Blood bank management of sickle cell patients at comprehensive sickle cell centers

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.

Barriers and Facilitators to Chronic Red Cell Transfusion Therapy in Pediatric Sickle Cell Anemia

Background: Chronic red cell transfusion (CRCT) therapy is one of a few effective disease-modifying therapies for children with sickle cell anemia (SCA). CRCT is recommended for primary and secondary stroke prevention for at-risk children with SCA and is sometimes used for other disease-related complications. However, CRCT can be resource- and time-intensive for patients/families, providers, and organizations. This study was conducted to provide a comprehensive, multilevel examination of barriers and facilitators to transfusion therapy in children with SCA from health care provider and caregiver perspectives. Methods: A qualitative descriptive approach was used to conduct key informant interviews in a sample of 26 caregivers and 25 providers across the United States. Interviews were analyzed using directed content analysis with the Multilevel Ecological Model of Health as an initial coding framework and the constant comparison method. Results: Ten barrier themes and 10 facilitator themes emerged across all ecological levels. Themes most commonly occurred on the patient and organizational levels. Key barriers themes included Logistical Challenges, Obtaining and Maintaining Venous Access, Alloantibodies/Alloimmunization and Reactions, and Iron Overload and Adherence to Chelation Therapy. Key facilitator themes included Nursing and Non-nursing Staff Support, Positive Child/Family Experiences, Logistical Help and Social Resources, Blood Bank and Access to Blood, and Transfusion-Specific Resources. Discussion: The comprehensive understanding of multilevel barriers and facilitators to transfusion therapy, including the role of nursing, in children with SCA can inform strategies to improve CRCT for patients/families and providers and can also be applied by organizations seeking to implement transfusion services for SCA.

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.

Molecular matching for patients with haematological diseases expressing altered RHD-RHCE genotypes

BACKGROUND AND OBJECTIVES

The high homology and the inverted orientation of RHD and RHCE may give rise to non-functional and aberrant RH alleles. RH genotyping is used to screen RH matched donors to African descent patients. This study aimed to define a strategy for testing RHD and RHCE variants in blood donors to provide compatible units for transfusion of patients with haematological diseases.

MATERIALS AND METHODS

Samples from 132 patients [101 Sickle cell disease (SCD), 14 myelodysplastic syndrome (MDS), 17 acute myelogenous leukaemia (AML)] and 198 Brazilian donors were studied. Major blood group alleles, RHD, RHCE alleles and RHD zygosity were determined by the blood-MLPA assay. Sequencing was performed to determine RHD and RHCE variant subtypes. A match was an RH genotype that did not encode Rh antigens absent in the patient, along with matching for ABO, MNS, KEL, FY, JK and DI antigens.

RESULTS

Overall, 7·6% of blood donors and 17.4% of patients presented RH genotypes that predict expression of partial Rh antigens or lack of high prevalence Rh antigens. From 23 patients with clinically relevant RH genotypes, 15 had available matched donors.

CONCLUSION

We report the presence of clinically relevant RH genotypes in SCD and in non-SCD patients. In our admixed population, many patients carry variant RHCE alleles in heterozygosity with normal RHCE alleles. Thus, our results suggest that donors could be selected based on the normal RH allele.

Transfusion service knowledge and immunohaematological practices related to sickle cell disease and thalassemia

Objectives

To assess current knowledge of National Heart, Lung and Blood Institutes (NHLBI) and Thalassemia International Federation (TIF) recommendations, blood banking practices and perceived challenges among transfusion services in the management of patients with haemoglobinopathies.

Background

Previous reports have demonstrated variations in transfusion practices for sickle cell disease (SCD) and thalassemia patients. Recently, NHLBI/TIF have provided transfusion recommendations for patients with haemoglobinopathies.

Methods

A cross‐sectional survey was conducted of transfusion services from the state of Georgia previously identified as having SCD/thalassemia populations. The survey assessed transfusion service practices in pre‐transfusion testing and blood product selection; awareness/implementation of NHLBI/TIF transfusion‐based recommendations and perceived challenges in transfusing haemoglobinopathy patients.

