[Objective] To compare next generation sequencing (NGS) library construction technology between probe hybridization capture and amplicon methods, and analyze the influencing factors of HLA genotyping resolution level and its prospects in clinical applications. [Methods] A total of 207 clinical samples with known typing results and samples from the proficiency testing plan were selected. The conformity rate of HLA genotyping results, allele coverage and typing data analysis indicators were confirmed, and the effects of two library construction methods on the level of HLA genotyping discrimination were compared. [Results] The concordance rate of 207 samples with the feedback results of PT or prior well-characterized HLA genotypes was 100%. Among them, 91 samples were captured using hybridization probe capture method. Compared with the original amplicon method, the hybridization probe capture method can distinguish the alleles of DRB1 and DPB1 that cannot be determined in 13 samples. The allelic imbalance of DRB1, DPA1, and DQB1 loci in 6 samples was resolved. Three samples were found to have missed detection of alleles at the DQA1 and DQB1 loci. [Conclusion] The performance indicators of hybridization probe capture and amplicon performance confirmation meet the requirements of clinical detection of HLA genotyping, which provides an experimental method and basis for clinical application.

[Objective] To resolve the ambiguities of HLA genotyping generated by next generation sequencing (NGS) using nanopore sequencing technology. [Methods] A total of 38 samples with ambiguous HLA genotyping by NGS in our laboratory were collected, and HLA-A, -B, -C, -DRB1, -DRB3/4/5, -DQA1, -DQB1, -DPA1 and -DPB1 loci in these samples were amplified using primers in the same commercial NGS HLA genotyping kit, then subjected to third-generation library construction, and sequenced on the nanopore sequencer. The sequencing data were converted into Fastq files and analyzed by software, and the genotypes of 11 HLA loci were obtained. The ambiguities were counted directly. [Results] The high-resolution genotyping at the second domain of 11 HLA loci of 38 samples using the third generation sequencing (TGS) were consistent with the results of the NGS method at a rate of 100%. The genotypes for the HLA-A, -B, -C, -DRB3, -DRB4, -DQA1 and -DPA1 loci by TGS were all only one result, and the discrimination rate for ambiguities of the HLA-A, -B, -C, and -DQA1 loci (all caused by the difficulty in phasing due to the short NGS read length) was 100%. Among the HLA-DRB1, -DRB5, -DQB1 and -DPB1 loci, the discrimination rate of TGS for the ambiguities caused by non-amplification of exon 1 was 0% and by the short NGS read length was 100%. [Conclusion] Nanopore technology was used to identify the ambiguities of 11 HLA loci in this study, and the ambiguities caused by the short read length disadvantage of the NGS method could be solved effectively and the accuracy of HLA genotyping would be improved.

[Objective] To study the relationship between the expression intensity of HLA-Ⅰ platelet antibodies in patients with platelet transfusion refractoriness (PTR) and platelet cross-matching, and to further evaluate other factors in order to provide relevant data support for improving platelet transfusion efficiency and optimizing platelet transfusion regimens. [Methods] Luminex single antigen flow cytometry was used to detect platelet specific antibodies in 35 patients with hematological disease. Subsequently, the Capture-P method was employed to perform 102 crossmatchings between plasma with HLA-Ⅰ antibodies and platelets with known HLA-Ⅰ genotypes. The cross-matching results were assessed and the clinical transfusion outcomes were tracked. [Results] The positive detection rate of HLA-Ⅰ and HPA antibodies in this study was 48.6% (17/35). The negative rate of cross-matching in 102 cases was 37.3% (38/102). Multiple factors affect platelet cross-matching, such as HLA-Ⅰ antibody expression level and antibody type, antigen expression level, cross-reactivity group and eplets. Among them, the expression level and antibody type of HLA-Ⅰ antibody are the main influencing factors. However, the effectiveness of clinical platelet transfusion is not completely determined by the compatibility of platelet cross-matching. [Conclusion] In addition to avoiding strong positive HLA-Ⅰ antibodies, clinical matching should also be vigilant against the serological cross-incompatibility caused by weak positive HLA-Ⅰ antibodies. It may be necessary to establish HLA-Ⅰ low expression antigen database as a better alternative platelet donor selection strategy, and gradually explore the effectiveness of ‘low expression mismatch’ strategy for clinical platelet transfusion.

