratory practices for requesting patient phenotyping and/or molecular RBC typing and for selecting phenotyped RBC units in various patient groups.

STUDY DESIGN AND METHODS

An electronic Qualtrics survey form was sent to 296 transfusion laboratories with questions designed to understand the practice of selecting phenotyped RBC units and reasons for requesting extended serology or molecular RBC typing.

RESULTS

49 (16.6 %) transfusion laboratories provided data. Reasons to request extended phenotyping and/or molecular RBC typing for patients included; chronic transfusion (n = 31 laboratories), sickle cell disease (n = 25), Thalassemia (n = 23), requirement for anti-CD38 or other MAB therapy (n = 23) or Myelodysplasia (n = 22). Forty-seven transfusion laboratories provided responses with reasons for requesting molecular RBC typing which included: predicting phenotype in patients with multiple antibodies (n = 31), prior to administering anti-CD38 or other MAB therapies (n = 29), for pregnancy related transfusions (n = 28) or for confirming the phenotype of recently transfused patients (n = 18).

CONCLUSION

Transfusion laboratory practices indicated that phenotyped RBC units were selected for patients requiring chronic transfusion support and/or undergoing MAB therapy. Requests for molecular RBC typing occurred for more complex patient requirements where serological investigations were not suitable or possible due to reagent restrictions.

Maintaining adequate donations and a sustainable blood supply: Lessons learned

Background

The availability of a safe blood supply is a key component of transfusion medicine. A decade of decreased blood use, decreased payment for products, and a dwindling donor base have placed the sustainability of the US blood supply at risk.

Study Design and Methods

A literature review was performed for blood center (BC) and hospital disaster management, chronically transfusion‐dependent diseases, and appropriate use of group O‐negative red blood cells (RBCs), and the Choosing Wisely campaign. The aim was to identify current practice and to make recommendations for BC and hospital actions.

Results

While BCs are better prepared to handle disasters than after the 9/11 attacks, messaging to the public remains difficult, as donors often do not realize that blood transfused during a disaster was likely collected before the event. BCs and transfusion services should participate in drafting disaster response plans. Hospitals should maintain inventories adequate for patients in the event supply is disrupted. Providing specialty products for transfusion‐dependent patients can strain collections, lead to increased use of group O RBCs, and create logistical inventory challenges for hospitals. The AABB Choosing Wisely initiative addresses overuse of blood components to optimally use this precious resource. Group O‐negative RBCs should be transfused only to patients who truly need them.

Conclusions

Collecting and maintaining a blood supply robust enough to handle disasters and transfusion‐dependent patients in need of specialty products is challenging. Collaboration of all parties should help to optimize resources, ensure appropriate collections, improve patient care, and ultimately result in a robust, sustainable blood supply.

Executive function in children with sickle cell anemia on transfusion: NIH toolbox utility in the clinical context

OBJECTIVE

The aim of this study was to establish the utility of the NIH Toolbox as a cognitive screener of executive functions in the clinical context. Additionally, we aimed to investigate whether age and time on transfusion were related to executive function performance. Method: Twenty-eight children and adolescents with sickle cell anemia (SCA) between 8 and 18 years (M = 13.28, SD = 3.05) on transfusion treatment were included. Participants completed five NIH Toolbox tasks (three executive function tasks and two non-executive function control tasks). Results: Mean scores on one of the three executive function measures (inhibitory control) fell below the average range (M = 81.36, SD = 14.01) with approximately 70% of children from both groups below the average range. Scores for processing speed (M = 86.82, SD = 22.01) and cognitive flexibility (M = 85.75, SD = 12.67) were low averages. As expected, scores on non-executive measures (language and memory) fell within the average range. No significant differences were observed between children with silent stroke and no stroke on executive function measures. Older age (p < .01) and length of time on transfusion (p < .05) predicted lower inhibitory control scores. Conclusions: Findings provide evidence for poor development of inhibitory control with age in this patient population. As the NIH Toolbox successfully highlighted expected deficits in this patient population, this study supports the use of this tool as a brief screening measure for children with SCD. The clinical and theoretical implications of the findings are discussed.

