Coagulation profiles and percentiles in neonates with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia: A step toward more accurate transfusion thresholds.

BACKGROUND: In the literature, there are no studies about the transfusion threshold for neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). In order to facilitate accurate interpretation of coagulation results in these neonates, we aimed to generate specific reference intervals in this specific population. METHODS: This retrospective study included all HIE neonates admitted from 2014 to 2022 to undergo TH. All infants during TH underwent blood exams, including the coagulation profile. Our primary outcome was to assess the estimates of the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for each parameter on admission (before transfusion). By the receiver operating characteristic (ROC) analysis, the area under the ROC curve (AUC) and the best cut-off point were used to evaluate the ability of the prothrombin time expressed as international normalized ratio (PT-INR) to predict the risk of any bleeding. RESULTS: A total of 143 infants were included in this study. On admission, the median fibrinogen value was 205 mg/dL, prothrombin time 18.6 seconds, PT-INR 1.50, activated partial thromboplastin time 38.3 seconds, thrombin time 18.6 seconds, antithrombin 57.0%. The optimal cut-off of PT-INR in predicting the risk of any bleeding was greater than 1.84 (AUC .623, p = .024). CONCLUSION: For the first time, we proposed the percentiles of coagulation parameters in our cohort of neonates with HIE. Furthermore, we found that a PT-INR greater than 1.84 can significantly predict the risk of any bleeding. Further studies are needed to determine if a restrictive versus a liberal transfusion approach can be equally safer for these high-risk infants.

Knowledge of blood transfusion practices among medical students and residents.

A study was conducted to assess and compare the knowledge of blood transfusion practices among medical students and residents in Lebanese and Saudi medical institutions. The online survey consisted of 26 questions: 4 about personal data and experience with transfusion and 22 about knowledge on transfusion practices in the areas of blood donation and donor selection, production and storage of blood components, selection of appropriate blood components, administration of blood components, transfusion reactions, and complications. One hundred and twenty-six students from Saudi Arabia, 84 students from Lebanon, 31 residents from Saudi Arabia, and 23 residents from Lebanon participated in the survey. There were no significant differences between students' and residents' levels of knowledge. Similarly, there was no difference between the students' level of knowledge in the two countries. The correct responses (48% and 46%, for students and residents, respectively) were below the acceptable limit of 60% for both groups. This reflects the need for more vigorous and well-structured education and training for both students and residents.

Analysis of the effect and influencing factors of a clinical competency-oriented prospective pre-job training programme on the comprehensive ability of new employees in the department of transfusion medicine.

BACKGROUND: The subject of pre-job training for transfusion service laboratory technicians is very important. The key is how to make a reasonable systematic training programme to improve the effectiveness of training. METHODS: A prospective training programme was conducted and an assessment was performed at enrollment (baseline) and reassessment after 3-months training, using the same tools with a validated questionnaire. RESULTS: Clinical competency-oriented prospective pre-job training significantly improves the clinical transfusion-related comprehensive skills of new employees. The post-training assessment score was significantly affected by undergraduate major. CONCLUSION: This study provided a clinical competency-oriented training programme for new employees in the department of transfusion medicine that could effectively enhance their comprehensive abilities.

"Something we must be proud of": An interview and document study of team improvisation in the Dutch convalescent plasma project group.

