Transfusion-related Acute Lung Injury Research Articles

Adverse effects of microparticles on transfusion of stored red blood cell concentrates

BackgroundSystemic and pulmonary coagulopathy and inflammation are important characteristics of transfusion-related acute lung injury (TRALI). Whether microparticles that accumulate in transfused red blood cell concentrates (RBCs) have proinflammatory and procoagulant potential and contribute to adverse reactions of RBC transfusions is unclear. AimTo investigate the ability of microparticles in stored RBCs to promote thrombin generation and induce human pulmonary microvascular endothelial cell (HMVEC) activation and damage. MethodsThe number and size of microparticles were determined by flow cytometric and nanoparticle tracking analyses, respectively. Thrombin generation and the intrinsic coagulation pathway were assayed by a calibrated automated thrombogram and by measuring activated partial thromboplastin time (aPTT), respectively. The expression of ICAM-1 and the release of cytokines by endothelial cells were detected by flow cytometric analyses. HMVEC damage was assessed by incubating lipopolysaccharide-activated endothelial cells with MP-primed polymorphonuclear neutrophils (PMNs). ResultsThe size of the microparticles in the RBC supernatant was approximately 100–300 nm. Microparticles promoted thrombin generation in a dose-dependent manner and the aPTT was shortened. Depleting microparticles from the supernatant of RBCs stored for 35 days by either filtration or centrifugation significantly decreased the promotion of thrombin generation. The expression of ICAM-1 on HMVECs was increased significantly by incubation with isolated microparticles. Furthermore, microparticles induced the release of interleukin-6 (IL-6) and interleukin-8 (IL-8) from HMVECs. Microparticles induced lipopolysaccharide-activated HMVEC damage by priming PMNs, but this effect was prevented by inhibiting the PMNs respiratory burst with apocynin. ConclusionMicroparticles in stored RBCs promote thrombin generation, HMVEC activation and damage which may be involved in TRALI development.

Classification of posttransfusion adverse events using a publicly available artificial intelligence system.

Correct classification of transfusion reactions is important not only for effective patient care and donor management but also for accurate tracking of events in hemovigilance systems. We compared the ability of a generative artificial intelligence (AI) system to correctly diagnose hypothetical clinical situations as transfusion reactions in comparison to previous studies reporting the accuracy of transfusion medicine (TM) specialists in assessing these cases. An AI system was requested to assess 36 case scenarios to provide a diagnosis, severity, and imputability of the transfusion reactions using the CDC National Healthcare Safety Network (NHSN) criteria. Responses were compared to an expert panel's classifications and to the published responses of a panel of TM specialists. Additionally, the AI's responses were compared to the TM specialists' prior attempts to use the TrDDx web-based algorithm for the five most challenging cases. The AI's classification accuracy varied widely depending on the NHSN category. The AI accurately classified all transfusion-associated circulatory overload and transfusion-related acute lung injury cases, exceeding TM specialists' assessments. Conversely, it did not correctly identify any cases in select NHSN categories such as DSTR. Overall accuracy among all diagnostic categories was 48.7% for AI responses versus 72.1% for prior TM specialist responses (p = 0.005). AI-generated responses included non-standard terminology, limited severity assessments, and no imputability determinations. A generative AI system may have a role in helping healthcare providers to consider transfusion reaction categories that might be missed, but caution is advised in applying the AI's output to transfusion reaction classification at present.

Preservation of recipient plasma sphingosine-1-phosphate levels reduces transfusion-related acute lung injury.