Red blood cell exchange in an emergency in sickle cell disease

Red blood cell exchange (RBCEx) has become a standard therapy to remove abnormal red blood cells (RBCs) in patients with sickle cell disease (SCD). In the last few decades, numerous RBCEx procedures have been performed chronically during regular programs, while numerous procedures have also been performed in an emergency for several indications, this therapeutic option being very efficient in vital and emergency situations. In both groups of indications, large amounts of sickle RBCs have to be removed, which requires great precision and the setting of specific hematological targets. The aim of this review is to discuss the aims, clinical and biological targets, and the requirements and precautions when performing RBCEx in an emergency. Moreover, we analyze how improvement of the techniques as well as the clinical and biological targets has led to optimization of the procedures in emergency settings. We also consider the outstanding issues that require additional investigation.

Blood Transfusion Frequency and Indications in Yemeni Children with Sickle Cell Disease

Background

Blood transfusion is an essential component in the care of patients with sickle cell disease (SCD), but it might be associated with serious acute and delayed complications. This study was aimed to describe red cell transfusion patterns and indications among hospitalized SCD children in a low-resource setting. Patients and Methods. A retrospective, descriptive study of all children (≤16 years) with SCD who received blood transfusion therapy during their hospital admissions in the pediatric department at Al-Sadaqa Teaching Hospital in Aden, Yemen, for a period of one year.

Results

Out of 217 hospitalized children with SCD, 169 (77.9%) were transfused and received 275 RBC transfusion episodes. The mean age of transfused children was 6.9 ± 4.6 years and 103 (60.9%) were males, with a male/female ratio of 1.6 : 1 (p=0.004). Hemoglobin (Hb) levels were significantly lower in the transfused than in the nontransfused (Hb 5.5 ± 1.5 vs. 7.7 ± 1.5 g/dL, p=0.03). Pretransfusion Hb levels were ˂7.0 g/dL in 86.2% and ˂5.0 g/dL in 39.3% of patients. Single transfusion was given to 122 (72.2%) and 5 or more transfusions in 9 (4.15%) of patients on different occasions. Simple (top-up) transfusion was used in all transfusion events. Commonest indications for transfusion were anemic crises (41.1%), vasoocclusive crises (VOC) (13.8%), VOC with anemic event (11.3%), acute chest syndrome (8.7%), and stroke (7.3%).

Conclusion

Intermittent blood transfusion remains a common practice for the management of children with acute SCD complications. Main indications were acute anemic crises, severe pain crises, ACS, and stroke. In limited resource settings, such as Yemen, conservative transfusion policy appears to be appropriate.

Role of prophylactic and therapeutic red blood cell exchange in pregnancy with sickle cell disease: Maternal and perinatal outcomes

BACKGROUND AND AIM

The incidence of fetomaternal complications during pregnancy is high for women with sickle cell disease (SCD), which is the most common hematologic genetic disorder worldwide. Prophylactic red blood cell exchange (pRBCX) has been shown to be efficient, safe, and feasible for preventing complications. The aim of this study was to observe maternal, perinatal, and neonatal outcomes of pregnancies in which pRBCX was.

METHOD

This was a single-center, retrospective, cross-sectional study, which recruited 46 consecutive adult pregnant women with SCD between January 2012 and June 2019. Obstetric features, SCD-related complications, and fetomaternal outcomes were compared between the 27 patients who received prophylactic exchange and the 19 who did not (therapeutic exchange was performed in 7 and was not performed in 12 cases).

RESULTS

Painful crises, preeclampsia, and preterm birth rates were significantly higher in the group that did not receive prophylactic exchange (control group; P = .001, P = .024, and P = .027, respectively). There was one maternal mortality in the control group (P = .41). Incidence of adverse fetal or maternal complications was significantly higher in the control group (P = .044 and P = .007, respectively).

CONCLUSIONS

Our center's experience over a 7.5-year period, as described above, demonstrates that pRBCX in SCD affects the course of pregnancy positively by ameliorating negative fetomaternal outcomes.

