Platelet Transfusion Research Articles

Linezolid-Associated Thrombocytopenia: Assessment of Risk Factors in Patients without Hemato-Oncologic Diseases.

Background: Linezolid is used for Gram-positive bacterial infections. Thrombocytopenia is one of its main adverse effects resulting from myelosuppression. Several studies have assessed risk factors that may increase the risk of this adverse effect. However, most studies included patients with hemato-oncologic diseases, which may confound such assessments. This study aimed to investigate risk factors for linezolid-associated thrombocytopenia in patients without hemato-oncologic diseases. Methods: This was a multicenter retrospective case-control study of adult patients treated with linezolid twice daily for ≥3 days. Patients with hemato-oncologic diseases, active dengue fever, active COVID-19, baseline platelet count <100 × 103/mm3, concurrent therapy with trimethoprim/sulfamethoxazole or valproic acid, and a recent platelet transfusion within 7 days were excluded. Thrombocytopenia was defined as a drop in platelet count below 100 × 103/mm3. Results: Out of 158 evaluated patients, 33 developed thrombocytopenia, indicating an incidence rate of 20.9%. Of all the risk factors assessed, creatinine clearance of <60 mL/min and bacteremia/infective endocarditis were significantly associated with linezolid-associated thrombocytopenia (adjusted odds ratios, 3.25 and 5.95; 95% CI 1.12-9.45 and 1.23-28.66; p = 0.031 and 0.026, respectively). End of therapy platelet counts were significantly lower in the cases than in the controls (79 vs. 243 × 103/mm3; p < 0.001). Similarly, the percentage of platelet count change was significantly different (-55.1% vs. -10.2%; p < 0.001). Conclusions: In our study, the incidence rate of linezolid-associated thrombocytopenia was 20.9%, and we found that patients with renal impairment and bacteremia may need close monitoring of platelet counts. Prospective studies are warranted to evaluate the potential need for renal dose adjustment.

Reliability of the DI-60 Digital Image Analyzer for Detecting Platelet Clumping and Obtaining Accurate Platelet Counts.

Pseudothrombocytopenia caused by platelet clumping (PC) can lead to unnecessary platelet transfusions or underdiagnosis of hematologic neoplasms. To overcome these limitations, we assessed the capacity of the Sysmex DI-60 digital morphology analyzer (Sysmex, Kobe, Japan) for detecting PC and determining an accurate platelet count in the presence of PC. For this purpose, 135 samples with or without PC (groups Y and N, respectively) were processed by an examiner (a hematologic specialist) using both the Sysmex XN-9000 and DI-60 analyzers. Although the platelet aggregate (PA) and giant platelet (GP) counts reported by the DI-60 and the examiner exhibited strong correlations, they proved inadequate as effective indicators for screening samples containing PC. Between the PA and GP counts and four platelet indices (the platelet distribution width [PDW], mean platelet volume [MPV], platelet large cell ratio [P_LCR], and plateletcrit [PCT]) reported by the XN-9000, we observed statistically significant correlations (both overall and with group Y), but they were relatively weak. The platelet counts determined using the DI-60 and light microscopy in group Y showed substantial variations. Although the performance of the DI-60 was reliable for detecting PA and GP in smear images, such fixed areas are not representative of whole samples. Further, in the presence of PC, the resulting platelet counts determined using the DI-60 were not sufficiently accurate to be accepted as the final count.

Absorbed Dose-Response Relationship in Patients with Gastroenteropancreatic Neuroendocrine Tumors Treated with [177Lu]Lu-DOTATATE: One Step Closer to Personalized Medicine.

