Delayed Hemolytic Transfusion Reaction Research Articles

Alloimmunization and consequential delayed hemolytic transfusion reactions in sickle cell disease patients: A case series

Abstract: Alloimmunization is a significant complication of blood transfusion, especially in sickle cell patients, and may lead to a delayed hemolytic transfusion reaction (DHTR). DHTR is defined as evident hemolysis and a positive direct antiglobulin test (DAT) 24 h to 28 days posttransfusion with either a positive eluate or a newly identified alloantibody in the plasma. Hyperhemolysis syndrome (HS) is a fatal form of DHTR in which the posttransfusion hemoglobin (Hb) level is less than the pretransfusion Hb level. In this case series, we have reported three cases of alloimmunized sickle cell disease patients with clinically significant DHTR. The second case is typical of HS. All three cases were DAT positive, alloimmunized with multiple alloantibodies, and had substantial hemolysis posttransfusion. In this series, we have provided an algorithmic approach to resolve such complex immunohematological problems and have highlighted some of the limitations of serology methods. High-dose corticosteroid and intravenous immunoglobulin prove to be an effective treatment for DHTR.

Screening and Identification of Erythrocyte Antibodies: A Narrative Literature Review

Red blood cell (RBC) alloimmunization, the development of antibodies against foreign red blood cell antigens, is a critical concern in transfusion medicine. Alloantibodies can lead to adverse transfusion reactions, including hemolytic disease of the fetus and newborn (HDFN) and delayed hemolytic transfusion reactions (DHTR). This comprehensive literature review explores the intricacies of RBC alloimmunization, focusing on the screening and identification of erythrocyte antibodies. We delve into the prevalence and clinical significance of various alloantibodies, the underlying immunological mechanisms, and the evolution of laboratory techniques for their detection. Additionally, we discuss the challenges and future directions in managing alloimmunization, emphasizing the importance of personalized medicine and innovative approaches to ensure safe and effective blood transfusions.

Utility of hemoglobin electrophoresis to distinguish between severe delayed hemolytic transfusion reaction versus hyperhemolysis syndrome

Delayed hemolytic transfusion reaction (DHTR) and hyperhemolysis syndrome (HHS) are both complications of red blood cell transfusions in patients with sickle cell disease.Clinically, both present with hemolysis and can be difficult to differentiate. Hemoglobin electrophoresis may aid in the diagnosis. Herein we describe a case in which a patient with hemoglobin SC disease presented with features of severe hemolysis several days after initiation of red blood cell exchange. Increase in reticulocyte count and complete absence of hemoglobin A on electrophoresis during this event supported the diagnosis of severe DHTR, indicating a rapid and selective destruction of the transfused red blood cells. Ability to interpret the hemoglobin electrophoresis can help clinicians distinguish between these two severe transfusion complications in patients living with sickle cell disease. It is important to identify the presence or absence of concomitant HHS, as patients with HHS tend to have a worse prognosis and there is a higher rate of recurrence of HHS with subsequent transfusions. Accurate diagnosis can lead to prompt management and decrease morbidity and mortality.

A Case Report of Hyperhemolytic Syndrome in Sickle Cell Disease, with a Special Focus on Avoiding the Use of Transfusions

A Case Report of Hyperhemolytic Syndrome in Sickle Cell Disease, with a Special Focus on Avoiding the Use of Transfusions

Decreasing alloimmunization-specific mortality in sickle cell disease in the United States: Cost-effectiveness of a shared transfusion resource.

Red blood cell alloimmunization and consequent delayed hemolytic transfusion reaction (DHTR) incidence and mortality in patients with sickle cell disease (SCD) are high. A shared transfusion resource has decreased both in other countries, while in the United States cost concerns persist. We conducted a Markov cohort simulation of a birth cohort of alloimmunized patients with SCD to estimate lifetime DHTR incidence, DHTR-specific mortality, quality-adjusted life expectancy (QALE), and costs with the implementation of a shared transfusion resource to identify antibody history versus without (i.e., status quo). We conducted our analysis using a lifetime analytic time horizon and from a United States health system perspective. Implementation of shared transfusion resource projects to decrease cumulative DHTR-specific mortality by 26% for alloimmunized patients with SCD in the United States, relative to the status quo. For an average patient population of 32 000, this intervention would generate a discounted increment of 4000 QALYs at an incremental discounted cost of $0.3 billion, resulting in an incremental cost-effectiveness ratio of $75 600/QALY [95% credible interval $70 200-81 400/QALY]. The results are most sensitive to the baseline lifetime medical expenditure of patients with SCD. Alloantibody data exchange is cost-effective in 100% of 10 000 Monte Carlo simulations. The resource would theoretically need a minimum patient population of 1819 patients or cost no more than $5.29 million annually to be cost-effective. By reducing DHTR-specific mortality, a shared transfusion resource in the United States projects to be a life-saving and cost-effective intervention for patients with SCD in the United States.

