[Current Status of Application and Quality Evaluation of Commercial Platelet Pathogen Reduction Technology --Review].

With the development of transfusion medicine, platelet pathogen contamination is of increasing concern to the industry. Currently, pathogen reduction technology (PRT) has been successfully applied to platelets and achieved good results. This paper provides an overview of the research progress of commercial platelet PRT, a comprehensive analysis of the current application status of platelet PRT, preclinical mechanism studies, clinical cohort studies and alternative or complementary strategies, and makes recommendations to provide a scientific basis for safeguarding blood safety in China and developing platelet PRT products applicable to our national conditions.

Small volume platelet concentrates for neonatal use are more susceptible to shear-induced storage lesion.

The impact of the biophysical environment on the platelet storage lesion (PSL) has mainly focused on reduced temperature storage, overlooking the significance of storage-induced shear stress. Shear stress in platelet storage refers to the frictional force acting parallel to the bag surface and exists solely through the implementation of agitation. This study investigates whether minimizing exposure to agitation-induced shear stress can alleviate the unexplained loss of function in stored platelet concentrates for neonatal transfusion (neonatal PCs). Using particle tracking analysis, fluid motion was measured in neonatal and adult platelet storage bags under agitation frequencies ranging from 20-60 rpm. Platelets stored at 20-60 rpm agitation over 8 days were examined by biochemical analysis, aggregation, and expression of activation markers. Results indicate that neonatal PCs experience significantly higher storage-induced shear stress compared to adult doses, leading to reduced functionality and increased activation from day 2 of storage. Adjusting the neonatal PC agitation frequency to 20 rpm improved functionality in early storage, while 40 rpm maintains this improvement throughout storage with reduced activation, compared to 60 rpm storage. This study confirms that small volume PC storage for neonatal use contributes to the PSL through the induction of shear stress, suggesting further evaluation of the recommended agitation frequency for neonatal PCs or postponement of the production of neonatal PCs until requested for neonatal transfusion.

Context Approximately 1­5% of all neonates and up to 50% of critically ill newborns, present with low platelet counts, and will require platelet transfusion support.Platelet concentrates stored for neonatal transfusion have previously shown an accelerated reduction in quality during storage compared to platelet concentrates stored for adult transfusion and therefore may not provide as effective a therapeutic product.The current study hypothesized this loss of function over storage (known as the platelet storage lesion) to be a result of shear stress induced by agitation, exacerbated by the use of smaller bags in the neonatal preparation.Findings Our findings show that storage of platelet concentrates as smaller bags suitable for neonatal transfusion accelerates the platelet storage lesion, which experience a 4-fold greater shear stress than the adult preparation.The shear stress experienced by platelet concentrates stored for neonatal transfusion could be reduced by reducing the speed of agitation, thereby reducing the extent of the platelet storage lesion.Impact This study provides evidence that small volume storage promotes shear stress in platelet concentrates stored for neonatal transfusion, and optimizing storage conditions to reduce the shear stress induced by agitation can help to offset the platelet storage lesion.Further evaluation is required to establish a recommended agitation frequency for platelet concentrates stored for neonatal transfusion. An alternative strategy might include postponement of the production of platelet concentrates for neonatal transfusion until a neonatal transfusion is requested.

Formation of Single-Species and Multispecies Biofilm by Isolates from Septic Transfusion Reactions in Platelet Bag Model.

During 2018-2021, eight septic transfusion reactions occurred from transfusion of platelet units contaminated with Acinetobacter spp., Staphylococcus saprophyticus, Leclercia adecarboxylata, or a combination of those environmental organisms. Whether biofilm formation contributed to evasion of bacterial risk mitigations, including bacterial culture, point-of-care testing, or pathogen-reduction technology, is unclear. We designed a 12-well plate-based method to evaluate environmental determinants of single-species and multispecies biofilm formation in platelets. We evaluated bacteria isolated from septic transfusion reactions for biofilm formation by using crystal violet staining and enumeration of adherent bacteria. Most combinations of bacteria had enhanced biofilm production compared with single bacteria. Combinations involving L. adecarboxylata had increased crystal violet biofilm production and adherent bacteria. This study demonstrates that transfusion-relevant bacteria can produce biofilms well together. More work is needed to clarify the effect of biofilms on platelet bacterial risk control strategies, but US Food and Drug Administration-recommended strategies remain acceptable.