[177Lu]Lu-DOTATATE has been approved for progressive and inoperable gastroenteropancreatic neuroendocrine tumors (GEP-NETs) that overexpress somatostatin receptors. The absorbed doses by limiting organs and tumors can be quantified by serial postinfusion scintigraphy measurements of the γ-emissions from 177Lu. The objective of this work was to explore how postinfusion [177Lu]Lu-DOTATATE dosimetry could influence clinical management by predicting treatment efficacy (tumor shrinkage and survival) and toxicity. Methods: Patients with GEP-NETs treated with [177Lu]Lu-DOTATATE between 2016 and 2022 and who underwent dosimetry were included. Absorbed doses were calculated for healthy organs (liver, kidneys, bone marrow, and spleen) and tumors using PLANET Dose and the local energy deposition method based on serial posttreatment SPECT/CT. Up to 5 lesions per site were selected and measured on images collected at baseline and 3 mo after treatment end (measurement masked to the somatostatin receptor imaging uptake). For toxicity assessment, laboratory parameters were regularly monitored. Clinical data, including time to death or progression, were collected from the patients' health records. Correlations between absorbed doses by organs and toxicity and between absorbed doses by lesions and tumor volume variation were studied using regression models. Results: In total, 35 dosimetric studies were performed in patients with mostly grade 2 (77%) tumors and metastases in liver (89%), lymph nodes (77%), and bone (34%), and 146 lesions were analyzed: 1-9 lesions per patient, mostly liver metastases (65%) and lymph nodes (25%). The median total absorbed dose by tumors was 94.4 Gy. The absorbed doses by tumors significantly decreased between cycles. The absorbed dose by tumors was significantly associated with tumor volume variation (P < 0.001) 3 mo after treatment end, and it was a significant prognostic factor for survival. Toxicity analysis showed a correlation between the decrease of hematologic parameters such as lymphocytes or platelet concentrations and the absorbed doses by the spleen or bone marrow. The mean absorbed dose by the kidneys was not correlated with nephrotoxicity during the studied period. Conclusion: In patients treated with [177Lu]Lu-DOTATATE for GEP-NETs, tumor and healthy organ dosimetry can predict survival and toxicities, thus influencing clinical management.

Proliferation of psychrotrophic bacteria in cold-stored platelet concentrates.

Platelet concentrates (PC) are stored at 20-24°C to maintain platelet functionality, which may promote growth of contaminant bacteria. Alternatively, cold storage of PC limits bacterial growth; however, data related to proliferation of psychotrophic species in cold-stored PC (CSP) are scarce, which is addressed in this study. Eight laboratories participated in this study with a pool/split approach. Two split PC units were spiked with ~25 colony forming units (CFU)/PC of Staphylococcus aureus, Klebsiella pneumoniae, Serratia liquefaciens, Pseudomonas fluorescens and Listeria monocytogenes. One unit was stored under agitation at 20-24°C/7 days while the second was stored at 1-6°C/no agitation for 21 days. PC were sampled periodically to determine bacterial loads. Five laboratories repeated the study with PC inoculated with lyophilized inocula (~30 CFU/mL) of S. aureus and K. pneumoniae. All species proliferated in PC stored at 20-24°C, reaching concentrations of ≤109 CFU/mL by day 7. Psychrotrophic P. fluorescens and S. liquefaciens proliferated in CSP to ~106 CFU/mL and ~105 CFU/mL on days 10 and 17 of storage, respectively, followed by L. monocytogenes, which reached ~102 CFU/mL on day 21. S. aureus and K. pneumoniae did not grow in CSP. Psychrotrophic bacteria, which are relatively rare contaminants in PC, proliferated in CSP, with P. fluorescens reaching clinically significant levels (≥105 CFU/mL) before day 14 of storage. Cold storage reduces bacterial risk of PC to levels comparable with RBC units. Safety of CSP could be further improved by implementing bacterial detection systems or pathogen reduction technologies if storage is beyond 10 days.

Evidence Cornered: Transfusion Evidence Summary - Platelet transfusion before CVC placement in patients with thrombocytopenia (PACER trial).

Evidence Cornered: Transfusion Evidence Summary - Platelet transfusion before CVC placement in patients with thrombocytopenia (PACER trial).

Clinical outcomes in critically ill children on extracorporeal membrane oxygenation with severe thrombocytopenia

