Objective: To establish a method for the genotyping of fetal M blood group antigen by extracting cell-free fetal DNA (cff-DNA) from maternal plasma, so as to guide the management of M antigen-negative pregnant women with IgG anti-M antibody during pregnancy. Methods: A realtime fluorescent quantitative PCR (realtime PCR) method was established. The specificity and sensitivity of the method were validated by dilution of genomic DNA. Subsequently, a total of 12 M antigen-negative pregnant women were enrolled. The cff-DNA was extracted from maternal plasma, and fetal M antigen genotyping was performed by realtime PCR. Fetuses were classified as M-positive or M-negative according to the presence or absence of amplification curve. The accuracy of the method was validated by comparing fetal M antigen genotyping results with the serological results using the cord or peripheral blood of the neonate at birth. Results: Among the 12 M antigen-negative pregnant women, anti-M was detected in five cases, of which four cases had IgG anti-M, and one case had fetal anemia. The results of fetal M antigen genotyping showed that 9 cases were M-positive (9/12, 75%) and 3 cases were M-negative (3/12, 25%). Serological results of blood samples collected after birth from four M-positive fetuses and one M-negative fetus were consistent with the genotyping results. Conclusion: We have, for the first time, established a non-invasive prenatal genotyping method for fetal M antigen using maternal plasma cff-DNA, and preliminarily demonstrated the feasibility of this method.

Objective: To conduct screening for rare blood types within important blood group systems for the Chinese population, such as Rh, Duffy, Kidd, P1Pk, Diego, and MNS, in the Guangzhou region, and to establish a corresponding rare blood type database and physical repository. Methods: The saline medium microplate method was used to screen blood donors with the ccDEE phenotype combined with either Jk(a-) or Jk(b-). The polybrene microplate method was employed to screen for donors with Fy(a-), s(-), Lu(b-), Di(b-), k(-), and p phenotypes. The urea lysis microplate method was applied to screen for the Jk(a-b-) phenotype. A high-resolution melting (HRM) curve method was established for screening some donors with the Di(b-) phenotype. Subsequently, expanded phenotyping of antigens in the Rh, Kidd, MNS, Duffy, P1Pk, Lewis, Kell, and Lutheran blood group systems was performed on identified rare blood type donors using monoclonal antibodies. The test results are entered into the Rare Blood Type Bank Management System of the Guangzhou Blood Center, enabling functions such as confirmation reminders and cryopreservation storage when the donor donates again. Red blood cells of rare blood types are processed into frozen red blood cells for long-term storage. Results: Among voluntary blood donors, 16 cases of the ccDEE combined with Jk(a-) phenotype were identified (0.221 7%, 16/7 216); 10 cases of the ccDEE combined with Jk(b-) phenotype (0.138 6%, 10/7 216); 78 cases of the Fy(a-) phenotype (0.169 5%, 78/46 012); 39 cases of the Lu(b-) phenotype (0.138 2%, 39/28 214); 31 cases of the s(-) phenotype (0.081 8%, 31/37 913); 22 cases of the Di(b-) phenotype (0.029 9%, 22/73 691); 30 cases of the Jk(a-b-) phenotype (0.010 1%, 30/298 250); and 1 case of the k(-) phenotype (0.001 3%, 1/77 382), which was further identified as KELnull phenotype (K0). No p phenotype donors were identified (0/88 528). A total of 228 units of frozen red blood cells were prepared. The screening results were compared and analyzed with rare blood type data from other regions. Conclusion: This study, through a combination of different screening methods, significantly improved the efficiency of rare blood type screening while remaining cost-effective. By conducting large-scale screening and performing data informatization processing, a database and physical repository of rare blood types in the Guangzhou region were successfully established. This provides a strong guarantee for the timely supply of blood to patients with difficult-to-match and rare blood types in the region, effectively enhances the level of transfusion safety in the region, and offers a practical paradigm for constructing a comprehensive blood transfusion support system.