Results

Responses were received from 35 of 49 (71%) institutions. Only institutions indicating transfusing SCD or thalassemia patients (32) were included in analysis. Seventy‐one percent of non‐sickle cell treatment centres (SCTCs) and 20% of non‐thalassemia treatment centres follow NHLBI and TIF recommendations to perform a red blood cell phenotype beyond ABO/Rh(D) and provide Rh and Kell prophylactically matched units for SCD and thalassemia patients, respectively. Forty percent of institutions (33% of non‐SCTCs) employ RBC genotyping to evaluate the red cell phenotype for SCD patients. Over 77% of institutions do not utilise a reliable method to identify SCD patients prior to transfusion, such as a required question/answer field on type/screen or crossmatch orders.

Conclusion

Many healthcare systems' transfusion practices for haemoglobinopathy patients are discordant with NHLBI/TIF recommendations. Efforts are needed to increase awareness and implementation of current recommendations among all transfusion services seeing these patients.

Red cell transfusion in paediatric patients with thalassaemia and sickle cell disease: Current status, challenges and perspectives

Notwithstanding the high safety level of the currently available blood for transfusion and the decreasing frequency of transfusion-related complications, administration of labile blood products to paediatric patients still poses unique challenges and considerations. The incidence of thalassaemia and sickle cell disease in the paediatric population may be high enough under specific racial and geographical contexts. Red cell transfusion is the cornerstone of β-thalassaemia treatment and one of the most effective ways to prevent or correct specific acute and chronic complications of sickle cell disease. However, this life-saving strategy comes with its own complications, such as additional iron overload, alloimmunization and haemolytic reactions, among others. In paediatrics, the dependency of the transfusion outcome upon disease and other recipient characteristics is more prominent compared with the adults, owing to differences in developmental maturity and physiology that render them more susceptible to common risks, exacerbate the host response to transfused cells, and modify the type or the clinical severity of the transfusion-related morbidity. The adverse branch of red cell transfusion is likely the overall effect of several factors acting synergistically to shape the clinical phenotype of this therapy, including inherent donor/blood unit variables, like antigenicity, red cell deformability and extracellular vesicles, as well as recipient variables, such as history of alloimmunization and inflammation level at time of transfusion. This review focuses on paediatric patients with β-thalassaemia and sickle cell disease as a recipient group with distinct transfusion-related characteristics, and introduces new concepts for consideration, not adequately studied and elucidated so far.

Whole-exome sequencing for RH genotyping and alloimmunization risk in children with sickle cell anemia

RH genes are highly polymorphic and encode the most complex of the 35 human blood group systems. This genetic diversity contributes to Rh alloimmunization in patients with sickle cell anemia (SCA) and is not avoided by serologic Rh-matched red cell transfusions. Standard serologic testing does not distinguish variant Rh antigens. Single nucleotide polymorphism (SNP)-based DNA arrays detect many RHD and RHCE variants, but the number of alleles tested is limited. We explored a next-generation sequencing (NGS) approach using whole-exome sequencing (WES) in 27 Rh alloimmunized and 27 matched non-alloimmunized patients with SCA who received chronic red cell transfusions and were enrolled in a multicenter study. We demonstrate that WES provides a comprehensive RH genotype, identifies SNPs not interrogated by DNA array, and accurately determines RHD zygosity. Among this multicenter cohort, we demonstrate an association between an altered RH genotype and Rh alloimmunization: 52% of Rh immunized vs 19% of non-immunized patients expressed variant Rh without co-expression of the conventional protein. Our findings suggest that RH allele variation in patients with SCA is clinically relevant, and NGS technology can offer a comprehensive alternative to targeted SNP-based testing. This is particularly relevant as NGS data becomes more widely available and could provide the means for reducing Rh alloimmunization in children with SCA.