Introduction As international guidelines suggest keeping the platelet count between 50 and 100 × 109 cells/L in children on extracorporeal membrane oxygenation (ECMO), platelet transfusions are administered to two-thirds of ECMO days, and up to 70% of these patients still bleed. We aim to describe outcomes in critically ill children who develop severe thrombocytopenia on ECMO. Methods Single-center retrospective study, enrolling critically ill children on ECMO admitted at Children’s Memorial Hermann, TX, between 1/2018 and 12/2022, with at least one platelet count below 50 × 109 cells/L (severe thrombocytopenia). Platelet counts were measured four times a day. We report platelet transfusion, bleeding, hemolysis, and clotting events within 6 h after transfusion, as well as ECMO duration and mortality. Results We enrolled 54 patients representing 337 ECMO days and 1190 platelet counts. Median weight was 3.7 kg and 54% were male. Severe thrombocytopenia was observed in 56% of platelet counts. Severe thrombocytopenia was not associated with bleeding in the subsequent 6 h (18% vs 20%, p = .95), but was associated with more frequent platelet transfusions (18% vs 11%, p = .001). There was no correlation between time spent with severe thrombocytopenia and the duration of ECMO (R2 = 0.03). While the time spent with severe thrombocytopenia was not associated with on-ECMO mortality rate ( p = .36), there was an association with in-hospital mortality rate ( p = .003). Conclusions Our results indicate a restrictive platelet transfusion strategy is not associated with higher proportions of subsequent bleeding, duration of ECMO, or on-ECMO mortality rate. Multicenter studies are needed to evaluate further the appropriateness of this strategy.

The platelet concentrates’ the hallmark in regeneration

Numerous studies have been done on the use of biocompatible materials in regenerative medicine. Platelet concentrates, also known as concentrated growth factor, platelet-rich fibrin, and platelet-rich plasma, are the result of centrifuging blood to separate out the platelets. Platelet concentrations have generated a great deal of discussion in both soft and hard tissue engineering. In fact, growth factors, fibrin matrix, and platelets are among the components of autologous platelet concentrate that are essential for the healing of wounds. Modern techniques for tissue restoration by increasing the properties of autologous platelet concentrates are the subject of current research. The usage of platelet concentrates and their role in tissue regeneration are addressed in the current study, along with a number of new advances and its biological effects.

Platelet Transfusions: The Good, the Bad, and the Ugly.

Platelet Transfusions: The Good, the Bad, and the Ugly.

Digital light processing‐based additive manufacturing of orientation‐controlled Al2O3 ceramics with improved damage tolerance

AbstractDigital light processing (DLP) provides a promising avenue for constructing ceramic parts with high precision and complex shapes, yet the inherent brittleness and strength‐toughness trade‐off hinder their wide applications. Here, according to DLP 3D printing, the textured alumina ceramic components with horizontally aligned textured microstructure were successfully created by adding anisotropically shaped platelets. As a critical process in the preparation of textured ceramics, the alumina platelets were aligned horizontally during printing by using the special shear fields and forming capabilities of DLP technology. The shrinkage, density, microstructure, mechanical performance, and damage‐tolerance behavior of alumina parts with different platelet concentrations were examined, and the toughening mechanisms were investigated. The strength and toughness of ceramics with 5 vol.% platelet addition are increased by 22% and 43%, respectively, as compared with those without platelets. The improved damage tolerance capabilities were primarily ascribed to the collaborative toughening mechanisms stimulated by the platelet addition, including crack branching, crack deflection, uncracked‐ligament bridging, and platelet pull‐out, which increased the crack tortuosity and consumed more fracture energy. The strategy opens up new opportunities to design complex 3D ceramic geometries with bio‐inspired layered or textured architectures, providing optimized damage tolerance.

Comparison of etoposide combined with G-CSF and cyclophosphamide combined with G-CSF in the mobilization of autologous peripheral blood stem cells in patients with multiple myeloma

