Guidelines on red cell transfusion in sickle cell disease. Part I: principles and laboratory aspects

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.

Transfusion Support of Patients with Myelodysplastic Syndromes

Patients with MDS often suffer from anemia, and less often thrombocytopenia, and thus are a frequently transfused population. Red blood cell (RBC) transfusion may be used to improve functional capacity and quality of life in this population, while platelet transfusion is typically used to decrease bleeding risk. Despite the frequency of transfusion in patients with MDS, there are few well-defined guidelines for RBC and platelet transfusion support in this patient population. Transfusion is not without risk-patients with MDS who are frequently transfused may develop alloantibodies to RBC antigens, which can lead to hemolytic transfusion reactions and delays in obtaining compatible RBCs. Regular communication between clinicians and blood bank physicians is crucial to ensure that patients with MDS receive the most appropriate blood products.

VWF-ADAMTS13 axis dysfunction in children with sickle cell disease treated with hydroxycarbamide vs blood transfusion

Previous studies have reported elevated von Willebrand factor (VWF) levels in patients with sickle cell disease (SCD) and demonstrated a key role for the VWF-ADAMTS13 axis in the pathobiology of SCD vaso-occlusion. Although blood transfusion is the gold standard for stroke prevention in SCD, the biological mechanisms underpinning its improved efficacy compared with hydroxycarbamide are not fully understood. We hypothesized that the improved efficacy of blood transfusion might relate to differences in VWF-ADAMTS13 axis dysfunction. In total, 180 children with a confirmed diagnosis of SCD (hemoglobin SS) on hydroxycarbamide (n = 96) or blood transfusion (n = 84) were included. Despite disease-modifying treatment, plasma VWF and VWF propeptide were elevated in a significant proportion of children with SCD (33% and 47%, respectively). Crucially, all VWF parameters were significantly higher in the hydroxycarbamide compared with the blood transfusion cohort (P < .05). Additionally, increased levels of other Weibel-Palade body-stored proteins, including factor VIII (FVIII), angiopoietin-2, and osteoprotegerin were observed, indicated ongoing endothelial cell activation. Children treated with hydroxycarbamide also had higher FVIII activity and enhanced thrombin generation compared with those in the blood transfusion cohort (P < .001). Finally, hemolysis markers strongly correlated with VWF levels (P < .001) and were significantly reduced in the blood transfusion cohort (P < .001). Cumulatively, to our knowledge, our findings demonstrate for the first time that despite treatment, ongoing dysfunction of the VWF-ADAMTS13 axis is present in a significant subgroup of pediatric patients with SCD, especially those treated with hydroxycarbamide.

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.

Global burden of transfusion in sickle cell disease

Sickle cell disease (SCD) is the most common hereditary hemoglobinopathy. The underlying pathophysiology of the red blood cell (RBC) leads to pan-systemic complications which manifest at an early age. While curative and disease-modifying treatments exist for SCD, a key intervention in the management and treatment of SCD is RBC transfusion, which can alleviate or prevent many complications. SCD patients often require chronic RBC transfusion therapy which can result in complications, such as iron overload, alloimmunization and infection. In low- and middle-income countries (LMICs), SCD patients lack appropriate access to healthcare such as newborn screening, health education, prophylaxis for infection, and treatments to reduce both mortality and SCD-related adverse effects. Poor access to RBCs for transfusion, coupled with donated blood not meeting safety standards set by the World Health Organization, presents a significant barrier for patients requiring chronic transfusions in LMICs. Unmet needs associated with blood collection, blood component processing and recipient matching all pose a serious problem in many LMICs, although this varies depending on geographic location, political organizations and economy. This review aims to provide an overview of the global burden of SCD, focusing on the availability of current treatments and the burden of chronic RBC transfusions in patients with SCD.

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.

