Allergic Transfusion Reactions Research Articles

Food and inhaled allergens may play a more prominent role in allergic transfusion reactions than previously recognized.

Correlations between allergic transfusion reactions (ATRs) and allergic predisposition to food and inhaled allergens have been consistently reported. Food or pollen allergens circulating in the blood can be indirectly identified using the basophil activation test. In some cases, food or pollen allergens have been identified in transfused blood products that cause ATRs.

A Survey of Acute Transfusion Reactions in Thalassemic Patients in Pakistan: A Single Centre Experience

Background: Blood transfusion reactions are characterized as adverse reactions linked to whole blood or any of its constituent parts, encompassing a spectrum of severity levels, from minor to potentially life-threatening. The administration of blood products is a common practice to enhance the hemodynamic status and overall clinical well-being of patients. However, it's important to note that transfusing blood components comes with potential complications, both infectious and non-infectious in nature. Objective: The current study aim to evaluate the type and frequency of transfusion reactions in thalassemic patients at Hamza Foundation Welfare Hospital and Blood Services, Peshawar. Method: The current study was a descriptive cross-sectional study. The data was collected from 152 participants through a self-generated questionnaire during the 4 months (from April to July 2022) study period. Results: The overall frequency of febrile non-hemolytic reactions (FNHTR), allergic transfusion reactions (ATR), and acute hemolytic transfusion reactions (AHTR) was 84%. Among the 152 participants, 91 (59.8%) were males, and 61 (40.2%) were females. Of the total males, 83 (55.6%) experienced transfusion reactions, while 46 (30%) of the females had transfusion reactions. Specifically, 56 males and 36 females experienced FNHTRs, 22 males and 4 females experienced ATRs, and 5 males and 6 females experienced AHTRs. Fever was observed predominant symptom 69.7% and 52.6% among FNHTR and AHTR, anxiety was predominantly observed in 34.8% in ATRs. Conclusion: Among the transfusion reaction types, FNHTRs emerged as the most common, followed by ATRs and AHTRs. Key words: Febrile Non-Hemolytic Reaction, Allergic Transfusion Reaction, Hemolytic Transfusion Reactions

Acetaminophen and Chlorpheniramine Maleate Premedication among Patients with Chronic Transfusion: a Prospective, Randomized Controlled Trial

Introduction: Patients with chronic transfusion, especially those with transfusion-dependent thalassemia, are susceptible to transfusion reactions. Acetaminophen and/or chlorpheniramine maleate (CPM) are commonly used as premedication in Thailand, although their efficacy in preventing transfusion reactions remains unclear. This study aims to evaluate the efficacy of acetaminophen and CPM in preventing febrile nonhemolytic transfusion reaction (FNHTR) and allergic transfusion reaction (ATR) before leukocyte-poor packed red cells (LPRC) transfusion.Methods: This study is a prospective, randomized controlled trial involving patients with chronic transfusionaged 18 years. Patients were randomly assigned to either receive oral acetaminophen and intravenous CPM or placebo (calcium carbonate and normal saline) before LPRC transfusion. The primary endpoint was the combined incidence of FNHTR and ATR amongpatients receiving premedication compared with those receiving placebo. This study was registered at Thai Clinical Trial Registry Study ( TCTR20221011002).Results: Ninety-four patients were recruited, with 46 in the premedication arm and 48 in the placebo arm. The incidence of FNHTR and allergic transfusion reaction in the premedication arm and the placebo arm was 0% and 2.1%, respectively (P = 0.33). FNHTR occurred in one patient in the placebo arm, and no patients presented ATR. No adverse events were reported with any medication.Conclusions: Among patients with chronic transfusion receiving LPRC, the incidence of FNHTR or ATR is low. Premedication with oral acetaminophen and intravenous CPM did not have benefits in preventing transfusion reactions. Therefore, acetaminophen and CPM could be safely omitted in chronic transfused patients without a history of transfusion reactions

Decreasing Premedication for Blood Transfusions: A Quality Improvement Project.

