Hemolytic Transfusion Reactions Research Articles

Immunological Compatibility of Novel Enzyme-Converted Universal Blood Donor Cells

Introduction: In transfusion, unintentional mismatching of blood groups remains one of the most common causes of serious and sometimes fatal adverse reactions. Scarcity of certain blood types is another major transfusion challenge. The ABO blood group specificity is determined by the terminal monosaccharides, N-acetylgalactosamine on A and galactose on B RBCs. To create a universal blood supply, cell surface engineering has been studied as a method to minimize the immunological rejection of donor cells. Enzymatic removal of immunodominant sugars would uncover universally acceptable H-antigen (O group RBC). However, enzymatic conversion of A-type RBCs was lagging due to a lack of very active and specific glycosidases and the complex nature of the A blood group antigen. In this research, the performance of two novel enzymes that act together extremely efficiently to convert A-type RBCs to universal donor O RBCs, with high specificity for A antigen, is evaluated. Optimal conversion conditions are explored, as well as the immunological compatibility of the converted RBCs. Materials & Methods: Whole blood samples are collected from consenting A donors (with approval from the University of British Columbia clinical research ethics board), washed and diluted to 10 % hematocrit in PBS buffer (pH7.4). The washed RBCs were treated with the newly developed glycosidases for 1 h at 37 oC. The efficiency of the newly developed glycosidases and the characterization of enzyme converted O (ECO)-RBCs were evaluated by gel-column based micro typing system (MTS) cards against A antigen and flow cytometry using anti A and H antibodies. Safety and compatibility of ECO-RBCs were assessed by blood group serology studies. In brief, ECO-RBCs were incubated in Rh-matched sera collected from diverse donors and any serum reactivity against ECO-RBCs was assessed using anti IgG MTS cards and flow cytometry using anti C3d (complement protein) antibody. To further confirm the cross-matching of ECO-RBCs, the monocyte monolayer assay (MMA), a clinically used method, was performed using monocytes collected from B and O blood donors to assess the phagocytic activity against ECO-RBCs pre-incubated with serum samples. Phagocytic activity against ECO-RBCs was calculated using the monocyte index (MI). Results: Anti A MTS cards and flow cytometry analysis of antigen A and H expression, after enzymatic treatment, confirmed successful conversion of A blood group to universal O group. Our studies showed no significant hemolysis and no complement protein (C3d) deposition on ECO-RBCs pre-incubated with diverse sera, demonstrating the compatibility. Serology studies showed that ECO-RBCs are compatible with most sera (~50 donors) studied under transfusion conditions, though serum reactivity was shown by some O and B sera. A MI value of ≤ 6 % was obtained for all ECO-RBCs indicating minimal risk of an acute hemolytic reaction associated with ECO-RBC transfusion. Conclusions: We have developed novel glycosidases that efficiently remove immunodominant A antigen from RBC surfaces with high specificity to create universal blood donor cells at neutral pH and at enzyme concentrations that are much lower than those previously required. Based on preliminary results, ECO-RBCs have the potential to increase donor blood supply and thereby greatly advance the field of transfusion.

Drugs and Conditions That May Mimic Hemolysis.

Visual inspection of posttransfusion plasma for hemolysis is a key laboratory method in the investigation of possible acute hemolytic transfusion reactions (AHTRs). Many substances and physiologic conditions can mimic hemolysis in vitro. Isolated reports describe specific cases of interference, but a comprehensive listing is lacking. Using an illustrative case, we summarize available literature on substances and conditions that may mimic hemolysis in vitro. We further describe other substances and conditions that may discolor plasma but are unlikely to be mistaken for hemolysis on visual inspection. At least 11 substances and conditions have been reported to discolor plasma, in colors ranging from orange to red to brown, including relatively common therapies (eg, eltrombopag, hydroxocobalamin, iron dextran). Other substances are unlikely to be encountered in everyday practice but may mimic hemolysis in particular patient populations. Additional substances may cause plasma discoloration, ranging from blue to green to white, and are associated with a wide variety of therapies and conditions. An awareness of the possible preanalytic confounding factors that may mimic hemolysis can aid in the workup of a suspected AHTR. Review of the medical record, use of ancillary testing, and consideration for nonimmune causes of hemolysis can aid in ruling out AHTR.