Plateletcrit and absolute immature platelet count are not impacted by platelet transfusions: a single-centre prospective study.

BACKGROUND: This is the first study in which the impact of platelet transfusions on seven platelet indices was evaluated in platelet transfusion-dependent patients admitted in the ICU. STUDY DESIGN AND METHODS: Among a cohort of 21 ICU patients prospectively studied over eleven months, a total of 19 ICU patients were enrolled. Seven platelet indices were measured before and then, within 18-24 h, after platelet transfusions using the Sysmex XN-10 analyser and statistically investigated as follows: i) apheresis vs. pooled platelet transfusions; ii) pre- vs. post-platelet transfusions; and iii) platelet count (PC) increment vs. PC decrement group. RESULTS: A 79.2% of platelet transfusion episodes in ICU patients showed an increase in PC increment within 18-24 h, of which 73.7% had a peak percentage immature platelet fraction (%-IPF) above 10.0% during their stay. No difference was observed in the measurements of platelet indices between the apheresis and pooled platelet transfusion doses (all p > 0.05). Of the seven platelet indices investigated, plateletcrit (PCT) and absolute immature platelet count (A-IPF) were not influenced by platelet transfusions and thus proven to be stable (0.06 vs. 0.07%, p = 0.0901 and 4.6 vs. 4.9 × 109/L, p = 0.4559, respectively), despite their close proximity to platelet transfusion. But the overall effectiveness of these indices in detecting changes over time was not hindered. CONCLUSION: A-IPF and PCT are stable after platelet transfusions, regardless of whether patient's respond to or do not respond to platelet transfusion doses. PCT and A-IPF may thus prove useful in monitoring patient transfusion support and guiding management in thrombocytopenic patients.

Lowering platelet-count threshold for transfusion in preterm neonates decreases the number of transfusions without increasing severe hemorrhage events.

Thrombocytopenia is common in preterm neonates and can be associated with hemorrhage. Most platelet transfusions are prophylactic. Previously, higher platelet-count thresholds were recommended for neonates, but this recommendation has been questioned in recent studies. In the PlaNeT2 trial, mortality and serious bleeding were more frequent in neonates with the highest platelet-count threshold than in others. Following this trial, we changed our platelet transfusion practice by lowering the platelet-count threshold for prophylactic transfusion from 50,000 to 25,000/mm3. We conducted a before-after retrospective cohort study to quantify the frequency of platelet transfusions and assess the new protocol by analyzing death and serious hemorrhage events. This retrospective monocentric study included neonates born before 37 weeks of gestation with platelet count < 150,000/mm3 during the 2 years preceding the new platelet transfusion protocol (high prophylactic transfusion threshold, 50,000/mm3) and during the 2 years after the new platelet transfusion protocol (low prophylactic transfusion threshold, 25,000/mm3). The primary outcome was the proportion of neonates receiving at least one platelet transfusion in both groups. We also compared the proportion of deaths and severe hemorrhage events. A total of 707 neonates with thrombocytopenia were identified. In the high-threshold group, 99/360 (27.5%) received at least one platelet transfusion as compared with 56/347 (16.1%) in the low-threshold group (p < 0.001). The groups did not differ in proportion of deaths or severe hemorrhage events. CONCLUSIONS: A reduced platelet-count threshold for transfusion allowed for a significant reduction in the number of platelet transfusions without increasing severe hemorrhage events. WHAT IS KNOWN: • A recent randomized trial suggested that restrictive platelet-count thresholds for platelet transfusion could be beneficial for preterm neonates. WHAT IS NEW: • On lowering the platelet-count threshold for transfusion from 50,000 to 25,000/mm3, the number of transfusions significantly decreased without increasing severe hemorrhage events in a neonatal intensive care unit.

Comparison of Therapeutic Effect of Apheresis Platelets and Buffy Coat-Derived Platelet Concentrates.

BACKGROUND: The study aimed to investigate the difference in clinical efficacy between apheresis platelets and buffy coat-derived platelet concentrates infusion in patients with hematological diseases. METHODS: A total of 218 patients with hematological diseases were enrolled in Xi'an Central Hospital, from January 2023 to October 2023, and randomly divided into two groups: 109 patients were treated with apheresis platelet transfusion (AP group) and 109 patients with buffy coat derived platelet concentrates (BC-PC group). Platelet counts were measured before and 24 hours after transfusion, and the corrected platelet ascending number (CCI) and platelet recovery rate (PPR) were calculated. The clinical efficacy and blood transfusion reaction were observed. RESULTS: After 24 hours of platelet transfusion, there was no significant difference in the platelet count between the AP and BC-PC groups (p > 0.05). However, CCI and PPR significantly differed between the two groups (p < 0.05). Moreover, the incidence of transfusion reaction in the AP group was significantly lower than in the BC-PC group. CONCLUSIONS: The clinical efficacy of buffy coat-derived platelet concentrates is lower than that of apheresis platelets, but it can also improve the patient's condition and quality of life. Therefore, clinicians could rationally use BC-PC, according to the actual situation of the patients.

