Balanced resuscitation with whole blood versus component therapy in critically injured preadolescent children: Getting there faster with fewer exposures

PURPOSE

Balanced blood product resuscitation with red blood cells, plasma, and platelets can be achieved using whole blood (WB) or component therapy (CT). However, balanced resuscitation of younger children with severe traumatic hemorrhage may be complicated by delays in delivering all blood components and concerns regarding multiple product exposures. We hypothesized that WB achieves balanced resuscitation faster than CT, with fewer product exposures and improved clinical outcomes.

METHODS

Children younger than 12 years receiving balanced resuscitation within 4 hours of arrival were identified from the 2017 to 2019 Trauma Quality Improvement Program database. Time to balanced resuscitation was defined as the time of initiation of WB or all three components. Patient characteristics, resuscitation details, and outcomes were compared between WB and CT groups. Time to balanced resuscitation was compared using Kaplan-Meier analysis and Cox regression modeling to adjust for covariates. Additional multivariable regression models compared number of transfusion exposures, intensive care unit (ICU) length of stay, and mortality.

RESULTS

There were 390 patients (109 WB, 281 CT) with median age 7 years, 12% penetrating mechanism, 42% severe traumatic brain injury, and 49% in-hospital mortality. Time to balanced resuscitation was shorter for WB versus CT (median, 28 vs. 87 minutes; hazard ratio [HR], 2.93; 95% confidence interval [CI], 2.31-3.72; p < 0.0001). Whole blood patients received fewer transfusion exposures (mean, 3.2 vs. 3.9; adjusted incidence rate ratio, 0.82; 95% CI, 0.72-0.92; p = 0.001) and lower total product volumes (50 vs. 85 mL/kg; p = 0.01). Intensive care unit stays trended shorter for WB versus CT (median, 10 vs. 12 days; adjusted HR, 1.32; 95% CI, 0.93-1.86), while in-hospital mortality was similar (50% vs. 45%; adjusted odds ratio, 1.11; 95% CI, 0.65-1.88).

CONCLUSION

In critically injured preadolescent children receiving emergent transfusion, WB was associated with faster time to balanced resuscitation, fewer transfusion exposures, lower blood product volumes, and a trend toward shorter ICU stays than CT.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Development and evaluation of trigger tools to identify pediatric blood management errors

BACKGROUND

Pediatric patient blood management (PBM) programs require continuous surveillance of errors and near misses. However, most PBM programs rely on passive surveillance methods. Our objective was to develop and evaluate a set of automated trigger tools for active surveillance of pediatric PBM errors.

MATERIALS AND METHODS

We used the Rand-UCLA method with an expert panel of pediatric transfusion medicine specialists to identify and prioritize candidate trigger tools for all transfused blood products. We then iteratively developed automated queries of electronic health record (EHR) data for the highest priority triggers. Two physicians manually reviewed a subset of cases meeting trigger tool criteria and estimated each trigger tool's positive predictive value (PPV). We then estimated the rate of PBM errors, whether they reached the patient, and adverse events for each trigger tool across four years in a single pediatric health system.

RESULTS

We identified 28 potential triggers for pediatric PBM errors and developed 5 automated trigger tools (positive patient identification, missing irradiation, unwashed products despite prior anaphylaxis, transfusion lasting >4 hours, over-transfusion by volume). The PPV for ordering errors ranged from 38-100%. The most frequently detected near miss event reaching patients was first transfusions without positive patient identification (estimate 303, 95% CI: 288-318 per year). The only adverse events detected were from over-transfusions by volume, including 4 adverse events detected on manual review that had not been reported in passive surveillance systems.

DISCUSSION

It is feasible to automatically detect pediatric PBM errors using existing data captured in the EHR that enable active surveillance systems. Over-transfusions may be one of the most frequent causes of harm in the pediatric environment.

Increased platelet to red blood cell transfusion ratio associated with acute kidney injury in children with life-threatening bleeding

INTRODUCTION

Transfusion may increase the risk of organ failure through immunomodulatory effects. The primary objective of this study was to assess for patient or transfusion-related factors that are independently associated with the risk of acute kidney injury (AKI) and acute respiratory distress syndrome (ARDS) in a cohort of children with life-threatening bleeding from all etiologies.

METHODS

In a secondary analysis of the prospective observational massive transfusion in children (MATIC) study, multivariable logistic regression was performed in an adjusted analysis to determine if blood product ratios or deficits were independently associated with AKI or ARDS in children with life-threatening bleeding.

RESULTS

There were 449 children included with a median (interquartile range, IQR) age of 7.3 years (1.7-14.7). Within 5 days of the life-threatening bleeding event, AKI occurred in 18.5% and ARDS occurred in 20.3% of the subjects. Every 10% increase in the platelet to red blood cell transfusion ratio is independently associated with a 12.7% increase in the odds of AKI (adjusted odds ratio 1.127; 95% confidence interval 1.025-1.239; p-value .013). Subjects with operative or medical etiologies were independently associated with an increased risk of AKI compared to those with traumatic injury. No transfusion-related variables were independently associated with the risk of developing ARDS.

CONCLUSION

The use of increased platelet to red blood cell transfusion ratios in children with life-threatening bleeding of any etiology may increase the risk of AKI but not ARDS. Prospective trials are needed to determine if increased platelet use in this cohort increases the risk of AKI to examine possible mechanisms.

Patient sex and outcomes in children with life-threatening hemorrhage

BACKGROUND

Recent data suggest female sex imparts a survival benefit after trauma in adults. The independent associations between patient sex and age with outcomes have not been examined in children with life-threatening hemorrhage (LTH) from all etiologies.

STUDY DESIGN AND METHODS

In a secondary analysis of a multicenter prospective observational study of children with LTH, Massive Transfusion in Children (MATIC), we analyzed if patient sex and age were associated with differences in severity of illness, therapies, and outcomes. Primary outcomes were 24 hour mortality and weight-adjusted transfusion volume during LTH. Kruskal-Wallis, chi-square testing, and multivariable linear regression were used for adjusted analyses.

RESULTS

Of 449 children, 45% were females and 55% were males. Females were more commonly younger, white, and with less trauma as the etiology of LTH compared to males. Markers of clinical severity were similar between groups, except injury severity score (ISS) was higher in females in the trauma subgroup. In terms of resuscitative practices, females received greater weight-adjusted total transfusion volumes compared to males (76 (40-150) mL/kg vs. 53 (24-100) mL/kg), as well as increased red blood cells (RBCs), plasma, and platelets compared to males. After adjustment for confounders, female sex and age 0-11 years were independently associated with increased transfusion volume during LTH. There were no differences in mortality or adverse outcomes according to patient sex.

CONCLUSION

Patient sex and age may impact factors associated with LTH and therapies received. Studies in developmental hemostasis are needed to determine the optimal transfusion strategy for LTH according to patient sex and age.

Post-transfusion biotin-labeled red blood cell survival studies in pediatric sickle cell disease with antibodies of uncertain significance

BACKGROUND

Red blood cell (RBC) antibodies are common in multiply transfused patients with sickle cell disease (SCD). Unlike RBC alloantibodies, the potential of autoantibodies to cause post-transfusion hemolysis may be uncertain. Biotin-labeling provides a direct measurement of red cell survival (RCS) over time, thus can be used to assess the clinical significance of RBC antibodies. Antibodies to biotinylated RBC (B-RBC) occasionally are detected after exposure, which may impact B-RBC survival in subsequent RCS studies.

STUDY DESIGN AND METHODS

Pediatric patients with SCD receiving monthly chronic transfusions underwent RCS studies, receiving aliquots of allogeneic RBC labeled at distinct densities of biotin (2-18 μg/mL). B-RBC survival was followed for 4 months post-transfusion, and B-RBC antibody screening for 6 months. Patients with warm autoantibodies (WAA) or B-RBC antibodies are reported here.

RESULTS

RBC antibodies were detected during RCS in four patients: one with WAA, one with WAA followed by B-RBC-specific antibodies, and two with transient B-RBC antibodies within the first 5 weeks of exposure. B-RBC half-lives (T50 ) ranged 37.6-61.7 days (mean 47.8 days). There was no evidence of increased hemolysis or accelerated B-RBC clearance in the presence of WAA or B-RBC antibodies.

DISCUSSION

Biotinylation of allogenic RBC can be used to assess the possible effects of RBC antibodies on transfusion survival in individual cases, particularly when it is uncertain if the detected antibodies may result in hemolysis. In the cases presented here, neither WAA nor B-RBC antibodies were associated with significant shortening of B-RBC survival in individuals with SCD.

Neonatal Blood Banking Practices

There is little formal guidance to direct neonatal blood banking practices and, as a result, practices vary widely across institutions. In this vulnerable patient population with a high transfusion burden, considerations for blood product selection include freshness, extended-storage media, pathogen inactivation, and other modifications. The authors discuss the potential unintended adverse impacts in the neonatal recipient. Concerns such as immunodeficiency, donor exposures, cytomegalovirus transmission, volume overload, transfusion-associated hyperkalemia, and passive hemolysis from ABO incompatibility have driven modifications of blood components to improve safety.

Optimizing RBC Transfusion Outcomes in Patients with Acute Illness and in the Chronic Transfusion Setting

Red blood cell (RBC) transfusion is a common clinical intervention used to treat patients with acute and chronic anemia. The decision to transfuse RBCs in the acute setting is based on several factors but current clinical studies informing optimal RBC transfusion decision making (TDM) are largely based upon hemoglobin (Hb) level. In contrast to transfusion in acute settings, chronic RBC transfusion therapy has several different purposes and is associated with distinct transfusion risks such as iron overload and RBC alloimmunization. Consequently, RBC TDM in the chronic setting requires optimizing the survival of transfused RBCs in order to reduce transfusion exposure over the lifespan of an individual and the associated transfusion complications mentioned. This review summarizes the current medical literature addressing optimal RBC-TDM in the acute and chronic transfusion settings and discusses the current gaps in knowledge which need to be prioritized in future national and international research initiatives.