Low haptoglobin in pregnancy: physiological or intravascular hemolysis?

Abstract A woman in her second trimester of pregnancy (24 weeks of gestation), diagnosed with B-cell acute lymphoblastic leukemia, received induction chemotherapy. On day six of treatment, she required transfusion with two red cell (RBC) units for anemia. Less than 12 hours later, laboratory results included elevated total bilirubin, 4.3 mg/dL [reference interval <=1.2 mg/dL], direct bilirubin, 0.3 mg/dL [reference interval <=0.3 mg/dL], haptoglobin below detection limit, <10 mg/dL [reference interval: 30 - 200 mg/dL], and normal lactate dehydrogenase (LD), 186 U/L [reference interval: 122 - 241 U/L]. These tests were ordered without any clinical suspicion for intravascular hemolysis, and upon receiving the results, the primary team consulted transfusion medicine due to concern for an acute hemolytic transfusion reaction (AHTR). After finishing the corresponding workup, the patient did not meet the Center of Disease Control (CDC) criteria for AHTR. The patient was discharged and on follow-up visits her haptoglobin increased to 15 mg/dL (25 weeks 3 days of gestation). Later, during her third trimester (27 weeks 3 day of gestation), haptoglobin increased to 142 mg/dL; LD always remained normal. Hemolysis is not associated with normal LD. Instead, some literature suggest that pregnant patients may have lower haptoglobin levels than reported in the non-pregnant population, with a nadir occurring in the second trimester. It is possible that low haptoglobin in this population may be due to the combination of hemodilution and a high estrogen state. But no literature is available that provide trimester-specific reference intervals for haptoglobin, which may lead to misinterpretation. Inspired by this case, we developed a quality improvement project to determine trimester-specific reference intervals for haptoglobin in pregnancy. Haptoglobin was tested on remnant serum samples (BD Vacutainer SST) collected from routine outpatient pregnancy patients (n=401; at least 80 samples per trimester) using Roche/Hitachi cobas c systems. Derived nonparametric reference intervals were 22-188 mg/dL for first trimester, 29-177 mg/dL for second trimester, 53-185 mg/dL for third trimester, and 30-185 mg/dL for the entire sample population. While overall reference intervals were similar, consistent with previous reports, we noticed a shift in haptoglobin distribution to the low end in the second trimester [29 (CI95% 7-35) mg/dL; median 98 mg/dL] in comparison with first trimester [22 (CI95% 15-47) mg/dL; median 113 mg/dL p = 0.34] and third trimester [29 (CI95% 7-35); median 112 mg/dL p=0.34].In the case described, the first haptoglobin below limit of detection could have been due to the combination of pregnancy (second trimester), recent red cell transfusion of RBC units (28 days old) and hyperhydration with crystalloids as part of the chemotherapy plan. This case also serves as a reminder that laboratory tests should be ordered mindfully, to aid in confirming or ruling out clinically suspected syndromes/diseases that are unlikely.

Continuing Profound Impact of Continued Education Sessions on Blood Bank Specimen Labeling Years Later at the Veteran Affairs Medical Center

Abstract Introduction/Objective Proper patient identification is a critical safety element for transfusion medicine, particularly for the prevention of acute hemolytic transfusion reactions (AHTR). Mislabeled specimens have been documented to carry an increased risk of patient misidentification. Therefore, the submission of a mislabeled specimen to the blood bank generally results in a specimen rejection with a redraw. At the Philadelphia Veteran Affairs Medical Center, an identification bracelet with alphanumeric code is used to help improve transfusion safety but also has additional patient labeling requirements. The redrawing of blood bank specimens poses risks in phlebotomy, and a quality improvement initiative was previously undertaken to educate staff on proper blood specimen and band labeling and usage to prevent labeling errors, improve safety in patient care, and reduce intended redraws. Methods/Case Report Colorful laminated posters delineating the labeling requirements and process for blood bank specimens collected using the blood bank system were made and distributed at the time of in-service training by the blood bank in 2017 to the areas of the hospital whereby errors had been noted to occur in the past. The dedicated in-service training was repeated prior to the change in the identification blood band from the Hollister Ident-ATM Blood Recipient Band (Precision Diagnostics Corporation, Valencia CA) to the Typenex Blood Bands (Typenex Medical, Chicago IL) on 11/12/2019. As part of the quality metrics of the blood bank, blood bank specimen labeling errors was tracked from 2017 to track the persistence of the effect of the initial training. Results (if a Case Study enter NA) The percentage of properly labeled specimens as a percentage of total specimens increased after the in-service training; specifically, an increase from a low of 97% (December 2017) to a high of 99% (August 2018). The percentage of properly labeled specimens remains at the increased level of 99% and above even at the 4.5-year mark in mid-2022. Conclusion The continued availability of laminated educational posters on blood specimen labeling for the clinical service areas combined with initial in-service education can have lasting effects to improve the quality of care even years after the initial in-service education sessions.