Platelet transfusion enhances pro-aggregatory status shortly after coronary artery bypass grafting (CABG while modulating platelet pro-inflammatory state 1-week post-surgery.

During coronary artery bypass grafting (CABG), the surgical procedure, particularly the manipulation of the major arteries of the heart, induces a significant inflammatory state that may compromise platelet function to the extent that platelet transfusion is required. Given stored platelets as a major source of biological mediators, this study investigates the effects of platelet transfusion on the major pro-aggregatory, pro-inflammatory and immunomodulatory markers of platelets. Platelets from 20 patients, 10 who received platelet transfusion and 10 without, were subjected to flow cytometery where P-selectin and CD40 ligand (CD40L) expressions and PAC-1 binding (activation-specific anti GPIIb/GPIIIa antibody) analysed at five-time points of 24 h before surgery, immediately, 2 h, 24 h and 1 week after surgery. Analysis of intra-platelet transforming growth factor-beta-1 (TGF-ß1) was also conducted using western blotting. Patients with platelet transfusion showed increased levels of P-selectin, CD40L and intra-platelet TGF-ß1 2-h after surgery compared to those without transfusion (p < 0.05). PAC-1 binding was increased 24 h after surgery in transfused patients (p < 0.05). Given the significant post-transfusion elevation of platelet TGF-ß1, P-sel/CD40L reduction in transfused patients a week after was of much interest. This study showed for the first time the significant effects of platelet transfusion on the pro-inflammatory, pro-aggeregatory and immunomodulatory state of platelets in CABG patients, which manifested with immediate, midterm and delayed consequences. While the increased pro-inflammatory conditions manifested as an immediate effect of platelet transfusion, the pro-aggregatory circumstances emerged 24 h post-transfusion. A week after surgery, attenuations of pro-inflammatory markers of platelets in transfused patients were shown, which might be due to the immunomodulatory effects of TGF-ß1.

Cumulative donor-specific antibody threshold predicts platelet transfusion response in HLA-alloimmunized patients.

ABSTRACT: Up to a third of patients with hemato-oncologic conditions who have received multiply transfusions develop immune-mediated platelet transfusion refractoriness. Yet factors that influence posttransfusion platelet corrected count increments (CCI) in patients with HLA-alloimmune platelet transfusion refractoriness remain less well elucidated. Recent advances in HLA antibody characterization using fluorescent bead-based platforms enable the study of donor-specific antibody (DSA) avidity (as measured by mean fluorescence intensity [MFI]) and its impact on HLA-alloimmune platelet transfusion refractoriness. In this large retrospective study of 2012 platelet transfusions among 73 HLA-alloimmunized patients, we evaluated the impact of cumulative HLA DSA-MFI alongside other donor, platelet component, and patient characteristics on CCI at 2 and 24 hours after transfusion. As part of a quality improvement initiative, we also developed and tested a computerized algorithm to optimize donor-recipient histocompatibility based on cumulative DSA-MFI and sought other actionable predictors of CCI. In multivariate analyses, cumulative HLA DSA-MFI of ≥10 000, major/bidirectional ABO-mismatch, splenomegaly, transfusion reactions, and platelet storage in additive solution negatively affected 2-hour but not 24-hour posttransfusion CCI. The DSA-MFI threshold of 10 000 was corroborated by greater antibody-mediated complement activation and significantly more CCI failures above this threshold, suggesting the usefulness of this value to inform "permissive platelet mismatching" and to optimize CCI. Furthermore, DSA-MFI decreases were deemed feasible by the computer-based algorithm for HLA-platelet selection in a pilot cohort of 8 patients (122 transfusions) evaluated before and after algorithm implementation. When HLA-selected platelets are unavailable, ABO-identical/minor-mismatched platelet concentrates may enhance 2-hour CCI in heavily HLA-alloimmunized patients with platelet transfusion refractoriness.