Prophylactic Platelet Transfusion: Is There Evidence of Benefit, Harm, or No Effect?

The optimal use of prophylactic platelet transfusion remains uncertain in a number of clinical scenarios. Platelet count thresholds have been established in patients with hematologic malignancies, yet thresholds backed by scientific data are limited or do not exist for many patient populations. Clinical scenarios involving transfusion thresholds for thrombocytopenic patients with critical illness, need for surgery or invasive procedures, or those involving specials populations like children and neonates, lack clear evidence for discerning favorable outcomes without undue risk related to platelet transfusion. In addition, while prophylactic platelet transfusions are administered with the goal of enhancing hemostasis, increasing evidence supports critical nonhemostatic roles for platelets related to innate and adaptive immunity, inflammation, and angiogenesis, which may impact patient responses and outcomes. Here we review several recent studies conducted in adult or pediatric patients that highlight the limitations in our current understanding of prophylactic platelet transfusion. Together, these studies underscore the need for additional research, especially in the form of robust randomized clinical trials and integrating additional parameters beyond the platelet count. Future research at the basic, translational, and clinical levels will best define the optimal role for prophylactic transfusion across the lifespan and its broader impact on health and disease.

Antibody-mediated antigen loss switches augmented immunity to antibody-mediated immunosuppression

Antibodies against fetal red blood cell (RBC) antigens can cause hemolytic disease of the fetus and newborn (HDFN). Reductions in HDFN due to anti-RhD antibodies have been achieved through use of Rh immune globulin (RhIg), a polyclonal antibody preparation that causes antibody-mediated immunosuppression (AMIS), thereby preventing maternal immune responses against fetal RBCs. Despite the success of RhIg, it is only effective against 1 alloantigen. The lack of similar interventions that mitigate immune responses toward other RBC alloantigens reflects an incomplete understanding of AMIS mechanisms. AMIS has been previously attributed to rapid antibody-mediated RBC removal, resulting in B-cell ignorance of the RBC alloantigen. However, our data demonstrate that antibody-mediated RBC removal can enhance de novo alloimmunization. In contrast, inclusion of antibodies that possess the ability to rapidly remove the target antigen in the absence of detectable RBC clearance can convert an augmented antibody response to AMIS. These results suggest that the ability of antibodies to remove target antigens from the RBC surface can trigger AMIS in situations in which enhanced immunity may otherwise occur. In doing so, these results hold promise in identifying key antibody characteristics that can drive AMIS, thereby facilitating the design of AMIS approaches toward other RBC antigens to eliminate all forms of HDFN.

Association of blood product ratios with early mortality in pediatric trauma resuscitation: A time-dependent analysis from the National Trauma Databank

BACKGROUND

Injured children with severe hemorrhage often receive blood product transfusions with ratios of plasma and platelets to packed red blood cells (PRBCs) approaching 1:1:1. Whether blood product ratios vary during pediatric resuscitation is unknown. This study (1) described precise timing of pediatric blood product administration, (2) characterized changes in blood product ratios over time, and (3) evaluated the association of blood products with early mortality while incorporating time-varying factors.

METHODS

Pediatric (younger than 18 years) trauma patients receiving high-volume transfusion (>40 mL/kg total products or >2 U PRBC or whole blood, during first 4 hours) were obtained from the 2017 to 2019 Trauma Quality Improvement Program database. The time of each individual product transfusion was recorded, along with demographics, injury details, and times of death. Patients were assigned to blood product groups at 15-minute intervals: high plasma/PRBC ratio (>1:1) with platelets, high plasma/PRBC ratio (>1:1) without platelets, low plasma/PRBC ratio (<1:1), PRBC only, and whole blood. Cox proportional hazards modeling for 24-hour mortality was performed, including blood product group as a time-varying variable and adjusting for relevant covariates.

RESULTS

Of 1,152 included patients (median age, 15 years; 32% penetrating, 28% severe traumatic brain injury [sTBI]), 18% died within 24 hours. During the resuscitation period, the number of patients in high-ratio groups increased over time, and patients switched blood product groups up to six times. There was no significant difference in mortality by blood product group. Among patients with sTBI, there was a strong trend toward lower mortality among high plasma/PRBC without platelets versus high plasma/PRBC with platelets (hazard ratio, 0.55; p = 0.07).

CONCLUSION

No significant association of high ratios or whole blood with mortality was seen when time-varying factors were incorporated. The impact of balanced resuscitation strategies, particularly platelet transfusion, may be greatest among patients with sTBI. Optimizing balanced resuscitation for children requires appropriately designed prospective studies.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

Blood group A enhances SARS-CoV-2 infection

Among the risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ABO(H) blood group antigens are among the most recognized predictors of infection. However, the mechanisms by which ABO(H) antigens influence susceptibility to COVID-19 remain incompletely understood. The receptor-binding domain (RBD) of SARS-CoV-2, which facilitates host cell engagement, bears significant similarity to galectins, an ancient family of carbohydrate-binding proteins. Because ABO(H) blood group antigens are carbohydrates, we compared the glycan-binding specificity of SARS-CoV-2 RBD with that of galectins. Similar to the binding profile of several galectins, the RBDs of SARS-CoV-2, including Delta and Omicron variants, exhibited specificity for blood group A. Not only did each RBD recognize blood group A in a glycan array format, but each SARS-CoV-2 virus also displayed a preferential ability to infect blood group A-expressing cells. Preincubation of blood group A cells with a blood group-binding galectin specifically inhibited the blood group A enhancement of SARS-CoV-2 infection, whereas similar incubation with a galectin that does not recognize blood group antigens failed to impact SARS-CoV-2 infection. These results demonstrated that SARS-CoV-2 can engage blood group A, providing a direct link between ABO(H) blood group expression and SARS-CoV-2 infection.

Associations of donor, component, and recipient factors on hemoglobin increments following red blood cell transfusion in very low birth weight infants

BACKGROUND

Anemia in very low birth weight (VLBW) infants is common and frequently managed with red blood cell (RBC) transfusions. We utilized a linked vein-to-vein database to assess the role of blood donors and component factors on measures of RBC transfusion effectiveness in VLBW infants.

STUDY DESIGN AND METHODS

We linked blood donor and component manufacturing data with VLBW infants transfused RBCs between January 1, 2013 and December 31, 2016 in the Recipient Epidemiology Donor Evaluation Study-III (REDS III) database. Using multivariable regression, hemoglobin increments and subsequent transfusion events following single-unit RBC transfusion episodes were examined with consideration of donor, component, and recipient factors.

RESULTS

Data on VLBW infants (n = 254) who received one or more single-unit RBC transfusions (n = 567 units) were linked to donor demographic and component manufacturing characteristics for analysis. Reduced post-transfusion hemoglobin increments were associated with RBC units donated by female donors (-0.24 g/dL [95% confidence interval (CI) -0.57, -0.02]; p = .04) and donors <25 years old (-0.57 g/dL [95% CI -1.02, -0.11]; p = .02). For RBC units donated by male donors, reduced donor hemoglobin levels were associated with an increased need for subsequent recipient RBC transfusion (odds ratio 3.0 [95% CI 1.3, 6.7]; p < .01). In contrast, component characteristics, storage duration, and time from irradiation to transfusion were not associated with post-transfusion hemoglobin increments.

CONCLUSION

Donor sex, age, and hemoglobin levels were associated with measures of RBC transfusion effectiveness in VLBW infants. Mechanistic studies are needed to better understand the role of these potential donor factors on other clinical outcomes in VLBW infants.

Pediatric firearm injury related emergency department visits and hospitalizations: a population-based study in the United States

Background

Firearm injury (FI) is the leading cause of death in children and adolescents in the United States (US). We describe the epidemiology of pediatric FI-associated emergency department (ED) visits and hospitalizations in the US stratified by race and ethnicity.

Methods

Data on pediatric (0-17-year-olds) FI were analyzed using the 2019 Nationwide Emergency Department Sample (NEDS) and Kids' Inpatient Database (KID), the largest all-payer databases in the US for ED visits and pediatric hospitalizations, respectively. FI encounters were stratified by race and ethnicity. Poisson regression was used to identify factors associated with in-hospital mortality. Sampling weights were applied to generate nationally representative estimates.

Findings

There were 7017 pediatric ED visits with FI (NEDS); 85.0% (5961/7017) were male and 73.0% (5125/7017) were adolescents (15-17 years). Overall, 5.5% (384/7017) died in the ED; 53.1% (3727/7017) of ED encounters did not result in hospitalization. There were 2817 pediatric FI hospitalizations (KID); 84.1% (2369/2817) were male and 71.6% (2018/2817) were adolescents; 51.4% (1447/2817) of FI were unintentional, 42.8% (1207/2817) were assault-related, and 5.8% (163/2817) were self-inflicted. Black children had the highest proportion (52.6%; 1481/2817) of hospitalizations among all race and ethnicities (p < 0.0001 vs. White). White children had the highest proportion of hospitalizations for self-inflicted injuries (16.6% [91/551] vs. 4.9% [25/504; p < 0.0001] in Hispanics and 1.7% [24/1481] in Blacks; p < 0.0001). The majority (56.5%; 1591/2817) of hospitalizations were patients from low-income zip codes (median annual-household-income <$44,000); 70% (1971/2817) had Medicaid as the primary insurance payer. Overall, 8.0% (225/2817) died during FI-associated hospitalizations. Self-inflicted injuries had the highest in-hospital mortality (prevalence ratio = 8.20, 95% CI = 6.06-11.10 vs. unintentional).

