Objective: To investigate the impact of RHAG 808A variant, commonly identified in the Chinese population, on RhAG protein, RhD and RhCE antigens expression through in vivo and in vitro expression analysis. Methods: A missense mutation of RHAG gene (c. 808G>A, p. Val270Ile) with high frequency was found in KMxD database. Bioinformatics analysis was performed using Polyphen-2 and Provean software. High resolution melting (HRM) method was utilized to screen for the variant carriers in the blood donors. The expression of RhAG protein, RhD and RhCE antigens on the surface of red cells of variant carriers were detected via flow cytometry. Wild-type and mutant vectors of RHAG were constructed and transfected into HEK 293T cells for in vitro expression analysis. Then, the expression of RhAG protein, RhD and RhCE antigens were analyzed by flow cytometry. Results: Polyphen-2 and Provean software suggested that the amino acid change (p. Val270Ile) of RhAG protein may be harmful or neutral respectively. Among the 999 blood donors from Guangzhou Blood Center, 4 homozygous carriers and 99 heterozygous carriers of RHAG 808A mutant allele were identified. The frequency of this allele was 5.4% (107/1 998). No significant differences in RhAG protein, RhD and RhCE antigens expression level was identified between the homozygous carriers, heterozygous carriers of RHAG 808A variant allele and the wild-type individuals. In vitro analysis for antigen expression study obtained the similar results. Conclusion: The RHAG 808A variant allele commonly identified in the Chinese population has no effect on the expression of RhAG protein, RhD and RhCE antigens, so the variant should be a population polymorphism site.

Objective: To investigate the distribution of GP (B-A-B) hybrid glycophorins in several Chinese minority populations from southern regions of China (Guangdong & Guizhou). Methods: Whole blood samples were collected from 536 blood donors representing 15 different Chinese ethnic minority groups, including She, Bouyei, Yi and Miao, as well as Chuanqing populations. Genomic DNA was extracted and GYP (B-A-B) genotyping was conducted by high resolution melting (HRM) minority method using the GYPB pseudoexon 3-specific primers. Direct sequencing of GYPB pseudoexon 3 was performed in the samples with variant curves. Results: Only one genotype of GP (B-A-B) hybrid glycophorins (GYP Mur/GYPB) was identified among these 536 samples. In total, 15 She (15/162, 9.26%), 18 Bouyei (18/113, 15.93%), 3 Yi (3/79, 3.80%), 3 Chuanqing (3/45, 6.67%), 2 Bai (2/42, 4.76%), 3 Miao (3/40, 7.50%), 1 Shui (1/12, 8.33%), 2 Gelao (2/12, 16.67%), 1 Tujia (1/8, 12.50%) and 1 Dong (1/6, 16.67%) blood donors with heterozygous GYP Mur allele were identified. Among 8 Hui, 5 Manchu, 2 Mongolian, 1 Yao and 1 Li donors, no GYP (B-A-B) hybrid gene carrier was found. In addition, four nucleotide polymorphisms (SNPs) were identified in 6 samples with a variant melting curve detected by HRM. Conclusion: GP. Mur is the most common type of GP (B-A-B) hybrid glycophorins among Chinese minority populations, with frequency varying across different populations. It is recommended to involve GP. Mur reagent cells in the antibody screening cells for populations with a high frequency of GYP Mur allele.