Red cell storage age policy for patients with sickle cell disease: A survey of transfusion service directors in the United States

In patients with sickle cell disease (SCD), the effects of the red cell storage lesion are not well defined. The objective of this study was to determine the prevalence of transfusion services that limit red cell units by storage age for patients with SCD. We developed a 22 question survey of transfusion service director opinions and their corresponding blood bank policies. Target subjects were systematically identified on the AABB website. Responses were recorded in SurveyMonkey and summarized using standard statistical techniques. Ninety transfusion service directors responded to the survey. Response rate was 22%. Only 23% of respondents had storage age policies in place for patients with SCD, even though 36% of respondents consider older units to be potentially harmful in this patient population. Of those with a policy, a less-than 15 day storage age requirement was most often used (75%), but practices varied, and most respondents (65%) agreed that evidence-based guidelines regarding storage age are needed for patients with SCD. Policies, practices and opinions about the risks of older units for patients with SCD vary. As patients with SCD may have unique susceptibilities to features of the red cell storage lesion, prospective studies in this population are needed to determine best practice.

Red blood cell storage duration is not associated with clinical outcomes for acute chest syndrome in children with sickle cell disease

BACKGROUND

Providers commonly transfuse sickle cell disease (SCD) patients with fresh red blood cells (RBCs) as treatment for acute chest syndrome (ACS). The objective of this study was to determine if there is an association between the storage duration of RBCs and length of hospitalization and oxygen requirement after transfusion in pediatric SCD patients with ACS.

STUDY DESIGN AND METHODS

This is a retrospective cohort study of pediatric SCD patients with ACS treated with a simple RBC transfusion over 8.5 years at a single institution. Multivariate generalized estimation equation analysis was used to identify associations between storage duration of RBCs and outcome measures.

RESULTS

A total of 234 ACS episodes in 131 subjects were included. The median storage duration of the oldest unit of transfused RBCs was 17 days (interquartile range, 11-26). The majority of ACS episodes, 77.4%, were treated with 1 unit of transfused RBCs; 20.9% received 2 units; and 1.7% received 3 or more units of RBCs. There was no association between the storage duration of the oldest unit of transfused RBCs and either duration of hospitalization or supplemental oxygen requirement after transfusion in multivariate analyses.

CONCLUSION

This retrospective study is one of the first to investigate the role of the storage lesion in children with SCD and does not support the preferential transfusion of fresh RBCs for ACS. Ultimately, a randomized controlled trial is necessary to determine whether the storage age of RBCs affects outcomes for patients with SCD and ACS.

Changing practice: red blood cell typing by molecular methods for patients with sickle cell disease

BACKGROUND

Extended red blood cell (RBC) antigen matching is recommended to limit alloimmunization in patients with sickle cell disease (SCD). DNA-based testing to predict blood group phenotypes has enhanced availability of antigen-negative donor units and improved typing of transfused patients, but replacement of routine serologic typing for non-ABO antigens with molecular typing for patients has not been reported.

STUDY DESIGNS AND METHODS

This study compared the historical RBC antigen phenotypes obtained by hemagglutination methods with genotype predictions in 494 patients with SCD. For discrepant results, repeat serologic testing was performed and/or investigated by gene sequencing for silent or variant alleles.

RESULTS

Seventy-one typing discrepancies were identified among 6360 antigen comparisons (1.1%). New specimens for repeat serologic testing were obtained for 66 discrepancies and retyping agreed with the genotype in 64 cases. One repeat Jk(b-) serologic phenotype, predicted Jk(b+) by genotype, was found by direct sequencing of JK to be a silenced allele, and one N typing discrepancy remains under investigation. Fifteen false-negative serologic results were associated with alleles encoding weak antigens or single-dose Fy(b) expression.

CONCLUSIONS

DNA-based RBC typing provided improved accuracy and expanded information on RBC antigens compared to hemagglutination methods, leading to its implementation as the primary method for extended RBC typing for patients with SCD at our institution.

Ideal donors, imperfect results in sickle cell disease

In this issue of Blood, Chou et al report findings from an observational study of alloimmunization in patients with sickle cell disease (SCD) receiving blood transfusions from ethnically matched donors.

Cost-effectiveness of prospective red blood cell antigen matching to prevent alloimmunization among sickle cell patients

BACKGROUND

Sickle cell disease is associated with extensive health care utilization; estimated lifetime costs exceed $460,000 per patient. Approximately 30% of chronically transfused sickle cell patients become alloimmunized to red blood cell antigens, but these patients cannot be identified a priori. Prospective antigen matching can prevent alloimmunization, but is costly and may not benefit most patients.