Management of Delayed Hemolytic Transfusion Reaction in a Patient with Sickle Cell Disease: A Case Report

Background: Sickle cell disease (SCD) is a group of inherited blood disorders characterized by abnormalities in hemoglobin (Hb), leading to distortion in shape of red blood cells (RBCs) and their breakdown, potentially blocking blood flow and resulting in pain and anemia. This can significantly impact the patient’s quality of life. Patients often require multiple blood transfusions to prevent complications associated with SCD by reducing the concentration of damaged hemoglobin. However, one of the significant complications of blood transfusions is Delayed Hemolytic Transfusion Reaction (DHTR), which occurs due to RBC alloimmunization (i.e., formation of antibodies against donor RBC antigens). DHTR can manifest as a sudden decrease in hemoglobin levels, which may progress to rapid multiorgan failure and death. Thus, prompt diagnosis is crucial for timely management. This case report highlights the diagnosis and management of a 56-year-old African American female with SCD who presented with bilateral severe knee pain and low Hb levels. Case Presentation: The patient’s symptoms, past medical history, and investigation findings led to a diagnosis of DHTR. Management was conducted within the framework of Bloodless Medicine, incorporating strategies to minimize blood loss and optimize erythropoiesis. Treatment included the use of erythropoietin (EPO) to manage hemoglobin levels and the administration of opioids and supplemental oxygen for symptom relief. Conclusion: Our case report highlights the challenges and various management strategies employed in treating DHTR in SCD patients. It emphasizes the importance of early recognition of the complication and compares the risks and benefits of additional blood transfusions in such patients. By presenting this case, we aim to contribute to the growing literature on DHTR in SCD patients and highlight the need for further research and optimized management strategies in this population.

Alloimmunization and hyperhemolysis in sickle cell disease.

Alloimmunization against red blood cell antigens and delayed hemolytic transfusion reaction (DHTR) are major barriers to transfusion in sickle cell disease (SCD). In SCD, DHTR is a potentially life-threatening. Blood group polymorphism in SCD patients, who are of African ancestry and frequently exposed to antigens they do not carry; an inflammatory clinical state; and occasional transfusion in acute situations are risk factors for alloimmunization and DHTR. In patients at risk, the transfusion indication must be balanced against the risk of developing DHTR. However, when transfusion is absolutely necessary, protocols combining the prevention of exposure to immunogenic antigens with immunosuppressive treatments must be implemented, and patients should be carefully monitored during posttransfusion follow-up. This close monitoring makes it possible to diagnose hyperhemolysis as soon as possible; to avoid retransfusion, which can exacerbate hemolysis; and to administer specific treatments, such as anticomplement therapy, in severe cases. Finally, in patients with severe disease, hematopoietic stem cell transplantation may be indicated. However, transfusion is also required in this context, and its management is complex because these risks must be taken into account.

Delayed Hemolytic Transfusion Reactions Could be Prevented by a National Alloimmunization Registry