Objective: To genotype 50 RhD variant samples from Guangzhou, China, using our previously established genotyping strategy, thereby providing guidance for transfusion management and antenatal monitoring in RhD-variant individuals. Methods: Between June and August 2024, fifty samples identified as RhD variants during RhD-negative confirmation testing at Guangzhou Blood Center were collected. Serological testing for the D antigen was performed with two different anti-D reagents, and the epitope profiles of the D antigen were determined using a commercial panel of monoclonal anti-D reagents containing nine kinds of monoclonal anti-D. Genomic DNA was extracted, and high-resolution melting (HRM) analysis was applied to detect the Asian-type DEL (RHD 1227A). Subsequently, RHD genotyping was carried out using Multiplex Ligation-dependent Probe Amplification (MLPA) and Sanger sequencing. Results: Among the 50 D variant samples, 17 (34.0%) Asian type DEL samples were detected by HRM, including 13 cases with RHD DEL1/01N.01 genotype and 4 cases with RHD DEL1/DEL1 genotype. Eleven (11/50, 22.0%) samples were typed as DVI by the epitope profiles of D antigen. The epitope profiles of D antigen combined with Sanger sequencing of exon 6 identified 5 (5/50, 10.0%) cases of RHD weak partial 15/01N.01. MLPA combined with Sanger sequencing identified two cases of RHD DVI.3/DEL1, representing 4.0% (2/50) of the samples. Additionally, the following RHD genotypes were each detected in one case: RHD weak D type 18/01N.04, RHD weak D type 72/01N.01, RHD weak D type 95/DEL1, RHD weak D type 114/DEL1, RHD weak D type 136/DEL1, RHD weak D type 147/01N.01, RHD 496G/496G, RHD 536C/01N.01, RHD 689A/689A, RHD 689A/DEL1, RHD DEL32/DEL1, RHD DV.1/01N.01, RHD DV.5/01N.01, RHD 01.01/01N.01, and RHD 01/01N.01. Conclusion: Fifty D variant individuals were typed using our previously established serological and molecular approach. These findings provide guidance for precision transfusion therapy in RhD variant patients and inform evidence-based decisions regarding anti-D immunoglobulin prophylaxis for RhD variant pregnant women.

Objective To investigate the distribution,phenotype and genotype of D-elute type(Del)in blood donors with RhD negative blood in Guangzhou,so as to understand the molecular biological background of DEL blood group in this area.Methods During the period from November 1,2021 to June 30,2022,the RhD-negative blood initially screened by saline method was confirmed by indirect anti-human globulin test(IAT)serology,and RhCE phenotype was determined by RhCE typing card.A total of 1 146 RhD-negative samples,including all RhD-negative samples with RhCE C+(n=459)and a randomly selected subset of RhCE C-(n=175),were subjected to adsorption-elution(Del)screening(a total of 634 sam-ples).DNA from Del-positive samples was extracted for real-time fluorescent PCR detection of the RHD gene c.1227 locus using high-resolution melting curve analysis(HRM).For samples without mutations detected at the RHD?1227 locus by HRM,restriction fragment length polymorphism polymerase chain reaction(PCR-RFLP)was performed to amplify the prod-uct which was subsequently digested with Pst I enzyme and analyzed by electrophoresis to determine RHD gene haplotypes.Sanger sequencing was performed for exon sequencing(exon 1-10)of the RHD gene,and gene mutations were analyzed u-sing SeqMan software.Suspected Del-positive samples were subjected to RHD whole gene analysis using third-generation sin-gle-molecule sequencing technology.Results Among the 634 confirmed RhD-negative samples,229(36.1%)displayed Del phenotype,accounting for20%(229/1 146)of the total confirmed RhD-negative samples.The RhCE phenotypes of the 229 DEL cases were as follows:Ccee in 181 cases,CCee in 40 cases,CcEe in 7 cases,and ccEe in 1 case.HRM combined with RHD haplotype analysis showed that there were 170 cases with RHD gene as RHD?1227A/01N.01,32 cases with RHD gene as RHD?1227A/1227G,26 cases with RHD gene as RHD?1227A/1227A,and 6 cases with RHD gene as RHD?1227G/1227G(sequencing results included 1 case of weak D type 12,4 cases of D-,and 1 case of RHD?01EL.02).Con-clusion The individual genotype of DEL blood donors in Guangzhou area is mainly characterized by RHD?1227A/01N.01,and their RhCE phenotypes are all C+.HRM can be used as a molecular biology method for routine screening of Asian-type DEL blood type genes.