Premedication administration to patients who are to receive blood transfusions continues despite evidence of a lack of benefit when given to prevent febrile nonhemolytic or mild allergic transfusion reactions. Reviews of ordering practices and staff surveys on an adult inpatient hematology-oncology unit in our multisite oncology medical center indicated a lack of standardization and overuse of premedication in blood transfusions and a lack of knowledge of when it was appropriate to use premedication. A literature search was performed, and the evidence led to a proposal for a quality improvement (QI) project focused on development of an evidence-based algorithm to guide clinicians in when to administer which premedication, development of clear documentation for premedication plans, integration of the documented premedication plans into electronic orders for blood products, and staff education. Interventions included a hospital-wide algorithm and an electronic order to be integrated with a premedication plan for each patient on the adult hematology-oncology unit. Seven months after implementation of the intervention, premedication use among patients decreased by 57.6%, and the transfusion reaction rate decreased from 1% to 0.8%. Staff knowledge as measured by responses to pre- and postintervention surveys on the appropriate use of premedication also improved. Evidence-based interventions can reduce the incidence of premedication use in patients receiving blood transfusions.

Assessment of the Relationship between Adverse Allergic Transfusion Reaction and Serum IgE Level

Background: Allergic transfusion reactions (ATRs) are common adverse events during blood transfusions, ranging from mild urticaria to severe anaphylactic shock. Elevated serum immunoglobulin E (IgE) levels are known to mediate these reactions. This study aimed to assess the relationship between serum IgE levels and the Presence of ATRs in patients receiving fresh frozen plasma (FFP) transfusions. Methods: A cross-sectional observational study was conducted at the Department of Transfusion Medicine, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh, from March 2019 to August 2021. The study included 55 patients aged 5-60 years who received FFP transfusions. Demographic data, clinical symptoms, and IgE levels were recorded. Data were analyzed using SPSS version 26, with statistical significance set at p<0.05. Result: The majority of participants were males (94.55%) and aged 11-20 years (45.45%). Most patients (85.45%) received multiple units of FFP. Clinical symptoms included itching (56.36%), urticarial rash (29.09%), vomiting (7.27%), and hypotension (7.27%). Raised IgE levels were found in 52.73% of participants, and a significant association was observed between elevated IgE levels and the presence of allergic reactions (p<0.01). Patients with allergic reactions had significantly higher mean IgE levels (521.4±434.6 IU/mL) compared to those without allergic reactions (67.8±33.2 IU/mL). Conclusion: Elevated serum IgE levels are significantly associated with the Presence of ATRs in patients receiving FFP transfusions. Monitoring IgE levels can help predict and manage allergic reactions, thereby improving transfusion safety and patient outcomes.

Blood transfusion-associated anaphylaxis in perioperative- and non-perioperative patients in Western Norway 2002-2021.

Anaphylaxis after blood transfusion is a feared complication accounting for severe morbidity. A retrospective study was performed at Haukeland University Hospital, Bergen, Norway, to investigate the rate and features of transfusion-associated anaphylaxis (TAA) occurring between 2002-2021. Identified cases of TAA were studied by an immunologist and an allergist to extract information about general characteristics, amplifying factors, co-morbidity, treatment, and treatment responses. TAA was reported as perioperative or non-perioperative. We identified 29 cases of TAA: 13 perioperative and 16 non-perioperative. Allergic transfusion reaction had an incidence rate of 34/100,000 transfusions and TAA a rate of 7/100,000 transfusions. The incidence of allergic reactions and TAA increased 2.6- and 6.4-fold during the study period. The first perioperative TAA was discovered 12 years into the study period but was equally frequent as non-perioperative transfusion-associated anaphylaxis in the last five years of the study period. 52% of the TAA cases had relevant co-morbidity and 100% of them had amplifying factors. Although only 38% of the non-perioperative patients received epinephrine as treatment, 94% of them had a good treatment response to their total treatment regimen. Poorer treatment response was observed with higher age, more cardiovascular- and respiratory disease, higher use of amplifying and sedating medications and a higher severity score. Our findings indicate that TAA, especially in the perioperative setting, is underdiagnosed. The increased incidence of TAA in our study is temporally related to the introduction of a national hemovigilance program, introduction of standardized laboratory testing for anaphylaxis and increased multidisciplinary focus on the condition. In conclusion, increased awareness of TAA, and especially in the perioperative setting, is needed. A multidisciplinary approach is necessary to improve identification and reporting of TAA.

Pilot study on the use of basophil activation tests and skin tests for the prevention of allergic transfusion reactions.