Abstract Evanescence of alloantibodies to RBC antigens places patients at risk of delayed hemolytic transfusion reactions (DHTRs) unless the transfusion service is aware of their alloantibody history. In the past year, three patients with sickle cell disease (SCD) developed a DHTR at our institution because their pre-transfusion testing did not reflect their full alloimmunezation. We sought to determine how often the pre-transfusion antibody screen is negative or fails to show the full alloimmunization profile. We reviewed the electronic records of all current adult patients with SCD receiving chronic outpatient RBC transfusions (including red cell exchange) to collect demographic and laboratory results to answer this question. Our analysis included 162 patients of African-American descent: 80 (49%) males and 82 (51%) females, with an average age of 34 years. The majority, 92 or 56%, had a history of alloimmunization with a mean number of 3 antibodies (range: 1-10). The most common were to the C, E, and K antigens. The next two most common alloantibodies were nonspecific, representing alloimmunization to an antigen that could not be further determined, followed by the D antigen. In 81 patients, the most recent antibody screen did not reflect their history, with most being completely negative (n=69), and the rest (n=12) unable to detect all alloantibodies of which they had a history. The antibodies most often undetectable were: Anti-E, Anti-C, and Anti-D. These are simultaneously the second, first, and fifth most common antibodies in this population, all of which are considered clinically significant and capable of causing a hemolytic transfusion reaction. Of note, the alloantibodies implicated in the recent DHTRs we observed, were to the JKa, Jkb, Fya and the S antigens. In addition, 28 individuals (17% of the total) had at least one antibody to a low incidence antigen (LIA) such as Goa, V, Vs, Jsa, Kpa and Lua. Five (3%) patients were exclusively sensitized to one or more low incidence antigens. Considering that commercially available reagent red cells utilized to perform pre-transfusion testing may lack LIAs, knowing the history of alloimmunization is the only way to prevent hemolytic reactions. In conclusion, evanescence and limitations of the commercially available reagents to test patients with SCD prior to a transfusion place them at increased risk of transfusion reactions. One potential way to minimize risk from the latter is to perform serologic crossmatching of all units intended for patients with SCD, independent of the result of the antibody screen. This is the practice we have instituted several years ago in our transfusion service. However, the solution to both problems is a national repository of alloimmunization histories accessible to all transfusion services. Such informatics tools would help avoid DHTRs in patients with and without SCD.

Delayed Blood Transfusion Adverse Reactions Caused by Hypothermia Cardiopulmonary Bypass and Its Coping Strategies

To investigate a case of delayed hemolytic transfusion reaction (DHTR), and find the reason and coping strategies to prevent similar incidents in the future. Relative antibody identification was carried out, suitable erythrocytes was screened, and relevant indicators after transfusion were evaluated. Medical record and laboratory report of the patient were reviewed, the cause was analyzed, and corresponding treatment was carried out. The patient suffered from DHTR caused by IgM anti-M antibody and low body temperature cardiopulmonary bypass. After anti-hemolytic treatment, the patient was gradually improved, the bilirubin gradually decreased, and finally cured and discharged. When the transfusion department finds any antibodies which have activity at room temperature but no respond at 37 ℃, they should communicate with clinical medical staff in time. Warm transfusion should be used during blood transfusion to prevent transfusion-related hemolytic reaction.

Delayed haemolytic transfusion reaction in paediatric patients with sickle cell disease: A retrospective study in a French national reference centre.

Delayed haemolytic transfusion reaction (DHTR) is a life-threatening haemolytic anaemia following red blood cell transfusion in patients with sickle cell disease, with only scarce data in children. We retrospectively analysed 41 cases of DHTR in children treated between 2006 and 2020 in a French university hospital. DHTR manifested at a median age of 10.5 years, symptoms occurred a median of 8 days after transfusion performed for an acute event (63%), before surgery (20%) or in a chronic transfusion programme (17%). In all, 93% of patients had painful crisis. Profound anaemia (median 49 g/L), low reticulocyte count (median 140 ×109 /L) and increased lactate dehydrogenase (median 2239 IU/L) were observed. Antibody screening was positive in 51% of patients, and more frequent when there was a history of alloimmunisation. Although no deaths were reported, significant complications occurred in 51% of patients: acute chest syndrome (12 patients), cholestasis (five patients), stroke (two patients) and kidney failure (two patients). A further transfusion was required in 23 patients and corticosteroids were used in 21 to reduce the risk of additional haemolysis. In all, 13 patients subsequently received further transfusions with recurrence of DHTR in only two. The study affords a better overview of DHTR and highlights the need to establish guidelines for its management in children.

The complexities of transfusion reactions: Coexistence of a delayed haemolytic transfusion reaction and post-transfusion purpura.