【Objective】 To identify the specificity of alloantibody against high-frequency antigens in one case suffering with severe hemolytic diseases of the fetus and newborn (HDFN) and to screen for matching blood for transfusion. 【Methods】 The HDFN test and the antibody serological identification tests in the mother were performed. Several common high frequency antigens of maternal red blood cells (RBCs) were determined. IgG subtype coated on the RBCs of the newborn was determined. The phagocytic efficiency of the antibody was tested using the monocyte phagocytosis of sensitized erythrocyte by flow cytometry in vitro. Sanger sequencing of DI gene was performed in the mother, father and mother’s brother. The diluted maternal plasma was used for large scale screening of matching blood using IAT in Coomb’s gel card. 【Results】 Di(b-) phenotype was identified in the mother of the newborn and anti-Di^b (titer: 512) related HDN was detected in the newborn. IgG1 and IgG2 subtypes of anti-Di^b were detected and the rate of monocyte phagocytosis was 88.83%(74.7/84.09). The compatible blood was not detected in the maternal relatives. Subsequently, the newborn received the matching RBCs of two Di(b-) donors identified from 5 520 blood donors and discharged from the hospital. We screened out 17 Di(b-) donors out of 51 334 blood donors, indicating that the distribution frequency of Di(b-) among blood donors in Guangzhou was about 0.033% (17/51 334). 【Conclusion】 By serology and molecular biology methods, the newborn was identified with HDFN caused by anti-Di^b, and an effective large-scale screening method for Di (b -) rare blood types was established to find matching blood, which supported the establishment of rare Di(b-) blood database.

[Abstract] [Objective] To further identify the RhD phenotype and RHD genotype in the individual who have RhD negative phenotype in the primary screening, and to analyze the effect of c. 801+2T>G mutation on RhD phenotype by minigene splicing assay. [Methods] The serologic test was performed for RhD phenotype identification and absorption-elution test was performed by using monoclonal anti-D. Sanger sequencing was used to analyze the sequence of RHD genes and the newly identified splicing site mutations of RHD genes were used to construct pSplicePOLR2G micro gene expression plasmids. By using an in vitro micro gene splicing system, the mRNA splicing results were detected and analyzed using agarose and capillary electrophoresis to predict their impact on RhD phenotype. [Results] The serological test results showed that the patient's blood type was RhD-negative, but the anti-D absorption-elution test was positive, indicating a Del phenotype. The rare genotype RHD^*(1227A/801+2G) was identified in this individual. The c. 801+2T>G was a novel mutation at 5'-splice site of intron 5. The minigene splicing assay showed that c. 801+2T>G resulted in a complete skipping of RHD exon 5 in the mature transcript, forming a transcript without exon 5. [Conclusion] An individual carrying a novel mutation c. 801+2T>G in the RHD gene was found to exhibit a Del phenotype, but also carry the Asian Del allele c. 1227G>A. It was speculated that the c. 801+2T>G mutation caused RhD negative or Del phenotype based on the results of minigene splicing assay in vitro.

Objective To summarize the current situation of the implementation of the death case discussion system in county-level medical institutions and analyze the existing problems,to attempt to make suggestions for improvement.Methods Judgmental sampling method was used in this study.A self-made questionnaire was used to conduct field investigation on the im-plementation of the death case discussion system in 16 county-level medical institutions in Chongqing,and semi-structured inter-views were conducted with medical staff.Results All county-level medical institutions have established death case discussion system,but there are many differences in connotative quality.There are many problems in system implementation,such as unclear scope of death case discussion,formality,irregular discussion,poor quality of connotation and lack of systematic supervision.Conclusion As a core medical system,the death case discussion system is an important tool for medical quality management.The medical quality management and medical staff must place a high value on the significance of death case discussion.In order to enhance medical quality and ensure patient safety,we must adhere to the principles of openness and honesty,systematic criti-cism,non-recrimination and non-punishment to conduct death case discussion in time and standardize,keep a record of death case discussions and enhance supervision.