Variant RHD alleles and Rh immunization in patients with sickle cell disease

RH diversity among patients and donors contributes to Rh immunization despite serologic Rh-matched red cell transfusions. Anti-D can occur in D+ patients with RHD variants that encode partial D antigens. Anti-D has also been reported in patients with conventional RHD transfused primarily with units from Black donors who frequently have variant RHD. We report 48 anti-D in 690 D+ transfused individuals with sickle cell disease, categorized here as expressing conventional D, partial D or D antigen encoded by RHD*DAU0. Anti-D formed in a greater proportion of individuals with partial D, occurred after fewer D+ unit exposures, and remained detectable for longer than for those in the other categories. Among all anti-D, 13 had clinical or laboratory evidence of poor transfused red cell survival. Most individuals with anti-D were chronically transfused, including 32 with conventional RHD who required an average of 62 D- units/year following anti-D. Our findings suggest that patients with partial D may benefit from prophylactic D- or RH genotype-matched transfusions to prevent anti-D. Future studies should investigate whether RH genotype-matched transfusions can improve use of valuable donations from Black donors, reduce D immunization and minimize transfusion of D- units to D+ individuals with conventional RHD or DAU0 alleles.

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.

Quantitative MRI evaluation of bone marrow in sickle cell disease: relationship with haemolysis and clinical severity

AIM

To evaluate bone marrow fat fraction using the Dixon technique (FFDix) of magnetic resonance imaging (MRI) as a potential biomarker of haemolysis and clinical severity in the overall assessment and follow-up of sickle cell disease (SCD) patients.

MATERIAL AND METHODS

The present study was a cross-sectional study in which healthy individuals and SCD patients (matched for age, sex, and weight) were subjected to MRI of the lumbar spine and pelvis to quantify FFDix in the bone marrow using the Dixon technique. SCD severity was analysed by clinical and laboratory data, and an online calculator. A high degree of haemolysis was defined using the cut-off values haemoglobin (Hb) ≤10 g/dl, lactate dehydrogenase (LDH) ≥325 U/l, reticulocytes ≥3% and total bilirubin (TB) ≥1.2 mg/dl. Pearson's correlation, receiver operating characteristic (ROC) curve and binary logistic regression analysis were performed.

RESULTS

Forty-eight SCD patients (26 homozygous: HbSS and 22 compound heterozygous: HbSC) and 48 healthy individuals participated in the study. FFDix was lower in SCD patients than in the control group, showing even lower values in the HbSS subtype and patients with a higher degree of haemolysis. HbSC patients with a higher degree of haemolysis using hydroxyurea (medium dosage 9.8 mg/kg/day) had lower FFDix. ROC curves and odds ratios for detecting patients with a higher degree of haemolysis at the different FFDix measurement sites demonstrated excellent performance: iliac bones (cut-off ≤16.75%, AUC = 0.824, p<0.001), femoral heads (cut-off ≤46.7%, AUC = 0.775, p=0.001), lumbar vertebrae (cut-off ≤7.8%, AUC = 0.755, p=0.002).

CONCLUSION

Decreased FFDix is indicative of higher degree of haemolysis and SCD severity with great potential as a non-invasive biomarker contributing to the overall assessment and follow-up of SCD patients.

An Overview of Solid Organ Transplantation in Patients With Sickle Cell Disease

Sickle cell disease is a common genetic disorder affecting >300 000 people across the world. The vast majority of patients cared for in high-resource settings live well into adulthood, but many develop a high burden of disease complications. Good standard of care including disease-modifying agents and transfusion programs limits the number of patients who develop end-stage organ disease, but for those that do, the prognosis can be very poor. Solid organ transplantation is a well-established mode of treatment for patients with sickle cell disease and kidney or liver failure, but appropriate patient selection and perioperative management are important for achieving good outcomes. Hematopoietic stem cell transplantation and gene therapy may offer novel treatment options for adult patients with chronic organ damage in the future, but these are not yet widely available. For now, good, holistic care and early intervention of end-organ complications can minimize the number of patients requiring solid organ transplantation later in life.