Utility of thromboelastography with platelet mapping for monitoring platelet transfusion in qualitative platelet disorders.

BACKGROUND: Patients with pathogenic variants in RASGRP2 (inherited platelet disorder (IPD)-18) exhibit normal platelet counts but impaired platelet aggregation and αIIbß3 activation. Moderate-to-severe bleeding episodes require patients to be transfused with platelets and/or pro-hemostatic agents. We recently demonstrated that hemostatic efficacy of transfused platelets is limited by dysfunctional endogenous platelets in a mouse model of IPD-18 (Rasgrp2-/- mice), as dysfunctional platelets were recruited to the forming hemostatic plug but did not participate in clot contraction. Thus, higher amounts of transfused platelets were required to outcompete these dysfunctional cells and to reverse bleeding. OBJECTIVE: We here studied the usefulness of thromboelastography with platelet mapping (TEG-PM) for ex vivo monitoring of the hemostatic potential in Rasgrp2-/- mice transfused with various amounts of wild-type (WT) platelets. METHODS: Whole blood (WB) samples from WT and Rasgrp2-/- mice were tested in TEG-PM and parameters for clot formation and contraction (K time, α-angle, maximum amplitude [MA]) were measured. RESULTS: Rasgrp2-/- WB samples did not contract in TEG-PM, consistent with a critical role of this protein in αIIbß3 activation. Addition of WT platelets improved TEG parameters in a ratio-dependent manner, consistent with our recent in vivo studies showing impaired hemostasis at a 5:1, but not at a 2:1 ratio of mutant to WT platelets. K and α values were identified as better predictors of transfusion efficacy than MA, the most platelet-dependent TEG parameter. CONCLUSION: This proof-of-concept study supports the use of TEG-PM to monitor platelet transfusion ratios and hemostatic potential in IPD-18 and potentially other platelet disorders.

Immune interactions and regulation with CD39+ extracellular vesicles from platelet concentrates.

Introduction: CD39 plays an important role in the immunoregulation and inhibition of effector cells. It is expressed on immune cells, including Tregs, and on extracellular vesicles (EVs) budding from the plasma membrane. Platelet transfusion may induce alloimmunization against HLA-I antigens, leading to refractoriness to platelet transfusion with severe consequences for patients. Tregs may play a key role in determining whether alloimmunization occurs in patients with hematologic disorders. We hypothesized that CD39+ EVs might play an immunoregulatory role, particularly in the context of platelet transfusions in patients with hematologic disorders. Such alloimmunization leads to the production of alloantibodies and is sensitive to the regulatory action of CD39. Methods: We characterized CD39+ EVs in platelet concentrates by flow cytometry. The absolute numbers and cellular origins of CD39+ EVs were evaluated. We also performed functional tests to evaluate interactions with immune cells and their functions. Results: We found that CD39+ EVs from platelet concentrates had an inhibitory phenotype that could be transferred to the immune cells with which they interacted: CD4+ and CD8+ T lymphocytes (TLs), dendritic cells, monocytes, and B lymphocytes (BLs). Moreover, the concentration of CD39+ EVs in platelet concentrates varied and was very high in 10% of concentrates. The number of these EVs present was determinant for EV-cell interactions. Finally, functional interactions were observed with BLs, CD4+ TLs and CD39+ EVs for immunoglobulin production and lymphoproliferation, with potential implications for the immunological management of patients.

A safety and feasibility analysis on the use of cold-stored platelets in combat trauma.