Objective: The effect and safety of etoposide combined with G-CSF were compared with those of cyclophosphamide combined with G-CSF in autologous peripheral blood mobilization in patients with multiple myeloma (MM) . Methods: Patients with MM who received autologous peripheral blood stem cell mobilization and collection in the Department of Hematology, Beijing Chaoyang Hospital Affiliated to Capital Medical University from January 1, 2020 to July 31, 2023 were included. A total of 134 patients were screened by propensity score matching technology according to a 1∶1 ratio. A total of 67 cases were each treated with ETO combined with G-CSF mobilization scheme (ETO group) and CTX combined with G-CSF mobilization scheme (CTX group). Their clinical data were retrospectively analyzed. Results: ①Collection results: the ETO and CTX groups [2 (1-3) d vs 2 (1-5) d; P<0.001] and CD34(+) cells [7.62×10(6) (2.26×10(6)-37.20×10(6)) /kg vs 2.73×10(6) (0.53×10(6)-9.85×10(6)) /kg; P<0.001] were collected. The success rate of collection was 100.0% (67/67) versus 76.1% (51/67) (P<0.001). Excellent rate of collection was 82.1% (55/67) versus 20.9% (14/67; P<0.001). Two patients in the ETO group switched protocols after 1 day of collection, and 11 patients in the CTX group switched protocols after 1-2 days of collection. ②Adverse reactions: granular deficiency with fever (21.5%[14/65] vs. 10.7%[6/56]; P=0.110), requiring platelet transfusion [10.7% (7/65) vs 1.8% (1/56) ; P=0.047]. ③Until the end of follow-up, 63 cases in the ETO group and 54 cases in the CTX group have undergone autologous transplantation. The median number of CD34(+) cells infused in the two groups was 4.62×10(6) (2.14×10(6)-19.89×10(6)) /kg versus 2.62×10(6) (1.12×10(6)-5.31×10(6)) /kg (P<0.001), neutrophil implantation time was 11 (9-14) d versus 11 (10-14) d (P=0.049), and platelet implantation time was 11 (0-19) d vs. 12 (0-34) d (P=0.035). One case in the CTX group experienced delayed platelet implantation. Conclusion: The mobilization scheme of etoposide combined with G-CSF requires relatively platelet transfusion, but the collection days are shortened. The collection success rate, excellent rate, and the number of CD34(+) cells obtained are high, and the neutrophil and platelet engraftment is accelerated after transplantation.

Neurocognitive function in procedures correcting severe aortic valve stenosis: patterns and determinants.

Neurocognitive changes occurring after a surgical aortic valve replacement (SAVR) or transcatheter aortic valve implantation (TAVI) procedure for the correction of severe aortic stenosis (AS) have not been widely addressed and, if addressed, have produced conflicting results. The purpose of this study is to identify the pre-procedural neurocognitive pattern and its determinants in a setting of elderly (>65 years) patients with severe AS undergoing SAVR or TAVI and the changes occurring at a 2-3 month follow-up. This was a prospective cohort study included in the Italian Registry on Outcomes in Aortic Stenosis Treatment in Elderly Patients. Patients were assessed both before and after (2-3 months) the procedure using the Montreal Cognitive Assessment (MoCA) test. Data on periprocedural demographics, clinical factors, and outcome measures were collected. Before the procedure, 70% of the patients demonstrated a MoCA score <23 points, which was indicative of cognitive dysfunction. The factors associated with neurocognitive dysfunction were age, functional capacity, chronic heart failure, and hemoglobin levels. After the procedure, there was an overall improvement in the MoCA score of the patients, but 28% of the patients showed a reliable worsening of their condition. The factors associated with MoCA worsening were platelet transfusions and the amount of red blood cell units transfused. The correction of severe AS leads to an improvement in neurocognitive function after 2-3 months. This improvement does not differentiate between SAVR and TAVI after matching for pre-procedural factors. The only modifiable factor associated with pre-procedural neurocognitive function is anemia, and anemia correction with red blood cell transfusions is associated with a worsening of neurocognitive function. This leads to the hypothesis that anemia correction before the procedure (with iron and/or erythropoietin) may limit the risk of a post-procedural worsening of neurocognitive function.

Central venous catheters do not increase the hemorrhagic risk in acute promyelocytic leukemia patients during induction therapy.