Interpretation

Black children and children with lower household incomes were disproportionately impacted by FI resulting from assaults and accidents, while White children had the highest proportion of self-inflicted FI injuries. Public health and legal policy interventions are needed to prevent pediatric FI.

Funding

US National Institutes of Health.

Prior immunization against an intracellular antigen enhances subsequent red blood cell alloimmunization in mice

Antibodies against red blood cell (RBC) alloantigens can increase morbidity and mortality among transfusion recipients. However, alloimmunization rates can vary dramatically, as some patients never generate alloantibodies after transfusion, whereas others not only become alloimmunized but may also be prone to generating additional alloantibodies after subsequent transfusion. Previous studies suggested that CD4 T-cell responses that drive alloantibody formation recognize the same alloantigen engaged by B cells. However, because RBCs express numerous antigens, both internally and externally, it is possible that CD4 T-cell responses directed against intracellular antigens may facilitate subsequent alloimmunization against a surface RBC antigen. Here, we show that B cells can acquire intracellular antigens from RBCs. Using a mouse model of donor RBCs expressing 2 distinct alloantigens, we demonstrate that immune priming to an intracellular antigen, which would not be detected by any currently used RBC compatibility assays, can directly influence alloantibody formation after exposure to a subsequent distinct surface RBC alloantigen. These findings suggest a previously underappreciated mechanism whereby transfusion recipient responders may exhibit an increased rate of alloimmunization because of prior immune priming toward intracellular antigens.

Associations between ABO non-identical platelet transfusions and patient outcomes-A multicenter retrospective analysis

BACKGROUND

Due to platelet availability limitations, platelet units ABO mismatched to recipients are often transfused. However, since platelets express ABO antigens and are collected in plasma which may contain ABO isohemagglutinins, it remains controversial as to whether ABO non-identical platelet transfusions could potentially pose harm and/or have reduced efficacy.

STUDY DESIGN AND METHODS

The large 4-year publicly available Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) database was used to investigate patient outcomes associated with ABO non-identical platelet transfusions. Outcomes included mortality, sepsis, and subsequent platelet transfusion requirements.

RESULTS

Following adjustment for possible confounding factors, no statistically significant association between ABO non-identical platelet transfusion and increased risk of mortality was observed in the overall cohort of 21,176 recipients. However, when analyzed by diagnostic category and recipient ABO group, associations with increased mortality for major mismatched transfusions were noted in two of eight subpopulations. Hematology/Oncology blood group A and B recipients (but not group O) showed a Hazard Ratio (HR) of 1.29 (95%CI: 1.03-1.62) and intracerebral hemorrhage group O recipients (but not groups A and B) showed a HR of 1.75 (95%CI: 1.10-2.80). Major mismatched transfusions were associated with increased odds of receiving additional platelet transfusion each post-transfusion day (through day 5) regardless of the recipient blood group.

DISCUSSION

We suggest that prospective studies are needed to determine if specific patient populations would benefit from receiving ABO identical platelet units. Our findings indicate that ABO-identical platelet products minimize patient exposure to additional platelet doses.

Cryoprecipitate for the treatment of life-threatening hemorrhage in children

BACKGROUND

Hypofibrinogenemia is an important risk factor for poor outcomes in children with severe bleeding. There is a paucity of data on the impact of cryoprecipitate transfusion on outcomes in pediatric patients with life-threatening hemorrhage (LTH).

STUDY DESIGN AND METHODS

This secondary analysis of a multicenter prospective observational study of children with LTH investigated subjects who were categorized by receipt of cryoprecipitate during their resuscitation and according to the etiology of their bleeding: trauma, operative, and medical. Bivariate analysis was performed to identify variables associated with 6-hour, 24-hour and 28-day mortality. Cox Hazard regression models were generated to adjust for potential confounders.

RESULTS

Cryoprecipitate was transfused to 33.9% (152/449) of children during LTH. The median (Interquartile range) time to cryoprecipitate administration was 108 (47-212) minutes. Children in the cryoprecipitate group were younger, more often female, with higher BMI and pre-LTH PRISM score and lower platelet counts. After adjusting for PRISM score, bleeding etiology, age, sex, red blood cell volume, platelet volume, antifibrinolytic use and cardiac arrest, cryoprecipitate administration was independently associated with lower 6-hour mortality, Hazard Ratio (95% CI), 0.41 (0.19-0.89), (p=0.02) and 24-hour mortality, Hazard Ratio (95% CI), 0.46 (0.24-0.89), (p=0.02).

CONCLUSION

Cryoprecipitate transfusion to children with LTH was associated with reduced early mortality. A prospective randomized trial is needed to determine if cryoprecipitate can improve outcomes in children with LTH. This article is protected by copyright. All rights reserved.

Epsilon aminocaproic acid is associated with acute kidney injury after life-threatening hemorrhage in children

BACKGROUND

Antifibrinolytic medications have been associated with reduced mortality in pediatric hemorrhage but may contribute to adverse events such as acute kidney injury (AKI).

STUDY DESIGN AND METHODS

We conducted a secondary analysis of the MAssive Transfusion in Children (MATIC), a prospectively collected database of children with life-threatening hemorrhage (LTH), and evaluated for risk of adverse events with either antifibrinolytic treatment, epsilon aminocaproic acid (EACA) or tranexamic acid (TXA). The primary outcome was AKI and secondary outcomes were acute respiratory distress syndrome (ARDS) and sepsis.

RESULTS

Of 448 children included, median (interquartile range) age was 7 (2-15) years, 55% were male, and LTH etiology was 46% trauma, 34% operative, and 20% medical. Three hundred and ninety-three patients did not receive an antifibrinolytic (88%); 37 (8%) received TXA and 18 (4%) received EACA. Sixty-seven (17.1%) patients in the no antifibrinolytic group developed AKI, 6 (16.2%) patients in the TXA group, and 9 (50%) patients in the EACA group (p = 0.002). After adjusting for cardiothoracic surgery, cyanotic heart disease, pre-existing renal disease, lowest hemoglobin pre-LTH, and total weight-adjusted transfusion volume during the LTH, the EACA group had increased risk of AKI (adjusted odds ratio 3.3 [95% CI 1.0 - 10.3]) compared to no antifibrinolytic. TXA was not associated with AKI. Neither antifibrinolytic treatment was associated with ARDS or sepsis.

CONCLUSION

Administration of EACA during LTH may increase the risk of AKI. Additional studies are needed to compare the risk of AKI between EACA and TXA in pediatric patients. This article is protected by copyright. All rights reserved.

Proceedings of the 2022 NHLBI and OASH state of the science in transfusion medicine symposium

BACKGROUND

State of the Science (SoS) meetings are used to define and highlight important unanswered scientific questions. The National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, and the Office of the Assistant Secretary for Health (OASH), Department of Health and Human Services held a virtual SoS in transfusion medicine (TM) symposium.

STUDY DESIGN AND METHODS

In advance of the symposium, six multidisciplinary working groups (WG) convened to define research priorities in the areas of: blood donors and the supply, optimizing transfusion outcomes for recipients, emerging infections, mechanistic aspects of components and transfusion, new computational methods in transfusion science, and impact of health disparities on donors and recipients. The overall objective was to identify key basic, translational, and clinical research questions that will help to increase and diversify the volunteer donor pool, ensure safe and effective transfusion strategies for recipients, and identify which blood products from which donors best meet the clinical needs of specific recipient populations.

RESULTS

On August 29-30, 2022, over 400 researchers, clinicians, industry experts, government officials, community members, and patient advocates discussed the research priorities presented by each WG. Dialogue focused on the five highest priority research areas identified by each WG and included the rationale, proposed methodological approaches, feasibility, and barriers for success.

DISCUSSION

This report summarizes the key ideas and research priorities identified during the NHLBI/OASH SoS in TM symposium. The report highlights major gaps in our current knowledge and provides a road map for TM research.

Storage differentially impacts alloimmunization to distinct red cell antigens following transfusion in mice

INTRODUCTION

The impact of blood storage on red blood cell (RBC) alloimmunization remains controversial, with some studies suggesting enhancement of RBC-induced alloantibody production and others failing to observe any impact of storage on alloantibody formation. Since evaluation of storage on RBC alloimmunization in patients has examined antibody formation against a broad range of alloantigens, it remains possible that different clinical outcomes reflect a variable impact of storage on alloimmunization to specific antigens.

METHODS

RBCs expressing two distinct model antigens, HEL-OVA-Duffy (HOD) and KEL, separately or together (HOD × KEL), were stored for 0, 8, or 14 days, followed by detection of antigen levels prior to transfusion. Transfused donor RBC survival was assessed within 24 h of transfusion, while IgM and IgG antibody production were assessed 5 and 14 days after transfusion.

RESULTS

Stored HOD or KEL RBCs retained similar HEL or KEL antigen levels, respectively, as fresh RBCs, but did exhibit enhanced RBC clearance with increased storage age. Storage enhanced IgG antibody formation against HOD, while the oppositive outcome occurred following transfusion of stored KEL RBCs. The distinct impact of storage on HOD or KEL alloimmunization did not appear to reflect intrinsic differences between HOD or KEL RBCs, as transfusion of stored HOD × KEL RBCs resulted in increased IgG anti-HOD antibody development and reduced IgG anti-KEL antibody formation.

CONCLUSIONS

These data demonstrate a dichotomous impact of storage on immunization to distinct RBC antigens, offering a possible explanation for inconsistent clinical experience and the need for additional studies on the relationship between RBC storage and alloimmunization.