Racial Disparity in Antibody Against High Prevalence Antigen; Anti-U

Abstract Introduction/Objective Anti-U is an IgG antibody directed against the U antigen, which usually forms after exposure to U antigen via blood transfusion and/or pregnancy. U antigen is located on glycophorin B (GYPB) as part of the MNS blood group system. Approximately 2% of the African American population lacks this antigen, making them prone to developing anti-U. Anti-U can cause hemolytic disease of fetus and newborn (HDFN) and hemolytic transfusion reactions (HTR). Methods/Case Report A 60-year-old African American male underwent aortic valve surgery. The patient was A Pos with a negative antibody screen. During surgery, the patient was transfused with 3 random units of packed red blood cells (PRBCs). The postoperative course was uncomplicated, and the patient was discharged home. 6 months later, the patient was admitted for another procedure and was expected to require blood products. Thus, a type and screen test was ordered, revealing pan reactivity on screening cells. This prompted further investigation. Antibody detection was performed with the solid-phase technique followed by the tube method with Polyethylene glycol (PEG) as an enhancement medium. PEG technique is the next choice of method if the solid phase requires extended antibody work up, which was the case in our patient. PEG tube method successfully identified Anti-U, and the patient's phenotype was confirmed to be U negative. Results (if a Case Study enter NA) N/A. Conclusion It is imperative to stress the importance of racial disparity while investigating antibodies against high prevalence. In our case, our suspicion was high for Anti-U, given that patient was of African American descent. Tube methods with PEG and Solid Phase techniques are usually used for antibody identification. It is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they have to prevent further exposure.

Prevalence and Specificities of Immune Red Cell Antibodies in Adult Patients with Sickle Cell Anaemia and Blood Donors in Uyo, South-South Nigeria: A Case-Control Study

Background: Sickle cell anaemia (SCA) is a major public health issue in Sub-Saharan Africa, including Nigeria. Transfusion of red blood cells is an essential therapeutic modality in SCA. Repeated RBC transfusions can cause alloimmunization resulting in haemolytic transfusion reactions, transfusion refractoriness among other complications. Aims and Objectives: The study aimed to determine the prevalence and specificities of immune erythrocyte alloantibodies among adult patients with SCA compared with healthy HbAA blood donors in Uyo, South-South Nigeria. Materials and Methods: All participants were interviewed using a structured questionnaire to obtain information on bio- data, blood transfusion history and other relevant SCA history. Antibody screening and identification were carried out using tube agglutination method with commercially made panel of cells. Results: A total of 160 subjects were studied. They were made up of 80 SCA patients and 80 healthy HbAA blood donors. Prevalence of red cell alloimmunization among multi-transfused patients with SCA was observed to be 11.3%. Alloantibodies identified were mainly against Rh antigens contributing 66.7% (anti-E 22.2%, anti-C 22.2%, anti-D 11.1% and anti-e 11.1%). Antibodies directed against Kell and Lutheran blood group antigens together constituted 33.3%. No antibody was detected in the controls. Advancing age (30 years and above) and ABO blood group were statistically associated with alloimmunization (P values of 0.043 and 0.013, respectively). Conclusion: Repeated blood transfusion is associated with the development of alloantibodies. Immunohaematologic tests in transfusion care of SCA patients should be improved to include extended red cell phenotyping and routine alloantibody screening and identification.