In acute promyelocytic leukemia (APL), hemorrhage, particularly intracranial hemorrhage, is the most common cause of early death. A central venous catheter (CVC) may provide a greater guarantee of safety and comfort to APL patients. However, CVCs have seldom been attempted in APL patients during induction therapy because of concerns about increasing the risk of hemorrhagic complications after this invasive procedure. To evaluate the hemorrhagic risk after CVC placement in APL patients during induction therapy, we retrospectively analyzed 95 newly diagnosed patients with APL from January 2010 to December 2022. Among these patients, 39 patients in the CVC group and 56 patients in the non-CVC group were included. Laboratory and clinical parameters of the two groups were collected and compared. There were no significant differences in median platelet, fibrinogen (Fbg), D-dimer, prothrombin time (PT), white blood count (WBC) and hemoglobin (Hb) between the CVC and non-CVC groups on the first day of the visit (day 0) and the following days (day 4, day 7, day 11, day 14, day 18 and day 21) (p = 0.382, p = 0.805, p = 0.456, p = 0.902, p = 0.901 and p = 0.097, respectively). The consumption of transfused platelets and Fbg was not significantly different between the CVC group and non-CVC group (5.0 vs. 4.5 units, p = 0.34, and 6.8 vs. 6.0, p = 0.36, respectively). The last day of platelet and Fbg transfusion was also not significantly different (21 vs. 19, p = 0.238 and 7.5 vs. 8.5, p = 0.684, respectively). The incidences of total hemorrhagic events and hemorrhagic death were lower in the CVC group than in the non-CVC group (17.9% vs. 37.5%, p = 0.04 and 0% vs. 16.1%, p = 0.01, respectively). The 30-day survival rate was not significantly different (92.3% vs. 82.1%, respectively, p = 0.145) for the CVC group compared with the non-CVC group. Our study suggested that CVCs did not increase the hemorrhagic risk in APL patients during induction therapy and that a CVC should be considered in this type of clinical situation.

Platelets retain function and can be stored following disruption of human leucocyte antigens.

Antibodies to human leucocyte antigen (HLA) Class-I antigens can lead to refractoriness to platelet transfusion. Although this can be overcome by transfusion of HLA-compatible platelets, they are not always available. Disruption of HLA antigens on platelets by acid treatment may be a suitable alternative when no other components are available. The aim of this study was to assess the effect of HLA disruption and subsequent storage of platelet components. Platelet components were treated with 0.9% saline or citric acid solution (pH 3.0), and then stored until expiry (Day 7). HLA and platelet glycoprotein expression, platelet viability, activation and sialylation were measured by flow cytometry. Release of soluble factors was measured by ELISA and metabolism by biochemistry analyser. Reactivity to patient anti-sera containing anti-HLA antibodies was measured using platelet immunofluorescence tests (PIFTs) and monoclonal antibody immobilization of platelet antigen (MAIPA) assays. Platelet function was measured using aggregometry and thromboelastography (TEG). Acid treatment reduced detection of HLA Class-I on platelets by 75%, with significant reductions in reactivity to patient anti-sera. Acid treatment reduced platelet content and viability, increased platelet activation and accelerated metabolism. Glycan cleavage was increased by acid treatment. Treatment reduced platelet activation following agonist stimulation by ADP and TRAP-6, but platelets remained functional, displaying increased aggregation response and reduced time to clot formation by TEG. Although HLA disruption had some detrimental effects, acid-treated platelets remained functional, retaining their capacity to respond to agonists and form clots, and with further development could be used to support refractory patients.

Impact of systematic variations in hematocrit and platelet count on thrombelastometry tissue factor activated assay parameters.

Thromboelastogram testing is increasingly being used to manage patients with massive bleeding. An earlier study found that the test results were influenced by the hematocrit (Hct) and platelet (PLT) concentrations. This study sought to determine if these factors confounded the results of a different manufacturer's thromboelastography testing. Using freshly collected whole blood from volunteers and stored red blood cells (RBC) and plasma, the whole blood was manipulated to achieve different Hct values and PLT concentrations. Each reconstituted whole blood sample was tested in triplicate on the ROTEM Delta device and the ExTEM results were recorded. Many of the ExTEM results varied according to the Hct and PLT concentration. In particular, the ExTEM clot formation time (CFT) was abnormally long when the Hct was 45% and the PLT concentration was ≤75 × 109/L, normalizing only when the PLT count was ≥100 × 109/L. CFT samples with Hct 25% and 35% were also abnormal with low PLT concentrations but normalized at lower PLT concentrations compared to the Hct 45% samples. The ExTEM angle also demonstrated abnormal results when the Hct was 45% and the PLT concentration was ≤50 × 109/L. The ExTEM A10 and maximum clot firmness (MCF) tests tended to also be abnormal when the Hct was between 25% and 45% and the platelet concentrations were below 75 × 109/L. While thromboelastogram testing is gaining popularity for managing bleeding patients, clinicians should be aware of these confounding factors when making transfusion decisions based on their results.