Blood donor, component, and recipient-specific factors associated with venous thromboembolism in transfused hospitalized adult patients: Data from the recipient epidemiology and donor evaluation Study-III (REDS-III)

OBJECTIVE

Growing evidence suggests multiple pathophysiological mechanisms linking red blood cells (RBC) transfusions to thrombosis. This study examined blood donor, component, and recipient factors which may be associated with thromboembolic outcomes following RBC transfusion.

METHODS

We utilized the Recipient Epidemiology Donor Evaluation Study-III (REDS-III) database on patients transfused in 12 hospitals between 2013-2016. Stratified Cox proportional hazards regression models with time-dependent exposures were used to examine associations of donor and component modification characteristics on venous thromboembolism (VTE) in patients transfused RBC units.

RESULTS

59,603 patients were transfused 229,500 RBC units during 79,298 hospitalizations with post-transfusion VTE occurring in 1869 (2.4%) of patients. In adjusted regression analyses, a per RBC-unit risk of VTE was present for gamma irradiation (HR = 1.03; 95% CI: 1.02-1.03), female donor sex (HR = 1.01; 95% CI: 1.00-1.01), storage duration greater than 5 weeks (HR = 1.01; 95% CI: 1.01-1.02), AS-1 storage solution (HR = 1.01; 95% CI: 1.00-1.01), and apheresis-derived collections (HR = 1.01; 95% CI: 1.01-1.02). Among recipient factors, male sex (HR = 1.03; 95% CI: 1.02-1.04), pre-transfusion hemoglobin level (HR = 0.94; 95% CI: 0.94-0.94), body mass index strata (HR = 1.11; 95% CI: 1.08-1.14), and principal diagnoses including malignancy (HR = 1.13; 95% CI: 1.10-1.16), cardiac arrest (HR = 1.38; 95% CI:1.07-1.77) and hip fracture (HR = 1.59; 95% CI:1.53-1.66) were associated with VTE in adjusted analyses.

DISCUSSION

We identified several donor, component, and recipient-specific factors associated with VTE in transfused hospitalized adult patients. In adjusted models, the dose-dependent associations of donor and component-specific factors with VTE were modest and unlikely to be clinically significant in the majority of transfused patients. Additional mechanistic and clinical studies linking blood donor and component factors with thrombotic outcomes are needed.

Iron supplementation and the risk of bronchopulmonary dysplasia in extremely low gestational age newborns

BACKGROUND

The aim of this study was to determine the relationship between iron exposure and the development of bronchopulmonary dysplasia (BPD).

METHODS

A secondary analysis of the PENUT Trial dataset was conducted. The primary outcome was BPD at 36 weeks gestational age and primary exposures of interest were cumulative iron exposures in the first 28 days and through 36 weeks' gestation. Descriptive statistics were calculated for study cohort characteristics with analysis adjusted for the factors used to stratify randomization.

RESULTS

Of the 941 patients, 821 (87.2%) survived to BPD evaluation at 36 weeks, with 332 (40.4%) diagnosed with BPD. The median cohort gestational age was 26 weeks and birth weight 810 g. In the first 28 days, 76% of infants received enteral iron and 55% parenteral iron. The median supplemental cumulative enteral and parenteral iron intakes at 28 days were 58.5 and 3.1 mg/kg, respectively, and through 36 weeks' 235.8 and 3.56 mg/kg, respectively. We found lower volume of red blood cell transfusions in the first 28 days after birth and higher enteral iron exposure in the first 28 days after birth to be associated with lower rates of BPD.

CONCLUSIONS

We find no support for an increased risk of BPD with iron supplementation.

TRIAL REGISTRATION NUMBER

NCT01378273. https://clinicaltrials.gov/ct2/show/NCT01378273 IMPACT: Prior studies and biologic plausibility raise the possibility that iron administration could contribute to the pathophysiology of oxidant-induced lung injury and thus bronchopulmonary dysplasia in preterm infants. For 24-27-week premature infants, this study finds no association between total cumulative enteral iron supplementation at either 28-day or 36-week postmenstrual age and the risk for developing bronchopulmonary dysplasia.

ABO blood group antigens and differential glycan expression: Perspective on the evolution of common human enzyme deficiencies

Enzymes catalyze biochemical reactions and play critical roles in human health and disease. Enzyme variants and deficiencies can lead to variable expression of glycans, which can affect physiology, influence predilection for disease, and/or directly contribute to disease pathogenesis. Although certain well-characterized enzyme deficiencies result in overt disease, some of the most common enzyme deficiencies in humans form the basis of blood groups. These carbohydrate blood groups impact fundamental areas of clinical medicine, including the risk of infection and severity of infectious disease, bleeding risk, transfusion medicine, and tissue/organ transplantation. In this review, we examine the enzymes responsible for carbohydrate-based blood group antigen biosynthesis and their expression within the human population. We also consider the evolutionary selective pressures, e.g. malaria, that may account for the variation in carbohydrate structures and the implications of this biology for human disease.

Blood component ratios in children with non-traumatic life-threatening bleeding

BACKGROUND AND OBJECTIVES

In paediatric trauma patients, there are limited prospective data regarding blood components and mortality, with some literature suggesting decreased mortality with high ratios of plasma and platelets to red blood cells (RBCs) in massive transfusions; however, most paediatric massive transfusions occur for non-traumatic aetiologies and few studies assess blood product ratios in these children. This study's objective was to evaluate whether high blood product ratios or low deficits conferred a survival benefit in children with non-traumatic life-threatening bleeding.

MATERIALS AND METHODS

This is a secondary analysis of the five-year, multicentre, prospective, observational massive transfusion epidemiology and outcomes in children study of children with life-threatening bleeding from US, Canadian and Italian medical centres. Primary interventions were plasma:RBC and platelets:RBC (high ratio ≥1:2 ml/kg) and plasma and platelet deficits. The primary outcome was mortality at 6 h, 24 h and 28 days. Multivariate logistic regression models were used to determine independent associations with mortality.

RESULTS

A total of 222 children were included from 24 medical centres: 145 children (median [interquartile range] age 2.1 years [0.3-11.8]) with operative bleeding and 77 (8.0 years [1.2-14.7]) with medical bleeding. In adjusted analyses, neither blood product ratios nor deficits were associated with mortality at 6 h, 24 h or 28 days.

CONCLUSION

This paper addresses a lack of prospective data in children regarding optimal empiric massive transfusion strategies in non-traumatic massive haemorrhage and in finding no decrease in mortality with high plasma or platelet to RBC ratios or lower deficits supports an exploratory analysis for mortality.

Pediatric traumatic hemorrhagic shock consensus conference research priorities

BACKGROUND

Traumatic injury is the leading cause of death in children and adolescents. Hemorrhagic shock remains a common and preventable cause of death in the pediatric trauma patients. A paucity of high-quality evidence is available to guide specific aspects of hemorrhage control in this population. We sought to identify high-priority research topics for the care of pediatric trauma patients in hemorrhagic shock.

METHODS

A panel of 16 consensus multidisciplinary committee members from the Pediatric Traumatic Hemorrhagic Shock Consensus Conference developed research priorities for addressing knowledge gaps in the care of injured children and adolescents in hemorrhagic shock. These ideas were informed by a systematic review of topics in this area and a discussion of these areas in the consensus conference. Research priorities were synthesized along themes and prioritized by anonymous voting.

RESULTS

Eleven research priorities that warrant additional investigation were identified by the consensus committee. Areas of proposed study included well-designed clinical trials and evaluations, including increasing the speed and accuracy of identifying and treating hemorrhagic shock, defining the role of whole blood and tranexamic acid use, and assessment of the utility and appropriate use of viscoelastic techniques during early resuscitation. The committee recommended the need to standardize essential definitions, data elements, and data collection to facilitate research in this area.

CONCLUSION

Research gaps remain in many areas related to the care of hemorrhagic shock after pediatric injury. Addressing these gaps is needed to develop improved evidence-based recommendations for the care of pediatric trauma patients in hemorrhagic shock.

Pediatric traumatic hemorrhagic shock consensus conference recommendations

ABSTRACT

Hemorrhagic shock in pediatric trauma patients remains a challenging yet preventable cause of death. There is little high-quality evidence available to guide specific aspects of hemorrhage control and specific resuscitation practices in this population. We sought to generate clinical recommendations, expert consensus, and good practice statements to aid providers in care for these difficult patients.The Pediatric Traumatic Hemorrhagic Shock Consensus Conference process included systematic reviews related to six subtopics and one consensus meeting. A panel of 16 consensus multidisciplinary committee members evaluated the literature related to 6 specific topics: (1) blood products and fluid resuscitation for hemostatic resuscitation, (2) utilization of prehospital blood products, (3) use of hemostatic adjuncts, (4) tourniquet use, (5) prehospital airway and blood pressure management, and (6) conventional coagulation tests or thromboelastography-guided resuscitation. A total of 21 recommendations are detailed in this article: 2 clinical recommendations, 14 expert consensus statements, and 5 good practice statements. The statement, the panel's voting outcome, and the rationale for each statement intend to give pediatric trauma providers the latest evidence and guidance to care for pediatric trauma patients experiencing hemorrhagic shock. With a broad multidisciplinary representation, the Pediatric Traumatic Hemorrhagic Shock Consensus Conference systematically evaluated the literature and developed clinical recommendations, expert consensus, and good practice statements concerning topics in traumatically injured pediatric patients with hemorrhagic shock.

Clinical features and neurological outcomes in pediatric immune-mediated thrombotic thrombocytopenic purpura: A report from a large pediatric hematology center

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a potentially life-threatening disorder characterized by microangiopathic hemolytic anemia, thrombocytopenia, and severely reduced or absent ADAMTS13 (A disintegrin and metalloprotease with thrombospondin type 1 repeats, member 13) activity, with varying degrees of organ dysfunction. As TTP is rare in pediatrics, most of the medical and scientific literature has largely reported on adult patients. As a result, limited data exist regarding the clinical features, comorbidities, treatment response, and long-term outcomes in pediatric patients with immune-mediated TTP.