Cold-stored (CS) platelets are once again being reintroduced for clinical use. Transfused CS platelets offer benefits over room temperature-stored (RTS) platelets such as increased hemostatic effects and prolongation of shelf-life. Despite these advantages little is known about their association with transfusion-related acute lung injury (TRALI). TRALI is associated with prolonged storage of RTS platelets and has a mortality of >15%. Determining the safety of CS platelets is important considering their proposed use in TRALI-vulnerable populations with inflammation such as surgical patients or patients with trauma. Donor platelet-derived ceramide causes TRALI, whereas donor platelet sphingosine-1-phosphate (S1P) is barrier protective. Females have higher plasma levels of S1P than males. Cold temperatures increase S1P levels in cells. Therefore, we hypothesized that female (donors or recipients) and/or CS platelets would decrease TRALI. To test this, we compared how male and female donor and recipient allogeneic platelet transfusions of CS (4°C) versus RTS (23°C) platelets stored for 5 days influence murine TRALI. Transfusion of CS platelets significantly reduced recipient lung tissue wet-to-dry ratios, bronchoalveolar lavage total protein, lung tissue myeloperoxidase enzyme activity, histological lung injury scores, and increased plasma sphingosine-1-phosphate (S1P) levels compared with RTS platelet transfusions. Female as opposed to male recipients had less TRALI and higher plasma S1P levels. Female donor mouse platelets had higher S1P levels than males. Mouse and human CS platelets had increased S1P levels compared with RTS platelets. Higher recipient plasma S1P levels appear protective considering females, and males receiving platelets from females or male CS platelets had less TRALI.NEW & NOTEWORTHY Transfusion-related acute lung injury (TRALI) though relatively rare represents a severe lung injury. The sphingolipid sphingosine-1-phosphate (S1P) regulates the severity of platelet-mediated TRALI. Female platelet transfusion recipient plasmas or stored platelets from female donors have higher S1P levels than males, which reduces TRALI. Cold storage of murine platelets preserves platelet-S1P, which reduces TRALI in platelet-transfused recipients.

Usage of blood components in obstetric practice

Transfusion of blood and its components form an important component in obstetric care. Almost 5% of pregnant mothers require some sort of red cell and/or component transfusion as part of their obstetric management. Although red cell usage in large parts of developed countries are coming down, its usage in obstetric care is increasing. About 27% of maternal deaths in the world are due to hemorrhage. There are many causes where transfusion with different blood components is required in obstetric practice; to name a few are – accidental hemorrhage, placenta previa, hemoglobinopathies, pre-eclamptic toxemia, postpartum hemorrhage, amniotic fluid embolism, disseminated intravascular coagulation, malaria, etc. Certain complications and challenges of transfusion such as transfusion related acute lung injury, microangiopathy, Thrombotic thrombocytopenic purpura, isoimmunization, and transfusion-associated cardiac overload occur with increased frequency in pregnant mothers. Transfusion requirement around peripartum period is uncertain and sometimes could be massive. Hence, both obstetrician and transfusion experts should remain prepared for this eventuality. Transfusion of blood products even though has never been safer than it is today; yet, this procedure carries with it many immunological, infectious, and other complications, hence, should be used judiciously and very cautiously. Several procedures such as apheresis and intraoperative cell salvage are being increasingly used nowadays for various facets of management and obstetric care. Present review condenses on the knowledge of usage of blood and blood products in obstetric care.

TRALI and TACO syndrome. Pathophysiology, diagnosis and treatment: a review

INTRODUCTION: TRALI (transfusion-related acute lung injury) and TACO (transfusion-associated circulatory overload) are severe post-transfusion reactions with high hospital mortality, uncertainty in pathophysiologic mechanisms and a blurred clinical presentation often lead to these conditions being underdiagnosed or missed by clinicians. OBJECTIVE: To analyze and summarize the current understanding of the pathophysiology, differential diagnosis and treatment of TRALI and TACO syndrome. To highlight the best approaches and current practices to improve treatment efficacy and awareness among specialists. MATERIALS AND METHODS: Articles in the following databases were analyzed: PubMed, eLibrary. The main inclusion criteria were: free access to the full content of the publications, compliance with the review topics concerning pathophysiology, diagnosis and treatment of TRALI- and TACO-syndrome. Exclusion criteria: abstracts, conference proceedings and editorial letters, as well as publications not indexed in specialized abstract databases. RESULTS: This article presents the main reference points, thanks to which clinicians can make a differential diagnosis among posttransfusion complications and select the optimal treatment. Since TACO is a simulated cardiogenic pulmonary edema as a result of altered cytokine profile, and TRALI-syndrome is a consequence of specific immunologic conflict between donor and recipient after hemotransfusion, these conditions should be differentiated in the inpatient setting, and specialists should use the full range of modern laboratory and instrumental methods. CONCLUSIONS: Despite a large number of studies, the pathophysiologic mechanisms of TRALI and TACO remain somewhat unclear, and current approaches to diagnosis and treatment are not effective. Therefore, the existing gaps in the diagnostics of posttransfusion reactions should be clarified in further studies, and clinicians should be extra vigilant in their choice of diagnosis.