Adverse events of red blood cell transfusions in patients with sickle cell disease

Blood transfusion is a common medical intervention for patients with sickle cell disease (SCD) and disease related complications. While patients with SCD are at risk for all transfusion related adverse events defined by the National Healthcare Safety Network (NHSN) Biovigilance Component Hemovigilance Module Surveillance Protocol, they are uniquely susceptible to certain adverse events. This review discusses risk factors, mitigation strategies, and management recommendations for alloimmunization, hemolytic transfusion reactions, hyperviscosity and transfusion-associated iron overload in the context of SCD.

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.

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.

Tocilizumab in the management of posttransfusion hyperhemolysis syndrome in sickle cell disease: The experience so far

BACKGROUND

Posttransfusion hyperhemolysis syndrome is a rare but life-threatening form of delayed hemolytic transfusion reaction with lysis of both transfused and autologous red cells, seen predominantly in patients with sickle cell disease. Macrophage activation is thought to play a major role in its pathophysiology. Standard treatment is with intravenous immunoglobulin and steroids but refractory cases pose a major clinical problem. Tocilizumab is a humanized monoclonal antibody against the IL-6 receptor that can inhibit IL-6 induced macrophage activation.

METHODS AND MATERIALS

We describe the case of a 33-year-old woman with sickle cell anemia and posttransfusion hyper hemolysis syndrome refractory to standard therapy, treated with Tocilizumab. We also review all cases reported in the literature where Tocilizumab was used for posttransfusion hyperhemolysis.

RESULTS

Treatment with Tocilizumab was well tolerated with no observed adverse events. There was no further drop in Hb after day 2 of treatment with subsequent continuous gradual improvement. Her bilirubin dropped significantly after the first dose and continued to improve, while ferritin and LDH reduced significantly after day 2 of treatment with Tocilizumab and continued to drop thereafter. Like in our case, all other cases in the literature where Tocilizumab was used for posttransfusion hyperhemolysis led to rapid clinical responses and no adverse events.

DISCUSSION

Even though the number of cases of posttransfusion hyper hemolysis syndrome treated with Tocilizumab are few, they have all been associated with rapid clinical responses with no observed adverse events suggesting that the role of Tocilizumab in this context needs to be further explored.

Assessing and managing people with sickle cell disease presenting with vaso-occlusive crisis in the emergency department

Sickle cell disease is a group of inherited blood disorders characterised by atypical haemoglobin molecule structures (haemoglobin S) which can manifest as painful vaso-occlusive crises, chronic anaemia and progressive organ damage. This article aims to raise greater awareness of sickle cell disease, its acute manifestations and the potential for rapid clinical deterioration that can occur in patients with this condition. The article outlines the main aspects of the assessment and management of patients presenting to the emergency department (ED) with vaso-occlusive crisis, describes the barriers to effective care that they commonly experience and explains how their care could be improved. The authors emphasise the importance of timely management of these patients by ED staff, including emergency nurses.

Sickle cell disease patients in two London trusts: Genotyping including RH variants

BACKGROUND

All SCD patients need extended RBC antigen typing (by serology or genotyping) for provision of extended RH, K matched blood and to guide RBC selection in those with complex transfusion requirements. Genotyping can also identify RH variants which can cause sensitisation even when extended RH phenotypically matched blood is provided and alloantibodies associated with RH variants can cause HTRs.

OBJECTIVES

To review the use of RBC genotyping in SCD patients at two London trusts (ICHNT, LNWH) with a focus on RH variants.

METHODS

Retrospective review with data collected from clinical notes, local and national pathology reporting systems.

RESULTS

A 311/482 (64%) ICHNT patients and 181/346 (52%) LNWH patients had extended genotyping. Of genotyped patients, 68 (22%) ICHNT and 31 (17%) LNWH patients had RH variants. Eight ICHNT patients had RH variants and corresponding antibodies associated with RH variants; 4/8 received multiple transfusions with antigen positive RBCs but had no evidence of haemolysis. One LNWH patient had a RH variant with corresponding alloantibody but could not be investigated further for possible HTR.