Comparative Sensitivity of Solid-Phase Versus PEG Enhancement Assays for Detection and Identification of Red Blood Cell Antibodies

Abstract Introduction/Objective Identifying antibodies to red blood cell (RBC) antigens is one of transfusion medicine’s most critical and challenging issues. There are 354 RBC antigens recognized by the International Society of Blood Transfusion. Accurate identification of clinically significant alloantibodies is imperative for identifying and preventing hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. We compared the performance of the tube (polyethylene glycol–indirect antiglobulin test [PEG-IAT]) and solid-phase techniques for antibody identification. Methods/Case Report We performed a retrospective study on all antibody screens and identifications performed between 2007–2021 at Stanford Hospital. Over this period, 631,535 antibody screens were performed predominantly using an automated solid-phase technique. Subsequent antibody identification studies were performed using manual tube testing (PEG-IAT) and automated solid-phase techniques. Results (if a Case Study enter NA) Antibody screening resulted in 28,316 (4.5%) positive samples with at least one antibody. Antibody identification performed on both platforms identified 50 discordant [DMH1] samples. 8 anti-Jka, 2 anti-Jkb, 1 anti-S, and 1 anti-M were detected by automatic solid-phase technique but were not detected by PEG-IAT. 20 anti-E, 6 anti-K, 2 anti-Fya, 2 anti-c , 2 anti-C, 2 anti-Fyb, 1 anti-cE[DMH2] , 1 anti-e,1 anti-M, and 1 anti-S were detected by PEG-IAT but were negative by automated solid-phase technique. Anti-E had the least sensitivity (98.99%) in the automated solid-phase technique, while anti-Jkb had the least sensitivity (98.78%) in PEG-IAT. Conclusion This is the first robust 15-year study comparing methodologic sensitivity to detect clinically significant alloantibodies. The incidence of discordant results between the PEG-IAT and solid-phase technique was low. Among discordant samples, anti-Jka was commonly detected by solid-phase but not by PEG-IAT. In contrast, anti-E was commonly detected by PEG-IAT but not by the solid phase.

Analysis of ABO subgroups which result in ABO discrepancies in Iranian blood donors

The ABO blood group system plays a vital role in the blood transfusion and transplantation medicine [ [1] Hosseini‐Maaf B. Hellberg Å. Chester M.A. Olsson M.L. An extensive polymerase chain reaction–allele‐specific polymorphism strategy for clinical ABO blood group genotyping that avoids potential errors caused by null, subgroup, and hybrid alleles. Transfusion. 2007; 47: 2110-2125 Crossref PubMed Scopus (43) Google Scholar ]. It consists of the major A, B, O alleles and many of subtypes with weak expression of A or B antigens on red blood cells. The results of both forward and reverse ABO typing are necessary for ABO blood group typing, as they are both necessary for interpreting the results [ [2] Arumugam P. Hamsavardhini S. Ravishankar J. Bharath R. Resolving ABO discrepancies by serological workup‐an analysis of few cases. Int J Res Med Sci. 2017; 5: 893-900 Crossref Google Scholar ]. ABO discrepancies may be due to technical or human errors, weak subgroups, the transient expression of antigens in some disease like carcinomas and mixed-filled agglutination after massive or chronic transfusion [ 3 Kaur G. Kaur P. Basu S. Kaur R. Blood group discrepancies at a tertiary care centre–analysis and resolution. Int J Lab Hematol. 2014; 36: 481-487 Crossref PubMed Scopus (18) Google Scholar , 4 Meny G. Recognizing and resolving ABO discrepancies. Immunohematology. 2017; 33: 76-81 Crossref PubMed Google Scholar , 5 Storry J.R. Condon J. Hult A.K. Harrison A. Jørgensen R. Olsson M.L. An age‐dependent ABO discrepancy between mother and baby reveals a novel A weak allele. Transfusion. 2015; 55: 422-426 Crossref PubMed Scopus (7) Google Scholar ]. The incidence of ABO discrepancies among blood donors was reported from 0.02 % to 0.06 %, Also the ABO subgroups are considered the most common cause of ABO discrepancies [ 3 Kaur G. Kaur P. Basu S. Kaur R. Blood group discrepancies at a tertiary care centre–analysis and resolution. Int J Lab Hematol. 2014; 36: 481-487 Crossref PubMed Scopus (18) Google Scholar , 6 Sharma T. Garg N. Singh B. ABO blood group discrepancies among blood donors in Regional Blood Transfusion Centre GTB Hospital, Delhi, India. Transfus Apher Sci. 2014; 50: 75-80 Abstract Full Text Full Text PDF PubMed Scopus (13) Google Scholar , 7 Makroo R.N. Kakkar B. Agrawal S. Chowdhry M. Prakash B. Karna P. Retrospective analysis of forward and reverse ABO typing discrepancies among patients and blood donors in a tertiary care hospital. Transfus Med. 2019; 29: 103-109 Crossref PubMed Scopus (10) Google Scholar ]. Weak ABO subgroups are categorized as type II (Weak/missing antigen) or type IV (due to presence of Anti–A1) ABO discrepancy [ [8] Jain A. Gupta A. Malhotra S. Marwaha N. Sharma R.R. An ABO blood grouping discrepancy: Probable B (A) phenotype. Transfus Apher Sci. 2017; 56: 459-460 Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar ]. Mistyped A and B weak blood group as O and B(A) as cisAB and AxB during routine serologic tests can have serious consequences, such as hemolytic adverse transfusion reactions [ [9] Jiao L.X. Zhang J.Y. Chen L. Yu X.L. Han Y. Yang F. et al. Gene identification of rare B (A) blood group. Transfus Apher Sci. 2017; 56: 855-857 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar ].