Retracted: Clinical Factors of Blood Transfusion-Related Acute Lung Injury and Changes in Levels of Treg-Related Cytokines.

[This retracts the article DOI: 10.1155/2022/7344375.].

Patient Blood Management: Moving Above and Beyond the Optimal Use of Blood!

Transfusion of blood components or products is among the most common procedures performed during a patient’s stay in the hospital. However, apart from being life-saving in exsanguination, blood transfusion is also associated with adverse events such as transfusion-transmitted infections, allergic reactions, transfusion-associated circulatory overload, transfusion-related acute lung injury, and transfusion-related immunomodulation with nosocomial infections and cancer recurrence. These potentially fatal complications have raised perennial concerns among healthcare professionals with regard to blood transfusion and patient outcomes. Thus, in the last few decades, the safety of the blood product has remained the key focus area for almost every stakeholder, whether end user or policy maker. Optimal use of blood is a globally recognized and recommended policy that ensures that the right amount and type of blood component is transfused to the right patient at the right time. Essentially, it focuses on improving the safety and effectiveness of the clinical transfusion process. However, with the evolving knowledge around transfusion science, increasing involvement of surgeons, anesthesiologists, and other specialists in transfusion offerings and proceedings, and the accumulating evidence on the fact that blood transfusion can, often, be more detrimental to a patient’s clinical status rather than benefiting it, has led to the endorsement and establishment of policy(ies) for optimal use of blood. Patient blood management (PBM), a concept coined and introduced almost two decades ago, encompasses, rather comprehensively, not just the policies and procedures of optimal use of blood and restricting transfusion to as minimum as possible but has a scope that spans much beyond that. PBM is driven and implemented through the three-pillar and nine-field matrix that incorporates the objectives of optimizing hematopoiesis, minimizing bleeding and blood loss, and harnessing and optimizing the physiological tolerance of anemia within the preoperative, intraoperative, and postoperative settings. PBM focuses on patient safety rather than product safety and, thus, ensures adopting a customized approach toward judicious and clinical use of the precious resource, blood. The principles and practices of PBM gained significant relevance and acceptability in the past few years, especially after the pandemic of COVID-19 when the World Health Organization issued a policy brief on its urgent implementation. Through this review article, we intend to establish not just the impact of PBM implementation towards improvement in patient outcomes but also the fact that the relevance and means of PBM extend far above and beyond just the optimal use of blood.

Massive Transfusion/Hemorrhage Protocols Versus Goal-Directed Bleeding Management: Science Gone Eerie?

Key questions in bleeding management are “Why does my patient bleed?” and “How to fix it?” To answer the first question, the high negative predictive value of viscoelastic testing can be used to identify coagulopathic bleeding. Accordingly, goal-directed bleeding management (GDBM) guided by viscoelastic testing has been shown to be an effective and essential part of the second pillar of patient blood management (PBM) with the aim to improve patients’ outcomes and safety. Patient’s medical and drug history – with a focus on medication with oral anticoagulants and antiplatelet drugs – are important in emergency, urgent, and elective surgery. Furthermore, risk scores have been developed and validated for traumatic and obstetric hemorrhage and can be helpful tools to predict severe hemorrhage and the need for massive transfusion. Acidosis, hypocalcemia, anemia, and hypothermia (“diamond of death in trauma”) are important basic conditions for hemostasis and good predictors of coagulopathy and should be closely monitored by blood gas analysis and corrected in bleeding patients. Earlier time to hemostasis was associated with decreased mortality in trauma studies. Therefore, GDBM aims to stop the bleeding as soon as possible and avoid the main killers in blood transfusion: Transfusion-associated circulatory overload, transfusion-related acute lung injury, transfusion-related immune modulation, and thrombosis. Thromboelastometry-guided bleeding management follows the concepts of Good Medical Practice and Precision Medicine. Here, rotational thromboelastometry (ROTEM)-guided bleeding management algorithms are using a stepwise approach based on the sequence “Treat first what kills first:” (1) Fibrinolysis management, (2) clot firmness management, (3) thrombin generation management, and (4) avoidance of hypercoagulability and thrombosis. Here, thromboelastometry can not only identify patients with hypercoagulability and increased risk of thrombosis but also ROTEM-guided bleeding management can avoid thromboembolic complications, too. This may support the idea of personalized antithrombotic therapy guided by viscoelastic testing in the postoperative period. Finally, PBM is not about blood transfusion: It is about patients’ outcomes. Accordingly, several meta-analyses based on more than 20 randomized controlled trials on the effect of viscoelastic testing-guided perioperative bleeding management did not only demonstrate a significant reduction in transfusion requirements but also a significant reduction in mortality and postoperative acute kidney injury. The reduction in postoperative acute kidney injury again has a significant impact on long-term survival. Accordingly, recent PBM guidelines recommend the implementation of viscoelastic testing-guided bleeding management algorithms with a 1B or 1A recommendation. This is also addressed in the World Health Organization policy brief about the urgent need to implement PBM in all member states in a timely manner. However, even if the number of national activities is increasing, there is still a long way to go.

