Objective: To establish a rapid, accurate, and decentralized workflow for bacterial whole-genome sequencing (WGS) and risk profiling within the shelf-life of platelet concentrates, and to characterize the species, virulence, antimicrobial resistance (AMR), and immune evasion mechanisms of co-existing bacteria in qualified platelet products, thereby providing a scientific basis for transfusion safety assessment. Methods: Three units of platelet concentrates, which tested negative by routine bacterial screening, were collected from the Chengdu Blood Center between May and June 2025. Samples were enriched at 37℃under six aerobic and nine anaerobic conditions for 7 days. Using a culturomics strategy, aliquots were plated for isolation on days 1, 3, 5, and 7 to obtain cultivable isolates, with negative culture controls included to exclude contamination. High-molecular-weight genomic DNA was extracted via mechanical grinding, purified, and size-selected. Sequencing libraries were constructed and sequenced on the G-seq500 single-molecule nanopore sequencing platform. Genomes were assembled using Flye and polished with NextPolish, with quality evaluated by BUSCO and CheckM. Taxonomic identification was performed using GTDB-Tk. Functional annotation and database comparisons were conducted to analyze virulence factors, AMR genes, and genes related to immune evasion and environmental adaptation. Results: Viable bacteria were successfully isolated from all three qualified platelet units within their shelf life. The isolates were identified as Bacillus albus, Niallia taxi, and Staphylococcus warneri. Nanopore sequencing generated 92 227-109 813 reads (totaling 680-758 Mb) with an N50 of 7 625-8 584 bp and Q20/Q30 scores of 97%/93%, respectively. All three genomes were assembled into complete circular chromosomes with 1-3 plasmids, achieving >93% completeness. Functional analysis revealed that B. albus carried multiple hemolysins, metalloproteases, and multidrug resistance genes, indicating the highest potential pathogenicity and AMR risk. S. warneri exhibited a typical multidrug resistance profile and regulatory network characteristic of coagulase-negative staphylococci, suggesting intermediate virulence. N. taxi harbored few canonical virulence factors and lacked functional AMR determinants, presenting a "low-virulence, low-resistance" profile. Notably, all three strains were enriched in genes encoding antimicrobial peptide resistance systems (e.g., dltABCD, mprF, GraRS, BceAB) and antioxidant enzymes, suggesting a strong capacity to withstand immune stress in the blood environment. Conclusion: Viable bacteria can be recovered from qualified platelet concentrates that test negative by routine screening. Nanopore WGS enables rapid strain-level identification and comprehensive risk profiling of virulence, resistance, and immune adaptation traits. The functional repertoires of these "co-existing" isolates range from environmental adaptation to potential pathogenicity, representing an underappreciated risk for transfusion-transmitted infections in susceptible recipients.

Objective: To construct gene recombinant expression plasmids of human anti-P antibody with IgG1 and kappa chain based on the human hybridoma cell line. Methods: Starting from the specific RT-PCR products encoding the variable regions of the IgH chain and IgL chain of the anti-P monoclonal cell line, appropriate restriction enzyme digestion sites were introduced at both ends of the VH and VL fragments through nested PCR. The plasmids carrying the antibody constant region and the nested PCR products of VH and VL were ligated by the action of T4 ligase and subsequently transferred into competent E. coli DH5ɑ, and positive clones were selected in the antibiotic resistant LB medium. After sequence confirmation, recombinant plasmids DNA were transfected into HEK293T cells, and the recombinant antibody obtained in the culture supernatant. The characteristics of recombinant expression antibodies were determined by using rapid antibody isotying kit, serological agglutination tests and flow cytometry. Results: Recombinant gene expression vectors, pFUSEss-CHIg-hG1+VH, pFUSE2ss-CLIg-hκ+VL, were successfully constructed. Human IgG1 kappa light chain antibodies were detected in the supernatant of HEK293T cells transient transfected with recombinant plasmids. After the supernatant was ultra-filtered and concentrated, it could cause agglutination reactions with P antigen-positive red blood cells. The mean fluorescence intensity (MFI) of the reaction between recombinant antibodies and antigen-positive red blood cells in flow cytometry experiments was higher than that of antigen-negative red blood cells. Conclusion: The experimental study on the conversion of red blood group antibody types by genetic engineering technology represents a beneficial exploration towards establishing a feasible technical route for the development of genetic recombination and modification of antibodies reagent.