Background and Aims: The COVID-19 pandemic has revealed the importance of organizational resilience, the ability to effectively respond to a disruptive event before, during, and after it occurs. Team improvisation is an important component of organizational resilience as it describes characteristics of team skills and contextual qualities to create order from chaos. In Spring 2020, the Dutch national blood bank, began the convalescent plasma project (CCP). We aimed to study which elements of team improvisation in the CCP group were found and how lessons learned can contribute towards a non-crisis situation for blood establishments. Methods: Using Vera and Crossan's framework of improvisation, semi-structured interviews with eight members of the CCP group were conducted. This was simultaneous to performing a document analysis of 21 Intranet posts and seven internal reports. MAXDA 2020 was used to conduct deductive and inductive thematic analyses. Results: The CCP group showed strong characteristics of expertise and memory, teamwork quality, experimental culture, and real-time information and communication that enabled them to improvise in all aspects of the donation process. Improvisation examples included comprehensive communication methods to identify and obtain new donors, asking additional intake questions and collecting additional aliquots to store while waiting for an internal antibody test to be developed, and regulatory respondents allowing a flexible change control procedure to meet the pace of the crisis. Training was evident to a lesser degree. Conclusion: While improvisation impacted set routines and procedures, the safety and quality of the product were not affected. Regarding organizational resilience, our results showed that the CCP group "coped" well using elements of team improvisation. Blood establishments may consider introducing improvisational training and innovation teams throughout the organization for future preparedness and improving organizational resilience.

The enigma of sickle cell hepatopathy: Pathophysiology, clinical manifestations and therapy.

Sickle cell disease (SCD) is one of the most common genetic disorders in the world predominantly affecting economically disadvantaged populations. There is a notable discrepancy between the growing adult SCD population and available diagnostic and therapeutic interventions for SCD. Sickle cell hepatopathy (SCH) is an all-inclusive term to describe the acute and chronic liver manifestations of SCD. The pathophysiology of SCH follows no defined pattern or sequence that poses challenges to clinicians and researchers alike. Evidence is lacking for this underreported disease at various levels from diagnostic to therapeutic options. This paper reviews the basic pathophysiology, clinical features, biochemical and radiological findings of various SCH manifestations and outlines the management of each condition. Old and new therapy options in SCD including hydroxyurea, red blood cell exchange transfusion, ursodeoxycholic acid, voxelotor, l-glutamine and crizanlizumab have been reviewed to investigate the role of these options in treating SCH. The role of liver transplant, haematopoietic stem cell transplant and gene therapy in SCH patients have been reviewed.

Implementation and early outcomes with Pathogen Reduced Cryoprecipitated Fibrinogen Complex.

OBJECTIVES: Cryoprecipitated antihemophilic factor (cryo) has been used for fibrinogen replacement in actively bleeding patients, dysfibrinogenemia, and hypofibrinogenemia. Cryo has a shelf life of 4 to 6 hours after thawing and a long turnaround time in issuing the product, posing a major limitation of its use. Recently, the US Food and Drug Administration approved Pathogen Reduced Cryoprecipitated Fibrinogen Complex (INTERCEPT Fibrinogen Complex [IFC]) for the treatment of bleeding associated with fibrinogen deficiency, which can be stored at room temperature and has a shelf life of 5 days after thawing. METHODS: We identified locations and specific end users with high cryoprecipitate utilization and waste. We partnered with our blood supplier to use IFC in these locations. We analyzed waste and turnaround time before and after implementation. RESULTS: Operative locations had a waste rate that exceeded nonoperative locations (16.7% vs 3%) and were targeted for IFC implementation. IFC was added to our inventory to replace all cryo orders from adult operating rooms, and waste decreased to 2.2% in these locations. Overall waste of cryoprecipitated products across all locations was reduced from 8.8% to 2.4%. The turnaround time for cryoprecipitated products was reduced by 58% from 30.4 minutes to 14.6 minutes. CONCLUSIONS: There has been a substantial decrease in waste with improved turnaround time after IFC implementation. This has improved blood bank logistics, improved efficiency of patient care, and reduced costly waste.

Hospital policy of tranexamic acid to reduce transfusion in major non-cardiac surgery (TRACTION): protocol for a phase IV randomised controlled trial.