Identifying new safety risk of human serum albumin: a retrospective study of real-world data.

Objective: To mine and analyze the adverse reaction signals of human serum albumin (HSA) using the FDA adverse event reporting system (FAERS) database for the safe clinical use of this drug. Methods: Data cleaning and analysis of adverse event reports in the FAERS database for a total of 76 quarters from Q1 2004 to Q4 2022 were performed using the reporting odds ratio (ROR), Medicines and Healthcare Products Regulatory Agency (MHRA), and Bayesian confidence propagation neural network (BCPNN). Gender-differentiated signal detection was used to investigate the gender differences in the occurrence of HSA adverse events. Results: Through a combination of three methods, a total of 535 adverse event reports were identified. These reports involved 1,885 cases of adverse reactions, with respiratory, thoracic, and mediastinal disorders, as well as general disorders and administration site conditions, as the most common. One noteworthy new signal was the occurrence of transfusion-related acute lung injury. Additionally, gender-differentiated signals were present, with females experiencing paraesthesia, hypertension, pulmonary oedema, loss of consciousness, and vomiting. Conclusion: This study has revealed that HSA poses a risk of causing transfusion-related acute lung injury. It has also been observed that adverse reactions, including paraesthesia, hypertension, pulmonary oedema, loss of consciousness, and vomiting, are more prevalent in females. These findings should be taken into account when using HSA in a clinical setting.

Review of haemovigilance at the Rabat Regional Blood Transfusion Centre in Morocco (2017-2021).

blood transfusion remains an essential therapeutic intervention, but the occurrence of transfusion reactions makes its administration even more complex. Vigilant reporting of such reactions by recipients of blood products is essential for effective haemovigilance. This study aimed to determine the frequency and nature of transfusion reactions. conducted over five years (2017-2021) at the Haemovigilance Department of the Rabat Regional Blood Transfusion Centre, this retrospective study exploited incident forms notified by health establishments and data from the regional blood transfusion centre's computer system. from 1 January 2017 and 31 December 2021, the Rabat Regional Blood Transfusion Centre distributed 435,651 labile blood products to various healthcare establishments, which reported 191 transfusion reactions involving 191 patients. The median age of the patients was 44.3 years, with an overall cumulative incidence of transfusion reactions of 0.44 per 1000 labile blood products delivered. The predominant reactions were non-haemolytic febrile and allergic reactions, accounting for 41.36% and 35.60% respectively. Grade 1 reactions accounted for 87% of all reactions recorded. During the study period, three deaths were recorded, with ABO incompatibility and transfusion-related acute lung injury (TRALI) accounting for two and one case respectively. Transfusion reactions involving erythrocyte components were significantly more frequent than those involving platelet and plasma components. this study revealed a relatively low incidence of transfusion reactions (0.44%), dominated by non-haemolytic febrile and allergic reactions. Several levels of failure were identified, in particular under-reporting of reactions and inadequate training in transfusion practices and haemovigilance, as well as the need for an effective electronic transfusion reaction reporting system to facilitate reporting and identification of underlying problems and risk factors to improve the quality of transfusion care provided to patients.

The incidence of transfusion-related acute lung injury using active surveillance: A systematic review and meta-analysis.