Objective: To investigate the factors associated with HLA antibody formation in patients undergoing platelet transfusion and to evaluate the intervention effect of leukocyte depletion technology. Methods: The study enrolled 2 518 patients who received platelet transfusions from March 1, 2021 to March 31, 2025. HLA antibodies were detected using a solid-phase agglutination method. The effects of gender, age, the number of platelet transfusions, and leukocyte depletion on the formation of HLA antibodies were analyzed. Results: Gender, age, and the number of platelet transfusions were identified as independent risk factors for HLA antibody formation. Female patients exhibited a 1.64-fold higher risk compared to males (OR 1.64, 95% CI 1.31-2.07). Compared with patients under 18 years of age, those aged 18-60 and over 60 showed a 35% and 40% reduction in antibody formation risk, respectively (OR 0.65, 95% CI 0.50-0.86; OR 0.60, 95% CI 0.44-0.83). Compared with patients who received single platelet transfusion, those with 2 and ≥3 transfusions were associated with a 2.02-fold and 14.50-fold increased risk, respectively (OR 2.02, 95% CI 1.49-2.74; OR 14.50, 95% CI 11.16-18.84). The HLA antibody positivity rate was significantly higher in the non-leukocyte-depleted group (20.76%) than in the leukocyte-depleted group (14.31%) (χ =12.27, P<0.01). However, after multivariate adjustment, absence of leukocyte depletion was not an independent predictor of HLA antibody formation. Interaction analysis between the number of transfusions and leukocyte depletion revealed that: 1) Among patients receiving 2 transfusions, no significant difference in antibody formation risk was observed between the group with 1 non-leukocyte-depleted transfusion and the fully depleted group (P>0.05), whereas the group with 2 non-leukocyte-depleted transfusions had a 1.64-fold higher risk (OR 1.64, 95% CI 1.19-2.28); 2) Among patients receiving ≥3 transfusions, the groups with 1, 2, and 3 non-leukocyte-depleted transfusion exhibited 25.45-, 10.59-, and 11.45-fold higher risks, respectively (OR 25.45, 95% CI 10.73-60.36; OR 10.59, 95% CI 5.07-22.14; OR 11.45, 95% CI 8.76-14.96), compared with the fully depleted group. In patients who received 1 platelet transfusion, compared with patients who received platelets filtered by the hospital blood bank, the risk of HLA antibody formation was reduced by 65% (OR 0.35, 95% CI 0.18-0.69) in patients who received platelets filtered by the blood station. There was no statistically significant difference in the risk of antibody formation between the group that received platelets filtered twice by the hospital blood bank and the group that received platelets filtered once (P>0.05). Conclusion: Female, younger age (under 18), and increased number of platelet transfusions are significant risk factors for HLA antibody formation. Leukocyte depletion effectively reduces the incidence of HLA antibody positivity. For female patients with a history of pregnancy and pediatric patients under 18 years of age, and patients receiving ≥3 platelet transfusions, leukocyte-depleted apheresis platelets from the blood station should be the preferred choice.

Objective: To investigate the current knowledge status of transfusion medicine among pediatricians/postgraduates and the reliability of large language models (LLMs) for assisted learning, and to assess changes in pediatricians' transfusion medicine knowledge before and after the implementation of the "Pediatric Transfusion Guideline" (hereafter referred to as the "Guideline"). Methods: In January 2022 (prior to the implementation of the "Guideline"), a questionnaire was developed based on the "Guideline" content and distributed to pediatricians. Subsequently, in July 2025 (after the implementation of the "Guideline"), the "Pediatric Transfusion Medicine Knowledge Questionnaire" was designed based on the content of the January 2022 questionnaire. This questionnaire survey was conducted on pediatricians/postgraduates and LLMs. We analyzed the level of transfusion medicine knowledge among pediatricians/postgraduates and the reliability of LLMs for assisted learning, and compared the accuracy of pediatricians' responses before and after "Guideline" implementation. Results: The survey results after the implementation of the "Guidelines" revealed that pediatricians/postgraduates achieved response accuracy rates exceeding 80% on the topic of "Patient Blood Management". However, response accuracy rates were below 30% for topics including "Types and Indications of Blood Components/Products" and "E-valuation of Transfusion Efficacy". The pediatricians' accuracy rates for related questions before and after the implementation of the "Guidelines" were 14.7%-68.9% and 3%-38%, respectively, and the comparison of accuracy rates for each question showed significant differences (P<0.001). The accuracy rates of the LLMs on the questionnaire were all below 90%. Among them, Doubao (81.1%) and Kimi (86.4%) achieved relatively higher accuracy rates, while Tencent Yuanbao (Hunyuan) had the lowest accuracy rate at only 59.5%. Conclusion: The implementation of the "Guideline" may have improved pediatricians' knowledge level of pediatric transfusion medicine. However, their knowledge level of pediatric transfusion remains low, and LLMs cannot yet provide absolutely reliable guidance. Systematic training in pediatric transfusion medicine is urgently needed.