BACKGROUND: Damage-control resuscitation has come full circle, with the use of whole blood and balanced components. Lack of platelet availability may limit effective damage-control resuscitation. Platelets are typically stored and transfused at room temperature and have a short shelf-life, while cold-stored platelets (CSPs) have the advantage of a longer shelf-life. The US military introduced CSPs into the battlefield surgical environment in 2016. This study is a safety analysis for the use of CSPs in battlefield trauma. METHODS: The Department of Defense Trauma Registry and Armed Services Blood Program databases were queried to identify casualties who received room-temperature-stored platelets (RSPs) or both RSPs and CSPs between January 1, 2016, and February 29, 2020. Characteristics of recipients of RSPs and RSPs-CSPs were compared and analyzed. RESULTS: A total of 274 patients were identified; 131 (47.8%) received RSPs and 143 (52.2%) received RSPs-CSPs. The casualties were mostly male (97.1%), similar in age (31.7 years), with a median Injury Severity Score of 22. There was no difference in survival for recipients of RSPs (88.5%) versus RSPs-CSPs (86.7%; p = 0.645). Adverse events were similar between the two cohorts. Blood products received were higher in the RSPs-CSPs cohort compared with the RSPs cohort. The RSPs-CSPs cohort had more massive transfusion (53.5% vs. 33.5%, p = 0.001). A logistic regression model demonstrated that use of RSPs-CSPs was not associated with mortality, with an adjusted odds ratio of 0.96 (p > 0.9; 95% confidence interval, 0.41-2.25). CONCLUSION: In this safety analysis of RSPs-CSPs compared with RSPs in a combat setting, survival was similar between the two groups. Given the safety and logistical feasibility, the results support continued use of CSPs in military environments and further research into how to optimize resuscitation strategies. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Neuraxial Anesthesia Following Thrombocyte Transfusion in Women with Severe Thrombocytopenia Prior to a Cesarean Delivery: A Retrospective Study and Literature Review.

BACKGROUND: Cesarean delivery (CD) is one of the most common surgeries performed worldwide, with increasing yearly rates. Although neuraxial techniques remain the preferred anesthesia method for CD, maternal thrombocytopenia remains a prominent contraindication. Formation of spinal\epidural hematomas are extremely rare, however the minimal thrombocyte count required for safe neuraxial anesthesia is still under debate. Although transfusion of thrombocytes for the purpose of neuraxial anesthesia is still not recommended, patients with severe thrombocytopenia (less than 50 × 103/uL) are given thrombocyte transfusion for surgical hemostasis. OBJECTIVES: To evaluate the anesthetic approach to caesarean deliveries in parturients with severe thrombocytopenia who received thrombocyte transfusion aimed for improved surgical hemostasis. METHODS: We conducted a single center, retrospective cohort study. Results: A total of five cases were found, four of which were given spinal anesthesia immediately following thrombocyte transfusion. One patient was denied spinal anesthesia because her thrombocyte count following transfusion failed to reach safe levels. None of our cases had anesthesia-related complications recorded. CONCLUSIONS: We examined the anesthetic management parturients with severe thrombocytopenia who needed cesarean delivery and were transfused with thrombocytes for surgical hemostasis. In such cases, spinal anesthesia may be considered due to the serious risks associated with general anesthesia.

Platelet Storage-Problems, Improvements, and New Perspectives.

Platelet transfusions are routine procedures in clinical treatment aimed at preventing bleeding in critically ill patients, including those with cancer, undergoing surgery, or experiencing trauma. However, platelets are susceptible blood cells that require specific storage conditions. The availability of platelet concentrates is limited to five days due to various factors, including the risk of bacterial contamination and the occurrence of physical and functional changes known as platelet storage lesions. In this article, the problems related to platelet storage lesions are categorized into four groups depending on research areas: storage conditions, additive solutions, new testing methods for platelets (proteomic and metabolomic analysis), and extensive data modeling of platelet production (mathematical modeling, statistical analysis, and artificial intelligence). This article provides extensive information on the challenges, potential improvements, and novel perspectives regarding platelet storage.

Platelet transfusions in adult ICU patients with thrombocytopenia: A sub-study of the PLOT-ICU inception cohort study.

BACKGROUND: Platelet transfusions are frequently used in the intensive care unit (ICU), but current practices including used product types, volumes, doses and effects are unknown. STUDY DESIGN AND METHODS: Sub-study of the inception cohort study 'Thrombocytopenia and Platelet Transfusions in the ICU (PLOT-ICU)', including acutely admitted, adult ICU patients with thrombocytopenia (platelet count <150 × 109/L). The primary outcome was the number of patients receiving platelet transfusion in ICU by product type. Secondary outcomes included platelet transfusion details, platelet increments, bleeding, other transfusions and mortality. RESULTS: Amongst 504 patients with thrombocytopenia from 43 hospitals in 10 countries in Europe and the United States, 20.8% received 565 platelet transfusions; 61.0% received pooled products, 21.9% received apheresis products and 17.1% received both with a median of 2 (interquartile range 1-4) days from admission to first transfusion. The median volume per transfusion was 253 mL (180-308 mL) and pooled products accounted for 59.1% of transfusions, however, this varied across countries. Most centres (73.8%) used fixed dosing (medians ranging from 2.0 to 3.5 × 1011 platelets/transfusion) whilst some (mainly in France) used weight-based dosing (ranging from 0.5 to 0.7 × 1011 platelets per 10 kg body weight). The median platelet count increment for a single prophylactic platelet transfusion was 2 (-1 to 8) × 109/L. Outcomes of patients with thrombocytopenia who did and did not receive platelet transfusions varied. CONCLUSIONS: Among acutely admitted, adult ICU patients with thrombocytopenia, 20.8% received platelet transfusions in ICU of whom most received pooled products, but considerable variation was observed in product type, volumes and doses across countries. Prophylactic platelet transfusions were associated with limited increases in platelet counts.