INTRODUCTION: Tranexamic acid (TXA) is an inexpensive and widely available medication that reduces blood loss and red blood cell (RBC) transfusion in cardiac and orthopaedic surgeries. While the use of TXA in these surgeries is routine, its efficacy and safety in other surgeries, including oncologic surgeries, with comparable rates of transfusion are uncertain. Our primary objective is to evaluate whether a hospital-level policy implementation of routine TXA use in patients undergoing major non-cardiac surgery reduces RBC transfusion without increasing thrombotic risk. METHODS AND ANALYSIS: A pragmatic, registry-based, blinded, cluster-crossover randomised controlled trial at 10 Canadian sites, enrolling patients undergoing non-cardiac surgeries at high risk for RBC transfusion. Sites are randomised in 4-week intervals to a hospital policy of intraoperative TXA or matching placebo. TXA is administered as 1 g at skin incision, followed by an additional 1 g prior to skin closure. Coprimary outcomes are (1) effectiveness, evaluated as the proportion of patients transfused RBCs during hospital admission and (2) safety, evaluated as the proportion of patients diagnosed with venous thromboembolism within 90 days. Secondary outcomes include: (1) transfusion: number of RBC units transfused (both at a hospital and patient level); (2) safety: in-hospital diagnoses of myocardial infarction, stroke, deep vein thrombosis or pulmonary embolism; (3) clinical: hospital length of stay, intensive care unit admission, hospital survival, 90-day survival and the number of days alive and out of hospital to day 30; and (4) compliance: the proportion of enrolled patients who receive a minimum of one dose of the study intervention. ETHICS AND DISSEMINATION: Institutional research ethics board approval has been obtained at all sites. At the completion of the trial, a plain language summary of the results will be posted on the trial website and distributed in the lay press. Our trial results will be published in a peer-reviewed scientific journal. TRIAL REGISTRATION NUMBER: NCT04803747.

Pharmacokinetic-Guided Hydroxyurea to Reduce Transfusions in Ugandan Children with Sickle Cell Anemia: Study Design of the Alternative Dosing And Prevention of Transfusions Trial.

INTRODUCTION: People with sickle cell anemia (SCA) may require frequent blood transfusions to treat acute and chronic complications. Hydroxyurea is a life-saving treatment for SCA that could also decrease the need for blood transfusions. Inadequate medication access and challenges in dose optimization limit the widespread use of hydroxyurea in Africa. If feasible, pharmacokinetic (PK) dosing might improve dose determination to minimize toxicities and maximize clinical benefits. The Alternative Dosing And Prevention of Transfusions (ADAPT, NCT05662098) trial will analyze the impact of hydroxyurea on transfusion rate and serve as a pilot study to evaluate the feasibility of PK-guided hydroxyurea dosing in Uganda. METHODS: Herein we describe the rationale and design of ADAPT, a prospective cohort study of ∼100 children with SCA in Jinja, Uganda. The primary hypothesis is that hydroxyurea will decrease blood transfusion use by ≥ 50%, comparing the transfusion incidence rate ratio between a 3-month pretreatment and a 12-month treatment period. A key secondary hypothesis is that our PK-dosing approach will generate a suitable hydroxyurea dose for ≥80% of participants. Every ADAPT participant will undergo hydroxyurea PK testing, and if a dose is generated within 15-35 mg/kg/day, participants will start on their individualized dose. If not, they will start on a default dose of 20 mg/kg/day. Hydroxyurea dose optimization will occur with periodic dose adjustments. CONCLUSION: Overall, demonstrating the reduction in blood transfusion utilization with hydroxyurea treatment would provide leverage to increase hydroxyurea access, and PK-guided hydroxyurea dosing should optimize the safe and effective treatment of SCA across sub-Saharan Africa.

A survey assessing knowledge and attitude about blood donation among blood donors in Jordan.