Objective: To systematically analyze the current status and influencing factors of platelet supply in medical institutions across China, and to explore the problems and future development directions of the existing supply models. Methods: From February 25 to March 5, 2025, a web-based questionnaire survey was performed. A self-designed questionnaire was distributed to staff in the blood transfusion departments of medical institutions nationwide in China. Data on the current status and influencing factors of platelet supply were collected and analyzed. Results: A total of 2 268 responses were collected in this survey, with 1 366 valid questionnaires finally included, covering 33 provinces, autonomous regions, and municipalities directly under the central government across China. The survey revealed that platelet supply in Chinese medical institutions exhibited a pattern of "sufficient in the eastern region, stable in the central region, and scarce in the western region": adequate in East China; generally favorable in South China except Guangxi; centered on Beijing and Tianjin in North China; basically met but with insufficient reserves in Central China; subject to seasonal fluctuations in Northeast China; only meeting the baseline supply in Yunnan, Guizhou, and Sichuan in Southwest China; and notably short in Qinghai, Ningxia, and Xinjiang in Northwest China. Family donor mobilization was required in 81.2% (1 109/1 366) of institutions, whereas this proportion was only 12.7% (173/1 366) among institutions with sufficient supply. Tertiary hospitals constituted the main users, among which tertiary Class A hospitals had the highest sufficiency rate, and secondary Class B hospitals showed the most pronounced shortage. A total of 84% (1 147/1 366) of institutions lacked a professional management team; only 19% (266/1 366) had an inventory warning system, of which 88% (234/266) considered it effective. Platelet reservation required 3 days in 33% (458/1 366) of institutions. The mandatory transfusion rate was 30.55% (29/118) when the reservation lead time exceeded 3 days, representing an increase of 5.98% compared with 24.57% (55/180) in the same-day reservation group. For optimization, most institutions called for improved blood donation services, strengthened education and incentives, establishment of regional coordination and policy collaboration, and supplementary suggestions focused on technologies for extending platelet shelf life. Conclusion: Regional imbalance in platelet supply across China is prominent, with supply shortages in some provinces, reliance on family donor mobilization in most institutions, weak grassroots support capacity, imperfect management systems, and supply timeliness constraining clinical practice. Systematic improvements are needed in optimizing blood donation services, strengthening regional coordination, improving relevant policies, and developing platelet preservation technologies, so as to enhance the level of supply security and patient safety.

Objective: To statistically analyze the association between blood donation intervals and the incidence of adverse reactions to blood donation based on blood donor data from Shenzhen. Methods: Basic data and records of adverse reactions to blood donation among voluntary whole blood donors in Shenzhen from January 2017 to June 2025 were extracted. A total of 795 404 whole blood donations were recorded, including 502 743 from males and 292 661 from females, with 1 088 and 751 cases of adverse reactions, respectively. Analyses were performed using R software, including restricted cubic spline (RCS), binary logistic regression, and generalized estimating equations (GEE) to evaluate the correlation between donation intervals and adverse reactions. Results: A total of 1 839 cases of adverse reactions were recorded, accounting for 0.23% of the total donations. Both binary logistic regression analysis and the generalized estimating equations (GEE) model showed that there was no significant difference in the incidence of adverse reactions between male and female donors with an interval of ≥6 months compared to those with an interval of ≥3 months but<6 months. Furthermore, using the 3-5 month interval group as the reference, the analysis indicated that the incidence of adverse reactions significantly increased in males with a 9-12 month interval, while no statistically significant differences were observed across any of the female subgroups. Conclusion: There was no significant correlation between adverse reactions to blood donation and the donation interval. Compared with a donation interval of ≥6 months, an interval of<6 months does not lead to an increase in the incidence of adverse reactions among male or female donors. The findings of this study may help enhance the willingness of blood donors to participate.