Transfusion support in patients with sickle cell disease

Blood transfusions are an integral component of the management of acute and chronic complications of sickle cell disease. Red cells can be administered as a simple transfusion, part of a modified exchange procedure involving manual removal of autologous red cells and infusion of donor red cells, and part of an automated red cell exchange procedure using apheresis techniques. Individuals with sickle cell disease are at risk of multiple complications of blood transfusions, including transfusional hemosiderosis, auto- and alloimmunization to minor red cell and human leukocyte antigens, delayed hemolytic transfusion reactions, and hyper-hemolysis. In low- and middle-income countries in sub-Saharan Africa, where a directed donor system is prevalent and limited laboratory methods are in place to perform extended red cell phenotyping, leukodepletion of cellular products, and infectious disease screening, there are additional challenges to providing safe and adequate transfusion support for this patient population. We review current indications for acute and chronic transfusions in sickle cell disease that are derived primarily from randomized controlled trials and observational studies in children living in high-income countries. We will highlight populations with unique transfusion needs, such as pregnant women and children, as well as the role of the transfusion medicine consultative service for individuals with sickle cell disease planning to have curative hematopoietic stem cell transplantation or gene therapy. Finally, we will discuss risk factors for alloimmunization in individuals with sickle cell disease, emerging new strategies to prevent alloimmunization in this population, and critical gaps in the implementation of transfusion guidelines for sickle cell disease in high- and low-income countries.

Manual erythroexchange in sickle cell disease: multicenter validation of a protocol predictive of volume to exchange and hemoglobin values

Manual erythroexchange (MEEX) was proven to be effective and safe in the management of sickle cell disease (SCD). The goal is to quickly reduce the percentage of hemoglobin S (HbS%). A national survey of the Italian Society for Thalassemia and Hemoglobinopathies (SITE) observed a great variability among MEEX protocols none of which were found to be predictive of the values of HbS% and hemoglobin (Hb) after the exchange. Two equations to estimate the HbS% and Hb values to be obtained after MEEX were developed based on the results of the MEEX procedures in place in the centers participating in the present study. A standard protocol was subsequently defined to evaluate the volumes to exchange to obtain the target values of HbS% and Hb. The protocol was tested in 261 MEEX performed in SCD patients followed in the 5 participating centers that belong to the Italian Hemoglobinopathy Comprehensive Care Network, with the support of the SITE. The results showed a correlation between the estimated and measured values of HbS% and Hb (R_p 0.95 and 0.65 respectively, p < 0.001). A negligible bias was found for the prediction of HbS% and a bias of 1 g/dl for Hb. From consecutive MEEX, a rate of increase of HbS% between two exchanges of around 0.4% per day (p < 0.001) was measured. This protocol was shown to be effective and safe, as all patients reached the target value of HbS%. All the MEEX procedures were carried out with single venous access. No adverse events or reactions such as hypotension or electrolyte imbalance were reported nor were any complaints concerning the procedures received from patients.

Adverse outcome of acute splenic sequestration crisis in pregnancy

Background

Acute splenic sequestration crisis, characterized by abrupt fall in hemoglobin, splenomegaly, hypovolemia, and often thrombocytopenia, occurs infrequently in adults with sickle cell disease and extremely rarely during pregnancy.

Case

A 25-year-old woman with HbSC presented at 33 weeks' gestation with vaso-occlusive pain. Sudden worsening of abdominal pain and non-reassuring fetal surveillance on day 3 of admission led to emergent delivery. Acute splenic sequestration crisis was the diagnosis of exclusion based on clinical presentation and intra-operative hemoglobin of 37 g/L. Five- and 10-minute Apgar scores were 4. Neonatal brain magnetic resonance imaging revealed significant diffuse white matter abnormalities.

Conclusion

Acute splenic sequestration crisis in pregnancy must be considered in the differential diagnosis for this patient population as it can evolve rapidly and lead to maternal and fetal compromise.

Veno-Venous Extracorporeal Membrane Oxygenation in Adult Patients with Sickle Cell Disease and Acute Chest Syndrome: a Single-Center Experience

Acute chest syndrome (ACS) in adult patients with sickle cell disease represents a leading cause of death. It is characterized by a new density on chest X-ray accompanied by fever and/or respiratory symptoms. Currently, 49 adult patients with sickle cell disease are registered at our department. By now, 12 patients (24.5%) suffered from ACS and two patients showed multiple/recurrent (>2) episodes. Death in one patient was related to acute respiratory failure secondary to ACS. In three patients with ACS, invasive mechanical ventilation and subsequent veno-venous extracorporeal membrane oxygenation (VV-ECMO) was mandatory. Veno-venous ECMO was applied within 24 hours upon arrival to the intensive care unit (ICU). All patients were treated aggressively for ACS including exchange transfusions [packed red blood cell (pRBC) units 5-16] maintaining a Hb S threshold of <30.0% in addition to broad-spectrum antibiotics, resulting in a successful outcome following decannulation from VV-ECMO (49 hours, 251 hours, 30 min., and 98 hours, respectively). Limited information is presently available on the use of VV-ECMO in adult patients with sickle cell disease in the context of acute respiratory failure secondary to ACS. The adequate timing of the decision to place ECMO in critically ill adults with sickle cell disease, incapable of being treated by conventional mechanical ventilation secondary to very severe vaso-occlusive crisis (VOC), might further reduce mortality rates while treating the underlying condition.