[Objective] To study the inter-allelic recombination event occurring in the HLA-B locus, and to evaluate the molecular genetic mechanisms of a novel HLA allele, predict and analyze the impact of its amino acid residue changes on the three-dimensional structure. [Methods] HLA typing was taken with polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP) by Luminex. Sequence-based typing (SBT) and gene clone were used to analyze exons 1-4 sequences of HLA-B allele. In order to determine the exact site of inter-allelic recombination event occurring in the HLA-B locus, sequences of the HLA-B alleles were compared with the IMGT/HLA database by the program “Alignment”. After homology modeling using the Swiss-Model software, the three-dimensional structure of the molecules was simulated using the Swiss Pdb Viewer software, and the FATCAT online software was used to compare the differences in the three-dimensional structures of the molecules. [Results] HLA typing indicated the PCR-SSOP pattern did not match with any known HLA-B alleles, suspected to be a new HLA allele. The genetic clone sequencing results showed HLA-B alleles of the proband were B^*13∶02 and a novel allele. The HLA-B exon2 nucleotide sequence of the novel allele was different from any other known alleles. The novel allele has 12 nucleotides replaced when compared with the closest matching B^*35∶01∶01∶01 allele from c.259 to c.299, which result in 8 amino acids changes. The sequence was identical in B^*35∶01∶01∶01 in exon 1, exon 3, exon 4, intron 1, intron 2, intron 3 and at c.74 to c.258 in exon 2, and c.259 to c.343 sequence in exon 2 was identical in B^*46∶01∶01 by blast search. The structure of the mutant alleles was similar to that of B^*35∶01∶01∶01 and B^*46∶01∶01, and the local hydrogen bonds of amino acids p.63-p.79 were changed at the recombination site. [Conclusion] This study demonstrates a rare inter-allelic recombination event occurring in the HLA-B locus. It has been officially designated as HLA-B^*35∶186 by WHO Nomenclature Committee for Factors of the HLA System. It illustrates the process of novel allele, and provides new evidence for the further studying mechanisms of gene recombination and HLA polymorphism.

[Objective] To investigate the effect of Shenmai injection on the preservation quality of suspended red blood cells of high hemoglobin population in Xizang plateau. [Methods] Whole blood (400 mL, n=8) collected by the Xizang Autonomous Region Blood Center was centrifuged at 3 000 g for 10 minutes to remove most of the plasma, followed by the addition of 100 mL of MAP preservation solution to obtain plateau suspended red blood cells, which were then divided into three equal portions. One portion was the control group, and another part had 15 mL of MAP preservation solution added, which was the dosage group. The third portion involved diluting Shenmai injection with MAP, followed by addition of 15 mL of MAP preservation solution containing Shenmai to the red blood cells, resulting in a final concentration of Shenmai injection of 1%, which was the Shenmai group. Blood routine, pH value, electrolytes, glucose, lactate, free Hb, adenosine triphosphate (ATP), P50, phosphatidylserine (PS) and other indicators were detected at day 1, 21 and 35, respectively. [Results] The Hb concentration and Hct of the dosage group and the Shenmai group were significantly lower than those of the control group, with values of (179.3±17.8) vs (181.0±17.1) vs (199.1±19.5) g/L for Hb concentration and (53.2±2.6)% vs (53.3±2.5)% vs (58.4±3.1)% for Hct. The three groups maintained this pattern until the end of storage. In the middle and late stages of preservation, the glucose and Na⁺ contents in the dosage group and the Shenmai group were higher than those in the control group, while the lactate and K⁺ contents were lower than those in the control group. At the end of storage, the glucose and Na⁺ content of the Shenmai group was higher than that of the dosage group, while the lactate and K⁺ content were lower than that of the dosage group. From day 1 to day 35 of storage, the hemolysis rate of the Shenmai group was significantly lower than that of the control group and the dosage group. On day 21 and 35 of storage, the PS expression rate in the Shenmai group was significantly lower than that in the control group and the dosage group, which were (6.52±0.40)% vs (7.24±0.91)% vs (8.27±0.93)% and (7.29±0.53)% vs (9.37±0.82)% vs (8.39±0.76)%, respectively. [Conclusion] The hemolysis rate and PS of suspended red blood cells of Xizang high altitude prepared by adding Shenmai injection were significantly lower than those in the control group and the dosage group, which was conducive to reducing hemolysis and slowing down the aging of red blood cells, and had a certain improvement on the preservation quality of suspended red blood cells in Xizang plateau people.