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-related mortality. A concern with passive surveillance to detect transfusion reactions is underreporting. Our aim was to obtain evidence-based estimates of TRALI incidence using meta-analysis of active surveillance studies and to compare these estimates with passive surveillance. We performed a systematic review and meta-analysis of studies reporting TRALI rates. A search of Medline and Embase by a research librarian identified studies published between January 1, 1991 and January 20, 2023. Prospective and retrospective observational studies reporting TRALI by blood component (red blood cells [RBCs], platelets, or plasma) were identified and all inpatient and outpatient settings were eligible. Adult and pediatric, as well as general and specific clinical populations, were included. Platelets and plasma must have used at least one modern TRALI donor risk mitigation strategy. A random effects model estimated TRALI incidence by blood component for active and passive surveillance studies and heterogeneity was examined using meta-regression. Eighty studies were included with approximately 176-million blood components transfused. RBCs had the highest number of studies (n = 66) included, followed by platelets (n = 35) and plasma (n = 34). Pooled TRALI estimates for active surveillance studies were 0.17/10,000 (95% confidence intervals [CI]: 0.03-0.43; I2 = 79%) for RBCs, 0.31/10,000 (95% CI: 0.22-0.42; I2 = <1%) for platelets, and 3.19/10,000 (95% CI: 0.09-10.66; I2 = 86%) for plasma. Studies using passive surveillance ranged from 0.02 to 0.10/10,000 among the various blood components. In summary, these estimates may improve a quantitative understanding of TRALI risk, which is important for clinical decision-making weighing the risks and benefits of transfusion.

Crosstalk between neutrophil extracellular traps and immune regulation: insights into pathobiology and therapeutic implications of transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated death, occurring during or within 6 hours after transfusion. Reports indicate that TRALI can be categorized as having or lacking acute respiratory distress syndrome (ARDS) risk factors. There are two types of TRALI in terms of its pathogenesis: antibody-mediated and non-antibody-mediated. The key initiation steps involve the priming and activation of neutrophils, with neutrophil extracellular traps (NETs) being established as effector molecules formed by activated neutrophils in response to various stimuli. These NETs contribute to the production and release of reactive oxygen species (ROS) and participate in the destruction of pulmonary vascular endothelial cells. The significant role of NETs in TRALI is well recognized, offering a potential pathway for TRALI treatment. Moreover, platelets, macrophages, endothelial cells, and complements have been identified as promoters of NET formation. Concurrently, studies have demonstrated that the storage of platelets and concentrated red blood cells (RBC) can induce TRALI through bioactive lipids. In this article, recent clinical and pre-clinical studies on the pathophysiology and pathogenesis of TRALI are reviewed to further illuminate the mechanism through which NETs induce TRALI. This review aims to propose new therapeutic strategies for TRALI, with the hope of effectively improving its poor prognosis.

Rate of Acute Complications of Blood and Blood Products Transfusion among Children at Jafar Ibn Ouf Hospital, Khartoum, Sudan,2022

Blood transfusion is the process of transferring blood or blood products into one`s circulation intravenously. transfusions are used for various medical conditions to replace lost components of the blood. early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors, and platelets. Objectives: To assess the Rate of Acute Complications of Blood and Blood products Transfusion among Children at Jaffar Ibn Ouf Hospital, Khartoum, Sudan,2021. Methodology: It was a cross-sectional, Observational, descriptive hospital-based study. Data were collected using a checklist including brief clinical history and examination and laboratory investigation, type of blood transfusion, and short-term complications. Data were cleaned and entered into a Microsoft Excel data sheet and were analyzed using SPSS latest version software. Result: A total of 130 pediatric patients participated in this study their ages ranged from 1-17 years, most of them; 56 (43.1%) were aged less than 5 years. Of most patients, 89 (68.5%) had blood transfusions based on both clinical conditions and lab results, and 24 (18.5%) patients had blood transfusions based on their clinical conditions. In most patients, 124 (95.4%) had a complete transfusion. Only 15 (11.5%) patients developed blood reactions among them 8 (53.3%) patients developed febrile non-hemolytic transfusion reaction, 6 (40%) patients developed an allergic reaction, and 1 (6.7%) patient developed transfusion-related acute lung injury. According to patients’ outcomes; most of them 123 (94.6%) were discharged, and 2 (1.5%) cases of death. Conclusion: The main limitation of this study was that it was conducted in only one hospital,and the results may differ in other hospitals. Although our hospital serves a large geographical catchment area with numerous referrals, we do not know if current data accurately reflect the overall transfusion pattern in other similar health facilities or the country as a whole due to a lack of local comparable data. A multicenter survey is advised because it can provide more data and more solid conclusions.