STUDY DESIGN AND METHODS

A Markov-based model was constructed to compare the health and financial implications of four alternative antigen-matching strategies for chronically transfused sickle cell patients. The strategies varied by the group of patients receiving matched blood (all patients prophylactically or only patients with a history of alloimmunization [history-based]), and by the extent of antigen matching (limited to C, E, and K, or extended to 11 antigens). Direct medical costs and alloimmunization events were assessed over 10- and 20-year periods, for a hypothetical cohort of initially transfusion-naive patients and for a dynamic population.

RESULTS

Within a hypothetical cohort of initially transfusion-naive patients, implementing prophylactic limited matching for all chronically transfused patients instead of history-based limited matching is expected to cost an additional $765.56 million over 10 years, but result in 2072 fewer alloimmunization events. Within the same cohort, implementing prospective extensive matching is expected to cost $1.86 billion more than history-based extensive matching, but result in 2424 fewer alloimmunization events. Averting a single alloimmunization event using prospective matching would cost $369,482 to $769,284. Among a dynamic population over 10 years, prospective limited matching is expected to cost $358.34 million more than history-based limited matching.

CONCLUSIONS

While prospective matching for all transfused patients would reduce alloimmunization, this strategy requires considerable expenditure.

Acquired hemoglobin variants and exposure to glucose-6-phosphate dehydrogenase deficient red blood cell units during exchange transfusion for sickle cell disease in a patient requiring antigen-matched blood

Red blood cell exchange (RBCEx) is frequently used in the management of patients with sickle cell disease (SCD) and acute chest syndrome or stroke, or to maintain target hemoglobin S (HbS) levels. In these settings, RBCEx is a category I or II recommendation according to guidelines on the use of therapeutic apheresis published by the American Society for Apheresis. Matching donor red blood cells (RBCs) to recipient phenotypes (e.g., C, E, K-antigen negative) can decrease the risk of alloimmunization in patients with multi-transfused SCD. However, this may select for donors with a higher prevalence of RBC disorders for which screening is not performed. This report describes a patient with SCD treated with RBCEx using five units negative for C, E, K, Fya, Fyb (prospectively matched), four of which were from donors with hemoglobin variants and/or glucose-6-phosphate dehydrogenase (G6PD) deficiency. Pre-RBCEx HbS quantification by high performance liquid chromatography (HPLC) demonstrated 49.3% HbS and 2.8% hemoglobin C, presumably from transfusion of a hemoglobin C-containing RBC unit during a previous RBCEx. Post-RBCEx HPLC showed the appearance of hemoglobin G-Philadelphia. Two units were G6PD-deficient. The patient did well, but the consequences of transfusing RBC units that are G6PD-deficient and contain hemoglobin variants are unknown. Additional studies are needed to investigate effects on storage, in-vivo RBC recovery and survival, and physiological effects following transfusion of these units. Post-RBCEx HPLC can monitor RBCEx efficiency and detect the presence of abnormal transfused units.

Donor cycle and donor segmentation: new tools for improving blood donor management

BACKGROUND AND OBJECTIVES

An adequate donor population is of key importance for the entire blood transfusion chain. For good donor management, a detailed overview of the donor database is therefore imperative. This study offers a new description of the donor cycle related to the donor management process. It also presents the outcomes of a European Project, Donor Management IN Europe (DOMAINE), regarding the segmentation of the donor population into donor types.

MATERIALS AND METHODS

Blood establishments (BEs) from 18 European countries, the Thalassaemia International Federation and a representative from the South-Eastern Europe Health Network joined forces in DOMAINE. A questionnaire assessed blood donor management practices and the composition of the donor population using the newly proposed DOMAINE donor segmentation. 48 BEs in 34 European countries were invited to participate.

RESULTS

The response rate was high (88%). However, only 14 BEs could deliver data on the composition of their donor population. The data showed large variations and major imbalances in the donor population. In 79% of the countries, inactive donors formed the dominant donor type. Only in 21%, regular donors were the largest subgroup, and in 29%, the proportion of first-time donors was higher than the proportion of regular donors.

CONCLUSION

Good donor management depends on a thorough insight into the flow of donors through their donor career. Segmentation of the donor database is an essential tool to understand the influx and efflux of donors. The DOMAINE donor segmentation helps BEs in understanding their donor database and to adapt their donor recruitment and retention practices accordingly. Ways to use this new tool are proposed.