[Objective] To use Chitosan Methacryloyl (CSMA) loaded with artificial platelet-derived exosomes (aPexos) as the needle body material, and gelatin and carboxymethyl chitosan (CMCS) loaded with Epigallocatechin gallate(EGCG) as the backing material to prepare microneedles, aims to investigate the therapeutic effect and mechanism of aPexos-EGCG microneedles in the treatment of burn wound healing. [Methods] First, aPexos were extracted using ultrasound and gradient ultracentrifugation. The concentration, morphology, and growth factor content (TGF-β1, PDGF-BB, VEGF) of the exosomes were assessed using NTA, transmission electron microscopy, and ELISA kits. The aPexos and EGCG were then dissolved in the needle body and backing materials, respectively. The aPexos and EGCG were loaded into the needle body and backing layer, respectively. The morphology, mechanical properties, and puncture performance of the microneedles were examined, and the preparation conditions for the microneedles loaded with aPexos-EGCG were optimized. Finally, animal experiments and tissue staining were conducted to assess the efficacy of the aPexos-EGCG microneedles in promoting burn wound healing in rats. [Results] The size distribution of aPexos was mainly in the range of 50-150 nm, with an average diameter of 132.7±3.8 nm and an average concentration of approximately 2.88×10¹³±3.62×10¹² particles/mL. The concentrations of TGF-β1, PDGF-BB, and VEGF were approximately 1 363±135.9 ng/mL, 63.5±14.8 ng/mL, and 1 606.0±77.5 pg/mL, respectively. Mechanical property testing of the microneedles indicated that, compared with the blank microneedles, the drug-loaded microneedles had sufficient piercing ability to penetrate the stratum corneum of the skin. The results of the rat burn wound healing experiment showed that the wound healing rates of the d 3, d 7, aPexos-EGCG microneedle group compared to the control group showed significant differences, with respective values of (47.64±12.5)% vs (18.11±6.40)%, (87.45±5.57)% vs (79.85±5.03)%(P<0.05). Hematoxylin-eosin (HE) staining revealed more intact epidermal layers in the aPexos-EGCG microneedle group. Masson staining showed that the collagen deposition percentage in the aPexos-EGCG microneedle group was higher than in the control group. Immunofluorescence staining results indicated that the aPexos-EGCG microneedle group had a reduced content of M1-type macrophages and an increased content of M2-type macrophages. Additionally, the vascular markers CD31 and α-SMA showed elevated expression in this group, with significant differences compared to the other groups (P<0.05). [Conclusion] The aPexos-EGCG microneedle developed in this study exhibits good mechanical properties, capable of successfully penetrating the skin's stratum corneum and delivering aPexos and EGCG. aPexos promotes wound repair, while EGCG regulates the ratio of M1 and M2 macrophages at the wound site and suppresses the inflammatory response. This microneedle can effectively promote wound healing in rats with burn injuries, offering a novel approach for tissue repair.