CONCLUSIONS

Most patients (59%) had genotyping and a significant number had RH variants (99, 20%). A small proportion (9, 9%) had antibodies associated with RH variants, but with no evidence of clinically significant HTRs despite transfusions in four of them with antigen positive RBCs. All SCD patients should have RBC genotyping including RH variants (preferentially over extended phenotyping) to guide better selection of RBC units. However, where antigen negative blood cannot be provided, the risk of alloimmunisation is not inevitable and subsequent HTRs from antibodies associated with RH variants might not always occur.

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.

Recurrent Hyperhemolysis Syndrome in Sickle Cell Disease

Sickle cell disease is a disorder of hemoglobin. The abnormal hemoglobin S disrupts blood flow, thereby resulting in acute painful sickle cell crisis. These episodes frequently prompt packed red blood cell transfusions to replace a patient’s functional hemoglobin stores. Production of alloantibodies and autoantibodies to these transfusions can result in a rare, but serious, complication known as hyperhemolysis syndrome. Hyperhemolysis syndrome presents several challenges in regard to its acute management and the consequent difficulties in finding future compatible blood products. We report a case of recurrent hyperhemolysis syndrome. Both episodes occurred following orthopedic procedures, and the recurrent episode proved refractory to multiple treatments.

Hydroxyurea and blood transfusion therapy for Sickle cell disease in South Asia: inconsistent treatment of a neglected disease

Background

Hydroxyurea and blood transfusion therapies remain the main therapeutic strategies for Sickle cell disease. Preliminary data suggest substantial variation and inconsistencies in practice of these two therapeutic modalities in South Asia. In this systematic review we searched Medline, Cochrane library and Scopus for articles on usage of hydroxyurea and blood transfusion therapies for sickle cell disease in South Asia published in English between October 2005 and October 2020.

Results

We selected 41 papers: 33 from India, 3 from Sri Lanka, 2 each from Pakistan and Bangladesh and one from Nepal. Only 14 prospective trials focused on hydroxyurea therapy from which majority (n = 10; 71.4%) adopted fixed low dose (10 mg/kg/day) regimen. With hydroxyurea therapy, 12 and 9 studies reported significant reductions in vaso-occlusive crises and transfusion requirement respectively. Severe anaemia (haemoglobin level < 6–7 g/dl) was the commonest indicator (n = 8) for transfusion therapy followed by vaso-occlusive crisis.

Conclusions

Published data on the hydroxyurea and transfusion therapies in South Asia are limited and heterogeneous. A clear gap of knowledge exists about the nature of the sickle cell disease in the Indian subcontinent particularly from countries outside India necessitating further evidence-based assessments and interventions.

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.

Hemoglobin S identification in blood donors: A cross section of prevalence

Introduction

In Brazil, the sickle cell trait (SCT) has an average prevalence of 4% in the general population and 6–10% among Afro-descendants. Although SCT is highly prevalent, a large segment of the population ignores their status. The Therapeutic Guidelines prohibit the transfusion of SCT red blood cells into patients with hemoglobin disorders or severe acidosis and newborns.

Methods

This was a cross-sectional study with data from 37,310 blood donation candidates. The study included only eligible first-time donors qualified to be tested for the presence of hemoglobin S (HbS) at the Fundação Hemominas Juiz de Fora, Brazil. The variables studied were gender, skin color, age, type of donation, place of birth, blood type, result of the solubility test for hemoglobin S (HbST) and hemoglobin electrophoresis (HbEF). Statistical analysis was performed using the Q square test and the Kappa index of agreement for comparing biochemical methods. This project was approved by the National Research Ethics Committee.

Results

The analysis of first-time donor data showed that 7166 were considered eligible. A total of 127 of the 7166 donors were carriers of SCT (1.77%). Among the blood donors, 73.23% were from the local area. The HbST and HbEF were found to be 100% in concordance. Sensitivity was not tested in the present study.

Conclusions

The HbST is highly specific for identifying the HbS, but sensitivity was not tested in this study. The screening of blood donors for abnormal hemoglobins is useful, helping to detect and counsel heterozygous people. The study seeks to identify the prevalence of SCT in a region of Brazil.