Background: Recruitment of low risk blood donors can be challenging. Efforts should be made to increase the level of awareness and positive attitude towards blood donation. An essential step to achieve this is obtaining comprehensive data about the current situation of awareness, knowledge and attitudes of the population towards blood donation. Methods/materials: The present study was conducted at two blood donation centres in Amman, Jordan, during 2021. A total of 536 whole blood donors were included. Data regarding their demographic characteristics, blood donation history as well as their knowledge and attitudes regarding blood donation were collected by a questionnaire. Results: Four hundred ninety participants (91.4%) were males, whereas only 46 participants (8.6%) were females. Ninety seven subjects (18.1%) were first time donors, whereas 431 subjects (81.9%) had previous donations. The participants' median score in the knowledge section was 19.0 points (range 5-25 points). Based on a cut-off of 15 out of 28: 84% of the participants were knowledgeable. Similarly 97% of the participants had a positive attitude based on a cut-off of 17 out of 32 points. Multivariate analysis revealed that high knowledge score was significantly associated with study major and employment status, whereas a positive attitude was significantly associated with a higher income. More than half of first time donors stated lack of awareness as being the reason for not donating blood before. Conclusion: Measures to improve awareness, knowledge and attitudes towards blood donation should be implemented in order to meet the increasing demand for blood and blood components. Targeted campaigns, correction of some misconceptions and using different motivations are suggested.

Evaluation of activation characteristics of a canine platelet concentrate produced by a commercial double centrifugation system.

Introduction: In veterinary medicine there are few readily available products for platelet transfusion to patients with thrombocytopenia. Commercial tabletop platelet concentrating systems have recently become available to veterinarians, primarily directed towards uses associated with regenerative medicine. These systems could potentially be used to produce fresh concentrated platelets for use in transfusion medicine. This study evaluated the concentration, activation, and sterility of a double centrifugation platelet concentrate (PC) produced by a commercial benchtop system. Methods: Ten healthy dogs were studied. Whole blood was collected and mixed with ACD-A in a 1:7.6 ratio of ACD-A to whole blood. 12 mL of this mixture was processed into PC via single centrifugation, while 60 mL of the anticoagulated whole blood was processed via a commercial double centrifugation system. Both types of PC were evaluated for platelet concentration, CD62P expression with and without thrombin stimulation, and for sterility. Results: Mean platelet count in the double centrifuged PC was 863 ± 352 × 103/µL, with very low white blood cell contamination (median of 0.47 × 103 leukocyte/µL (range 0.15-2.18 × 103/µL)). The double-centrifuged PC had similar baseline activation characteristics (as determined by P-selectin expression) as the single centrifuge PC (0.76% vs. 0.72% unstimulated, 30.5% vs. 34.9% stimulated, p = 0.432). Discussion: The benchtop PC system studied here did not cause activation of platelets during production and produced a sterile product that can be further investigated as a source of fresh platelet concentrates for transfusion purposes.

When and why is red blood cell genotyping applicable in transfusion medicine: a systematic review of the literature.

This review aims to provide a better understanding of when and why red blood cell (RBC) genotyping is applicable in transfusion medicine. Articles published within the last 8 years in peer-reviewed journals were reviewed in a systematic manner. RBC genotyping has many applications in transfusion medicine including predicting a patient's antigen profile when serologic methods cannot be used, such as in a recently transfused patient, in the presence of autoantibody, or when serologic reagents are not available. RBC genotyping is used in prenatal care to determine zygosity and guide the administration of Rh immune globulin in pregnant women to prevent hemolytic disease of the fetus and newborn. In donor testing, RBC genotyping is used for resolving ABO/D discrepancies for better donor retention or for identifying donors negative for high-prevalence antigens to increase blood availability and compatibility for patients requiring rare blood. RBC genotyping is helpful to immunohematology reference laboratory staff performing complex antibody workups and is recommended for determining the antigen profiles of patients and prospective donors for accurate matching for C, E, and K in multiply transfused patients. Such testing is also used to determine patients or donors with variant alleles in the Rh blood group system. Information from this testing aides in complex antibody identification as well as sourcing rare allele-matched RBC units. While RBC genotyping is useful in transfusion medicine, there are limitations to its implementation in transfusion services, including test availability, turn-around time, and cost.