An Adjusted Process to Improve Efficiency and Efficacy of Adsorption Procedures to Resolve Warm Autoantibody Cases.

The presence of warm autoantibodies in patient plasma typically causes extended delays in patient care due to panreactive antibody identification tests. Adsorption is the primary method for resolution. A modified adsorption procedure was devised with the intent to minimize delays, and the aim of the study was to evaluate its efficacy. To evaluate the in-house developed (experimental) adsorption method, specimens were tested in parallel with the standard adsorption method described in the AABB Technical Manual, 20th edition. Specimens selected demonstrated panreactivity at the submitting facility and contained adequate volume for parallel adsorption studies. Ninety specimens were tested with both methods. Ninety specimens achieved complete adsorption with the experimental method and 88 specimens achieved complete adsorption with the standard method. Two underlying alloantibodies, which have been reported to cause hemolytic transfusion reactions and potential renal graft rejection, were detected using the experimental method that the standard method failed to detect. The experimental method demonstrated a significant reduction in rounds of adsorption required to resolve warm autoantibody reactivity, enhanced antibody detection ability with adsorbed plasma, and more cost-effective outcomes compared to the standard method. A follow-up study is planned to assess whether the incubation time can be decreased with the experimental method to further improve the efficiency of the method without sacrificing efficacy.