[Objective] To compare the characteristics of platelet-rich plasma derived exosomes (PRP-Exos) under different activation conditions and their differential effects on the proliferation capacit of human microvascular endothelial cells (HMEC-1) and human skin fibroblasts (BJ). [Methods] Ten healthy volunteers were recruited, and 10 mL of venous blood anticoagulated with EDTA-K2 was collected. PRP-Exos were prepared and extracted by the secondary centrifugation method. Transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blotting (WB) detection techniques were used to compare the morphological characteristics, particle size distribution, concentration, and the expression of surface marker proteins of PRP-Exos. Through in vitro cell culture, the differences in morphological changes and proliferation abilities of HMEC-1 and BJ cells induced by PRP-Exos in different activator groups were compared. [Results] 1) TEM observation showed that the morphologies of PRP-Exos in different activator groups were different. 2) NTA analysis showed that compared with the particle size of (109.60±2.71) nm in the normal saline group, the particle sizes of the thrombin group [(104.93±1.55) nm] and the mixed agent group [(103.83±1.58) nm] were relatively smaller, while the particle size of the calcium gluconate group [(113.57±4.70) nm] was larger and its particle size distribution range was wider. There were statistically significant differences among different groups (F=7.019, P<0.05). The concentration of exosomes obtained in the group with the mixture of calcium gluconate and thrombin was the highest [(4.87±0.63)×10⁶ particles/mL, P<0.001]. Both the thrombin group [(2.75±0.13)×10⁶ particles/mL, P < 0.01] and the calcium gluconate group [(3.82±0.06)×10⁶ particles/mL, P<0.001] obtained higher concentrations of exosomes compared with the normal saline group. The concentration in the calcium gluconate group was slightly higher than that in the thrombin group, and there was a significant difference between the two groups (P<0.05). 3) WB analysis showed that CD41, CD81, and TSG101 were expressed on the surface of PRP-Exos, and the protein signal intensities of CD41 and TSG101 in the group with the mixture of thrombin and calcium gluconate were the strongest (P<0.001). 4) The results of in vitro cell culture showed that PRP-Exos in the group with the mixture of thrombin and calcium gluconate could significantly promote the proliferation of HMEC-1 and BJ cells (P<0.05). [Conclusion] The PRP treated with the thrombin and calcium gluconate mixture group yielded the highest concentration of exosomes; under in vitro culture conditions, PRP-Exos from this group significantly promoted the proliferation of HMEC-1 and BJ cells.

[Objective] To establish a cryopreservation protocol for small-volume (≤1 mL) red blood cells (RBCs) and to evaluate the reactivity and stability of blood group antigens after cryopreservation, so as to explore its potential application in immunohematology reference laboratories. [Methods] Small-volume RBCs were cryopreserved for 120 days, followed by thawing and deglycerolization to restore the RBC components. The quality of the RBCs was assessed. Serum antibodies were serially diluted and reacted with RBCs before and after cryopreservation, and agglutination scores were recorded to quantitatively evaluate the reactivity and stability of blood group antigens such as Rh, Duffy, Lewis, Kidd, M, and H. Flow cytometry was used to analyze the percentage and mean fluorescence intensity of ABO antigen expression on RBCs before and after cryopreservation to assess the usability of cryopreserved RBCs in flow immunophenotyping and blood group subtype studies. [Results] The hemolysis rate of thawed and deglycerolized RBCs was (0.27±0.10)%, with a supernatant free hemoglobin level of (0.52±0.14) g/L, and the RBC recovery rate was (69.12±7.91)%. The direct antiglobulin test (DAT) was negative for all thawed RBCs. There was no difference in the reactivity of blood group antigens before and after cryopreservation, and no difference in the percentage and mean fluorescence intensity of A and B antigen expression on RBCs before and after cryopreservation. [Conclusion] The small-volume RBC cryopreservation protocol can be applied to immunohematology analysis in reference laboratories and is expected to be widely used in blood group identification, antibody screening, identification, and blood group-related research.