Mitochondrial Damage-Associated Molecular Patterns (DAMPs) Contribute to the Development of Murine Antibody-Mediated Transfusion-Related Acute Lung Injury (TRALI)

Transfusion-related acute lung injury (TRALI) is potentially life-threatening and has been ranked as the leading cause of transfusion-related fatalities since its description in the 1980s. With a 5 to 14% mortality rate, symptoms range from mild dyspnea, cough and fever to full-blown respiratory failure and severe hypoxemia, which usually occurs within 6 hours from the transfusion. To date, the pathogenesis is not fully understood, but it appears that TRALI requires two hits in order to be initiated; the first-hit is the patient's clinical condition often reflected by a state of inflammation while the second hit is the transfusion itself. Several published articles have shown that mitochondrial damage-associated molecular patterns (mtDAMPs) including extracellular mitochondria and mitochondrial DNA (mtDNA) are elevated in stored transfusion products that have been linked to adverse transfusion reactions. Using an in vivo murine model of TRALI where injection of a monoclonal anti-MHC class I antibody (34-1-2s) into LPS-primed BALB/c mice causes significant lung edema, we explored the possibility of whether mitochondria and mtDAMPs could act as first hits in TRALI induction. Mitochondria were prepared from mouse livers by differential centrifugation and purified on a density gradient. Intravenous injections of only mitochondria (2.5 x 10 8 per mouse) prior to injection with 34-1-2s caused TRALI characterized by significantly elevated lung wet/dry ratios (Figure 1A), temperature loss and lung neutrophil accumulation. In contrast, however, intraperitoneal injections of mitochondria did not prime as a first hit for 34-1-2s-induced TRALI suggesting that the route of the mitochondrial first hit is important in determining whether TRALI proceeds (Figure 1A.). Using a TLR9 agonist (ODN2395) to mimic mtDNA as a first hit, we also observed 34-1-2s-induced TRALI induction, and this could be prevented by the administration of a specific TLR9 antagonist (ODN4084F) 2h before the ODN2395 injection (Figure 1B). Of interest, the TLR9 antagonist was not sufficient to prevent TRALI induced by the iv whole mitochondria first hit, indicating that other mtDAMPS are also involved in the priming of the mice for TRALI. This study suggests that mitochondria and at least mtDNA can act as a first hit in antibody-mediated TRALI via stimulation of recipient TLR9 and that the first hit route maybe important in stimulating TRALI. Further investigations are underway to identify other mtDAMPS (such as N-formyl peptides) or a combination of DAMPs that are important for the first hit. Inhibition of mitochondrial DAMPS may be a potential therapy for transfusion recipients suffering from TRALI.

Production of recombinant humanized monoclonal anti-human neutrophil antigen (HNA) antibodies with potential applicability as standard antibodies.

Antibodies against human neutrophil antigen (HNA) are involved in the pathogenesis of neonatal alloimmune neutropenia, autoimmune neutropenia, and transfusion-related acute lung injury. The present methods for anti-HNA antibody identification strongly depend on the presence of standard antisera with known allo/isospecificities. Here, we aimed to produce recombinant humanized antibodies to HNA from available mouse monoclonal antibodies (MoAbs). RNAs were extracted from available hybridoma cells producing mouse anti-HNA antibodies recognizing HNA-1a (TAG-1), -1b (TAG-2), -2 (TAG-4), and FcγRIIIb, and the cDNA was synthesized. Recombinant fragments consisting of the variable regions of the H and L chains of the mouse MoAb ligated to the constant region of human IgG were incorporated into an expression vector and transfected into CHO cells. Antibody specificity of the selected humanized monoclonal antibodies was confirmed, and tested by the participants of the ISBT Granulocyte Immunobiology Working Party (GIWP) workshop 2020. GIFT results confirmed the specific reactivity of TAGH-1 to -4, except for a cross-reactivity of TAGH-2 with HNA-1a/a neutrophils, only in flow-cytometry. MAIGA results showed clear specificity of all humanized antibodies, but the selection of the appropriate capture monoclonal antibody was essential for the test. The results of the ISBT GIWP showed high concordance among the labs. These are the first humanized monoclonal antibodies to HNA-1 and HNA-2 antigens produced and they will be important standard reagents for laboratories testing for neutrophil antibodies. We plan to have these humanized MoAbs available through WHO.