METHODS

A single-center retrospective cohort study was conducted of all children and adolescents presenting to Children's Healthcare of Atlanta, Atlanta, Georgia, between the years 2001 and 2021 with immune-mediated TTP (iTTP). Clinical features, treatments, and outcomes, including long-term neurocognitive function, were analyzed.

RESULTS

Eighteen individuals were identified, six of whom had a total of 10 relapses, amounting to 28 episodes overall. Thirty-eight percent of the patients experienced exacerbations but, ultimately, 85% achieved a clinical response and clinical remission. Only one in-hospital death occurred (mortality rate 5.5%). Seventy-three percent of analyzed patients demonstrated long-term neurocognitive abnormalities, including cognitive delay, learning difficulties, and severe depression.

CONCLUSIONS

Children and adolescents recovering from iTTP are at high risk for neurocognitive deficits from initial and possibly ongoing microvascular disease. Due to risk for long-term neurological deficits, we recommend neuropsychological testing in addition to monitoring of other organ functions in all children with TTP, as well as long-term surveillance of ADAMTS13 activity during remission to detect and promptly treat early relapse.

Survey of intrauterine red blood cell (RBC) transfusion practices in the United States

BACKGROUND

A paucity of data exists about the current practice of fetal red blood cell (RBC) transfusion in the United States (US). This investigation describes intrauterine transfusion (IUT) RBC product selection and processing practices at different US institutions.

METHODS

A transfusion medicine and maternal-fetal medicine (MFM) team designed a survey to interrogate and characterize RBCs utilized for IUT. This survey was distributed to seventy US institutions with fetal treatment centers (October 2020-April 2021) identified through the NAFTNet (North American Fetal Therapy Network).

RESULTS

Thirty-seven institutions responded (response rate 53%, 37/70), but five were excluded for not performing IUTs. Most (84%; 27/32) performed 1-24 IUTs annually; two performed >50 IUTs/year. Group O, Rh(D) negative RBC units were always used by 66% (21/32), and 75% (24/32) provided hemoconcentrated RBCs by washing (17/24) or dry packing (6/24). Overall, 66% (21/32) targeted a hematocrit ≥75%. Fifty percent provided both leukocyte-reduced and CMV-negative RBC units. Irradiation of RBC units was performed within 6 h of issue at 63% (20/32) of sites. Most (81%, 26/32) used RBC units at <7 days of age after collection, 56% (18/32) always provided washed RBC units, while 19% (6/32) issued washed RBC only if fresh units are unavailable. Implicated maternal RBC alloantibodies were matched for 78% (25/32) of the time. The transfused volume was universally determined by the MFMs.

DISCUSSION

Heterogeneity and lack of standardization exist in RBC product selection and special processing steps for IUTs in the US. Hence, the establishment of a consensus to standardize IUT protocols is needed.

Innate immune Galectin-7 specifically targets microbes that decorate themselves in blood group-like antigens

Adaptive immunity can target a nearly infinite range of antigens, yet it is tempered by tolerogenic mechanisms that limit autoimmunity. Such immunological tolerance, however, creates a gap in adaptive immunity against microbes decorated with self-like antigens as a form of molecular mimicry. Our results demonstrate that the innate immune lectin galectin-7 (Gal-7) binds a variety of distinct microbes, all of which share features of blood group-like antigens. Gal-7 binding to each blood group expressing microbe, including strains of Escherichia coli, Klebsiella pneumoniae, Providencia alcalifaciens, and Streptococcus pneumoniae, results in loss of microbial viability. Although Gal-7 also binds red blood cells (RBCs), this interaction does not alter RBC membrane integrity. These results demonstrate that Gal-7 recognizes a diverse range of microbes, each of which use molecular mimicry while failing to induce host cell injury, and thus may provide an innate form of immunity against molecular mimicry.

Associated comorbidities, healthcare utilization & mortality in hospitalized patients with haemophilia in the United States: Contemporary nationally representative estimates

INTRODUCTION

Current in-hospital burden and healthcare utilization patterns for persons with haemophilia (PWH) A and B, including both children (ages < 18 years) and adults (ages ≥ 18 years), in the United States (US) are lacking.

AIM

To evaluate healthcare utilization, the prevalence of comorbidities, and mortality in hospitalized paediatric and adult PWH using a contemporary nationally representative cohort.

METHODS

Hospitalizations of PWH either as the primary reason for admission (principal diagnosis) or one of all listed diagnoses were identified using ICD-10 codes from the 2017 Nationwide Inpatient Sample (NIS), the largest publicly available all-payer inpatient discharge database in the US. Sampling weights were applied to generate nationally representative estimates.

RESULTS

The contemporary cohort included 10,555 hospitalizations (paediatrics, 18.3%; adults, 81.7%) among PWH as one-of-all listed diagnoses (n = 1465 as principal diagnosis). Median age (interquartile range) was 46 (24-66) years overall; adults, 54 (35-70) years and paediatric, 4 (1-11). The most common comorbidities in adults were hypertension (33.4%), hyperlipidaemia (23.6%), and diabetes (21.1%). In children, hemarthrosis (11.4%), contusions (9.6%), and central line infections (9.3%) were the most common. The overall mortality rate was 2.3%. Median hospital charges per haemophilia admission were $52,616 ($24,303-$135,814) compared to $26,841 ($12,969-$54,568) for all-cause admissions in NIS.

CONCLUSION

Bleeding and catheter-related infections are the significant reasons for paediatric haemophilia admissions. Adult haemophilia admissions tend to be associated with age-related comorbidities. Costs for haemophilia-related hospitalizations are higher than the national average for all-cause hospitalizations.

A case of Tn polyagglutination discovered by an ABO blood group discrepancy

BACKGROUND

Tn syndrome is an acquired form of polyagglutination arising from somatic mutations of hematopoietic stem cells. Tn red blood cells (RBCs) are agglutinable by naturally occurring anti-Tn antibodies in most adult sera. Current ABO typing reagents are monoclonal and do not detect polyagglutination on forward typing. However, herein we describe a case of Tn activation that was suspected due to cross-reactivity with a monoclonal anti-A reagent.

STUDY DESIGN AND METHODS

A 63-year-old man with myeloproliferative neoplasm, who historically typed as group O, demonstrated unexpected mixed field reactivity with anti-A reagent using a gel-based method. However, manual tube testing was consistent with the patient's historical group O type.

RESULTS

Lectin testing demonstrated reactivity with Salvia sclarea and Glycine soja, but not Arachis hypogea. The patient's RBCs produced positive crossmatches with healthy donor sera, but reactivity was eliminated by ficin pretreatment of the RBCs. Ficin treatment also resolved typing discrepancies on gel-based typing. No reactivity was noted using cord blood sera, and N antigen expression was diminished upon phenotyping. Tn activation was confirmed by detection of a novel 4-nucleotide deletion (c.395-398del) in exon 3 of C1GALT1C1 resulting in a truncated glycosyltransferase.

CONCLUSION

This case of acquired Tn polyagglutination due to a novel mutation was first suspected from an ABO phenotyping discrepancy. It highlights the cross-reactivity of anti-A reagent with Tn antigen when tested on a common gel-based method. Furthermore, the case demonstrates that review of patient history and test information can clarify discrepancies and guide resolution.

Neutralizing Antibodies Against Factor VIII Can Occur Through a Non-Germinal Center Pathway

Humoral immunity to factor VIII (FVIII) represents a significant challenge for the treatment of patients with hemophilia A. Current paradigms indicate that neutralizing antibodies against FVIII (inhibitors) occur through a classical CD4 T cell, germinal center (GC) dependent process. However, clinical observations suggest that the nature of the immune response to FVIII may differ between patients. While some patients produce persistent low or high inhibitor titers, others generate a transient response. Moreover, FVIII reactive memory B cells are only detectable in some patients with sustained inhibitor titers. The determinants regulating the type of immune response a patient develops, let alone how the immune response differs in these patients remains incompletely understood. One hypothesis is that polymorphisms within immunoregulatory genes alter the underlying immune response to FVIII, and thereby the inhibitor response. Consistent with this, studies report that inhibitor titers to FVIII differ in animals with the same F8 pathogenic variant but completely distinct backgrounds; though, how these genetic disparities affect the immune response to FVIII remains to be investigated. Given this, we sought to mechanistically dissect how genetics impact the underlying immune response to FVIII. In particular, as the risk of producing inhibitors is weakly associated with differences in HLA, we hypothesized that genetic factors other than HLA influence the immune response to FVIII and downstream inhibitor formation. Our data demonstrate that FVIII deficient mice encoding the same MHC and F8 variant produce disparate inhibitor titers, and that the type of inhibitor response formed associates with the ability to generate GCs. Interestingly, the formation of antibodies through a GC or non-GC pathway does not appear to be due to differences in CD4 T cell immunity, as the CD4 T cell response to an immunodominant epitope in FVIII was similar in these mice. These results indicate that genetics can impact the process by which inhibitors develop and may in part explain the apparent propensity of patients to form distinct inhibitor responses. Moreover, these data highlight an underappreciated immunological pathway of humoral immunity to FVIII and lay the groundwork for identification of biomarkers for the development of approaches to tolerize against FVIII.

Clodronate inhibits alloimmunization against distinct red blood cell alloantigens in mice

BACKGROUND

Alloimmunization can be a significant barrier to red blood cell (RBC) transfusion. While alloantigen matching protocols hold promise in reducing alloantibody formation, transfusion-dependent patients can still experience RBC alloimmunization and associated complications even when matching protocols are employed. As a result, complementary strategies capable of actively preventing alloantibody formation following alloantigen exposure are warranted.