Management of severe allergic transfusion reactions (ATR) is challenging. In this study, we investigate the usefulness of skin tests and basophil activation tests (BAT) in chronically transfused patients for the prevention of future ATR. BAT and skin tests were carried with the supernatant of red blood cell (RBC) units for a sickle-cell disease patient under chronic exchange transfusion who has presented a severe ATR, in order to prevent potential future ATR. If the results for both BAT and skin tests were negative, the RBC units could be transfused to the patient. If either one of the results was positive, the tested RBC unit was discarded for the patient. 192 RBC units were tested with both tests. The level of results concordance between the two tests was 95%. Out of the 169 negative units with both tests, 118 units were transfused to the patient for which he presented no ATR. In our study, combining both BAT and skin tests was associated with a good negative predictive value since we were able to safely transfuse our patient. Further studies are still necessary to confirm this result but this pilot study indicates that skin tests and BAT might help prevent ATR. When BAT is not available, skin tests may also be useful in preventing ATR.

Reevaluation of the medical necessity of washed red blood cell transfusion in chronically transfused adults.

Washing red blood cell (RBC) units mitigates severe allergic transfusion reactions. However, washing reduces the time to expiration and the effective dose. Automated washing is time- and labor-intensive. A shortage of cell processor tubing sets prompted review of medical necessity for washed RBC for patients previously thought to require washing. A single-center, retrospective study investigated discontinuing wash RBC protocols in chronically transfused adults. In select patients with prior requirements for washing, due to a history of allergic transfusion reactions, trials of unwashed transfusions were performed. Patient demographic, clinical, laboratory, and transfusion data were compiled. The per-unit washing cost was the sum of the tubing set, saline, and technical labor costs. Fifteen patients (median age 34 years interquartile range [IQR] 23-53 years, 46.7% female) were evaluated. These patients had been transfused with a median of 531 washed RBC units (IQR 244-1066) per patient over 12 years (IQR 5-18 years), most commonly for recurrent, non-severe allergic reactions. There were no transfusion reactions with unwashed RBCs aside from one patient with one episode of pruritus and another with recurrent pruritus, which was typical even with washed RBC. We decreased the mean number of washed RBC units per month by 72.9% (104 ± 10 vs. 28.2 ± 25.2; p < .0001) and saved US $100.25 per RBC unit. Washing of RBCs may be safely reconsidered in chronically transfused patients without a history of anaphylaxis. Washing should be implemented judiciously due to potential lack of necessity and logistical/operational challenges.

Analysis of Allergic Transfusion Reactions at a Children's Tertiary Care Center

Background: Transfusion reaction adverse events are a relatively rare occurrence in the United States. This is due to specific blood safety measures such as appropriate collection, preparation, testing, storage, and distribution of blood components as well as appropriate monitoring of patients receiving these transfusions. Several years of data have been collected by our institution's blood bank. Through our analysis, we have been able to describe the rate of transfusion- associated adverse events in pediatric patients at Children's Hospital of Michigan from 2018-2022. Objectives: The aim of this retrospective chart review was to assess the rate of allergic blood transfusion complications and reactions among pediatric patients at Children's Hospital of Michigan in Detroit, Michigan. Materials and Methods: An institution-based retrospective chart review was conducted for a total of 43,210 transfusions over a span of five years from 2018-2022. Results: There were a total of 43,210 transfusions. A total of 26,669 of these products were red blood cell (RBC) transfusions, 10,447 were platelets, 4,392 were plasma, and 1,702 were cryoprecipitate (combined plasma and cryoprecipitate was 6,094). A reported reaction was encountered in 176 of the 43,210 transfusions. These reported reactions were part of the patients' underlying diseases. A true acute transfusion reaction (ATR) was encountered in 116 of the 43,210 transfusions. Of the 116 transfusions, 66 (56.9%) were classified as allergic reactions. About 61% of those reactions were skin manifestations (urticaria, itching), 9% were respiratory symptoms (dyspnea, tachypnea), and the remaining 30% were both skin and respiratory symptoms. Of the total amount of RBC transfusions, 35 (0.131%) resulted in an allergic reaction. Similarly, 19 (0.182%) platelet and 12 (0.197%) plasma transfusions resulted in ATRs. ATRs were most associated with plasma, followed by platelets and RBC transfusions. Combining all transfusions received, these represented a total of 66 (0.153%) allergic transfusion reactions. These results are demonstrated in Figure 1. Conclusion: ATRs were observed in 0.268% of total transfusions (allergic reactions (0.153%) and other reactions (0.115%)) that occurred over the course of five years at our institution. This is about 1 in 655 blood components transfused that was associated with an allergic reaction (more commonly with plasma &amp;gt; platelets &amp;gt; packed RBCs). The rate of allergic reactions is less than what was reported by National Blood Collection and Utilization Survey 2017 (0.282%). This rate is also less than what is reported for children (0.53%) and adults (0.26%) in a meta-analysis (Wang Y, Sun W, Wang X, et al. Comparison of transfusion reactions in children and adults: A systematic review and meta-analysis. Pediatr Blood Cancer. 2022;69(9):e29842.). These lower rates could be secondary to changes in blood processing and under-reporting.