Complex Transfusion Management in a Sickle Cell Patient With Anti-Fy3 Alloimmunization: A Case Report.

Fy3 is a high-prevalence red blood cell antigen of the Duffy (Fy) blood group system. Anti-Fy3 antibodies are rare and solely arise in individuals with a Duffy null phenotype (Fy(a-b-)), which is a phenotype that mainly occurs in people of African descent. Clinically, anti-Fy3 antibodies can cause both acute and delayed hemolytic transfusion reactions in adults as well as hemolytic disease in fetuses and newborns. Here, we report the case of a 26-year-old male with sickle cell disease (SCD) and a history of anti-E alloantibodies, who was admitted to the hospital with a vaso-occlusive crisis (VOC) and associated low hemoglobin (Hb) level. For the latter he received one unit of antigen-matched and crossmatch-compatible packed red blood cells (pRBCs) without complications. Ten days later the patient was readmitted with a further VOC and associated low Hb level, again requiring a red cell transfusion. However, no crossmatch-compatible pRBCs could be identified. Laboratory testing demonstrated pan-reactivity with additional reference testing demonstrating the presence of anti-E, anti-Fy3 and anti-Jkb alloantibodies. This case highlights the diagnostic and therapeutic challenges associated with blood transfusion in SCD patients with rare alloimmunization profiles.

Mobile calculator application for estimating human erythrocyte antigen frequency in Korea.

OBJECTIVES: This study aimed to establish a comprehensive human erythrocyte antigen (HEA) frequency data set for Koreans. It also sought to develop a mobile app that facilitates the calculation of the frequencies of specific antigen-negative red blood cell units and the average number of units required for antigen typing. METHODS: Human erythrocyte antigen frequencies were compiled from large-scale blood donor data and 5 previous papers. Based on the collected data, we developed a mobile calculator app for HEA frequency and evaluated its usability. RESULTS: Human erythrocyte antigen frequency data for 20 blood group systems, including the ABO, Rh, MNS, Duffy, Kidd, and Diego systems, were established. The app was designed to enable users to select the desired phenotype from a drop-down menu and display the calculated frequency at the bottom. The number of units required for antigen typing to find 1 compatible red blood cell unit was also displayed. Five users participated in app evaluation and rated the functionality and information categories highly. In quizzes prompting users to calculate frequencies using the app, all participants provided correct answers, confirming the app's user-friendly functionality. CONCLUSIONS: This app, which encompasses comprehensive HEA frequency data, is expected to find multiple uses in transfusion medicine, including optimizing blood bank workflow and defining rare blood groups in Korea.

Characterising the challenges of managing difficult red blood cell alloantibodies in liver transplant recipients.

AIMS: Formation of red blood cell alloantibodies (RBCAs) complicates transfusion support in liver transplantation (LT). Difficult RBCAs (DAs, >3 antibodies or antibodies for which <25% donors are antigen negative) further challenge care. This study characterises DA outcomes relative to non-difficult RBCAs (NDAs). METHODS: Single-centre, retrospective analysis of LT patients (2002-2021). RBCAs were defined as clinically significant antibodies. DAs were compared with NDAs. RESULTS: 89 patients had clinically significant RBCAs (DA=50, NDA=39). More DAs were anti-Jka, anti-M; fewer were anti-E, anti-K (all p<0.05). DA patients often had multiple antibodies (44% vs 12.8% NDA, p=0.0022). Probability of finding antigen-negative blood was lower for DAs (17.4% vs 68.1% NDA, p<0.0001) as was RBCs received (9.4 vs 14.7 units in NDA, p=0.0036). Although survival was similar, patients with DAs had more adverse reactions (8% vs 0%, p=0.128). Some antibodies appeared to occur with specific liver diseases (such as primary sclerosing cholangitis, alcoholic steatohepatitis and recurrent disease); however, due to low sample size, definitive conclusions cannot be made. CONCLUSIONS: DA LT recipients contain >1 RBCA, have a lower probability of finding antigen negative blood and may experience more adverse transfusion event (ATE). Despite this, the incidence of ATEs was still quite low.