STUDY DESIGN AND METHODS

We examined whether pharmacological removal of macrophages using clodronate may provide an additional strategy to actively inhibit RBC alloimmunization using two preclinical models of RBC alloimmunization. To accomplish this, mice were treated with clodronate, followed by transfusion of RBCs expressing the HOD (HEL, OVA, and Duffy) or KEL antigens. On days 5 and 14 post transfusion, anti-HOD or anti-KEL IgM and IgG antibodies were evaluated.

RESULTS

Low dose clodronate effectively eliminated key marginal zone macrophage populations from the marginal sinus. Prior treatment with clodronate, but not empty liposomes, also significantly inhibited IgM and IgG anti-HOD alloantibody formation following transfusion of HOD RBCs. Similar exposure to clodronate inhibited IgM and IgG antibody formation following KEL RBC transfusion.

CONCLUSIONS

Clodronate can inhibit anti-HOD and anti-KEL antibody formation following RBC transfusion in preclinical models. These results suggest that clodronate may provide an alternative approach to actively inhibit or prevent the development of alloantibodies following RBC transfusion, although future studies will certainly be needed to fully explore this possibility.

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P): A research program striving to improve blood donor safety and optimize transfusion outcomes across the lifespan

BACKGROUND

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P) is a new iteration of prior National Heart, Lung, and Blood Institute (NHLBI) REDS programs that focus on improving transfusion recipient outcomes across the lifespan as well as the safety and availability of the blood supply.

STUDY DESIGN AND METHODS

The US program includes blood centers and hospitals (22 including 6 free-standing Children's hospitals) in four geographic regions. The Brazilian program has 5 participating hemocenters. A Center for Transfusion Laboratory Studies (CTLS) and a Data Coordinating Center (DCC) support synergistic studies and activities over the 7-year REDS-IV-P program.

RESULTS

The US is building a centralized, vein-to-vein (V2V) database, linking information collected from blood donors, their donations, the resulting manufactured components, and data extracts from hospital electronic medical records of transfused and non-transfused patients. Simultaneously, the Brazilian program is building a donor, donation, and component database. The databases will serve as the backbone for retrospective and prospective observational studies in transfusion epidemiology, transfusion recipient outcomes, blood component quality, and emerging blood safety issues. Special focus will be on preterm infants, patients with sickle cell disease, thalassemia or cancer, and the effect of donor biologic variability and component manufacturing on recipient outcomes. A rapid response capability to emerging safety threats has resulted in timely studies related to Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2).

CONCLUSIONS

The REDS-IV-P program endeavors to improve donor-recipient-linked research with a focus on children and special populations while also maintaining the flexibility to address emerging blood safety issues.

Sex Differences in the Association of Pretransfusion Hemoglobin Levels with Brain Structure and Function in the Preterm Infant

OBJECTIVE

To assess sex-specific differences in early brain structure and function of preterm infants after red blood cell (RBC) transfusions.

STUDY DESIGN

A single-center subset of infants with a birth weight <1000 g and gestational age 22-29 weeks were enrolled from the National Institute of Child Health and Human Development's Neonatal Research Network Transfusion of Prematures Trial. Hemoglobin (Hb) concentration obtained directly before each transfusion (pretransfusion Hb [ptHb]) was obtained longitudinally throughout each infant's neonatal intensive care unit stay and used as a marker of degree of anemia (n = 97). Measures of regional brain volumes using magnetic resonance imaging were obtained at ∼40 weeks postmenstrual age or at hospital discharge, if earlier (n = 29). Measures of brain function were obtained at 12 months corrected age using the Bayley Scales of Infant & Toddler Development, 3rd Edition (n = 34).

RESULTS

PtHb was positively correlated with neonatal cerebral white matter volume in males (B = +0.283; P = .006), but not females (B = -0.099; P = .713), resulting in a significant sex interaction (P = .010). Bayley-III gross motor scores and a pooled mean score were significantly lower in association with higher ptHb in females (gross motor score: B = -3.758; P = .013; pooled mean score: B = -1.225; P = .030), but not males (gross motor score: B = +1.758; P = .167; pooled mean score: B = +0.621; P = .359). Higher ptHb was associated with descriptively lower performance on multiple Bayley-III subscales in females, but not in males.

CONCLUSIONS

This study demonstrates sex-specific associations between an early marker of anemia and RBC transfusion status (ie, ptHb) with both neonatal white matter volume and early cognitive function at age 12 months in preterm infants.

Transfusion Ratios and Deficits in Injured Children With Life-Threatening Bleeding

OBJECTIVES

To assess the impact of plasma and platelet ratios and deficits in injured children with life-threatening bleeding.

DESIGN

Secondary analysis of the MAssive Transfusion epidemiology and outcomes In Children study dataset, a prospective observational study of children with life-threatening bleeding events.

SETTING

Twenty-four childrens hospitals in the United States, Canada, and Italy.

PATIENTS

Injured children 0-17 years old who received greater than 40 mL/kg total blood products over 6 hours or were transfused under activation of massive transfusion protocol.

INTERVENTION/EXPOSURE

Weight-adjusted blood product volumes received during the bleeding event were recorded. Plasma:RBC ratio (plasma/RBC weight-adjusted volume in mL/kg) and platelet:RBC ratio (platelet/RBC weight-adjusted volume in mL/kg) were analyzed. Plasma deficit was calculated as RBC mL/kg - plasma mL/kg; platelet deficit was calculated as RBC mL/kg - platelet mL/kg.

MEASUREMENTS AND MAIN RESULTS

Of 191 patients analyzed, median (interquartile range) age was 10 years (5-15 yr), 61% were male, 61% blunt mechanism, and median (interquartile range) Injury Severity Score was 29 (24-38). After adjusting for Pediatric Risk of Mortality score, cardiac arrest, use of vasoactive medications, and blunt mechanism, a high plasma:RBC ratio (> 1:2) was associated with improved 6-hour survival compared with a low plasma:RBC ratio (odds ratio [95% CI] = 0.12 [0.03-0.52]; p = 0.004). Platelet:RBC ratio was not associated with survival. After adjusting for age, Pediatric Risk of Mortality score, cardiac arrest, and mechanism of injury, 6-hour and 24-hour mortality were increased in children with greater plasma deficits (10% and 20% increased odds of mortality for every 10 mL/kg plasma deficit at 6 hr [p = 0.04] and 24 hr [p = 0.01], respectively); 24-hour mortality was increased in children with greater platelet deficits (10% increased odds of 24-hr mortality for every 10 mL/kg platelet deficit [p = 0.02)]).

CONCLUSIONS

In injured children, balanced resuscitation may improve early survival according to this hypothesis generating study. Multicenter clinical trials are needed to assess whether clinicians should target ratios and deficits as optimal pediatric hemostatic resuscitation practice.

Sex-specific cytokine responses and neurocognitive outcome after blood transfusions in preterm infants

BACKGROUND

The objective of this study was to determine sex-specific differences in inflammatory cytokine responses to red blood cell (RBC) transfusion in preterm infants in the neonatal period and their relationship to later neurocognitive status.

METHODS

Infants with a birth weight <1000 g and gestational age 22-29 weeks were enrolled in the Transfusion of Prematures (TOP) trial. The total number of transfusions was used as a marker of transfusion status. Nineteen cytokines and biomarkers were analyzed from 71 infants longitudinally during the neonatal period. Twenty-six infants completed the Bayley Scales of Infant & Toddler Development, 3rd Edition (Bayley-III) at 12 months' corrected age.

RESULTS

Nine cytokine levels were significantly elevated in proportion to the number of transfusions received. Of those, one cytokine showed a sex-specific finding (p = 0.004): monocyte chemoattractant protein-1, MCP-1, rose substantially in females (8.9% change per additional transfusion), but not in males (-0.8% change). Higher concentrations of MCP-1 exclusively were associated with worse Bayley-III scores: decreased cognitive raw scores (p = 0.0005) and motor scaled scores (p < 0.0001).

CONCLUSIONS

This study provides evidence of a sex-specific difference in the inflammatory response to RBC transfusions during neonatal life, with MCP-1 levels rising only in females and inversely correlating with neurocognitive status at 12 months old.

IMPACT

It is important to understand the risk factors for abnormal neurodevelopment in preterm infants, including anemia and RBC transfusion, in order to improve outcomes and provide potential targets for therapy. Our study investigates and provides the first evidence of sex-specific differences in inflammatory cytokine responses to RBC transfusions in preterm infants in the neonatal period, and their relationship to later cognitive outcomes. This study critically suggests that different transfusion thresholds may have a sex-specific effect on neurodevelopment: females have worse cognitive outcomes with increased number of transfusions, while males have worse outcomes with lower number of transfusions.

Glucose-6-phosphate dehydrogenase deficiency is more prevalent in Duffy-null red blood cell transfusion in sickle cell disease

BACKGROUND

Resistance to malaria infection may be conferred by erythrocyte genetic variations including glucose-6-phosphate dehydrogenase (G6PD) deficiency and lack of Duffy antigens. In red blood cell (RBC) transfusion, G6PD deficiency may shorten transfusion survival. Because Duffy-null units are commonly transfused in sickle cell disease (SCD) due to antigen matching protocols, we examined whether Duffy-null donor RBC units have a higher prevalence of G6PD deficiency.

MATERIALS AND METHODS

Pediatric patients with SCD on chronic transfusion therapy were followed prospectively for multiple transfusions. RBC unit segments were collected to measure G6PD activity and RBC genotyping. The decline in donor hemoglobin (ΔHbA) following transfusion was assessed from immediate posttransfusion estimates and HbA measurements approximately 1 month later.