Immune-mediated acute or delayed transfusion reactions occur when there is immunological incompatibility between transfused blood products and recipient's antibodies. Acute haemolytic transfusion reactions occur within 24 h and are delayed after 24 h up to 10 days following transfusion, whereas post-transfusion purpura (PTP) typically occurs 7-10 days post-transfusion. We present a case of a previously transfused and recently post-partum female who developed both delayed haemolytic transfusion reaction (DHTR) and PTP. A 42-year-old woman, G2P1, with non-alcoholic liver disease, portal hypertension and previous transfusion history with allogeneic anti-E, developed a severe DHTR and PTP following a complicated post-partum course and multiple transfusions. The antenatal and initial post-partum pre-transfusion antibody screens were negative. Subsequently five red cell antibodies, including anti-c, anti-Fya, anti-Jkb and anti-S and the reappearance of anti-E were, however, identified during follow-up investigations along with the anti-platelet antibody HPA-3a and human leukocyte antigen class I antibodies. Anti-E, anti-Jkb and anti-S were eluted from the circulating red blood cells. To our knowledge, there have been only two other case reports of DHTR and PTP occurring in the same patient.

A US-Wide Red Blood Cell Alloantibody Exchange Can Decrease Mortality and Produce Cost Savings in the Care of Alloimmunized Patients with Sickle Cell Disease

Introduction: Red blood cell (RBC) alloimmunization occurs after exposure to non-self RBC antigens through transfusion or pregnancy. Alloimmunization rates and consequently delayed hemolytic transfusion reaction (DHTR) mortality in patients with sickle cell disease (SCD) is particularly high. Interest in a blood bank information system vendor-based alloantibody exchange in the United States (US) is growing, though cost concerns exist. To investigate the impact of an exchange that enables alloantibody data-sharing across hospitals, we conducted the first disease simulation of allo-immunized patients with SCD to project lifetime cumulative DHTR-specific mortality without an alloantibody exchange (status quo) versus with a US-wide alloantibody exchange. We then additionally performed a cost-effectiveness analysis to identify whether investing in an alloantibody exchange would be cost-effective, cost saving or neither. Methods: We built a Markov simulation of alloimmunized patients with SCD in the US. Transition probabilities for DHTR incidence and DHTR-specific mortality were informed from the largest prospective (n=311) and retrospective (n=220) studies of DHTR incidence in people living with SCD. Age-, gender- and disease-specific background mortality probabilities were employed. Cumulative probability of DHTR was modeled from age 5, with a lifetime horizon. Costs were assessed from the health system perspective and effectiveness was calculated in quality-adjusted life-years (QALY). QALYs were informed by published lifetime simulation of patients living with SCD and matched controls. These were originally derived from a polynomial fit linking Euroqual-5 Dimensions to the visual analog scale for pain in patients with SCD in several studies. Cost-effectiveness was quantified using an incremental cost-effectiveness ratio (ICER), or net monetary benefits (NMB) if the intervention was found to be cost saving, either way incorporating a cost-effectiveness willingness-to-pay threshold of $100,000/QALY, as recommended practice. We assumed a lifetime operating cost of $10 million for an alloantibody exchange, that no patient with diagnosed DHTR has more than one DHTR recurrence, that an exchange would not be able to prevent all DHTRs (as up to 30% are not associated with a new detectable antibody in SCD), and utilized prior estimates for US allo-immunized population prevalence range of 20-44% for people living with SCD. We validated our estimate for DHTR reduction with that of the 10-year experience in the national Dutch Transfusion Register of Irregular Antibodies and Cross-match Problems (TRIX). We then conducted deterministic and probabilistic sensitivity analyses, varying all parameter estimates +/-20% and capturing uncertainty in all parameters simultaneously over 10,000 Monte Carlo simulations. Results: Base-case lifetime simulation comparing the strategies of implementing an alloantibody exchange versus not yields a decrease in cumulative lifetime DHTR-specific mortality (2.4% vs 5.7%, respectively; Figure 1). The absolute peak probability decrease of having a history of incident DHTR and being alive occurs at age 41 (10.6% vs 27.0%; Figure 1). The strategy of alloantibody exchange implementation accrues 22.08 per-person lifetime discounted QALYs [95% credible interval 22.03-22.12] versus 21.72 without [95% CI 21.61-21.82], corresponding to a per-person QALY increase of 0.357 with exchange implementation. The lifetime population benefit for an alloimmunized population living with SCD in the United States is up to 15,710 QALYs gained. Total lifetime costs accrue $1.0 billion with exchange as compared to $2.5 billion without. This yields population-level cost savings of $1.5 billion USD ($34,091 saved per alloimmunized patient registered in the exchange), with an accrued incremental NMB of $3 billion. In probabilistic sensitivity analysis the former is favored in 100% of 10,000 Monte Carlo simulations. Conclusion: By reducing DHTR-specific mortality, an alloantibody exchange is predicted to be a life- and cost-saving investment for alloimmunized people living with SCD. Although this analysis was limited to SCD, the impact of an alloantibody exchange would also bring benefit to patients who are alloimmunized in the context of diagnoses and states beyond SCD, such as myelodysplastic syndrome, thalassemia, autoimmune conditions, and pregnancy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Delayed haemolytic transfusion reaction due to Kidd antibodies.