Is drug interference still an issue for pretransfusion testing of patients on anti CD38 and other monoclonal antibody therapies?

Certain therapies that target CD markers on some blood cells can affect pretransfusion testing. Key examples are anti-CD38, CD47 monoclonal antibody (mAb) therapies such as daratumumab (DARA) and magrolimab, which have presented a challenge for transfusion medicine laboratories around the globe. Scientists have been faced with not only introducing a protocol to provide safe blood to patients but also investigating the most effective method to remove the pretransfusion pan-agglutinating interference caused. A number of papers in the last 5 years have reported on various methods to remove pretransfusion interference; however, most of these studies have been conducted only in a few countries. Most recent reviews on this topic have focused on techniques and reagents to remove pretransfusion interference, and dithiothreitol is currently the gold standard for removing DARA interference. However, it was clear from this review that while many laboratories have developed processes for addressing interference in pretransfusion testing, and DARA interference may not be a major issue, there are still laboratories around the world, that may not have adequately addressed this issue. In addition, the impact of mAb interference on widely used techniques such as flow cytometry is unclear.

Peroperative administration of tranexamic acid in Roux-en-Y and one-anastomosis gastric bypass to reduce haemorrhage in patients with morbid obesity: protocol for randomised controlled trial (PATRY trial).

INTRODUCTION: By implementation of Enhanced Recovery After Bariatric Surgery protocols and day-care surgery, early discharge poses a challenge if excessive bleeding occurs after bariatric surgery. Tranexamic acid (TXA) has demonstrated efficacy in other surgical fields and in bariatric pilot studies. This trial aims to assess the efficacy of peroperative administration of TXA in reducing haemorrhage in patients undergoing gastric bypass surgery. METHOD AND ANALYSIS: This is a multicentre, phase III, double-blind randomised controlled trial in six high-volume bariatric centres in the Netherlands. A total of 1524 eligible patients, aged 18 years or older, undergoing primary gastric bypass surgery (either Roux-en-Y gastric bypass or one-anastomosis gastric bypass) will be randomised between TXA and placebo (1:1, variable block, stratified for centre, day-care/overnight stay and type of surgery) after obtaining informed consent (2.5% less haemorrhage, power 80%, 2-sided-α 0.05 and 10% dropout). Exclusion criteria are pregnancy, amedical history of acute bleeding (without cause), venous thrombotic events (VTEs), epilepsy, anticoagulant use and iatrogenic bleeding during surgery (aside from staple line). The primary outcome is postoperative haemorrhage requiring intervention within 30 days postoperatively. Secondary outcome measures are staple line reinforcement, blood loss, duration of surgery, postoperative haemoglobin, vital parameters, minor and major complications, side effects of TXA (nausea, hypotension and VTE), length of hospital stay and directly made costs. ETHICS AND DISSEMINATION: Written informed consent will be obtained from all participants. The protocol has been approved by the Medical Research Ethics Committees United, Nieuwegein, on 7 February 2023 (registration number: R22.102). Results will be disseminated through peer-reviewed publications and conferences. TRIAL REGISTRATION NUMBER: NCT05464394.

A survey of medication and raw food use among canine blood donors.

BACKGROUND: Blood donors are screened for medication use to determine their health status and to ensure that the collection will be safe and efficacious for transfusion. Although stringent medication deferral guidelines exist for human blood donors, no consensus exists as to which medications should be permitted among canine donors. METHODS: A brief survey regarding canine donor screening methods was distributed to an online hematology and transfusion medicine group and included questions pertaining to commonly prescribed medications and consumption of a raw food diet. KEY FINDINGS: The survey results demonstrate that more than half of the respondents accept canine donors given thyroid supplements, whereas respondents were split as to whether they accept canine donors given antihistamines chronically. Most survey respondents exclude canine donors taking anti-inflammatory or anti-itch medications unless in acute circumstances and only after a washout period. More than half of the survey respondents exclude dogs fed a raw food diet. SIGNIFICANCE: The survey results demonstrate that there is no obvious agreement regarding which medications to permit in canine donors. Evidence-based guidelines are needed to inform best practices and the subsequent decisions made by donor programs.