Evaluation of bacterial safety approaches of platelet blood concentrates: bacterial screening and pathogen reduction.

This mini-review analyzed two approaches to screening bacterial contamination and utilizing pathogen reduction technology (PRT) for Platelet concentrates (PCs). While the culture-based method is still considered the gold standard for detecting bacterial contamination in PCs, efforts in the past two decades to minimize transfusion-transmitted bacterial infections (TTBIs) have been insufficient to eliminate this infectious threat. PRTs have emerged as a crucial tool to enhance safety and mitigate these risks. The evidence suggests that the screening strategy for bacterial contamination is more successful in ensuring PC quality, decreasing the necessity for frequent transfusions, and improving resistance to platelet transfusion. Alternatively, the PRT approach is superior regarding PC safety. However, both methods are equally effective in managing bleeding. In conclusion, PRT can become a more prevalent means of safety for PCs compared to culture-based approaches and will soon comprehensively surpass culture-based bacterial contamination detection methods.

Impact of Shelf-Life Extension on Platelet Availability: Results from an Inventory Management Modeling Study

&lt;b&gt;&lt;i&gt;Introduction:&lt;/i&gt;&lt;/b&gt; In Germany, demand for platelet transfusion is maintained or even increasing, despite a decrease in whole blood donations observed in the last decade. The shelf-life of platelet concentrates (PCs) in Germany is 4 days, which can be extended to 5 days if appropriate safety measures are used. This short shelf-life leads to decreased PC availability. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; We investigated the impact of PC shelf-life extension on PC shortage, using a mathematical simulation model based on the PC production and delivery statistics of the Frankfurt Institute of the German Red Cross Transfusion Service of Baden-Württemberg-Hessen. We used a 2.2-year dataset for PC production and delivery as input data for a Monte Carlo inventory management simulation, focusing on PC shortage. The model generated the daily stock (expressed as mean number of PC units ± standard deviation), mean PC age at release, mean number of expired PC units, and shortage rates (i.e., requiring the release of more PCs than available), overall and by PC blood group. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; Over 2.2 years, a total of 74,322 PC units were produced and 62,178 units were released at the Frankfurt Institute; the overall overproduction rate was 19.5%. Shortage rates decrease with an increase in PC shelf-life and/or increase in overproduction rates. At an overproduction rate of 20%, shortage rates would be reduced from 2.8% for a 4-day shelf-life to 0.7%, 0.3%, and 0.2%, for shelf-life lengths of 5, 6, and 7 days, respectively. Extending the PC shelf-life to 6 or 7 days would eliminate shortages almost entirely, including for rare bloods. &lt;b&gt;&lt;i&gt;Conclusion:&lt;/i&gt;&lt;/b&gt; These results can inform blood services and regulatory authorities on the potential medical and economic impact of extending PC shelf-life to 6 or 7 days.

Long-term cold storage of platelets for transfusion based on zwitterionic magnetic microgels

Hypothermic preservation of platelets at 22 °C with an agitation process realizes their rapid transfusion to treat hemorrhage and thrombocytopenia in the clinic. However, platelets suffer from activation, aggregation, and bacterial contamination during storage, resulting in a limited shelf life of 5 days. Cold storage in a refrigerator can effectively prevent bacterial growth, but this condition is challenging to preserve platelets, owing to cold-induced reactive oxygen species (ROS) overproduction or platelet desialylation. Here, we design a zwitterionic magnetic microgel assembly to preserve platelets for a long time without agitation at 4 °C. The microgel assembly can scavenge cold-induced ROS and provide a super-hydrophilic 3D environment to isolate platelets, preventing platelet activation, aggregation, and desialylation. Moreover, the antifouling property of microgel assembly at 4 °C can ensure the anti-bacterial environment for platelets. As a result, the cold storage time of platelets significantly extended to 7 days. This work serves as a springboard for the development of platelet-based clinical applications.