A delayed haemolytic transfusion reaction (DHTR) encompasses a positive direct antiglobulin test (DAT) developed anytime between 24 hours to 28days after cessation of transfusion, a positive eluate or a newly identified alloantibody in the plasma or serum along with features of haemolysis in the patient. Routinely, it is expected that with the transfusion of one unit of packed red cells in a patient of average height and weight, the haemoglobin level and hematocrit increase by 1 g/dL and 3% respectively. However, in a patient with DHTR, an inadequate rise of post-transfusion haemoglobin (<1g/dL) or rapid fall in haemoglobin back to pre-transfusion levels is observed. Kidd antibodies are particularly known to cause DHTR, maybe alone or in unison with other antibodies. Detection of these alloantibodies is consequential in providing good transfusion support to these patients. These events may be difficult to detect as they may present as varied clinical features or immunological nuisances. In this case series, we have presented three cases of DHTR with special emphasis on their clinical presentations, immunohaematological evaluations, laboratory parameters and the role of proper transfusion support in these patients to avoid further complications.

Risks and Benefits of Prophylactic Transfusion before Cholecystectomy in Sickle Cell Disease.

Preoperative transfusion (PT) reduces acute postoperative vaso-occlusive events (VOE) in sickle cell disease (SCD), but exposes patients to alloimmunization, encouraging a recent trend towards transfusion sparing. The aim of this study was to investigate the benefit–risk ratio of PT before cholecystectomy on the occurrence of postoperative VOE. Adult SCD patients who underwent cholecystectomy between 2008 and 2019 in our center were included. Patients’ characteristics, collected retrospectively, were compared according to PT. A total of 79 patients were included, 66% of whom received PT. Gallbladder histopathology found chronic cholecystitis (97%) and gallstones (66%). Transfused patients underwent more urgent surgeries and had experienced more painful vaso-occlusive crises (VOC) in the month before surgery (p = 0.05). Four (8.5%) post-transfusion alloimmunizations occurred, and two of them caused a delayed hemolytic transfusion reaction (DHTR) (4.3%). The occurrence of postoperative VOE was similar between the groups (19.2% vs. 29.6%, p = 0.45). Though not statistically significant, a history of hospitalized VOC within 6 months prior to surgery seemed to be associated to postoperative VOE among non-transfused patients (75% vs. 31.6%, p = 0.10). PT before cholecystectomy exposes to risks of alloimmunization and DHTR that could be avoided in some patients. Recent VOCs appear to be associated with a higher risk of postoperative VOE and prompt the preemptive transfusion of these patients.

Long-term Use of Eculizumab for Prolonged Hemolysis Following a Delayed Hemolytic Transfusion Reaction in Pediatric Sickle Cell: A Case Report.

Complement activation has been implicated in delayed hemolytic transfusion reaction (DHTR) in patients with sickle cell disease (SCD), and eculizumab has been reported as an effective treatment for patients with DHTR. Previously reported patients with SCD and DHTR responded well after a few doses of eculizumab. We report on the long-term use of eculizumab in a pediatric sickle cell patient with prolonged hemolysis of unknown etiology after a DHTR who had a slow and less sustained response. Long-term use of eculizumab in this young patient with SCD was successful with limited adverse effects.

S299: ROLE OF RED BLOOD CELL MEMBRANE-DERIVED PARTICLES ON ENDOTHELIAL DAMAGES DURING ONSET STAGE OF DELAYED HEMOLYTIC TRANSFUSION REACTION