RESULTS

Of 564 evaluable RBC units, 59 (10.5%) were G6PD deficient (23 severe, 36 moderate deficiency); 202 (37.6%) units were Duffy-null. G6PD deficiency occurred in 40 (19.8%) Duffy-null units versus 15 (4.5%) Duffy-positive units (p < .0001). In univariate analysis, the fraction of Duffy-null RBC units per transfusion was associated with greater decline in HbA (p = .038); however, in multivariate analysis, severe G6PD deficiency (p = .0238) but not Duffy-null RBC (p = .0139) were associated with ΔHbA.

CONCLUSION

Selection of Duffy-null RBC units may result in shorter in vivo survival of transfused RBCs due to a higher likelihood of transfusing units from G6PD deficient donors.

Procedural adverse events in pediatric patients with sickle cell disease undergoing chronic automated red cell exchange

BACKGROUND

Chronic automated red cell exchange (RCE) is increasingly employed for sickle cell disease (SCD). There is a paucity of data on the incidence of RCE adverse events (AEs) and potential patient and procedural risk factors for AEs.

METHODS

A retrospective review of pediatric SCD patients receiving chronic RCE over 3 years was performed to determine the frequency of AEs and identify procedural and patient AE risk factors. AE incidence, AE rate, incidence rate ratios (IRRs), and relative risks (RRs) were calculated based on various procedural and patient characteristics by univariable (UV) and multivariable (MV) analyses.

RESULTS

In 38 patients receiving 760 procedures, there were 150 (19.7%) AEs, 36 (4.7%) were symptomatic AEs. AE rates were 20.2 [95% CI 17.2, 23.6] and 4.8 [95% CI 3.49, 6.70] per 100 person months for AEs and symptomatic AEs, respectively. AE incidences were: hypocalcemia (117; 15.4%), dizziness (22; 3.0%), hypotension (15; 2.0%), and nausea (14; 1.8%). Patients with baseline Hct ≥30% experienced more total AEs and symptomatic AEs. Patients with pre-procedure systolic BP <50th percentile, severe CNS vasculopathy, and non-SCA genotype (HbSC or Sβ⁺ thalassemia) exhibited more total AEs. IHD depletion was not associated with an increased incidence of AEs or symptomatic AEs.

CONCLUSION

SCD patients with Hct ≥30%, systolic BP <50th percentile, severe CNS vasculopathy, and possibly non-SCA genotype may be at higher risk for RCE-related AEs. The effect of IHD on AE risk is likely minimal. Individualized AE risk assessment should be performed in all SCD patients undergoing chronic automated RCE.

Safety and tolerability of solvent/detergent‐treated plasma for pediatric patients requiring therapeutic plasma exchange: An open‐label, multicenter, postmarketing study

Background

This study investigated the real‐world safety and tolerability of solvent/detergent‐treated (S/D) plasma for pediatric patients requiring therapeutic plasma exchange (TPE).

Study design and methods

LAS‐213 was a multicenter, open‐label, interventional, phase 4 study. Patients (≥2 to ≤20 years) receiving TPE therapy were eligible. A total plasma volume of 40–60 ml/kg was recommended, with an infusion rate not exceeding 0.020–0.025 citrate/kg body weight/min (<1 ml/kg body weight/min). The primary endpoint was assessment of safety, monitoring the following: serious adverse events (SAEs), adverse drug reactions (ADRs), thrombotic events (TEs), thromboembolic events (TEEs), and specific laboratory tests.

Results

In total, 41 children (2 to <12 years [n = 15]; 12 to <17 years [n = 13]; ≥17 years [n = 13]) underwent 102 TPEs with a total of 135,137 ml of S/D plasma exchanged. Each patient group received between 1 and 6 TPEs (mean: 2.5 TPEs). Actual dose administered per TPE was 4–72 ml/kg (mean: 28.6 ml/kg), with a mean total volume of 1324.9 ml (range: 113–4000 ml). Overall safety was excellent for 96/102 (94.0%) TPEs. Six TPEs had a “moderate” safety profile for four patients experiencing eight ADRs. Of these, seven were mild in intensity and one (pyrexia) was moderate, all resolving by study end. Mild citrate toxicity (n = 2) was the most common ADR. One SAE was reported but was unrelated to the study drug. No TEs, TEEs, or changes in laboratory safety parameters were reported.

Conclusion

S/D plasma was well tolerated and demonstrated favorable safety, supporting the use of S/D plasma for TPE in pediatrics.

Transfusion Practices in Pediatric Cardiac Surgery Requiring Cardiopulmonary Bypass: A Secondary Analysis of a Clinical Database

OBJECTIVES

To describe blood component usage in transfused children with congenital heart disease undergoing cardiopulmonary bypass surgery across perioperative settings and diagnostic categories.

DESIGN

Datasets from U.S. hospitals participating in the National Heart, Lung, and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III were analyzed.

SETTING

Inpatient admissions from three U.S. hospitals from 2013 to 2016.

PATIENTS

Transfused children with congenital heart disease undergoing single ventricular, biventricular surgery, extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eight hundred eighty-two transfused patients were included. Most of the 185 children with single ventricular surgery received multiple blood products: 81% RBCs, 79% platelets, 86% plasma, and 56% cryoprecipitate. In the 678 patients undergoing biventricular surgery, 85% were transfused plasma, 75% platelets, 74% RBCs, and 48% cryoprecipitate. All 19 patients on extracorporeal membrane oxygenation were transfused RBCs, plasma, and cryoprecipitate, and 18 were transfused platelets. Intraoperatively, patients commonly received all three components, while postoperative transfusions were predominantly single blood components. Pretransfusion hemoglobin values were normal/low-normal for age for all phases of care for single ventricular surgery (median hemoglobin 13.2-13.5 g/dL). Pretransfusion hemoglobin values for biventricular surgeries were higher intraoperatively compared with other timing (12.2 g/dL vs 11.2 preoperative and postoperative; p < 0.0001). Plasma transfusions for all patients were associated with a near normal international normalized ratio: single ventricular surgeries median international normalized ratio was 1.3 postoperative versus 1.8 intraoperative and biventricular surgeries median international normalized ratio was 1.1 intraoperative versus 1.7 postoperative. Intraoperative platelet transfusions with biventricular surgeries had higher median platelet count compared with postoperative pretransfusion platelet count (244 × 109/L intraoperative vs 69 × 109/L postoperative).

CONCLUSIONS

Children with congenital heart disease undergoing cardiopulmonary bypass surgery are transfused many blood components both intraoperatively and postoperatively. Multiple blood components are transfused intraoperatively at seemingly normal/low-normal pretransfusion values. Pediatric evidence guiding blood component transfusion in this population at high risk of bleeding and with limited physiologic reserve is needed to advance safe and effective blood conservation practices.

Association of Blood Donor Sex and Age With Outcomes in Very Low-Birth-Weight Infants Receiving Blood Transfusion

IMPORTANCE

There are conflicting data on the association between blood donor characteristics and outcomes among patients receiving transfusions.

OBJECTIVE

To evaluate the association of blood donor sex and age with mortality or serious morbidity in very low-birth-weight (VLBW) infants receiving blood transfusions.

DESIGN, SETTING, AND PARTICIPANTS

This is a cohort study using data collected from 3 hospitals in Atlanta, Georgia. VLBW infants (≤1500 g) who received red blood cell (RBC) transfusion from exclusively male or female donors were enrolled from January 2010 to February 2014. Infants received follow-up until 90 days, hospital discharge, transfer to a non-study-affiliated hospital, or death. Data analysis was performed from July 2019 to December 2020.

EXPOSURES

Donor sex and mean donor age.

MAIN OUTCOMES AND MEASURES

The primary outcome was a composite outcome of death, necrotizing enterocolitis (Bell stage II or higher), retinopathy of prematurity (stage III or higher), or moderate-to-severe bronchopulmonary dysplasia. Modified Poisson regression, with consideration of covariate interactions, was used to estimate the association between donor sex and age with the primary outcome, with adjustment for the total number of transfusions and birth weight.

RESULTS

In total, 181 infants were evaluated, with a mean (SD) birth weight of 919 (253) g and mean (SD) gestational age of 27.0 (2.2) weeks; 56 infants (31%) received RBC transfusion from exclusively female donors. The mean (SD) donor age was 46.6 (13.7) years. The primary outcome incidence was 21% (12 of 56 infants) among infants receiving RBCs from exclusively female donors, compared with 45% (56 of 125 infants) among those receiving RBCs from exclusively male donors. Significant interactions were detected between female donor and donor age (P for interaction = .005) and between female donor and number of transfusions (P for interaction < .001). For the typical infant, who received a median (interquartile range) of 2 (1-3) transfusions, RBC transfusion from exclusively female donors, compared with male donors, was associated with a lower risk of the primary outcome (relative risk, 0.29; 95% CI, 0.16-0.54). The protective association between RBC transfusions from female donors, compared with male donors, and the primary outcome increased as the donor age increased, but decreased as the number of transfusions increased.

CONCLUSIONS AND RELEVANCE

These findings suggest that RBC transfusion from female donors, particularly older female donors, is associated with a lower risk of death or serious morbidity in VLBW infants receiving transfusion. Larger studies confirming these findings and examining potential mechanisms are warranted.

Transfusion practices for pediatric oncology and hematopoietic stem cell transplantation patients: Data from the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III (REDS-III)

BACKGROUND

To evaluate transfusion practices in pediatric oncology and hematopoietic stem cell transplant (HSCT) patients.

STUDY DESIGN AND METHODS

This is a multicenter retrospective study of children with oncologic diagnoses treated from 2013 to 2016 at hospitals participating in the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III. Transfusion practices were evaluated by diagnosis codes and pre-transfusion laboratory values.