In order to establish a method for the detection of serum antibodies to donkey-derived e-quine coronavirus(ECoV),recombinant ECoV N protein was expressed in E.coli system,purified by nickel column affinity chromatography and identified by Western blot.After optimizing the re-action conditions,the indirect ELISA(iELISA)detection method was established using the puri-fied recombinant protein as coating antigen and used to detect 143 clinical serum samples.The re-sults showed that the recombinant N protein,which has good reaction activity with serum antibod-y,was successfully expressed.The optimum conditions of the established iELISA method were as follows:the amount of antigen coated was 0.2 μg/well and overnight at 4 ℃,10％skimmed milk powder solution was sealed at 37℃ for 1.5 h,the dilution concentration of serum was 1∶200,and the enzyme-labeled secondary antibody diluted at 1∶10 000.The sensitivity test results showed that the positive serum could be diluted to 1∶6 400.The specificity test results showed that all an-tibodies to several donkey pathogens were negative.The repetitive test results showed that the in-tra-and inter-batch coefficients of variation were 2.90％-6.12％and 2.29％-7.88％respectively.The positive rate of clinical donkey serum was 57.3％.The iELISA established in this study pro-vides a technical support for epidemiological investigation and antibody surveillance.

In order to establish a method for the detection of serum antibodies to donkey-derived e-quine coronavirus(ECoV),recombinant ECoV N protein was expressed in E.coli system,purified by nickel column affinity chromatography and identified by Western blot.After optimizing the re-action conditions,the indirect ELISA(iELISA)detection method was established using the puri-fied recombinant protein as coating antigen and used to detect 143 clinical serum samples.The re-sults showed that the recombinant N protein,which has good reaction activity with serum antibod-y,was successfully expressed.The optimum conditions of the established iELISA method were as follows:the amount of antigen coated was 0.2 μg/well and overnight at 4 ℃,10％skimmed milk powder solution was sealed at 37℃ for 1.5 h,the dilution concentration of serum was 1∶200,and the enzyme-labeled secondary antibody diluted at 1∶10 000.The sensitivity test results showed that the positive serum could be diluted to 1∶6 400.The specificity test results showed that all an-tibodies to several donkey pathogens were negative.The repetitive test results showed that the in-tra-and inter-batch coefficients of variation were 2.90％-6.12％and 2.29％-7.88％respectively.The positive rate of clinical donkey serum was 57.3％.The iELISA established in this study pro-vides a technical support for epidemiological investigation and antibody surveillance.

Objective To assess the accuracy and consistency of point-of-care testing(POCT)technology in detecting D-dimer(DDI),Procalcitonin(PCT),and N-terminal pro B-type natriuretic peptide(NT-proBNP)in whole blood samples,as well as to validate its feasibility for rapid clinical diagnosis.Methods From July 8 to August 22,2022,a total of 104 paired DDI whole blood and plasma samples,496 paired PCT whole blood and serum samples,and 77 paired NT-proBNP whole blood and serum samples were collected.The consistency and accuracy of test results between whole blood and plasma/serum samples were assessed using the Mann-Whitney U test,regression analysis,relative sensitivity,relative specificity,Youden's index,and Kappa value.Results The test results of DDI,PCT,and NT-proBNP in whole blood and plasma/serum samples demonstrated excellent consistency,with correlation coefficients of r2=0.951 2,r2=0.942 8,and r2=0.991 6,respectively,and all P-values exceeding 0.05.At the medical decision levels,for DDI(0.55 μg/mL),the relative sensitivity,rela-tive specificity,Youden index,and Kappa value were 94.3%,94.1%,0.88,and 0.87,respectively.For PCT(0.5 ng/mL and 2.0 ng/mL),the relative sensitivities were 97.4%and 89.0%,the relative specificities were 95.8%and 98.3%,the Youden indices were 0.93 and 0.87,and the Kappa values were 0.93 and 0.89,respectively.For NT-proBNP(125 pg/mL),the relative sensitivity was 94.1%,the relative specificity was 100%,the Youden index was 0.94,and the Kappa value was 0.87.These findings confirm the high accuracy of whole blood sample testing and the strong concordance between the two methods.Conclusions This study confirmed the efficacy of POCT technology for detecting DDI,PCT,and NT-proBNP in whole blood samples.The results showed a high level of consistency compared to traditional plasma/serum methods,thereby reinforcing the clinical applicability of POCT for rapid diagnosis.