ALLOIMMUNIZATION PREVALENCE IN PATIENTS WITH SICKLE CELL DISEASE (SCD): ASSESSMENT OF THREE TRANSFUSION PROTOCOLS

RBC alloimmunization is a major complication associated with RBC transfusion in patients with SCD with serious complications for the patient including life-threatening delayed hemolytic transfusion reactions and an increase in the risks inherent to transfusion such as TRALI, infectious diseases and the hyperhemolysis syndrome. In addition, the presence of alloantibodies, which is often associated with the concomitant presence of autoantibodies, can lead to difficulty in finding compatible units, which can cause transfusion delays. The prevalence of alloimmunization vary according to the transfusion protocols used and may be reduced by matching for RBC antigens. Based on this, the aim of this study was to assess the prevalence of RBC alloimmunization in patients receiving transfusions with ABO and D matching, with phenotype matching for C, E and K antigens and with extended minor RBC antigen matching. A total of 368 patients with SCD, homozygous for HbS were enrolled. In this period, 81 patients received RBC units matched for ABO and RhD, 188 patients were matched for C, E and K and 99 patients were matched for ABO, Rh, K, Fya/Fy/b, Jka/Jkb and S/s antigens. Transfusion and antibody histories were obtained from our records, and antibody screening was done to assess the alloimmunization prevalence. Molecular typing was performed in all patients who had recent transfusions or a positive direct antiglobulin test by Laboratory Developed Tests (LDT) and HEA BeadChip (Immucor) to predict their antigen profile. RH variant alleles were determined in patient's antigen-positive who developed Rh antibodies using RHD and RHCE BeadChips (Immucor). Adsorption onto autologous RBC was also performed to aid the differentiation of autoantibodies from alloantibodies. Of the 368 patients evaluated, 128 were male and 240 female. Mean age was 37.4 years (range 18-60) and they received an average of 74 RBC units. Prevalence of alloimmunization in the SCD patients with ABO/RhD matched only units (n=81) was 54%. For individuals transfused with C, E and K matched units (n=188), alloimmunization prevalence was 13% and patients transfused with extended-matching units (n=99) the prevalence of alloimmunization was 0.8%. Antibody specificities developed by the patients receiving Rh and K matched units were: Anti-e, -D, -Jk a , -Jk b , -S, -Di a , -V and by the patients receiving extended matching were anti-C, -e, -V, -VS. The variant RHCE*ceS , RHCE*ceMO , RHD*DIIIa-CE(4-7)-D and RHD*DAU3 alleles were associated with the production of Rh antibodies in these patients and 9.8% of the alloimmunized patients developed autoantibodies. RBC alloimmunization rates shown to decrease to 24 % in patients with SCD transfused with RBCs matched for C, E and K antigens and to 1.5 % to patients with extended matching. Provision of RBC transfusions with limited and extended antigen matching is essential to reduce the rates of alloimmunization and hemolytic transfusion reactions in patients with SCD.

EVALUATION OF THE COST AND EFFECT OF PROPHYLACTIC GENOTYPIC MATCHING ON ALLOIMMUNIZATION AND AUTOIMMUNIZATION IN PATIENTS WITH SICKLE CELL DISEASE (SCD)

Blood transfusion is one of the mainstays of treatment for patients with SCD but despite of the beneficial effects, transfusion therapy can lead to red blood cell (RBC) alloimmunization with serious complications for the patient including life-threatening delayed hemolytic transfusion reactions and the hyperhemolysis syndrome. In addition, the presence of alloantibodies, which is often associated with the concomitant presence of autoantibodies, can lead to difficulty in finding compatible units, which can cause transfusion delays. To reduce alloimmunization some strategies have been implemented to provide antigen matched RBC transfusions to patients with SCD who need chronic transfusion support. In this context, phenotypic and genotypic matching protocols have been used. Based on this, the aim of this study was to evaluate the cost and the effect of prophylactic RBC transfusion genotypic matching on alloimmunization and autoimmunization in patients with SCD. Our study included 79 (33 male and 46 female) patients with SCD, homozygous for HbS, on chronic RBC transfusion therapy receiving prophylactic genotypic matching RBC transfusions in the last two years. In this period, patients received RBC units genotypic matched for Rh, K, Fya/Fy/b, Jka/Jkb, S/s, Doa/Dob and Dia antigens. Molecular matching was performed according to previous molecular typing results performed by the HEA BeadChip (Immucor) in patients and donors. Adsorption onto autologous RBC was also performed to aid the differentiation of autoantibodies from alloantibodies. The cost and availability of compatible units by performing genotypic matching were compared to serologic matching. The patients received a range of 5-215 units. And the median age in this group was 39 years old. Of the 79 patients, 17 (21.5%) were alloimmunized before they started receiving genotypic matched RBC transfusions. During this study-period only 2 patients (2.5%) with Rh variants developed alloantibodies (1 anti-C, 1 anti-e) and no patient produced autoantibody. Although the availability of compatible units has decreased when compared to serological matching, it was possible to find compatible units for most patients. A cost reduction of 30% was observed in the genotypic matching compared to the serological matching for the selected matched antigens. RBC transfusions with extended genotypic matching had significant effects on autoimmunization and alloimmunization rates in chronically transfused patients with SCD over two years. Alloimmunization rates have shown to decrease from a range of 21.5 to 2.5% in these patients. SCD patients may benefit from receiving prophylactic genotypic matching RBC transfusions as demonstrated by the reduction on the rates of alloimmunization, autoimmunization and cost.