Background: Delayed hemolytic transfusion reaction (DHTR) is a life-threatening complication of red blood cell (RBC) transfusion in sickle cell disease (SCD) patients, leading to the increase of plasma hemoglobin (Hb) and heme which are responsible for endothelial damage and organs failure. By the development of an in vitro model reproducing endothelial damages at the early phase of DHTR (Nguyen et al, ASH 2018), our previous study suggested that RBC membrane-derived particles released during the onset stage of DHTR could be also involved in DHTR physiopathology. Aims: In this study, we aim to determine the mechanism of endothelial damages induced by these RBC particles. Methods: Human Umbilical Vein Endothelial Cells (HUVECs) cultured in flow condition for 24 hours were perfused by either serum only (decomplemented or not) or serum containing either whole hemolysate (sonicated RBCs) or different hemolysate components or RBCs membranes (ghosts) under shear stress 1 dyne/cm2. Annexin V and Eculizumab were used for complement studies. Endothelial activation and damages were assessed by membrane CD54 (PECAM-1, Platelet endothelial cell adhesion molecule 1), CD106 (VCAM-1, Vascular Cell Adhesion Molecule-1) and actin network staining. The whole blood adhesion assays and platelets aggregation study on hemolysate-preconditioned HUVECs were performed in continuous flow. Confocal microscopy was used to study interaction between HUVECs and hemoglobin (Hb) and RBC membrane-derived particles. Results: Our fluidic model reproduced a hemolysate-induced pro-inflammatory phenotype and damages of HUVECs via NFkB signaling pathway in a TLR-4 independent manner. The most deleterious effects were observed in whole hemolysate conditions in which, an important quantity of RBC large-size particles (> 2 μm) mostly positive for C3 was detected. These effects on HUVECs were significantly reduced after their elimination by 14000 g centrifugation (Figure 1). Noteworthy, the suspension of ghosts induced a similar activation on HUVECs compared to whole hemolysate suggesting the major role of RBC membrane-derived particles in early hemolysis-induced endothelial damages. Confocal microscopy for intracellular compartment of hemolysate-treated HUVECs demonstrated that while the CD235a+ Hb+ particles were only found in whole hemolysate conditions, the Hb was detected similarly in all conditions tested. Selective blocking of RBCs particles and Hb endocytosis did not affect hemolysate-induced HUVECs activation. These observations demonstrate that in the very early stage (≤4H) of intravascular hemolysis, erythrocytes large-size particles can be internalized in HUVECs, but their internalization is not necessary for endothelial activation effect. Complement inactivation of serum or treatment of RBC particles by either Annexin V or Eculizumab could reduced their effects on endothelial activation suggesting a complement-dependent mechanism Image:Summary/Conclusion: This study suggested for the first time the major role of RBCs large-size particles on endothelial damages at the onset of DHTR in a complement-dependent manner justifying the complement blocking treatment in certain DHTR patients. Furthermore, we have also demonstrated the endocytosis of free Hb by HUVECs, but its pathological impact is still unclear. This endocytosis would facilitate the Hb clearance during a massive hemolysis? These new understandings will allow a better and earlier management to preserve endothelial functions.

Analyzing real world data of blood transfusion adverse events: Opportunities and challenges.

Blood transfusions are a vital component of modern healthcare, yet adverse reactions to blood product transfusions can cause morbidity, and rarely result in mortality. Therefore, accurate reporting of transfusion related adverse events (TRAEs) is paramount to improved transfusion practice. This study aims to investigate real-world data (RWD) on TRAEs by evaluating differences between ICD 9/10-based electronic health records (EHR) and blood bank-specific reporting. TRAE data were retrospectively collected from a blood bank-specific database between Jan 2015 and June 2019 as the reference data source and compared it to ICD 9/10 diagnostic codes corresponding to various TRAEs. Seven reactions that have corresponding ICD 9/10 diagnostic codes were evaluated: Transfusion related circulatory overload (TACO), transfusion related acute lung injury (TRALI), febrile non-hemolytic reaction (FNHTR), transfusion-related anaphylactic reaction (TRA), acute hemolytic transfusion reaction (AHTR), delayed hemolytic transfusion reaction (DHTR), and delayed serologic reaction (DSTR). These accounted for 33% of the TRAEs at an academic institution during the study period. Among 18637 adult blood transfusion recipients, there were 229 unique patients with 263 TRAE related ICD codes in the EHR, while there were 191 unique patients with 287 TRAEs identified in the blood bank database. None of the categories of reaction we investigated had perfect alignment between ICD 9/10 codes and blood bank specific diagnoses. Multiple systemic challenges were identified that hinder effective reporting of TRAEs. Identifying factors causing inconsistent reporting between blood banks and EHRs is paramount to developing effective workability between these electronic systems, as well as across clinical and laboratory teams.

Would a National Antibody Register contribute to improving patient outcomes?