Objective To assess the accuracy and consistency of point-of-care testing(POCT)technology in detecting D-dimer(DDI),Procalcitonin(PCT),and N-terminal pro B-type natriuretic peptide(NT-proBNP)in whole blood samples,as well as to validate its feasibility for rapid clinical diagnosis.Methods From July 8 to August 22,2022,a total of 104 paired DDI whole blood and plasma samples,496 paired PCT whole blood and serum samples,and 77 paired NT-proBNP whole blood and serum samples were collected.The consistency and accuracy of test results between whole blood and plasma/serum samples were assessed using the Mann-Whitney U test,regression analysis,relative sensitivity,relative specificity,Youden's index,and Kappa value.Results The test results of DDI,PCT,and NT-proBNP in whole blood and plasma/serum samples demonstrated excellent consistency,with correlation coefficients of r2=0.951 2,r2=0.942 8,and r2=0.991 6,respectively,and all P-values exceeding 0.05.At the medical decision levels,for DDI(0.55 μg/mL),the relative sensitivity,rela-tive specificity,Youden index,and Kappa value were 94.3%,94.1%,0.88,and 0.87,respectively.For PCT(0.5 ng/mL and 2.0 ng/mL),the relative sensitivities were 97.4%and 89.0%,the relative specificities were 95.8%and 98.3%,the Youden indices were 0.93 and 0.87,and the Kappa values were 0.93 and 0.89,respectively.For NT-proBNP(125 pg/mL),the relative sensitivity was 94.1%,the relative specificity was 100%,the Youden index was 0.94,and the Kappa value was 0.87.These findings confirm the high accuracy of whole blood sample testing and the strong concordance between the two methods.Conclusions This study confirmed the efficacy of POCT technology for detecting DDI,PCT,and NT-proBNP in whole blood samples.The results showed a high level of consistency compared to traditional plasma/serum methods,thereby reinforcing the clinical applicability of POCT for rapid diagnosis.

【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.

Objective To elucidate the prediction ability of monocyte monolayer assay(MMA)used in hemolytic dis-ease of fetus and newborn(HDFN)caused by IgG anti-M.Methods Plasma from eight pregnant women containing IgG an-ti-M were collected,and were divided into two groups(4 cases with HDFN,with severe clinical symptoms such as fetal hy-drops,and 4 cases without HDFN)according to the clinical outcomes.M antigen positive cells were sensitized with dithioth-reitol(DTT)treated plasma from eight pregnant women respectively.MMA was performed by coincubation with monocytes and sensitized M cells,along with negative and positive control set up.T-test was conducted to compare the difference in phagocytic efficiency between two groups.Results The phagocytic efficiency in group with HDFN were 15.37%,13.05%,9.17%and 24.50%respectively,with the mean value of 15.52%,while the group without HDFN were 8.74%,11.07%,5.12%and 6.23%respectively,with the mean value of 7.79%.There was no significant difference in phagocytic efficiency between two groups(P>0.05).The mean values of both groups were not significantly different from the negative control(P>0.05),but both were significantly lower than positive control(P<0.05).Conclusion The low phagocytic efficiency couldn't convince that the MMA is an effective predictor for the HDFN caused by IgG anti-M,indicating that another mech-anism might be responsible for it rather than monocyte phagocytosis.The assessment of the peak systolic velocity in middle cerebral artery of the fetal should be considered in the management for pregnant women who produce IgG anti-M to estimate the situation of fetal anemia.

Objective:To develop a genotyping method for the Junior blood type and report on a rare blood type with Jr(a-).Methods:Healthy O-type RhD+ volunteer donors of the Shenzhen Blood Center from January to May 2021 ( n=1 568) and a pedigree with difficult cross-matching ( n=3) were selected as the study subjects. Serological methods were used for proband′s blood type identification, unexpected antibody identification, and antibody titer determination. Polymerase chain reaction-sequence specific primer (PCR-SSP) method was used for typing the proband′s RHD gene. ABCG2 gene coding region sequencing and a PCR-SSP genotyping method were established for determining the genotypes of the proband and his family members and screening of Jra antigen-negative rare blood type among the 1 568 blood donors. Results:The proband′s ABO and RhD blood types were respectively determined as B and partial D (RHDDVI.3/RHD01N.01), Junior blood type Jra antigen was negative, and plasma had contained anti-D and anti-Jra. Sequencing of the ABCG2 gene revealed that the proband′s genotype was ABGG201N.01/ABGG201N.01 [homozygous c. 376C>T (p.Gln126X) variants], which is the most common Jr(a-) blood type allele in the Asian population. Screening of the voluntary blood donors has detected no Jr(a-) rare blood type. Statistical analysis of the heterozygotes suggested that the allelic frequency for ABCG2*01N.01 (c.376T) was 0.45%, and the frequency of Jr(a-) rare blood type with this molecular background was about 0.2‰. Conclusion:A very rare case of partial DVI.3 type and Jr(a-) rare blood type has been identified. And a method for identifying the Junior blood type through sequencing the coding regions of the ABCG2 gene and PCR-SSP has been established.

【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.