Whole blood transfusion and paroxysmal nocturnal haemoglobinuria meet again: Minor incompatibility, major trouble.

The field of transfusion medicine started out with whole blood transfusion to treat severe anaemia and other deficiencies, and then transitioned to component therapy, largely leaving the practice, and experiences, of whole blood transfusions behind. Currently, the field is circling back and whole blood is gaining ground as an alternative to massive transfusion protocols. Herein we describe a severely anaemic paroxysmal nocturnal haemoglobinuria (PNH) patient initially suspected of suffering from renal haemorrhage, receiving a standard low-titre group O whole blood transfusion during pre-hospital transportation. Following the transfusion, the patient suffered a clinically unmistakable haemolytic transfusion reaction requiring supportive treatment in the intensive care unit. Clinical observations are consistent with an acute haemolytic reaction. The haemolysis was likely due to minor incompatibility between the plasma from the transfused whole blood and the patient's PNH red cells. Recovery was uneventful. This revealed an unappreciated contraindication to minor incompatible whole blood transfusion, and prompted a discussion on the distinction between whole blood and erythrocyte concentrates, the different indications for use and the importance of emphasizing these differences. It also calls attention to patient groups where minor incompatibility can be of major importance.

Hyperhaemolysis Syndrome: A Review of Cases

Hyperhaemolysis is characterized by a haemolytic transfusion reaction that leads to life-threatening anaemia. It is usually suspected when there is a drop in haemoglobin level at least 24 hours after receiving allogeneic red cell transfusion. Decreasing haematocrit level, failure to respond to repeated RBC transfusions, markedly elevated LDH, absent haptoglobin, and gross haemoglobinuria are all suggestive of a haemolytic process. The aim of this review is to summarize and evaluate the cases from published literature to determine the features, management and outcome of reported cases of hyperhaemolysis syndrome.

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.

P29. Decreasing the rate of unnecessary pediatric deformity surgery allogenic blood transfusions

<h3>BACKGROUND CONTEXT</h3> Spinal deformity surgery is associated with a high perioperative blood loss and risk for allogenic blood transfusion (ABT). Previous studies have shown ABT has an increased risk of surgical site infection, acute hemolytic reaction, and transfusion-related lung injury. During our yearly review, our institution was noted to have a high rate of ABT compared to other hospitals in the United States. In this study, we examined the efficacy of strategies taken to decrease our transfusion rate. <h3>PURPOSE</h3> To decrease the rate of allogenic blood transfusions in a pediatric spinal deformity population by increasing awareness and scrutiny. <h3>STUDY DESIGN/SETTING</h3> Prospective cohort. <h3>PATIENT SAMPLE</h3> Patients included had a diagnosis of AIS, underwent posterior instrumentation and fusion (PSIF), were between ages 10-18, and had a major cobb angle between 45-70°. <h3>OUTCOME MEASURES</h3> Allogenic blood transfusion rate. <h3>METHODS</h3> Interventions to reduce ABT included a meeting with the postoperative care unit (PCU) and pediatric intensive care unit (PICU) where scoliosis patients recovered, encouraging increased use of cell saver or intraoperative blood salvage, a change in our postoperative protocol template stating, "notify spine surgery team if blood transfusion is considered," aweekly report of AIS surgeries and if transfusion occurred. <h3>RESULTS</h3> A total of 197 patients met criteria over 3 years. The rate of ABT from January 2019 to 2020 was 19.5% (15/77) and from January 2020 to 2021 13.3% (8/60). The interventions to reduce ABT rates were implemented between November 2020 to January 2021. From January 2021 to November 2021 only 5% (3/60) of patients received an ABT, representing a significant decrease from 2020 to 2021 (p<0.01). No significant difference in demographics between groups existed including gender or age. <h3>CONCLUSIONS</h3> The rate of ABT at our institution was significantly lowered from 19.5% to 5%. This was accomplished by increasing scrutiny prior to transfusion, including meeting with the postoperative care units, change in our protocol template and increasing scrutiny after transfusion by performing a weekly review of AIS surgeries and if transfusion occurred. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Remote Dispensing of Emergency Release Red Blood Cells.