RESULTS

A total of 4766 inpatient encounters of oncology and HSCT patients were evaluated, with 39.3% (95% confidence interval [CI]: 37.9%-40.7%) involving a transfusion. Red blood cells (RBCs) were the most commonly transfused component (32.4%; 95% CI: 31.1%-33.8%), followed by platelets (22.7%; 95% CI: 21.5%-23.9%). Patients in the 1 to <6 years of range were most likely to be transfused and HSCT, acute myeloid leukemia, and aplastic anemia were the diagnoses most often associated with transfusion. The median hemoglobin (Hb) prior to RBC transfusion was 7.5 g/dl (10-90th percentile: 6.4-8.8 g/dl), with 45.7% of transfusions being given at 7 to <8 g/dl. The median platelet count prior to platelet transfusion was 20 × 10⁹ /L (10-90th percentile: 8-51 × 10⁹ /L), and 37.9% of transfusions were given at platelet count of >20-50 × 10⁹ /L. The median international normalized ratio (INR) prior to plasma transfusion was 1.7 (10-90th percentile: 1.3-2.7), and 36.3% of plasma transfusions were given at an INR between 1.4 and 1.7.

DISCUSSION

Transfusion of blood components is common in hospitalized pediatric oncology/HSCT patients. Relatively high pre-transfusion Hb and platelet values and relatively low INR values prior to transfusion across the studied diagnoses highlight the need for additional studies in this population.

Marginal zone B cells mediate a CD4 T-cell-dependent extrafollicular antibody response following RBC transfusion in mice

Red blood cell (RBC) transfusions can result in alloimmunization toward RBC alloantigens that can increase the probability of complications following subsequent transfusion. An improved understanding of the immune mechanisms that underlie RBC alloimmunization is critical if future strategies capable of preventing or even reducing this process are to be realized. Using the HOD (hen egg lysozyme [HEL] and ovalbumin [OVA] fused with the human RBC antigen Duffy) model system, we aimed to identify initiating immune factors that may govern early anti-HOD alloantibody formation. Our findings demonstrate that HOD RBCs continuously localize to the marginal sinus following transfusion, where they colocalize with marginal zone (MZ) B cells. Depletion of MZ B cells inhibited immunoglobulin M (IgM) and IgG anti-HOD antibody formation, whereas CD4 T-cell depletion only prevented IgG anti-HOD antibody development. HOD-specific CD4 T cells displayed similar proliferation and activation following transfusion of HOD RBCs into wild-type or MZ B-cell-deficient recipients, suggesting that IgG formation is not dependent on MZ B-cell-mediated CD4 T-cell activation. Moreover, depletion of follicular B cells failed to substantially impact the anti-HOD antibody response, and no increase in antigen-specific germinal center B cells was detected following HOD RBC transfusion, suggesting that antibody formation is not dependent on the splenic follicle. Despite this, anti-HOD antibodies persisted for several months following HOD RBC transfusion. Overall, these data suggest that MZ B cells can initiate and then contribute to RBC alloantibody formation, highlighting a unique immune pathway that can be engaged following RBC transfusion.

Survey to inform trial of low-titer group O whole-blood compared to conventional blood components for children with severe traumatic bleeding

BACKGROUND

Low-titer group O whole-blood (LTOWB) is being used for children with life-threatening traumatic bleeding. A survey was conducted to determine current LTOWB utilization and interest in participation in a randomized control trial (RCT) of LTOWB versus standard blood component transfusion in this population.

STUDY DESIGN AND METHODS

Transfusion medicine (TM) directors and pediatric trauma directors at 36 US children's hospitals were surveyed by e-mail in June 2020. Hospitals were selected by participation in the Massive Transfusion Epidemiology and Outcomes in Children Study or being among the largest 30 children's hospitals by bed capacity per the Becker Hospital Review.

RESULTS

The response rate was 83.3% (30/36) from TM directors and 88.9% (32/36) from trauma directors. The median of massive transfusion protocol activations for traumatic bleeding was reported as 12 (IQR 5.8-20) per year by TM directors. LTOWB was used by 18.8% (6/32) of trauma directors. Survey responses indicate that 86.7% (26/30) of TM directors and 90.6% (29/32) of trauma directors either moderately or strongly agree that a LTOWB RCT is important to perform. About 83.3% (25/30) of TM directors and 93.8% (30/32) of trauma directors were willing to participate in the proposed trial. About 80% (24/30) of TM directors and 71.9% (23/32) of trauma directors would transfuse RhD+ LTOWB to male children, but fewer would transfuse Rh + LTOWB to females [20% (6/30) TM directors and 37.5% (12/32) of trauma directors].

CONCLUSIONS

A majority of respondents supported an RCT comparing LTOWB to component therapy in children with severe traumatic bleeding.

Variation in Neonatal Transfusion Practice

OBJECTIVE

To estimate the incidence of blood product transfusion, including red blood cells, platelets, and plasma, and characterize pretransfusion hematologic values for infants during their initial hospitalization after birth.

STUDY DESIGN

Retrospective cohort study using data from 7 geographically diverse US academic and community hospitals that participated in the National Heart Lung and Blood Institute Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) from 2013 to 2016. Pretransfusion hematologic values were evaluated closest to each transfusion and no more than 24 hours beforehand.

RESULTS

Data from 60 243 infants were evaluated. The incidence of any transfusion differed by gestational age (P < .0001), with 80% (95% CI 76%-84%) transfused at <27 weeks of gestation (n = 329) and 0.5% (95% CI 0.5%-0.6%) transfused at ≥37 weeks of gestation (n = 53 919). The median pretransfusion hemoglobin was 11.2 g/dL (10th-90th percentile 8.8-14.1) for the entire cohort, ranging from 10.5 g/dL (8.8-12.3) for infants born extremely preterm at <27 weeks of gestation to 13.0 g/dL (10.5-15.5) for infants born at term. The median pretransfusion platelet count (×10⁹/L) was 71 (10th-90th percentile 26-135) for the entire cohort, and was >45 for all gestational age groups examined. The median pretransfusion international normalized ratio for the entire cohort was 1.7 (10th-90th percentile 1.2-2.8).

CONCLUSIONS

There is wide variability in pretransfusion hemoglobin, platelet count, and international normalized ratio values for neonatal transfusions. Our findings suggest that a large proportion of neonatal transfusions in the US are administered at thresholds greater than supported by the best-available evidence and highlight an opportunity for improved patient blood management.

Blood transfusions in gunshot-wound-related emergency department visits and hospitalizations in the United States

BACKGROUND

The United States (US) leads all high-income countries in gunshot wound (GSW) deaths. However, previous US studies have not evaluated the national blood transfusion utilization patterns in hospitalized GSW patients.

METHODS

Data from 2016 to 2017 were analyzed from the Nationwide Emergency Department Sample (NEDS) and Nationwide Inpatient Sample (NIS), the largest all-payer emergency department (ED) and inpatient databases, respectively. Using stratified probability sampling, weights were applied to generate nationally representative estimates. Multivariable Poisson-regression models were used to estimate prevalence ratios (PR) of blood transfusion.

RESULTS

There were 168,315 ED visits and 58,815 hospitalizations (age = 18-90 years) following a GSW. The majority of hospitalizations were men (88.5%), age 18-24 years (31.8%), and assault-related GSW (51.3%). Blacks had the largest proportion (48.7%) overall of all GSW hospitalizations; Whites accounted for the highest proportion of intentional self-harm injuries (72.4%). Blood transfusions occurred in 12.7% of hospitalizations (12.0% red blood cell [RBC], 4.9% plasma, and 2.5% platelet transfusions). Only 1.9% of cases were associated with transfusion of all three blood components. Hospitalizations with major/extreme severity of illness had significantly higher prevalence of transfusion versus those with mild/moderate severity [crude PR = 4.79 (95%CI:4.15-5.33, p < .001)]. Overall, 8.2% of hospitalizations with GSW died, of whom 26.8% required blood transfusions, which was significantly higher than survivors [crude PR = 2.34 (95%CI:2.10-2.61, p < .001)]. The vast majority (95%) of the transfusions among those who died were within 48 h since admission.

CONCLUSIONS

Gun-related violence is a public health emergency in the US, and GSWs are a source of significant mortality, blood utilization, and health care costs.

Are We Forgetting About IgA? A Re-examination of Coronavirus Disease 2019 Convalescent Plasma

BACKGROUND

While convalescent plasma (CP) may benefit patients with COVID-19, fundamental questions remain regarding its efficacy, including the components of CP that may contribute to its therapeutic effect. Most current serological evaluation of CP relies on examination of total immunoglobulin or IgG-specific anti-SARS-CoV-2 antibody levels. However, IgA antibodies, which also circulate and are secreted along the respiratory mucosa, represent a relatively uncharacterized component of CP.

STUDY DESIGN AND METHODS

Residual samples from patients and CP donors were assessed for IgM, IgG, and IgA anti-SARS-CoV-2 antibody titers against the receptor-binding domain responsible for viral entry. Symptom onset was obtained by chart review.

RESULTS

Increased IgA anti-SARS-CoV-2 antibody levels correlated with clinical improvement and viral clearance in an infant with COVID-19, prompting a broader examination of IgA levels among CP donors and hospitalized patients. Significant heterogeneity in IgA levels was observed among CP donors, which correlated weakly with IgG levels or the results of a commonly employed serological test. Unlike IgG and IgM, IgA levels were also more likely to be variable in hospitalized patients and this variability persisted in some patients >14 days following symptom onset. IgA levels were also less likely to be sustained than IgG levels following subsequent CP donation.

CONCLUSIONS

IgA levels can be very heterogenous among CP donors and hospitalized patients and do not necessarily correlate with commonly employed testing platforms. Examining isotype levels in CP and COVID-19 patients may allow for a tailored approach when seeking to fill specific gaps in humoral immunity.