Regulation of iron homeostasis through the erythroferrone-hepcidin axis in sickle cell disease

Sickle cell disease (SCD) has a distinct pattern of transfusional iron overload (IO) when compared to transfusion-dependent β-thalassaemia major (TDT). We conducted a single institution prospective study to evaluate plasma biomarkers of iron regulation and inflammation in patients with SCD with IO (SCD IO cases, n = 22) and without IO (SCD non-IO cases, n = 11), and non-SCD controls (n = 13). Hepcidin was found to be inappropriately low, as evidenced by a significantly higher median hepcidin/ferritin ratio in non-SCD controls compared to SCD IO cases (0·3 vs. 0·02, P < 0·0001) and SCD non-IO cases (0·3 vs. 0·02, P < 0·0001), suggesting that certain inhibitory mechanism (s) work to suppress hepcidin in SCD. As opposed to the SCD non-IO state, where hepcidin shows a strong significant positive correlation with ferritin (Spearman ρ = 0·7, P = 0·02), this correlation was lost when IO occurs (Spearman ρ = -0·2, P = 0·4). Although a direct non-linear correlation between erythroferrone (ERFE) and hepcidin did not reach statistical significance both in the IO (Spearman ρ = -0·4, P = 0·08) and non-IO state (Spearman ρ = -0·6, P = 0·07), patients with highest ERFE had low hepcidin levels, suggesting that ERFE contributes to hepcidin regulation in some patients. Our results suggest a multifactorial mechanism of hepcidin regulation in SCD.

Arteriopathy Influences Pediatric Ischemic Stroke Presentation, but Sickle Cell Disease Influences Stroke Management

Background and Purpose- Sickle cell disease (SCD) and arteriopathy are pediatric stroke risk factors that are not mutually exclusive. The relative contributions of sickled red blood cells and arteriopathy to stroke risk are unknown, resulting in unclear guidelines for primary and secondary stroke prevention when both risk factors are present. We hypothesized that despite similarities in clinical presentation and radiographic appearance of arteriopathies, stroke evaluation and management differ in children with SCD compared with those without SCD. Methods- We compared presentation and management of children with and without SCD enrolled in the IPSS (International Pediatric Stroke Study) with acute arterial ischemic stroke, according to SCD and arteriopathy status. Regression modeling determined relative contribution of SCD and arteriopathy in variables with significant frequency differences. Results- Among 930 childhood arterial ischemic strokes, there were 98 children with SCD, 67 of whom had arteriopathy, and 466 without SCD, 392 of whom had arteriopathy. Arteriopathy, regardless of SCD status, increased likelihood of hemiparesis (odds ratio [OR], 1.94; 95% CI, 1.46-2.56) and speech abnormalities (OR, 1.67; 95% CI, 1.29-2.19). Arteriopathy also increased likelihood of headache but only among those without SCD (OR, 1.89; 95% CI, 1.40-2.55). Echocardiograms were less frequently obtained in children with SCD (OR, 0.58; 95% CI, 0.37-0.93), but the frequency of identified cardiac abnormalities was similar in both groups ( P=0.57). Children with SCD were less likely to receive antithrombotic therapy, even in the presence of arteriopathy (OR, 0.14; 95% CI, 0.08-0.22). Arteriopathy was associated with a significantly higher likelihood of antithrombotic therapy in children without SCD (OR, 5.36; 95% CI, 3.55-8.09). Conclusions- Arteriopathy, and not SCD status, was most influential of stroke presentation. However, SCD status influenced stroke management because children with SCD were less likely to have echocardiograms or receive antithrombotic therapy. Further work is needed to determine whether management differences are warranted.