Efficacy and safety of platelet additive solution-E stored platelet concentrates.

In 2018, platelet (PLT) additive solution-E (PAS-E) was introduced. The implementation of PAS-E was expected to diminish the number of allergic reactions in recipients following a PLT transfusion. Here, we evaluated the efficacy and safety of transfusions with PLTs stored in PAS-E. After implementation of PAS-E, data were collected from 2 cohorts of patients with hematological disorders as well as oncology patients, receiving PLTs in PAS-E. A similar patient group in a recent RCT, receiving PLTs in plasma, was used as a historical control group for both cohorts. Endpoints were corrected count increments (CCIs), bleeding scores (only reported in cohort 1), and the incidence of adverse reactions. In cohort 1, the mean 1-h CCI was 14.3 ± 6.9, and the 24-h CCI was 8.7 ± 5.6. In cohort 2, the 1-h CCI was 11.6 ± 7.8 and the 24-h CCI was 7.0 ± 6.1. In the control group, the 1-h CCI was 15.4 ± 5.5 and 24-h CCI 8.7 ± 4.8. Bleeding complications of WHO grade ≥2 occurred in 40% of patients in cohort 1 compared to 44% in plasma PCs. The incidence of adverse reactions was 1.2% in the two PAS-E cohorts, compared to 3.0% in plasma PCs. National hemovigilance data showed a significant reduction in allergic reactions with PAS-E PC transfusions as compared to plasma PCs with an odds ratio of 0.46 (CI 95% 0.37-0.58). The CCIs of PLTs in PAS-E were decreased compared to plasma PCs, but clinically acceptable. Allergic transfusion reactions were decreased in PAS-E PCs compared to plasma PCs.

P‐TS‐67 | Platelets Transfused &gt;5 mL/kg/h in Pediatric Patients Increases Occurrence of Allergic Transfusion Reaction

P‐TS‐67 | Platelets Transfused &gt;5 mL/kg/h in Pediatric Patients Increases Occurrence of Allergic Transfusion Reaction

Transfusion reactions associated with COVID-19 convalescent plasma in outpatient clinical trials.

COVID-19 convalescent plasma (CCP) is an important therapeutic option for outpatients at high risk of hospitalization from SARS-CoV-2 infection. We assessed the safety of outpatient CCP transfusions administered during clinical trials. We analyzed data pertaining to transfusion-related reactions from two randomized controlled trials in the U.S. that evaluated the efficacy of CCP versus control plasma in various ambulatory settings. Multivariable logistic regression was used to assess whether CCP was associated with transfusion reactions, after adjusting for potential confounders. The combined study reported 79/1351 (5.9%) adverse events during the transfusion visit, with the majority 62/1351 (4.6%) characterized by mild, allergic-type findings of urticaria, and/or pruritus consistent with minor allergic transfusion reactions; the other reported events were attributed to the patients' underlying disease, COVID-19, or vasovagal in nature. We found no difference in the likelihood of allergic transfusion reactions between those receiving CCP versus control plasma (adjusted odds ratio [AOR], 0.75; 95% CI, 0.43-1.31). Risk of urticaria and/or pruritus increased with a pre-existing diagnosis of asthma (AOR, 2.33; 95% CI, 1.16-4.67). We did not observe any CCP-attributed antibody disease enhancement in participants with COVID-19 or increased risk of infection. There were no life-threatening severe transfusion reactions and no patients required hospitalization related to transfusion-associated complications. Outpatient plasma administration was safely performed for nearly 1400 participants. CCP is a safe therapeutic option for outpatients at risk of hospitalization from COVID-19.