【Objective】 To study the effect of RHAG variants identified in Chinese population on mRNA splicing by minigene splicing assay(MSA) in vitro. 【Methods】 The pSplicePOLR2G minigene expression plasmids were constructed for 10 RHAG mutations with relatively high distribution frequency in Chinese population near splicing sites or synonymous mutations by analyzing the RHAG gene data in the KMxD database. Then, the wild-type and mutant plasmids were transfected into HEK 293T cells, and RNA was extracted 48 hours after transfection. After reverse transcription, specific primers were used for PCR amplification, and then agarose gel electrophoresis and capillary electrophoresis were performed to determine whether the mutations will affect the normal splicing of exons. 【Results】 MSA in vitro showed that 2 mutations (c.158-5delT, c. 807+ 3A>C) near the splicing site reduced the amount of normal transcripts slightly. The remaining 8 synonymous mutations(c.312G>A, c. 341+ 3G>A, c. 609C>T, c. 681G>A, c. 861G>A, c. 957T>A, c. 984T>C and c. 1139-7G>A) had no impact on the splicing of RHAG mRNA. 【Conclusion】 This study showed that RHAG gene was conservative in terms of splicing, and the mutations near splicing sites and synonymous mutations were less likely to cause abnormal splicing of RHAG gene.

【Objective】 To solve the difficulty of RhD blood group typing in a patient with double population(DP) of red blood cells for RhD antigen by serological and genotyping analysis. 【Methods】 Separation of the two populations of red blood cells of the patient was performed using capillary centrifugation method. ABO, RhD and RhCE typing, direct anti-human globulin test (DAT), irregular antibody screening, antibody identification and blood crossmatching of the patient were conducted using the standard serological methods. The hybrid Rhesus zygosity analysis of the RHD gene was performed by PCR-RFLP method. RHD and RHCE genotype of the patients were identified by PCR-SSP method. 【Results】 The patient was B type but with DP of red blood cells for RhD, Rhc and RhE antigens. DAT of the patient was positive and the alloanti-D was detected in serum. The RHD zygosity was D-/D- homozygote. PCR-SSP testing showed the RHD gene deletion (RHD * 01N. 01/01N.01 genotype) and Ccee of RHCE genotype in the patient, which was consistent with RHD zygosity analysis. 【Conclusion】 This is a special case with D-negative phenotype which was wrongly detected as D-positive type after D-positive red blood cells transfusion in emergency. When the DP of red cells for D antigen encountered like this case, the RhD typing can be accurately determined by using RHD genotyping analysis to provide strong evidence to the clinical blood transfusion.

【Objective】 To establish an experimental method for detecting phagocytosis of sensitized red blood cells in vitro by flow cytometry. 【Methods】 Mononuclear cells were isolated from the peripheral blood of blood donors and cultured in a cell incubator for 1 hour, and then adherent monocytes were isolated and obtained. Di^b-positive red blood cells (RBCs) were labeled with PKH26 and then sensitized with IgG anti-Di^b. The sensitized RBCs were added to monocytes for in vitro phagocytosis assay. Monocytes were labeled with FITC anti-human CD14, then phagocytosis was measured by flow cytometry, and the phagocytic efficiency was calculated. The method was used to detect the phagocytic efficiency of monocytes on human IgG anti-D sensitized RBCs with different titers. 【Results】 The phagocytic efficiency of monocytes was averaged at 5% (1.2%~7.6%, SD 3.30) versus 81% (71.4%~92.7%, SD 8.65) in the negative versus positive control group, respectively. Phagocytic activity of monocytes mediated by anti-D was correlated with the antibody titer. The phagocytosis efficiency was within 10% when the antibody titer was lower than 32 and increased sharply when the titer was between 32 to 128, it entered a plateau and stabilized at 80% at the titer above 256. 【Conclusion】 A detection platform for detecting phagocytosis-sensitized RBCs in vitro by flow cytometry has been successfully established. It can be used to assess the clinical significance of red blood cell allotype or autologous IgG antibodies.