[Objective] To explore the relationship between neutrophil activation under cardiopulmonary bypass (CPB) and the incidence of cardiac surgery-associated acute kidney injury (CS-AKI). [Methods] This prospective cohort study enrolled adult patients who scheduled for cardiac surgery under CPB at West China Hospital between May 1, 2022 and March 31, 2023. The primary outcome was acute kidney injury (AKI). Blood samples (5 mL) were obtained from the central vein before surgery, at rewarming, at the end of CPB, and 24 hours after surgery. Neutrophils were labeled with CD11b, CD54 and other markers. To assess the effect of neutrophils activation on AKI, propensity score matching (PSM) was employed to equilibrate covariates between the groups. [Results] A total of 120 patients included into the study, and 17 (14.2%) developed AKI. Both CD11b⁺ and CD54⁺ neutrophils significantly increased during the rewarming phase and the increases were kept until 24 hours after surgery. During rewarming, the numbers of CD11b⁺ neutrophils were significantly higher in AKI compared to non-AKI (4.71×10⁹/L vs 3.31×10⁹/L, Z=-2.14, P<0.05). Similarly, the CD54⁺ neutrophils counts were also significantly higher in AKI than in non-AKI before surgery (2.75×10⁹/L vs 1.79×10⁹/L, Z=-2.99, P<0.05), during rewarming (3.12×10⁹/L vs 1.62×10⁹/L, Z=-4.34, P<0.05), and at the end of CPB (4.28×10⁹/L vs 2.14×10⁹/L, Z=-3.91, P<0.05). An analysis of 32 matched patients (16 in each group) revealed that CD11b⁺ and CD54⁺ neutrophil levels of AKI were 1.74 folds (4.83×10⁹/L vs 2.77×10⁹/L, Z=-2.72, P<0.05) and 2.34 folds (3.32×10⁹/L vs 1.42×10⁹/L, Z=-4.12, P<0.05), respectively, of non-AKI at rewarming phase. [Conclusion] Neutrophils are activated during CPB, and they can be identified by CD11b/CD54 markers. The activated neutrophils of AKI patients are approximately 2 folds of non-AKI during the rewarming phase, with disparity reached peak between groups during rewarming. These findings suggest the removal of 50% of activated neutrophils during the rewarming phase may be effective to reduce the risk of AKI.

[Objective] To explore the accuracy and feasibility of non-invasive prenatal diagnosis of fetal RhE genotype using cell-free fetal DNA (cff-DNA) from maternal peripheral blood. [Methods] A total of 134 pregnant women with single fetuses and RhE-negative blood group were selected from our hospital from November 2023 to August 2024. Free DNA extraction kit was used to extract free DNA from peripheral blood of pregnant women, and the RhE blood group genotype of free DNA was detected by real-time fluorescent quantitative PCR (RT-qPCR). If the qPCR amplification signal of the sample was negative, the methylated RASSF1A gene was amplified, and the positive amplification result was used as a sign of successful extraction of cff-DNA. Serological microcolumn gel method was used to detect the phenotype of RhE blood group in neonatal peripheral blood. [Results] Among the 134 maternal peripheral blood samples, the cff-DNA detection of RhE blood group phenotypes was consistent with the RhE blood group genotyping of neonatal peripheral blood in 133 cases, including 90 cases of Rhee genotype and 43 cases of RhE genotype, with diagnostic concordance rate of 99.3%, sensitivity of 97.7%, specificity of 100%, youden index of 0.977, area under ROC curve of 0.995, the Kappa value of 0.983, positive predictive value of 100%, and negative predictive value of 98.9%. The sample of 1 case failed to be detected. After the amplification of methylated RASSFIA gene, it was confirmed that the reason for the failure was that no cff-DNA was extracted from the sample. The diagnostic concordance rates of the first, second and third trimesters were 93.8% (15/16), 100% (51/51) and 100% (67/67), respectively. Fisher's exact test method was used to calculate the P value, which was P>0.05, indicating that there was no statistical significance in the difference of diagnostic concordance rate among the three pregnancy periods, and there was no difference in the detection concordance rate of this method in different pregnancy periods. [Conclusion] The use of cff-DNA in maternal peripheral blood for the detection of fetal RhE blood group genotype is an accurate and highly feasible non-invasive prenatal diagnostic method, which is helpful for the clinical diagnosis of fetal and neonatal hemolytic disease caused by anti-E antibody.