Objective: To analyze the serological phenotypes and molecular genetic characteristics of a proband with ABO forward and reverse typing discrepancy and their family members, and to investigate the molecular genetic mechanism underlying the Ael/AelB phenotype caused by the c. 575T>C variant on an ABO A1.02 background. Methods: Serological testing and adsorption-elution assays were performed for blood group identification of the proband and family members. PCR-SBT, cloning sequencing, and Nanopore third-generation sequencing were used to analyze ABO gene variants and haplotypes. Phyre2 and PyMOL were used to predict the effect of the p. Ile192Thr variant on the structure of glycosyltransferase A (GTA), and plasma GTA activity was evaluated using an in vitro transferase assay. Results: Among thirteen family members, four members showed a serological phenotype consistent with the Ael subtype and one with the AelB subtype. Cloning sequencing and third-generation sequencing confirmed that five family members carried the ABO A1.02 (c. 575T>C) variant, which co-segregated with the weak A phenotype in the family. Structural modeling suggested that p. Ile192Thr may alter the local spatial conformation and hydrogen-bond interactions of GTA. Plasma GTA activity testing showed markedly reduced GTA activity in the tested individuals. Conclusion: The ABO A1.02 (c. 575T>C) variant is associated with the Ael/AelB phenotype. The p. Ile192Thr substitution may weaken A antigen expression by altering GTA conformation and reducing enzymatic activity. This study provides additional evidence for the role of this variant in the Ael/AelB phenotype from the perspectives of familial inheritance, full-length haplotype analysis, and functional assessment, which is important for accurate ABO subtype identification and individualized transfusion strategies.

Objective To systematically evaluate the risk factors associated with the occurrence of nosocomial infections(NI)in patients undergoing extracorporeal membrane oxygenation(ECMO)support.Methods A computerized systematic search was performed aross the Chinese databases including CNKI,Wanfang Database,China Biomedical Literature Database(CBMdisc),and Weipu,as well as the English databases such as PubMed,EMBase,Web of Science,and the Cochrane Library for case-control or cohort studies on the risk factors of hospital-acquired infections in patients undergoing ECMO support from the time of database construction to February 2023.The relevant literatures were screened by two researchers independently.Meta-analysis was performed using RevMan 5.4 software.Results A total of 20 papers,including 2 746 patients and 16 risk factors,were included.Meta-analysis results showed that older age[>50 years:odds ratio(OR)= 2.87,95％ confidence interval(95％ CI)was 1.24-6.63,P = 0.01;>65 years:OR = 1.66,95％ CI was 1.22-2.26,P = 0.001],combined hypertension(OR = 1.48,95％ CI was 1.01-2.15,P = 0.04),combined diabetes mellitus(OR = 1.40,95％ CI was 1.02-1.94,P = 0.04),sequential organ failure assessment(SOFA)was higher(OR = 1.06,95％ CI was 1.02-1.10,P = 0.000 7),the installation of ECMO in the intensive care unit(ICU,OR=1.48,95％ Ciwas 1.11-1.99,P=0.008),ECMO course(OR=1.27,95％ Ciwas 1.05-1.54,P = 0.01),ventilator-assistance for >48 hours(OR = 4.91,95％ CI was 2.40-10.05,P<0.000 1),and tracheotomy(OR = 9.56,95％ CI was 3.60-25.35,P<0.000 01)were identified as ECMO risk factors for hospital-acquired infections in patients.Conclusion Older age,combined hypertension,diabetes mellitus,higher SOFA,ECMO installation site in ICU,ECMO course,ventilator assistance>48 hours,tracheotomy are the risk factors for the occurrence of hospital-acquired infections in patients with ECMO,healthcare professionals should promptly identify the risk factors related to hospital-acquired infections,and take active and effective measures against controllable risk factors,including early intervention to prevent the occurrence of NI in ECMO patients.