Evaluation of the quality of platelet concentrates obtained in a Peruvian hospital.

Introduction: Platelet concentrates are blood products obtained from donor's blood, and their conservation must be subject to a strict quality control process to guarantee a safe and high-performance product in treating diseases that require their use. Methods: We designed a cross-sectional study to determine the total compliance rate in platelet concentrates obtained in the blood bank of the Cayetano Heredia Hospital in Lima during November and December of 2019. The Buffy method Coat obtained the platelet concentrates, and parameters such as platelet count and residual leukocytes, pH, and swirling effect were evaluated according to the National Hemotherapy and Blood Bank Program criteria. Results: The platelet count had a mean of 6.66 ± 3.94 x 10¹°/µL, the platelet concentrates had a mean of 56.30 ± 6.22 mL, and all, without exception, had the presence of the Swirling phenomenon. The pH had a mean of 7.64 ± 0.15, while the leukocyte count had a mean of 4.22 ± 3.51 x 107/µL. Regarding compliance by the parameters evaluated, it was evident that the platelet and leukocyte count had moderate compliance rates of 43.6% and 24.1%, while the pH and swirling effect had rates of 100% in both cases. The total compliance rate was 54.9% (95% confidence interval: 46.0 to 63.5). Conclusions: The compliance rate of platelet concentrates is moderate, and it is necessary to implement a process of continuous quality improvement in the blood bank.

Introducción: Los concentrados plaquetarios son hemoderivados obtenidos de la sangre, y su conservación debe estar supeditada a un estricto proceso de control de calidad para garantizar un producto inocuo y de alto rendimiento en el tratamiento de enfermedades que requieran su uso. Métodos: Diseñamos un estudio transversal que tuvo por objetivo determinar la tasa de conformidad total en concentrados plaquetarios obtenidos en el banco de sangre del Hospital Cayetano Heredia de Lima durante los meses de noviembre y diciembre del año 2019. Los concentrados plaquetarios fueron obtenidos por el método de Buffy Coat y se evaluaron parámetros como el recuento de plaquetas y leucocitos residuales, pH y efecto swirling, según criterios del Programa Nacional de Hemoterapia y Bancos de Sangre. Resultados: El recuento de plaquetas tuvo una media de 6.66 ± 3.94 x1010/µL y los concentrados plaquetarios tuvieron una media de 56.30 ± 6.22 mL, y todos sin excepción tuvieron presencia de fenómeno Swirling. El pH tuvo una media de 7.64 ± 0.15, mientras que el recuento de leucocitos tuvo una media de 4.22 ± 3.51 x107/µL. En cuanto al cumplimiento por parámetro evaluado, se evidenció que el recuento de plaquetas y leucocitos tuvieron tasas de conformidad de 43.6% y 24.1%, mientras que el pH y efecto swirling tuvieron tasas del 100% en ambos casos. La tasa de conformidad total fue 54.9% (CI95%: 46.0 a 63.5). Conclusiones: La tasa de conformidad de los concentrados plaquetarios es moderada, y se requiere implementar un proceso de mejora continua de la calidad en el banco de sangre.

Immature platelet counts in transfused platelet units given to neonates.