Objective: To statistically analyze the association between blood donor age and the incidence of adverse reactions based on whole blood donor data from Shenzhen. Methods: Data on basic characteristics and records of adverse donation reactions among voluntary whole blood donors in Shenzhen from January 2017 to June 2025 were extracted. A total of 795 404 whole blood donations were recorded, including 502 743 from males and 292 661 from females, with 1 088 and 751 cases of adverse reactions, respectively. Analyses were performed using R software, including restricted cubic spline (RCS) analysis, binary logistic regression, and generalized estimating equations (GEE) to evaluate the correlation between donor age and adverse reactions. Results: A total of 1 839 cases of adverse reactions were recorded, accounting for 0.23% of the total donations. Both binary logistic regression and GEE model revealed that, compared with the≤55 years age group, the incidence of adverse reactions was reduced in both male and female donors in the >55 years age group, with the difference being statistically significant in males. Using the <23 years age group as a reference, the incidence of adverse reactions significantly decreased in both male and female donors across the 23-30, 31-40, 41-50, and 51-60 age groups, with the differences being statistically significant. Conclusion: There is a negative correlation between the rate of adverse donation reactions and age, with the incidence of such reactions among whole blood donors over 55 years old being no higher than that among donors aged 55 years or younger. These findings carry positive significance for safeguarding the donation rights of older donors and meeting clinical blood demand.

Objective: To investigate the epidemiological characteristics, outcome patterns, and management strategies for blood donors with a positive direct antiglobulin test (DAT). Methods: A retrospective analysis was conducted on donation data from 808 386 donors from 2013 to 2023, focusing on those whose blood was discarded due to DAT positivity. Follow-up was performed on 125 DAT-positive donors, and 98 blood samples were collected. The samples were re-tested for DAT, DAT typing (IgG/C3d), and unexpected antibody screening using both the tube method and the microcolumn gel method. Results: Epidemiological characteristics: Retrospective data revealed 147 DAT-positive blood donors, yielding a positivity rate of 1/5 500. The DAT positivity rate using the tube method was 0.118‰ (49/416 893), lower than that of the microcolumn gel method at 0.25‰ (98/391 493). Among DAT-positive individuals, 44.2% (65/147) exhibited agglutination intensity<2+. Outcome analysis: The proportion of donors with positive DAT test results that converted to negative was 54.1% (53/98), with a conversion interval ranging from 8 to 117 months (mean 49.9 months). All donors in the negative conversion group had a previous DAT intensity<2+, whereas 95.6% (43/45) of the non-negative conversion group had intensity ≥2+ (P<0.001). Unexpected antibodies (anti-E, anti-M, etc.) were detected in 18 cases. Methodological differences: Review of results revealed 35 cases positive by both the DAT tube assay and microcolumn gel method. An additional 10 cases were positive by only one method: 5 were positive only by the tube assay, and 5 were positive only by the microcolumn gel method. Clinical validation: Among 14 DAT-positive donors who became negative and donated blood again, the clinical infusion efficacy of red blood cell products could be assessed in 10 cases, with 9 cases demonstrating effective infusion. Conclusion: Some DAT-positive blood donors may naturally convert to negative status, with the intensity of previous test results potentially serving as a key predictive factor for conversion. It is recommended to employ a combined approach of tube-based and microcolumn gel-based methods for retesting, concurrently screening for irregular antibodies. A tentative tiered management strategy is proposed: individuals with DAT intensity <2+ should be deferred for 12 months before retesting, while those with ≥2+ intensity should be permanently deferred.