Recipient Platelet-Derived Extracellular Vesicles (PEV) Suppress Antibody-Mediated Transfusion-Related Acute Lung Injury (TRALI)

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-related fatalities with a 5 to 14% mortality rate. Symptoms range from mild dyspnea, cough, fever to full-blown respiratory failure and severe hypoxemia within 6 hours from the transfusion. To date, the pathogenesis is not fully understood, but it appears that TRALI requires two hits in order to be initiated; the first-hit is the patient's clinical condition often reflected by a state of inflammation while the second hit is the transfusion itself (often containing anti-donor antibodies). Several reports have described platelet involvement in antibody-mediated TRALI, however, there are significant controversies that have arisen as to whether intact platelets actually play a role or not. On the other hand, platelet extracellular vesicles (PEV) have been found to accumulate in stored platelet units and are positively correlated with significant adverse transfusion reactions. Furthermore, in a murine antibody-independent model of TRALI, it was recently demonstrated that PEV increase in stored murine platelet concentrates and are associated with TRALI-induction via excess ceramide production. We have used an in vivo murine model of TRALI where liposaccharide (LPS)-primed BALB/c mice are injected with a murine monoclonal anti-MHC class I antibody (34-1-2s). This antibody-mediated TRALI model exhibits severe acute lung injury that closely mimics the human condition. We attempted to understand what role recipient PEV may play in antibody-dependent TRALI. Male BALB/c mice were administered LPS ip (0.1 mg/kg) 18 hrs prior to initiating TRALI. At time zero, the mice are injected iv with 34-1-2s (1 mg/kg) and subsequently, TRALI manifestations were monitored every 30 min, and at 90 min post-injection, blood and lungs were harvested for the indicated measurements. Results show that compared with isotype-control treated mice, animals administered 34-1-2s had significantly elevated lung Wet/Dry (W/D) ratios (measure of lung edema, Figure 1a) and pulmonary neutrophil accumulation. The TRALI mice had significant thrombocytopenia and elevated levels of PEV in their plasma as detected by High-sensitivity Flow Cytometry (Hs-FCM). To determine the role of in vivo generated PEV in antibody-mediated TRALI, mice were first administered amitriptyline (AMI), a potent inhibitor of PEV formation. AMI treatment significantly reduced plasma PEV levels, but after administration of 34-1-2s, TRALI responses (lung edema) were significantly enhanced in the AMI-treated mice (Figure 1). To determine if this effect was due to PEV-derived serotonin, mice were next treated with Prozac to deplete platelet/PEV stores of serotonin. Prozac-treated mice had normal levels of PEV after 34-12s administration and TRALI induction was not affected. Our results suggest that in antibody-mediated TRALI, recipient generated PEV play a suppressive role that is independent of serotonin. Further studies are underway to determine the mechanism(s) of PEV-mediated TRALI suppression. Thus, modulating PEV formation in recipients may be an effective therapy for reducing TRALI reactions.

The Cs a and Cs b Red Cell Antigens of the Cost Blood Group Collection Correspond to the HNA-3a and HNA-3b Neutrophil Antigens: Unexpected Twins with Implications for Sickle Cell Anemia

