上海市血液中心

[Objective] To design and establish a new method for flow cytometry-based detection of commonly observed highly expressed antigens on red blood cells, and to further evaluate the differences and distribution characteristics of antigen expression levels between ABO blood type homozygotes and heterozygotes in healthy individuals. [Methods] Residual blood samples after donor blood type identification by Shanghai Blood Center in April 2024 were collected. Among them, samples of 19 homozygous and 19 heterozygous individuals of type A and type B were selected. Then the expression level of ABO antigen on red blood cells were detected using the new method established in this study and the traditional aldehyde fixed red blood cell method. Both methods were tested independently three times and the results were compared. [Results] The mean values of the three detection results of the new method was (×105/RBC): AA homozygous 3.3±0.5, AO heterozygous 2.8±0.3, BB homozygous 3.6±0.3, BO heterozygous 3.1±2.8. The mean values of the three detection results of the aldehyde fixation method were AA homozygous 5.9±0.9, AO heterozygous 5.0±1.4, BB homozygous 3.8±0.6, and BO heterozygous 3.3±0.4. The average antigen distribution of each genotype followed a normal distribution. Comparing the average antigen expression levels of homozygotes and heterozygotes, both methods showed that A/B homozygotes had higher antigen levels than heterozygotes, with AA being 1.17 to 1.18 times that of AO and BB being 1.15 to 1.16 times that of BO. Comparing the inter batch differences in the three test results of two methods, the new method showed no significant difference in the three test results for four genotypes (P>0.05). The aldehyde fixation method showed significant differences in the test results for all three genotypes (P<0.01) except for BB homozygotes (P>0.05). The reliability and reproducibility of the new method were better than those of the traditional aldehyde fixation method. [Conclusion] The antigen expression level of ABO homozygotes is higher than that of heterozygotes, and the difference in antigen level between type A homozygotes and heterozygotes is slightly higher than that of type B. The new method is superior to traditional aldolization fixation methods.

[Objective] To explore the laboratory testing methods and clinical management strategies for immune hemolytic anemia induced by Ceftizoxime sodium drug-dependent antibodies. [Methods] Patient blood samples were subjected to blood typing, direct antiglobulin test, and unexpected antibody identification. Ceftizoxime sodium drug-dependent antibodies were detected using the immune complex method and drug-sensitized red cell method. The properties and titers of the drug antibodies were further assessed. Flow cytometry was used to assess the complement activation capacity of the drug antibodies in vitro. [Results] Direct antiglobulin tests (IgG and C3d) were positive. Ceftizoxime sodium drug-dependent antibodies were identified using both the immune complex method and the sensitized red cell method, their titers significantly increased following the addition of the drug. Flow cytometry confirmed the complement activation capability of these antibodies and identified 30 minutes as the optimal time for activation in vitro. The patient's condition improved rapidly after drug withdrawal and supportive transfusion, resulting in a favorable outcome. [Conclusion] Ceftizoxime sodium can cause drug-induced immune hemolytic anemia via complement activation mediated by drug-dependent antibodies. Serological testing is essential for diagnosing drug-induced hemolytic anemia. Clinicians should be vigilant for this adverse reaction. The offending drug must be promptly discontinued, and supportive care should be initiated upon the onset of symptoms.