BACKGROUND: Immature platelets, young and large platelets recently released from the bone marrow, have gained interest over the last decade as a clinically informative variable during thrombocytopenic presentations. These immature platelets are found in all donated platelet units, however, the role, if any, that these younger platelets play post transfusion is not known. It has also been reported that the immune response can affect responses to platelet transfusions. Thus, we looked at PLT increments in a cohort of neonates receiving platelet transfusions in our neonatal intensive care unit. METHODS: During a twelve-month period, platelet transfusions received by neonates born and not discharged from our institution at time of transfusion were retrospectively analyzed. In the study period a total of 33 patients received either a single or multiple transfusions during their hospitalization, for a total of 100 transfusion events. RESULTS: The cohort was mostly premature neonates with a mean gestational age of 29.6 weeks. The units transfused appeared to have a broad range of absolute immature platelet counts (A-IPC) but overall, it was similar between those receiving single or multiple transfusions. Considering that platelet count was similar among aliquots transfused, it appeared that count increments were influenced by higher A-IPC content of the aliquot especially among 2nd trimester and 3rd trimester premature neonates. Patients with higher baseline platelet count (PLT) tended to receive a single transfusion aliquot while those receiving multiple transfusions had lower baseline PLT (p = 0.0022). Looking at aliquot dose, regardless if receiving a single or multiple transfusions, younger patients received incrementally higher dose (ml/kg) with each transfusion. CONCLUSIONS: A-IPC in platelet aliquots transfused to neonates may influence post-transfusion PLT. Full effect of A-IPC in platelet aliquots may not be seen since irradiation of units may hamper immature platelets viability and function. Further research is needed to determine if A-IPC plays an active role to limit the need for further transfusions of patients receiving transfusions.

Cutibacterium acnes contamination does not enhance the proinflammatory profile of platelet concentrates.

BACKGROUND: Cutibacterium acnes, a common anaerobic platelet concentrate (PC) contaminant, has been associated with rare mild adverse transfusion reactions and is often considered a harmless commensal. Notably, C. acnes can cause chronic infections and has been shown to induce the release of proinflammatory cytokines by immune cells. Since elevated concentrations of proinflammatory factors in PCs have been linked to noninfectious adverse reactions, this study aimed to assess whether C. acnes could elicit the release and accumulation of proinflammatory factors during PC storage, thereby enhancing the risk of such reactions. STUDY DESIGN/METHODS: Four ABO-matched buffy coat PCs were pooled and split into six units, each were inoculated with either saline (negative control), a Staphylococcus aureus isolate (positive control, 30 colony forming units [CFU]/unit), or four C. acnes PC isolates (10 CFU/mL) and stored at 20-24°C with agitation. Bacterial counts, platelet activation, and concentration of proinflammatory factors were assessed on days 0, 3, and 5. N = 3. RESULTS: C. acnes counts remained stable, while S. aureus proliferated reaching 108CFU/mL by the end of PC storage. By day 5, no significant differences in platelet activation or proinflammatory cytokine profiles were observed in C. acnes-contaminated PCs compared to the negative control (p > .05), while there was a significant increase (p ≤ .05) in sCD40L concentration (day 3), and platelet activation and IL-8 concentration (day 5) in S. aureus-contaminated units. DISCUSSION: C. acnes contamination does not promote the accumulation of proinflammatory factors in the absence of proliferation during storage and may not enhance the risk of inflammatory reactions when transfused to patients.

Severe neonatal thrombocytopenia due to anti-HPA-4b alloantibodies: Third report described in a Caucasian mother.

BACKGROUND: Fetal and Neonatal Alloimmune Thrombocytopenia (FNAIT) results from maternal platelet alloimmunization against paternal antigens inherited by the fetus, most often due to the Human Platelet Antigen (HPA)-1 system in Caucasians. We investigated in 2023, a 30-year-old Caucasian woman Gravida 2 Para 1 who gave birth at 35 weeks of gestation to a male (body weight 2210 g) without signs of bleeding. A severe thrombocytopenia (platelet count at 3 G/L) was discovered incidentally a few hours after delivery in the context of the management of a respiratory distress. The newborn recovered after one platelet concentrate transfusion and normalized his platelet count at Day 5. STUDY DESIGN AND METHODS: FNAIT investigation was performed according to guideline recommendations. Platelet genotyping was carried out by multiplex PCR. Maternal serological investigation included Monoclonal Antibody-specific Immobilization of Platelet Antigens method (MAIPA) and Luminex technology. RESULTS: Parental and newborn genotyping pointed out an HPA-4 incompatibility between the mother and the newborn and the father. Serological investigation revealed an anti-HPA-4b alloantibody confirming the diagnosis of neonatal alloimmune thrombocytopenia. CONCLUSION: We described the third case of anti-HPA-4b alloantibody discovered in a Caucasian mother. This case strengthens the need for reference laboratory to genotype a panel of HPA alleles reflecting local genetic population diversity and for crossmatch of maternal serum with fresh paternal platelets in clinical suspected cases of neonatal alloimmune thrombocytopenia.