Transfusion therapy for sickle cell disease: a balancing act

Transfusion therapy is a key intervention in decreasing morbidity and mortality in patients with sickle cell disease (SCD). Current indications for acute and chronic transfusion therapy have significantly increased the number of RBC units transfused to patients with SCD worldwide. This review summarizes transfusion management for the treatment or prevention of neurologic and perioperative complications, acute chest syndrome, and acute anemia associated with SCD. Despite the recognized benefits of transfusion therapy, it is not without the risks of iron overload, alloimmunization, and delayed hemolytic transfusion reactions. Transfusional iron overload management includes automated RBC exchange, noninvasive imaging to monitor iron burden, and iron chelation with parenteral or oral agents. Although limited and extended RBC antigen matching reduces antibody formation, the prevalence of RBC alloimmunization in patients with SCD remains high. Recent studies demonstrate that RH genetic diversity in patients with SCD contributes to Rh alloimmunization, suggesting that even more refined RBC matching strategies are needed. Advances in molecular blood group typing offer new opportunities to improve RBC matching of donors and recipients and can be of particular benefit to patients with SCD.

Transfusion practices in the management of sickle cell disease: a survey of Florida hematologists/oncologists

The purpose of this study was to characterize transfusion practices in the management of sickle cell disease and to identify factors attributing to differences in prescribing practices among Florida hematologists/oncologists. A cross-sectional study was performed in 2005-2006 utilizing a mail survey. The survey instrument addressed practice characteristics, sickle cell patient populations, transfusion settings, indications and techniques, red blood cell phenotype specifications/modifications, use of practice guidelines, and educational resource utilization. One hundred fifty two physicians (75% adult-oriented, 25% pediatric) completed the survey. Non-academic practice settings (78 %) were the primary location. Pediatric practices had a larger percentage of patients with overt strokes, and receiving hydroxyurea therapy than adult-oriented practices. The majority of survey respondents did not request limited phenotypically matched red blood cells on a routine basis. The majority of pediatric practices (60%) had individually defined transfusion practice guidelines in contrast to 8% of adult-oriented practices. There were statistically significant differences for pediatric and adult-oriented practices in managing certain acute and chronic transfusion indications. Analysis of clinical vignette data revealed variation among hematologists/oncologists in the transfusion management of common clinical scenarios. The study underscores the need for the development and dissemination of comprehensive sickle cell transfusion guidelines and protocols.

Challenges of alloimmunization in patients with haemoglobinopathies

Red blood cell (RBC) transfusions can be life-sustaining in chronic inherited anaemias, such as thalassaemia, and the indications for blood transfusions in patients with sickle cell disease continue to expand. Complications of transfusions, such as allosensitization, can create significant medical challenges in the management of patients with haemoglobinopathies. This review summarizes key findings from the medical literature related to alloimmunization in haemoglobinopathies and examines potential measures to mitigate these risks. Areas where future studies are needed are also addressed.

Indications and complications of transfusions in sickle cell disease

Red cell transfusion remains an important part of the management of acute and chronic complications in SCD. The ongoing and emerging uses of transfusions in SCD may have significant benefits; however, the potential complications of transfusions also deserve careful consideration. In this report we review current indications for transfusions, transfusion complications, modifications of transfusion practices to mitigate risk, and potential considerations to improve transfusion outcomes.

Red blood cell alloimmunization in sickle cell disease: prevalence in 2010

BACKGROUND

Transfusion of red blood cells (RBCs) is frequently required for care of individuals with sickle cell disease (SCD). Alloimmunization rates are high and may be reduced by matching for RBC antigens that can cause alloimmunization.

STUDY DESIGN AND METHODS

During the PROACTIVE Feasibility Study, patients with SCD age 2 years or older admitted for pain without acute chest syndrome were enrolled for possible randomization to preventive blood transfusion or standard care. Transfusion and antibody histories were obtained at each site, and antibody screening was done, to assess transfusion burden and alloimmunization prevalence. Participating sites were surveyed regarding antigen matching practice.