Solvent/detergent treated pooled human plasma can decrease the recurrence of allergic transfusion reactions in pediatric, adolescent, and young adult patients.

Octaplas is a solvent/detergent (S/D)-treated pooled human plasma indicated for the treatment of thrombotic thrombocytopenic purpura (TTP) as well as multiple coagulation factor deficiency in patients with liver disease or undergoing liver transplantation or cardiac surgery. We aimed at providing pediatric, adolescent, and young adult evidence for the decrease in allergic transfusion reactions (ATRs) with S/D-treated plasma. A single-center retrospective review of patient records was performed from January 2018 through July 2022 for patients who received S/D treated plasma (Octaplas™; Octapharma). A total of 1415 units of S/D-treated plasma were transfused to nine patients at our institution. Patient ages ranged from 13 months to 25 years old. The reason to initiate transfusion with S/D treated plasma in six patients was mild to severe ATR to plasma-containing products and the need for therapeutic plasma exchange (TPE) or plasma transfusions (PTs). TPE or PT was performed for various clinical indications. Average S/D treated plasma volume per TPE or PT ranged from 200 to 1800 mL per event. During the study period, since initiating transfusions with S/D treated plasma, there have been no allergic or other transfusion reactions reported among these patients. We have successfully utilized S/D treated plasma over the last 4.5 years for pediatric, adolescent, and young adult patients who otherwise would have suffered ATR due to necessary TPE or PT. S/D treated plasma is an additional tool that can be utilized by transfusion services, including pediatrics, to safely transfuse their patients.

An Overview of the Identification, Prevention, and Management of Immunological Reactions to Blood Transfusion

lood transfusions are prevalent treatment procedures nowadays for various medical conditions that involve the administration of whole blood or separated blood components alone or in various combinations that can be administered intravenously; these are undertaken with therapeutic or curative goals in mind, they may carry associated risks and complications that must be weighed against the benefits before initiating therapy. A typical subset of complications associated with transfusions includes Transfusion reactions. These include Non-infectious (Acute and Delayed) and infectious complications. Non-infectious transfusion reactions include Immune-mediated reactions to blood components, such as Febrile Non-hemolytic Transfusion reactions (FNHTR), Allergic Transfusion reactions, Hemolytic Transfusion reactions (HTR), Transfusion-related Acute Lung Injury (TRALI), and Transfusion Associated Graft versus Host Disease (TAGVHD), these reactions have different mechanism and complications between them. They can be differentiated for the mechanism of action, presentation time, and clinic. Blood transfusion immunological reactions remain a significant concern in clinical settings, leading to various symptoms. Diagnosing these reactions requires careful monitoring and evaluation of the patient’s clinical status and laboratory parameters. The prevention methods for these reactions include pre-transfusion testing, selecting appropriate blood products, and using leukoreduced blood products. Treatment options may include supportive care, discontinuation of transfusion, and immunosuppressive therapy in severe cases. This article aims to provide an overview of how to identify immune-mediated transfusion reactions, manage them as they occur, and even prevent them if possible.

Guideline on the investigation and management of acute transfusion reactions.

Guideline on the investigation and management of acute transfusion reactions.

Do Children With an Allergic Transfusion Reaction Require Premedication For All Blood Products?

Children with a history of allergic transfusion reactions (ATRs) receive antihistamine premedication with or without hydrocortisone to prevent subsequent reactions. We aim to examine the frequency of developing ATRs to subsequent different blood product type transfusions. A retrospective chart review of children who received blood product transfusions (packed red blood cells, platelets, frozen plasma, intravenous immunoglobin, albumin, and cryoprecipitate) and developed ATRs. Cases were identified through Transfusion Transmitted Injuries Surveillance System- Ontario database with a complementary chart review. Demographics and subsequent transfusions records were described. During this period, 35,925 blood products were transfused to 4153 patients. Thirty-eight ATRs were reported in 30 patients. All ATRs were minor except 1 anaphylaxis to albumin transfusion. Seven patients (23%) developed multiple ATRs, and all of them were of the same blood product type. A total of 60 subsequent different blood product types were transfused to the 7 patients who had multiple ATRs; none of those transfusions caused ATR. In children with a history of ATR, developing a reaction to a different blood product type is rare. Hence, premedicating those transfusions is not warranted.