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.

Red blood cell exchange in sickle cell disease patient with multiple alloantibodies

There are several reports in medical literature about Red Cell Exchange (RCE) being routinely performed pre-operatively in sickle cell disease patients to provide immediate decrease in HbS concentration and prevent post-operative complications. We would like to present one such case of SCD who also had multiple allo-antibodies and had to undergo hemi-arthroplasty for avascular necrosis of head femur. Grouping and antibody screening was performed using column agglutination technique. 3-cell and 11- cell panel were used for antibody screening and identification, respectively. Automated RBC exchange was performed on apheresis machine Com. Tec using the standard PL1 kit (Fresenius Kabi, Germany). Multiple (anti-c, E) allo-antibodies were identified and successful pre-operative RCE was done with corresponding antigen-negative AHG compatible RBC units. Single RCE procedure reduced HbS concentration from 65% to 25%. The patient underwent uneventful hemi-arthroplasty and was discharged on post-operative day-7. Patient is on regular follow-up and continues to do well two months after the day of surgery. This is possibly the first case report from India, which illustrates successful automated RCE in a SCD patient with alloimmunization.

The haemoglobinopathy survey: The reality of transfusion practice in sickle cell disease and thalassaemia in England

OBJECTIVES

To establish, in an unselected population of London haemoglobinopathy patients, transfusion requirements, blood antigens/alloantibodies, transfusion modalities, burden of transfusion reactions and donor exposure.

BACKGROUND

Haemoglobinopathy patients are among the most highly transfused patient populations, and the overall population and number of patients on long-term transfusion programmes are increasing. To provide a safe and efficacious transfusion service for patients, it is important to understand current practice, morbidity associated with transfusion, efficacy of different transfusion modalities and geno-/phenotype requirements.

METHODS

Data on 4451 transfusion episodes in 760 patients from 12 London hospitals were collected retrospectively over a 6-month period in 2011.

RESULTS

Alloimmunisation prevalence was 17% for sickle cell disease (SCD) and 22% for thalassaemia, most commonly anti-Rh/Kell/Kp_a /C_w . Rh phenotypes differed between SCD (R_o r 59.8%/R₁ r 15.9%/R₂ r 15.6%) and thalassaemia (R₁ R₁ 29.6%/R₁ r 28.4%/R₁ R₂ 15.4%). Recording of pheno-/genotypes fell below recommendations. A 2-weekly manual exchange and 3-weekly automated exchange came closest to achieving presumptive targets. In adults with thalassaemia, the mean blood requirement was 36 units per year; for SCD, erythrocytapheresis was carried out every 7 weeks with 66 units; for manual exchange, it was 38 units every 4 weeks; and for simple transfusion, it was 30 units p.a. every 4 weeks.

CONCLUSION

Transfusion modality choice was influenced by the resources available-children mostly received simple transfusions, and adults received erythrocytapheresis; the relationships between frequency of exchanges/transfusion modality/target HbA% were not simple, possibly reflecting the difference in recipient erythropoiesis and consequent transfusion modality selection bias; adherence to existing and current guidelines regarding geno-/phenotyping was limited; and alloimmunisation had a low incidence and high prevalence in both disorders.

Transfusion support: Considerations in pediatric populations

Over 400,000 units of blood and blood products are transfused to pediatric patients annually, yet only sparse high-quality data exist to guide the preparation and administration of blood products in this population. The direct application of data from studies in adult patients should be undertaken with caution, as there are dissimilarities in the pathology and physiology between adult and pediatric patients. We provide an overview of available evidence in the field of pediatric transfusion medicine, summarizing indications for blood product transfusion, thresholds for transfusion and indications for blood product modifications.

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.