Optimal disease management and health monitoring in adults with sickle cell disease

In countries with access to organized health care, survival of children with sickle cell disease (SCD) has greatly improved, resulting in a growing population of adults with SCD. Transition from pediatric to adult care presents many challenges for the patient, who now faces the reality of emerging complications in many organs that are cumulative, adding to other age-related nonsickle conditions that interact and add to the disease morbidity. We recommend regular comprehensive annual assessments, monitoring for early signs of organ damage and joint clinics with relevant specialists, if applicable. While maintaining a low threshold for intervention with disease-modifying therapies, we should always keep in mind that there is no single complication that is pathognomonic of SCD, and nonsickle comorbidities should always be excluded and treated if present. We need to reevaluate our approach to managing adults with SCD by putting a greater emphasis on multidisciplinary care while proactively considering curative options (hematopoietic stem cell transplant and gene therapy) and experimental pharmacological agents for adults with SCD of all ages before complications render the patients ineligible for these treatments.

Red Blood Cells: Exchange, Transfuse, or Deplete

Erythrocytapheresis, red blood cell (RBC) depletion, and RBC exchange transfusions are apheresis techniques used to rapidly lower the circulating RBC mass or to exchange the patient erythrocyte mass with donor RBC. Automated RBC exchange is performed using an apheresis device, while manual RBC exchange is based on sequential phlebotomies and isovolemic replacement. Compared to simple RBC transfusions, RBC exchange offers several advantages, e.g., a lower risk for iron accumulation and efficient control of pathological erythrocyte populations. Disadvantages are the higher costs of the procedure, the increased use of donor RBC, and the requirement of apheresis devices and trained hospital staff. The most frequent indication for RBC exchange is sickle cell disease (SCD). RBC exchange transfusions are standard treatment in SCD patients with a history of or a risk for acute stroke and are clinical options for other acute complications of SCD. The most common indication for RBC depletion is the removal of donor RBC from the bone marrow grafts in major ABO-incompatible allogeneic hematopoietic stem cell transplantation to avoid immediate hemolysis. Rare indications for RBC exchange are severe infections with intraerythrocytic pathogens such as malaria or babesiosis and severe erythrocytosis or hereditary hemochromatosis where the aim is to rapidly decrease RBC populations or the iron content. However, only few high-quality studies are available looking at the efficacy of RBC exchange in the different disease entities, and treatment is often based on low levels of evidence and should therefore be decided in close collaboration with a transfusion medicine specialist.

Alteration of humoral, cellular and cytokine immune response to inactivated influenza vaccine in patients with Sickle Cell Disease

Introduction

Patients suffering from Sickle Cell Disease (SCD) are at increased risk for complications due to influenza virus. Annual influenza vaccination is strongly recommended but few clinical studies have assessed its immunogenicity in individuals with SCD. The aim of this study was to explore the biological efficacy of annual influenza vaccination in SCD patients by characterizing both their humoral and cell-mediated immunity against influenza antigen. We also aimed to investigate these immunological responses among SCD individuals according to their treatment (hydroxyurea (HU), chronic blood transfusions (CT), both HU and CT or none of them).

Methods

Seventy-two SCD patients (49 receiving HU, 9 on CT, 7 with both and 7 without treatment) and 30 healthy controls were included in the study. All subjects received the tetravalent influenza α-RIX-Tetra® vaccine from the 2016–2017 or 2017–2018 season.

Results

Protective anti-influenza HAI titers were obtained for the majority of SCD patients one month after vaccination but seroconversion rates in patient groups were strongly decreased compared to controls. Immune cell counts, particularly cellular memory including memory T and memory B cells, were greatly reduced in SCD individuals. Functional activation assays confirmed a poorer CD8⁺ T cell memory. We also document an imbalance of cytokines after influenza vaccination in SCD individuals with an INFγ/IL-10 ratio (Th1-type/Treg-type response) significantly lower in the SCD cohort.

Conclusion

SCD patients undergoing CT showed altered immune regulation as compared to other treatment subgroups. Altogether, the cytokine imbalance, the high regulatory T cell levels and the low memory lymphocyte subset levels observed in the SCD cohort, namely for those on CT, suggest a poor ability of SCD patients to fight against influenza infection. Nevertheless, our serological data support current clinical practice for annual influenza vaccination, though immunogenicity to other vaccines involving immunological memory might be hampered in SCD patients and should be further investigated.