Use of flow cytometry method to detect contaminations of platelet suspensions.

In this study, it was aimed to investigate bacterial contamination in apheresis platelet suspensions (APS) by automated blood culture system and flow cytometry method (FCM).33 spiked APS each using 11 bacterial strains (5 standard strains, 6 clinical isolates), were prepared in three different dilutions (1-10, 10-50, 50-100 cfu/mL), incubated in two different temperatures (35-37 °C and 22-24 °C) and different incubation times (18-96 h) evaluated by FCM. This three different dilutions were also inoculated into special platelet culture bottles (BacT/ALERT® BPA) and loaded into the blood culture system. Additionally 80 APSs routinely prepared in the Transfusion Center were evaluated by both FCM and the blood culture system. Platelets were lysed by freeze-thaw method.All spiked samples were positive with BacT/ALERT® BPA in 12-18 h. In 96 h incubation at 22-24 °C, the presence of bacteria was detected by FCM in all other samples (31/33) except low dilutions (1-10 and 10-100 CFU/ml) of K.pneumoniae standard strain. In the 35-37 °C, the presence of bacteria was detected by FCM in all samples (33/33) after 48 h of incubation. In routine APS one sample detected as positive (Bacillus simplex) with BacT/ALERT® BPA and no positivity was detected by FCM.The freeze-thaw method, which we have optimized for the lysis of platelets, is very practical and can be easily applied. The BacT/ALERT® system has been found to be very sensitive in detecting bacterial contamination in PSs. Flow cytometry method has been found to be successful, fast, easy to use and low cost in detecting bacterial contamination in PSs.

Increase of Phosphoprotein Expressions in Amotosalen/UVA-Treated Platelet Concentrates.

Background: Pathogen inactivation treatment (PIT) has been shown to alter platelet function, phenotype, morphology and to induce a faster aging of platelet concentrates (PCs). Key pieces of information are still missing to understand the impacts of PITs at the cellular level. Objectives: This study investigated the impact of amotosalen/UVA on PCs, from a post-translational modifications (PTM) point of view. Phosphoproteomic analyses were conducted on resting platelets, right after the amotosalen/UVA treatment and compared with untreated PCs. Method: A two-arm study setting was carried out to compare PIT (amotosalen/UVA) to untreated PCs, on day 1 post-donation. Based on a pool-and-split approach, 12 PCs were split into two groups (treated and untreated). Quantitative phosphoproteomics was performed using TMT technology to study the changes of phosphoproteins right after the PIT. Results: A total of 3,906 proteins and 7,334 phosphosites were identified, and 2,473 proteins and 2,214 phosphosites were observed in at least 5 to 6 replicates. Compared to untreated platelets, PIT platelets exhibited an upregulation of the phosphorylation effects, with 109 phosphosites identified with a higher than 2-fold change. Two pathways were clearly identified. The mitogen activated protein kinases (MAPKs) cascade, which triggers the granule secretion and the activation of the pS15 HSPB1. One of the shape change pathways was also observed with the inhibition of the Threonine 18 and Serine 19 phosphorylations on myosin light chain (MLC) protein after the amotosalen/UVA treatment. Conclusions: This work provides a deep insight into the impact of amotosalen/UVA treatment from a phosphoprotein viewpoint on resting platelets. Clear changes in phosphorylation of proteins belonging to different platelet pathways were quantified. This discovery corroborates previous findings and fills missing parts of the effect of photochemical treatments on platelets.