Patients with acute bleeding are frequently transfused with emergency release (ER) group O RBCs. This practice has been reported to be safe with a low rate of acute hemolytic transfusion reactions (AHRs). Records of patients who received ER RBCs over a 30-month period were examined at our hospitals. During this period, satellite refrigerators were on site in the emergency department (ED), which were electronically connected to the blood bank (electronically connected satellite refrigerator [ECSR]). Nurses accessing the refrigerator were required to give patient identification information, when known, prior to removal of the ER RBCs, allowing technologists the opportunity to check for previous serologic records and communicate directly with the ED if a serologic incompatibility was potentially present. In total, 935 patients were transfused with 1,847 units of ER RBCs. Thirty of these patients had a current (22/30) or historic (8/30) antibody. In 15 cases, incompatible RBCs were interdicted. In six cases, the transfusion was considered urgent, and an AHR occurred in four of these six (overall 0.4%), including one fatal AHR due to anti-KEL1. Use of KEL1-negative RBCs and ECSR merits consideration as approaches to mitigate the occurrence of ER RBC-associated AHRs.

A prospective observational study to compare transfusion outcomes in ABO identical versus ABO non-identical single donor platelet concentrates: An experience from a tertiary healthcare center in India.

ABO incompatible single donor platelet concentrates (SDPC) have a concern about unsatisfactory increments as well as possibility of hemolytic transfusion reaction. But from Indian population no study has commented on the clinical and laboratory outcome of ABO mismatched platelet transfusion. The aim of study was to compare transfusion outcomes in ABO identical versus ABO non-identical single donor platelet concentrates. In this prospective observational study, 400 SDPC transfusions among different patients were included. In group A (n=200), ABO identical SDPC transfusions and in group B (n=200) ABO non-identical SDPC transfusions were added. Corrective count increment (CCI), absolute count increment (ACI), percent platelet recovery (PPR) were calculated and incidents of hemolytic transfusion reactions were noted. In group A mean±SD of ACI, CCI and PPR were as 30.78±12.51, 15.10±6.677, 39,948.9±20,099.392. In group B, mean±SD of ACI, CCI and PPR were-25.4±15.65, 12.509±5.906, 33,559.2±22,150.304. And when CCI, ACI, PPR were compared with group A and group B, statistically significant differences were noted (P<0.05). There was statistically significant difference in CCI, ACI and PPR in oncology patients and other prophylactic recipients except patients with dengue and other infectious disease. But there was no hemolytic transfusion reaction noted in any group. Our study clearly establish the potential benefits of ABO-identical PLT transfusion. It also points out that in emergency conditions or when there is a paucity in inventory, ABO non-identical SDPC transfusion may be lifesaving and clinically significant.

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.

Evaluation of Low Concentration Dithiothreitol for Negating the Monoclonal Anti-CD38 Interference with Transfusion Compatibility Testing

To investigate the effectiveness and safety of low concentration dithiothreitol (DTT) in removing the interference of monoclonal anti-CD38 on transfusion compatibility testing, and develop a reasonable clinical transfusion strategy. The blood type, direct antiglobulin testing (DAT) and antibody screening were tested according to standard methods. Antibody screening cells and donor's red blood cells were treated by DTT 0.2, 0.1, 0.05, 0.02, 0.01 and 0.005 mol/L, and antibody screening and cross-matching of serums after monoclonal anti-CD38 treatment were performed by anti-human globulin card. The 0.01 mol/L DTT at 37℃ for 30 minutes could remove the effect of monoclonal anti-CD38 on antibody screening and cross-matching, meanwhile retain their effectiveness in detecting anti-K, anti-LW, anti-JMH, anti-Lub, anti-e, anti-Dia and anti-Jka alloantibodies. All the 10 patients had no acute or delayed haemolytic transfusion reactions and their routine blood tests showed that the red blood cells transfusion was effective. The 0.01 mol/L DTT is a safe and effective method for removing the interference of monoclonal anti-CD38 with transfusion compatibility testing, while retaining the ability to detect most alloantibodies.

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.