[Sickle cell disease]

The term "sickle cell disease" covers a group of genetic blood disorders caused by sickle hemoglobin (HbS) alone or in combination with other variants of the β‑globin locus. Sickle cell disease occurs frequently in sub-Saharan Africa, but is also common in Turkey, Greece, Sicily, the Middle East, India, and the Americas. Polymerization of deoxygenated sickle hemoglobin leads to decreased deformability of red blood cells. These altered erythrocytes can obstruct small blood vessels and cause acute episodes of pain, hemolytic anemia, and organ damage. Complications can vary between the different genotypes and it is important to be aware of the special features of the disease. Hydroxycarbamide has been shown to reduce the morbidity and mortality of patients with sickle cell disease. New drugs and novel treatment approaches such as gene therapy are currently being tested.

Red cell exchange for patients with sickle cell disease: an international survey of current practices

INTRODUCTION

Red cell exchange (RCE) therapy is increasingly used to treat patients with acute or chronic manifestations of sickle cell disease (SCD). However, little is known regarding the most safe and effective practice parameters associated with this particular therapy.

METHODS

A SCD subcommittee of members of the American Society for Apheresis (ASFA) developed a 122-question survey and administered it via email to other ASFA members. The survey inquired about clinical indications for treatment, practice patterns, and transfusion policies for RCE when used for patients with SCD.

RESULTS

Ninety-nine distinct institutions completed the survey. Twenty-one (21%) were from outside of the US. Twenty-two (22%) provided chronic transfusion therapy to >10 patients, and both adult (25%) and pediatric-focused services (20%) were represented. Common acute indications for RCE included acute chest syndrome, acute ischemic stroke, and pre-surgical prophylaxis. Common chronic indications included primary stroke prophylaxis, secondary stroke prophylaxis, and recurrent acute chest syndrome. Respondents most commonly set a post-RCE treatment target of 30% for the hematocrit and hemoglobin S levels, regardless of the therapeutic indication. Units for RCE were phenotypically matched in 95% of cases. About 40% of respondents reported using isovolemic hemodilution.

CONCLUSIONS

This survey solicited the current practice variations in RCE from a diverse range of practice sites. Many sites reported similar practice patterns and challenges but some variations emerged. To our knowledge, this survey represents the largest and most in-depth investigation of the use of RCE for patients with SCD, and could inform future studies in the field.

Blood utilization and characteristics of patients treated with chronic transfusion therapy in a large cohort of Brazilian patients with sickle cell disease

BACKGROUND

Red blood cell (RBC) transfusions are used in sickle cell disease (SCD) to treat acute complications or as chronic transfusion therapy (CTT) to prevent severe manifestations. The objectives of this study were to describe blood utilization and adverse events (AEs) associated with RBCs in the Brazilian SCD population and compare characteristics of patients treated or not with CTT.

STUDY DESIGN AND METHODS

A SCD cohort was established at six Brazilian centers. Medical and blood bank records were abstracted for clinical and transfusion history. Two controls not treated with CTT matched on center, SCD genotype, sex, and age were selected for each CTT case within the cohort to compare characteristics between the two groups.

RESULTS

Most of the 2794-member cohort had received a transfusion (75.0% of children and 89.2% of adults) with 29.2% of patients receiving transfusion in the prior year. There were 170 (10.6%) children and 115 (9.2%) adults treated with CTT. Children not treated with CTT were more likely to have pain and acute chest hospitalizations in the prior year (25.3% vs. 11.9%, p = 0.0003; and 22.0% vs. 10.7%, p = 0.002, respectively). Both iron overload and alloimmunization were more common in CTT cases compared to controls (65.6% vs. 17.0% and 36.2% vs. 15.9%, respectively). A higher proportion of adults treated with CTT demonstrated oxygen saturation of greater than 95% compared to controls not treated (51.1% vs. 39.2%), while there was no difference in oxygenation between children treated or not. Of 4501 transfusion episodes, 28 (0.62%) AEs were reported. There was no difference in AEs associated with transfusions for acute indications versus CTT.

CONCLUSION

Red blood cell transfusion was common in Brazilian SCD patients, with utilization driven by CTT. Transfusion reactions were not common; however, alloimmunization and iron overload were frequent among those on CTT, highlighting the need for novel clinical strategies to mitigate these risks.