RESULTS

A total of 237 patients (169 SS, 42 SC, 15 Sβ(0) -thalassemia, 11 Sβ(+) -thalassemia), 118 males and 119 females, were enrolled. Mean age was 19.3 years (range, 2.0-68.0); there were 122 children and 115 adults. A total of 75.8% had received at least a single transfusion of RBCs before the study. Thirty-four patients (14.4%) had a history of at least one alloantibody and 17 of these had more than one. When surveyed, 19 sites (83% of responders) reported antigen matching to at least include C, E, and K for transfusion of all patients with SCD.

CONCLUSION

Though antigen typing before transfusion of people with SCD and providing antigen-negative units is now widely employed by sickle cell centers, the alloimmunization rate remains quite high in contemporary sickle cell populations and may be due in large part to transfusions received at institutions not providing extended matching.

Sickle cell disease and stroke

Twenty-four percent of sickle cell disease (SCD) patients have a stroke by the age of 45 years. Blood transfusions decrease stroke risk in patients deemed high risk by transcranial Doppler. However, transcranial Doppler has poor specificity, and transfusions are limited by alloimmunization and iron overload. Transfusion withdrawal may be associated with an increased rebound stroke risk. Extended blood typing decreases alloimmunization in SCD but is not universally adopted. Transfusions for thalassemia begun in early childhood are associated with lower rates of alloimmunization than are seen in SCD, suggesting immune tolerance. Optimal oxygen transport efficiency occurs at a relatively low hematocrit for SCD patients because of hyperviscosity. Consequently, exchange rather than simple transfusions are more effective in improving oxygen transport efficiency, but the former are technically more demanding and require more blood units. Although viscosity is of importance in the noncerebral manifestations of SCD, inflammation may play a larger role than viscosity in the development of large-vessel stroke. The future of SCD stroke management lies in the avoidance of transfusion. Hydroxyurea and anti-inflammatory measures may reduce the need for transfusion. Recent genome-wide association studies may provide methods for modulating fetal hemoglobin production enough to attenuate stroke risk and other complications of SCD.

Prevalence of sickle cell disease in a northeastern region of the Democratic Republic of Congo: what impact on transfusion policy?

Transfusion therapy may save the lives of patients with sickle cell disease (SCD), but it is also associated with a high risk of transmission of infection. The aims of this study were to determine the prevalence of SCD in a northeastern region of the Democratic Republic of Congo (DRC), and to define ways in which the procedures involved in the security of transfusions should be improved. During a 3-month period in 2006/2007, 520 samples of umbilical cord blood were obtained through neonatal screening in five health centres in Kisangani. The samples were analysed using an isoelectric focusing technique. The estimated prevalence of sickle cell trait and SCD in the population tested was 23.3 and 0.96%, respectively. These numbers will be presented for the attention of the health authorities in DRC with responsibility for SCD and they will be asked to consider improvements in treatment procedures for SCD, such as blood transfusions, as a public health priority.

Current issues in blood transfusion for sickle cell disease

PURPOSE OF REVIEW

Although blood transfusion has been felt to be a beneficial therapy for sickle cell disease (SCD) since the 1950s, associated complications initially limited this therapy for these patients. With advances now reducing the side effects of transfusion and several landmark studies over the last decade clearly defining the efficacy for decreasing sickle cell morbidity, the indications for transfusion have increased. This review will discuss the indications, methods and goals of transfusion as well as complications and recent changes in transfusion therapy for SCD.

RECENT FINDINGS

Recently studies have established the efficacy of transfusion for prevention of stroke, treatment of acute chest syndrome and perioperative transfusion management of SCD. Pulmonary hypertension is increasingly recognized as a significant source of morbidity and mortality and is an evolving indication for transfusion therapy. Phenotypically matching transfused blood has been shown to decrease alloimmunization, and genotyping for antigen matching may help match donors to patients in the future.

SUMMARY

The increased use of transfusions may ultimately be balanced by hydroxyurea and other newer therapies developed as the complex pathophysiology of SCD is better understood; however, red cell transfusion is currently the most studied and accepted therapy for most acute and many chronic complications of SCD. Physicians caring for patients with sickle cell disease should be aware of the unique complications and transfusion requirements in this population.