Objective: To explore the association between the HLA antibody positivity rate in female blood donors and pregnancy history, number of pregnancies, interval from the last pregnancy to blood donation, and age, to identify associated variables using a univariate generalized additive model (GAM), and to further analyze the predictive role of characteristic variables for HLA antibody positivity using a random forest model. Methods: HLA antibody detection was performed on 391 female blood donors using the Luminex immunomagnetic bead method. The correlation between pregnancy-related factors and HLA antibodies was analyzed using the Chi-square test. Based on R software, a univariate GAM was first constructed to analyze the association types between characteristic variables and the HLA antibody positivity rate, followed by the construction of a random forest model to evaluate the predictive value of the variables. Results: Among the 391 female blood donors without a transfusion history, the overall HLA antibody positivity rate was 26.34%. The positivity rate in donors with a pregnancy history was significantly higher than that in those without (30.09% vs 9.72%, P<0.05), and HLA antibody positivity rate increased linearly with the number of pregnancies (P<0.05). In the univariate GAM, age and number of deliveries exhibited a non-linear association with the HLA antibody positivity rate (the positivity rate increased sharply between 25-35 years of age and stabilized after 3 deliveries). Besides, the interval from the last pregnancy to blood donation showed a linear association with the HLA antibody positivity rate, and the positivity rate decreased as the interval prolonged (P<0.05). In the random forest model, age (mean decrease gini=29.26) and interval from the last pregnancy to blood donation (mean decrease gini=22.02) were core predictive variables: age was more conducive to identifying positive samples, while the interval from the last pregnancy to blood donation was more helpful for excluding negative samples. The number of deliveries (mean decrease accuracy=16.98) made a significant contribution to predicting positive samples, whereas the number of abortions had no impact. The model had an AUC of 0.583 (95% CI: 0.593 8-0.770 2), indicating a certain predictive value. Conclusion: The associated variables identified by the univariate GAM model, including age, interval from the last pregnancy to blood donation, and number of deliveries, provide a basis for key variables in the random forest model. All three variables have predictive value for HLA antibody positivity, which can provide evidence-based support for personalized transfusion management and stratified screening of female blood donors in this region.

Objective: To analyze characteristics of hepatitis B infection in HBsAg-/HBV DNA+ blood donors in Taiyuan, so as to provide evidence for adjusting blood screening strategies. Methods: Blood samples of HBsAg-/HBV DNA+ donors were tested using enzyme-linked immunosorbent assay (ELISA), chemiluminescence assay, nucleic acid qualitative test, and nucleic acid quantitative test. Data on HBsAg-/HBV DNA+ donors in Taiyuan region from January 1, 2016 to December 31, 2024 were statistically analyzed to evaluate the detection rate, demographic characteristics, influencing factors of detection rate, nucleic acid quantitative results, and serological patterns of HBsAg-/HBV DNA+ donors. Results: From January 1, 2016 to December 31, 2024, 991 565 donor samples underwent nucleic acid testing in Taiyuan. A total of 309 HBsAg-/HBV DNA+ samples were detected, resulting in an HBsAg-/HBV DNA+ detection rate of 3.12 per 10 000. The detection rate varied significantly across different years (P<0.05). Males had a significantly higher HBsAg-/HBV DNA+ detection rate than females, first-time donors had a higher rate than repeat donors, and whole blood donors had a higher rate than apheresis donors (P<0.05). The detection rate also differed significantly among age groups (P<0.05). Logistic regression analysis showed that gender, age, donation frequency, and donation type were all influencing factors for HBsAg-/HBV DNA+ detection (all P<0.05). The predominant serological patterns among HBsAg-/HBV DNA+ donors were HBsAb+/HBcAb+ (43.69%, 135/309) or HBcAb+ alone (24.27%, 75/309). Viral load was detectable in 53.40% (165/309) of the HBsAg-/HBV DNA+ donors. Among these, 61.21% (101/165) donors had a viral load<20 IU/mL, and 94.55% (156/165) had a viral load<200 IU/mL. Donors with viral load<200 IU/mL primarily exhibited HBsAb+/HBcAb+ (41.67%, 65/156) or HBcAb+alone (36.54%, 57/156) serological patterns. Conclusion: The prevalence of HBsAg-/HBV DNA+ is low among blood donors in Taiyuan. Higher detection rates were observed in the 46-55 years age group, males, first-time donors, and whole blood donors. HBsAg-/HBV DNA+ donors exhibit specific serological patterns and generally have low viral loads, indicating a potential residual transfusion risk. It is recommended to add HBcAb testing, together with high-sensitivity nucleic acid testing technologies and donor follow-up, to ensure blood safety and guide donor reentry.