Utilising red cell antigen genotyping and serological phenotyping in sickle cell disease patients to risk-stratify patients for alloimmunisation risk

BACKGROUND

Alloimmunisation and haemolytic transfusion reactions (HTRs) can occur in patients with sickle cell disease (SCD) despite providing phenotype-matched red blood cell (RBC) transfusions. Variant RBC antigen gene alleles/polymorphisms can lead to discrepancies in serological phenotyping. We evaluated differences between RBC antigen genotyping and phenotyping methods and retrospectively assessed if partial antigen expression may lead to increased risk of alloimmunisation and HTRs in SCD patients at a tertiary centre in Canada.

METHODS

RBC antigen phenotyping and genotyping were performed by a reference laboratory on consenting SCD patients. Patient demographic, clinical and transfusion-related data were obtained from a local transfusion registry and chart review after research ethics board approval.

RESULTS

A total of 106 SCD patients were enrolled, and 91% (n = 96) showed additional clinically relevant genotyping information when compared to serological phenotyping alone. FY*02N.01 (FY*B GATA-1) (n = 95; 90%) and RH variant alleles (n = 52, 49%; majority accompanied by FY*02N.01) were common, the latter with putative partial antigen expression in 25 patients. Variability in genotype-phenotype antigen prediction occurred mostly in the Rh system, notably with the e antigen (kappa: 0.17). Fifteen (14.2%) patients had a history of alloimmunisation, with five having HTR documented; no differences in clinical outcomes were found in patients with partial antigen expression. Genotype/extended-phenotype matching strategies may have prevented alloimmunisation events.

CONCLUSION

We show a high frequency of variant alleles/polymorphisms in the SCD population, where genotyping may complement serological phenotyping. Genotyping SCD patients before transfusion may prevent alloimmunisation and HTRs, and knowledge of the FY*02N.01 variant allele increases feasibility of finding compatible blood.

Can CSF spectrophotometry for "Xanthochromia" be used to detect leaking subarachnoid aneurysms in patients with sickle cell anemia with negative MRI or CT angiogram despite hyperbilirubinemia?

CSF (Cerebrospinal Fluid) xanthochromia by spectroscopy should not be dismissed in the context of hyperbilirubinemia in a patient with sickle cell anemia. Xanthochromia detected by spectrophotometry offers a vital clue that further invasive diagnosis is required.

National comparative audit of blood transfusion: 2014 audit of transfusion services and practice in children and adults with sickle cell disease

OBJECTIVES

To determine the organisational resources in place; what blood was being transfused, why, how, where, when and by whom; whether laboratory support and policies met standards for patients with sickle cell disease (SCD).

BACKGROUND

SCD affects 14 000 people in the United Kingdom (UK). Standards and guidelines do not cover all aspects of transfusion in SCD and there are no data on their use; people may become very sick without warning presenting to non-specialist hospitals; blood services are increasingly supplying units for transfusion in SCD with little data on their use.

METHODS

A retrospective audit of transfusion services/practice for people with SCD who had received a transfusion in January-July 2014 in participating hospitals in the UK and Republic of Ireland (ROI).

RESULTS

Eighty-four hospitals submitted 1290 cases, 75% of cases came from 18 hospitals submitting 25 or more cases. Transfusions (91.2% [1164/1276]) were administered to patients with HbSS, 60% (732/1227) of patients needed Rh CE negative blood. Transfusion episodes (4528) were recorded, of which 84% were elective. Stroke prevention accounted for 42% of all transfusions; adults received 56% of transfusions of which 50% were automated red cell exchange (RCE), children received 44% of transfusions of which 87% were simple transfusions.

CONCLUSIONS

There was a paucity of appropriate clinical management protocols, adequately trained staff and network arrangements. The high numbers of children being transfused, disparity in transfusion modality between children and adults and the high frequency of the CE negative Rh phenotype were noted.

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.