Non-severe allergic transfusion reaction: A hidden cause of wastage of blood product and laboratory resources.

Blood transfusions are often needlessly aborted following a non-severe allergic reaction despite responding well to medication resulting into partial transfusion of the implicated blood product. This results in the wastage of untransfused blood component and resources spent on unnecessary laboratory work-up of these reactions. We aimed to review the amount of blood product and laboratory resource wastage associated with non-severe allergic transfusion reaction (ATR) in a tertiary care hospital. A total of 174,632 blood products were released and transfused during the study period (2019-2021). There were 336 adverse transfusion reactions with an estimated rate of 1.9 per 1000 blood products administered. Of 336, 145 (43%) were ATR, of which 141 (97%) were non-severe and 4 (3%) were severe. The most commonly associated symptom was found to be urticaria in 31 (22%). All non-severe ATR completely resolved with medication. Seventy-nine percent of the transfusions associated with non-severe ATRs were aborted, of which 37% were followed by additional transfusions. The estimated loss of blood product volume and the cost of non-severe ATR (including transfusion reaction work-up, discarded blood product and additional transfusion) was 11,185 ml (11 L) and Pakistani rupees 1,831,546 ($11,592.06 or €8598.78), respectively. Non-severe ATR was found to be associated with a significant proportion of laboratory resource wastage and that of blood product in our institution. Revision of institutional guidelines for management and lab work-up of transfusion reactions would be helpful in alleviating this unnecessary loss in a resource-constraint transfusion-setting.

344: THIRTY YEARS OF SOLVENT/DETERGENT-TREATED PLASMA FOR TRANSFUSION IN CRITICALLY ILL PATIENTS

Introduction: OctaplasLG (Octapharma AG, Switzerland) is a solvent/detergent (S/D)-treated plasma preparation made from pooled fresh frozen plasma (FFP). First used in 1989 as an FFP alternative, S/D plasma was developed to increase pathogen safety in treating acquired coagulation factor deficiencies during active bleeding, bleeding prevention, and therapeutic plasma exchange (TPE). Here, we review published literature on the efficacy, safety, and cost effectiveness of S/D plasma. Methods: Medline (PubMed) and Google Scholar were searched for articles reporting “octaplas” or “octaplasLG” efficacy and/or safety in clinical settings. Results: Efficacy/safety was shown for multiple indications in different patient groups, such as cardiac surgery (n=125/117 adult/pediatric patients receiving S/D plasma), liver disease (n=30/20), liver transplantation (n=269/5), hemodilution/blood loss (n=47 adults), obstetrics/gynecology (n=38 adults), and TPE (n=167/41), as well as in 162 critically ill neonates/pediatric patients. Studies demonstrated S/D plasma could improve standard coagulation markers comparable with FFP and was also associated with greater endothelial protection. S/D plasma had lower incidences of allergic and febrile non-hemolytic transfusion reactions, and transfusion-associated circulatory overload compared with FFP, and almost no confirmed cases of transfusion-related acute lung injury reported after >13 million units transfused. Studies suggested S/D plasma was more cost-effective than FFP due to lower risk of transfusion-related complications. Literature results showed some countries have replaced FFP with S/D plasma to improve plasma safety. A new freeze-dried form has been recently developed with similar biochemical quality to S/D plasma, and is of particular interest for pre-hospital settings, e.g., trauma, where rapid reconstitution/flexible storage improves logistics/utilization. Conclusions: Available evidence from 30 years of global use indicates that S/D plasma is an efficacious alternative to FFP in adult/pediatric patients for multiple indications, with a favorable safety profile. The clinical utility of S/D plasma is also expanding, with the freeze-dried form having the potential to further improve patient outcomes and reduce costs.

Continuous Platelet Infusion Is an Effective Alternative to Conventional Transfusion in Reducing Platelet Transfusions in Critically Ill Pediatric Patients with Refractory Thrombocytopenia