Recent genome-wide association and murine studies identified the human neutrophil antigen 3a/b polymorphism (HNA-3a/b) in SLC44A2 (rs2288904-G/A) as a risk factor in venous thromboembolism (VTE). We tested whether this polymorphism associates with clinical features in SCA patients in whose VTE and stroke are frequently encountered complications. Incidentally, we discovered that rare subjects with the homozygous HNA-3b/b genotype (genotype frequency &amp;lt; 2%) also carry the uncommon Cs(a-) red cell phenotype. Despite its discovery more than 50 years ago, the molecular basis of this red cell phenotype and the presumptive protein carrier for the antigens of the COST blood group collection (Cs a and Cs b) has remained unknown. Inspired by this fortuitous discovery, we hypothesized that rs2288904 and COST antigens are closely associated. Thus, we genotyped this SNP in a cohort of 35 Cs(a-) subjects and found that all of them showed a HNA-3b/b genotype, indicating that the high-frequency allele of rs2288904 (HNA-3a; 461G) encoding Arg154 might encode the Cs a antigen (COST1). Interestingly, anti-Cs a does not react with SLC44A2 null RBCs (exceptional VER- blood type) and SLC44A2 knockout K562 cell line, confirming that the COST antigens are carried on this protein. In addition, using a panel of K562 cells expressing HNA-3a or 3b antigens developed by CRISPR/Cas9 genome editing, we confirmed that anti-Cs a recognizes the HNA-3a antigen. Overall, our results confirmed that HNA-3 and COST antigens have the same molecular basis. As a result, the Cs a and Cs b red cell antigens can now be included in the CTL2 blood group system, encoded by the SLC44A2 gene. This new finding could be of medical and biological value because anti-HNA-3a may be responsible for severe cases of neonatal neutropenia and transfusion-related acute lung injury (TRALI). Current testing for HNA-3a antibodies includes the granulocyte agglutination test and granulocyteindirect immunofluorescence test, as recommended by the ISBT Working Party on Granulocyte Immunobiology. These classical methods, however, are cumbersome because they require fresh granulocytes that have to be prepared daily and used immediately. Consequently, screening for HNA-3a antibodies is restricted to a few expert laboratories. Therefore, we propose to use the simple indirect antiglobulin red cell agglutination test (IAT) and Cs(a-) RBCs to screen for this antibody in the plasma of donors and patients. Finally, given that the starting point for this project was the study of a potential association of the HNA-3 polymorphism with clinical and biological features in SCA patients, we found that the HNA-3b allele was significantly associated with a higher monocyte and platelet count (p&amp;lt;0.02) and the occurrence of leg ulcer (p=0.01), suggesting an important role of the SLC44A2 protein in the SCD physiopathology.

Complement activation drives antibody-mediated transfusion-related acute lung injury via macrophage trafficking and formation of NETs

AbstractTransfusion-related acute lung injury (TRALI) is one of the leading causes of transfusion-related fatalities and, to date, is without available therapies. Here, we investigated the role of the complement system in TRALI. Murine anti–major histocompatibility complex class I antibodies were used in TRALI mouse models, in combination with analyses of plasma samples from patients with TRALI. We found that in vitro complement activation was related to in vivo antibody-mediated TRALI induction, which was correlated with increased macrophage trafficking from the lungs to the blood in a fragment crystallizable region (Fc)-dependent manner and that this was dependent on C5. Human immunoglobulin G 1 variants of the murine TRALI-inducing antibody 34-1-2S, either unable to activate complement and/or bind to Fcγ receptors (FcγRs), revealed an essential role for the complement system, but not for FcγRs, in the onset of 34-1-2S–mediated TRALI in mice. In addition, we found high levels of complement activation in the plasma of patients with TRALI (n = 53), which correlated with elevated neutrophil extracellular trap (NET) markers. In vitro we found that NETs could be formed in a murine, 2-hit model, mimicking TRALI with lipopolysaccharide and C5a stimulation. Collectively, this reveals a critical role of Fc-mediated complement activation in TRALI, with a direct relation to macrophage trafficking from the lungs to the blood and an association with NET formation, suggesting that targeting the complement system may be an attractive therapeutic approach for combating TRALI.

P‐TS‐84 | The Incidence of Reported Transfusion Related Acute Lung Injury (TRALI) by Blood Component: A Systematic Review and Meta‐Analysis

P‐TS‐84 | The Incidence of Reported Transfusion Related Acute Lung Injury (TRALI) by Blood Component: A Systematic Review and Meta‐Analysis

P‐TS‐62 | Outpatient Transfusions and Transfusion‐Related Acute Lung Injury (TRALI) Among US Medicare Beneficiaries, Ages 65 and Older, During 2016‐2022

P‐TS‐62 | Outpatient Transfusions and Transfusion‐Related Acute Lung Injury (TRALI) Among US Medicare Beneficiaries, Ages 65 and Older, During 2016‐2022