Establishment and clinical application of the HLA genotype database of platelet-apheresis donors in Suzhou

The establishment of a platelet-apheresis donor database may provide a feasible solution to improve the efficacy of platelet transfusion in patients with immune platelet transfusion refractoriness (PTR). This study aimed to establish HLA genotype database in Suzhou, to provide HLA-I compatible platelets for PTR patients to ensure the safety and effectiveness of platelet transfusions. We used a polymerase chain reaction sequence-based typing (PCR-SBT) method to establish the database by performing high-resolution HLA-A, -B, and –C genotyping on 900 platelet-apheresis donors. HLA-I antibody was detected in patients using a Luminex device, and HLA-I gene matching was performed by an HLA-Matchmaker. We found that the highest frequency of the HLA-A allele was A*11:01 (17.06 %), followed by A*24:02 (14.67 %) and A*02:01 (13.61 %). The highest frequency of the HLA-B allele was B*46:01 (9.78 %), followed by B*40:01 (8.39 %) and B*13:02 (33 %). After the detection of platelet antibodies in 74 patients with immune PTR, we found 30 HLA-A antibodies and 48 HLA-B antibodies, and there were a variety of high frequency antibodies whose alleles were low in the donor database, such as HLA-A*68:02, and B*57:01. After avoiding donor-specific antibodies (DSA) matching, 102 of 209 platelet-compatible transfusions were effective, resulting in an effective rate of 48.8 %, which significantly improved the efficacy of platelet transfusion. The establishment of a platelet donor database is of great significance to improve the therapeutic effect of platelet transfusion in patients with hematologic disorder, and save blood resources, and it is also the premise and guarantee of precise platelet transfusion.

Comparative virulome analysis of four Staphylococcus epidermidis strains from human skin and platelet concentrates using whole genome sequencing.

Staphylococcus epidermidis is one of the predominant bacterial contaminants in platelet concentrates (PCs), a blood component used to treat bleeding disorders. PCs are a unique niche that triggers biofilm formation, the main pathomechanism of S. epidermidis infections. We performed whole genome sequencing of four S. epidermidis strains isolated from skin of healthy human volunteers (AZ22 and AZ39) and contaminated PCs (ST10002 and ST11003) to unravel phylogenetic relationships and decipher virulence mechanisms compared to 24 complete S. epidermidis genomes in GenBank. AZ39 and ST11003 formed a separate unique lineage with strains 14.1 .R1 and SE95, while AZ22 formed a cluster with 1457 and ST10002 closely grouped with FDAAGOS_161. The four isolates were assigned to sequence types ST1175, ST1174, ST73 and ST16, respectively. All four genomes exhibited biofilm-associated genes ebh, ebp, sdrG, sdrH and atl. Additionally, AZ22 had sdrF and aap, whereas ST10002 had aap and icaABCDR. Notably, AZ39 possesses truncated ebh and sdrG and harbours a toxin-encoding gene. All isolates carry multiple antibiotic resistance genes conferring resistance to fosfomycin (fosB), β-lactams (blaZ) and fluoroquinolones (norA). This study reveales a unique lineage for S. epidermidis and provides insight into the genetic basis of virulence and antibiotic resistance in transfusion-associated S. epidermidis strains.

Chemical and Microbiological Changes of Expired Platelet Concentrate.

Platelets are a commonly used blood component to prevent or treat bleeding in patients with thrombocytopenia or platelet dysfunction. They are stored at room temperature (22-24°C) for five days unless specific measures are taken to extend the shelf life to seven days or more. After five days, this study evaluated platelet units' biochemical changes and bacterial growth. Platelet concentrate was collected from 30 random donors: 8 females and 22 males. The collected samples were then placed on an agitator at room temperature and tested for their pH, protein content, and glucose levels using Roche Combur 100 Test® Strips. The Haemonetics eBDS™ System was used for bacterial detection. The measurements were taken on day five as the control and then repeated on days 7, 9, and 11 to observe any changes. On days 5 and 7, all parameters remained unchanged. However, glucose levels significantly changed (p=<0.0001) on days 9 and 11. Regarding pH, a significant change was observed on day 9 (p=0.033) and day 11 (p=0.0002). There were no significant changes in all parameters on days 5 and 7. However, glucose was substantially changed (p=<0.0001) on days 9 and 11. For pH, there was a significant change in pH on day 9 (p=0.033) and day 11 (p=0.0002). Our study found that platelet concentrate extension is possible for up to seven days. However, further studies are needed to evaluate platelet function during expiry time and to assess the stability of platelet morphology and function.