Background: Thrombocytopenia is often seen in critically ill children and platelet transfusions are needed to prevent or treat bleeding. However, some patients can exhibit platelet refractoriness (PR), characterized as a suboptimal rise in platelet count after platelet transfusion resulting in increased platelet transfusion to maintain the desired platelet target. Repeat platelet transfusions can increase the risk of transfusion-associated circulatory overload (TACO), allergic transfusion reaction and human leukocyte antigen (HLA) alloimmunization. To reduce the total platelet requirement and maintain platelet target, continuous platelet infusion (CPI), which involves transfusion of small volumes of platelets over an extended period of time, is utilized. However, data comparing the total platelet usage between CPI and conventional platelet transfusion (CPT) in critically ill children with PR are lacking. Objectives: Compare total platelet usage per day and peak platelet count between CPI and CPT in pediatric patients with PR. Methods: A retrospective cohort study was performed on all children who received CPI from February 2014 through December 2021 at a tertiary pediatric hospital. CPI was defined as: 1) for children weighing ≤35kg, transfusion of 5ml/kg apheresis platelets over 4 hours every 4-8 hours or 2) for children weighing >35kg, transfusion of 0.5 unit of apheresis platelet over 4 hours every 4-8 hours. Data collection included patient demographics, reason for admission, and bleeding history. A two-tailed paired sample t-test was used to compare platelet count trough and peak, and total platelet volume transfused per day, between CPT (before initiating CPI or pre-CPI) and during CPI (CPI). A P<0.05 was defined as statistically significant. This study was approved by the Institutional Review Board. Results: Sixteen children with PR received CPI with demographics summarized in Table 1. Median age at time of study was 6.1 years (IQR: 0.4-14). Patients were initiated on CPI by the Transfusion Medicine service due to suspected PR. All patients were admitted to the intensive care unit (ICU) when CPI was initiated. Prior to CPI, 10 (62.5%) children had bleeding symptoms, including 6 major bleeds (intracranial hemorrhage) and 4 clinically relevant non-major bleeds (1 post-surgical, 1 pulmonary, 1 mucocutaneous, and 1 gastrointestinal bleeding event). There was a no difference in the mean platelet trough with CPI (m= 20x109/L, s= 16.2) versus pre-CPI (m= 26x109/L, s= 22.4), (t(15) =-1.705, P=0.109). There was no difference in the platelet peak in the pre-CPI (m= 80x109/L, s= 44.6) versus CPI (m= 98x109/L, s= 56.1), (t(15) =-1.185, P=0.254). There was a statistically significant difference in the mean total volume of transfused platelets per day in patients receiving CPT, pre-CPI (m= 158.4 mL/day, s= 68.5) versus CPI (m= 132.6 mL/day, s= 67.1); there was less volume infused daily when patients received CPI (t(15) =2.530, p=0.023). Overall, both transfusion strategies achieved a similar platelet peak, but the CPI required significantly less platelet transfusion by volume per day compared to CPT (Figure 1). Conclusion: Our study demonstrated that those on CPI received a statistically significantly lower volume of platelet transfusion per day compared to CPT to maintain similar platelet counts. While a small sample size and wide variation in platelet counts likely limited the comparison of platelet peak and trough values, there was a trend towards higher platelet counts with CPI. This study suggests that CPI should be considered as alternative to CPT in critically ill children with PR, especially those at risk of TACO. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Basophil activation test for allergic and febrile non-haemolytic transfusion reactions among paediatric patients with haematological or oncological disease.

Allergic transfusion reactions (ATRs) and febrile non-haemolytic transfusion reactions (FNHTRs) are common, although their mechanisms remain unclear. Immunoglobulin E (IgE)-mediated type I hypersensitivity may be involved in the pathogenesis of ATR. A basophil activation test (BAT) may help elucidate this process. The BAT was based on peripheral blood samples from paediatric patients with a haematological or oncological disease and on samples of residual blood products transfused in each case. Dasatinib was used to evaluate whether basophil activation was mediated by an IgE-dependent pathway. Twenty-seven patients with and 19 patients without ATR/FNHTR were included in this study, respectively. The median BAT values associated with ATR- (n=41) and FNHTR-causing (n=5) blood products were 22.1% (range=6.1%-77.0%) and 27.8% (range=15.2%-47.8%), respectively, which were higher than the median value of 8.5% (range=1.1%-40.9%) observed in blood products without a transfusion reaction. Dasatinib suppressed basophil activity. BAT values were comparable in patients with ATR regardless of severity. Meanwhile, BAT values analysed with blood products non-causal for ATR/FNHTR were higher in patients with ATR/FNHTR than in those without. The IgE-mediated type I hypersensitivity may be involved in the pathogenesis of ATR and FNHTR. BAT analyses may help elucidate the underlying mechanisms and identify patients at risk.