Despite stringent testing protocols, there always remains a chance of a delayed haemolytic transfusion reaction (DHTR) occurring as a result of an undetected or unknown antibody. In this systemic review and meta-analysis, we aimed to investigate improvements to patient outcomes that could be achieved through the implementation of a national antibody registry. A series of searches through PubMed and SCOPUS identified a collection of articles with relevant information, restricted to full text, English language articles available through the RMIT Library service. 25 articles were considered for the review, four of these found to have relevant, extractable data for use in the meta-analysis. Alloantibody evanescence rates were analysed for the potential for reducing DHTRs associated with transfusion services, returning significant results indicating antibody evanescence rates of up to 68.4% in one study, with p-values less than 0.001. Due to the small number of included studies however, the interference values were quite high for these analyses at greater than 90% for each. Additional, beneficial side-effects of such a system were also considered, along with reductions in DHTRs. In conclusion it was determined that a National antibody registry would contribute to improving patient outcomes, however further studies could be performed to determine a stronger correlation, and exact levels of improvement that could be achieved.

Prevalence of Rhesus &amp; Kell phenotypes among blood donors of Bangladesh

The Rhesus blood group system is one of the most polymorphic and highly immunogenic systems in humans. Because of its high and strong immunogenicity Rh D antigen testing is mandatory before issuing a compatible blood. There are five major antigens i.e. DCEce in the Rhesus (Rh) blood group system. On the other hand from the immunogenicity point of view Kell antigen is next to the Rh system. Both of them may cause severe hemolytic transfusion reaction and hemolytic disease of fetus and new born. Exposure of Rhesus negative individuals to Rhesus positive blood through transfusion or pregnancy is most likely to stimulate production of Rhesus antibodies. These antibodies may cause Hemolytic Disease of Fetus and Newborn (HDFN) and Delayed Hemolytic Transfusion Reaction (DHTR). Like Rhesus antibodies, Kell antibodies may also cause HDFN and DHTR. So far we know, there is not enough study regarding antigens C, c, E &amp; e of Rh or K, k antigen of Kell blood group system regarding these antigens in the donors in Bangladesh, thereby exposing transfused patients to these antigens negative patients. To determine the phenotype prevalence of the Rh and Kell blood group systems in the blood donors in Bangladesh, a descriptive cross sectional study was done in the laboratory of Department of Transfusion Medicine, Bangabandhu Sheikh Mujib Medical University, during the period of 1st January 2020 to 31 December 2020. Rhesus Phenotype CCDee is highest (48.4%) &amp; CCDEe &amp; ccDEE both are lowest (0.4%). Most probable Rhesus Genotype CDe/CDe (R1R1) is highest (48.4%) and CDe/CDE (R1Rz) &amp; cDE/cDE (R2R2) both are lowest (0.4%). Kell Genotype kk is highest (99.2%) and Kk is lowest (0.8%). BSMMU J 2021; 14(3): 38-42

Extended phenotyping does not preclude the occurrence of delayed haemolytic transfusion reactions in sickle cell disease.

Delayed haemolytic transfusion reaction (DHTR) is a potentially life-threatening complication of red blood cell (RBC) transfusions in sickle cell disease (SCD) and is classically induced by reactivation of previously formed antibodies. Improved antigenic matching has reduced alloimmunization and may reduce DHTR risk. We conducted a retrospective cohort study to investigate the incidence rate of DHTR in SCD patients receiving extended matched units (ABO/RhDCcEe/K/Fya /Jkb /S). Occasional transfusion episodes (OTE) between 2011 and 2020 were reviewed for occurrence of DHTR symptoms using four screening criteria: decreased Hb, increased lactate dehydrogenase (LDH), pain, and dark urine. We included 205 patients who received a cumulative number of 580 transfusion episodes of 1866 RBC units. During follow-up, 10 DHTR events were observed. The incidence rate of DHTR was 13·8/1000 OTEs [95% confidence interval (CI): 7·37-22·2], with a cumulative incidence of 15·2% (95% CI: 8·4-24·0%) after 25 patients having received RBC units. One DHTR event was fatal (10%). Symptoms were misdiagnosed in four DHTR events (40%) as other acute SCD complications. Despite a lower incidence rate compared to most other studies, the incidence rate of DHTR in SCD remains high, in spite of extended matching of donor RBCs. Increased awareness of DHTR is of utmost importance to facilitate early diagnosis and, consequently, improve outcome.