[Objective] To systematically evaluate the lapse rate of voluntary blood donation in China, and to provide theoretical reference for blood centers to develop donor retention strategies. [Methods] Cross-sectional studies on the lapse rate of voluntary blood donation and its influencing factors, published between January 2015 and May 2024, were retrieved from the CNKI, Wanfang Data, VIP, PubMed, Web of Science and The Cochrane Library databases. Two reviewers independently screened the literature and extracted data, and Review Manager 5.4 software was used for meta-analysis. [Results] A total of 14 literature involving 428 343 lapsed blood donors were included. Meta-analysis showed that the overall lapse rate of blood donation in China was 47.0% [95% CI(33.0, 61.0)]; and age among 18 to 25[OR=1.40, 95% CI(1.02, 1.92)], no previous donation history [OR=4.54, 95% CI(2.13, 9.67)], relocation from the city of last donation [OR=2.89, 95% CI(1.13, 7.37)], low satisfaction [OR=1.80, 95% CI(1.42, 2.28)], adverse reactions [OR=1.92, 95% CI(1.07, 3.45)], and negative public opinion [OR=2.72, 95% CI(1.23, 6.02)] were the influential factors for blood donors. The sub group analysis results showed that the lapse rate of blood donation in China during different research period was 44.0%[95% CI (26.7, 62.4)] from 2017 to 2019 and 50.0%[95% CI(37.2, 63.1)] from 2020 to 2023; and the lapse rate of blood donors was 42.0%[95% CI(31.8, 52.8)] among platelet donors and 64.0%[95% CI(52.2, 83.2)] among whole blood donors. Sensitivity analysis suggests that the research results are stable, and the funnel diagram combined with Egger test and Begg' test shows that there is no publication bias. [Conclusion] The lapse rate of blood donation remains relatively high in China. Blood centers should take measures such as strengthening guidance for first-time blood donors, promoting refined services, implementing predictive interventions, and improving to monitor the social media to enhance blood donor's willingness for donating repeatedly and reduce the lapse rate of blood donors.

[Objective] To compare the efficacy of heat and acid elution methods for IgG anti-M and anti-Ku. [Methods] Ten samples with IgG anti-M and two samples with IgG anti-Ku were selected and standardized to a titer of 64. These antibodies underwent overnight absorption at 4℃ with O-type MM and kk-type erythrocytes, and then heat and acid elution methods were used on the absorbed sensitized erythrocytes respectively by detecting the titer of anti-M and anti-Ku in the eluate to compare the differences in the elution efficiency of IgG anti-M and anti-Ku between the two elution methods. [Results] In heat elution tests, all 10 anti-M samples showed positive results with titers ranging from 8 to 64, while 2 anti-Ku samples yielded negative results. In acid elution tests, all 10 anti-M samples demonstrated negative results, whereas both anti-Ku (n=2) samples exhibited positive reactions with consistent titers of 32. Following acid elution with subsequent heat elution, 8 of 10 anti-M samples showed positive results with titers ranging from 8 to 32, while 2 remained negative. Both anti-Ku samples demonstrated positive with titers of 4. [Conclusion] Heat elution demonstrated superior efficiency for IgG anti-M compared to acid elution, whereas acid elution showed greater efficacy for IgG anti-Ku than heat elution.

Objective To identify the phenotypes,antibodies and explore the molecular mechanisms of a patient who carries antibodies to RBC high-frequency antigens and his family members.Methods The antibody identification test was performed for the proband by serological methods,and targeted NGS was subsequently used to detect mutations that occurred in blood group genes.Blood samples were collected from the proband and his family members.Sanger sequencing was used to verify the mutation of the XK gene.The expression of Kell blood group antigens was detected by serological methods and flow cytometry.K0 cells were used to detect the antibody specificity of the proband.The morphology of red blood cells was detected by the scanning electron microscopy.The serum creatine kinase levels of the proband and his family members were analyzed by colorimetric methods.Results The results of the antibody identification test suggested that the proband might have antibodies to high-frequency antigens.NGS results suggested a homozygous mutation(c.107G＞A)in exon 1 of the XK gene in the proband,resulting in a truncated XK protein.The Sanger sequencing results of the proband were consistent with the NGS results,and the mutation was not found in other family members.The expression of Kell blood group antigens of the proband was not found by serological methods and flow cytometry.The results of the antibody specificity test showed that the proband had anti-Km antibodies.Spike-like changes were identified on red blood cells,and serum creatine kinase level was elevated in the proband.Conclusion In this study,the McLeod phenotype caused by homozygous mutation(c.107G＞A)of XK gene was identified in Chinese individuals for the first time by the phenotype and molecular mechanism studies.The results of genotyping and phenotyping suggested that the McLeod phenotype caused by the mutation was compatible with the phenotypes of McLeod and K0.