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Objective:To investigate the molecular biological mechanism of Bw07 allele and its transferase alteration carried by a proband of ABw07 subtype.Methods:A 2-year-old male child was selected as the research object. The peripheral blood of the proband and his parents was identified for ABO blood type by the test tube method, and the ABO subgroup PCR-SSP detection and ABO gene sequencing were performed on the three individuals to determine their blood type genotypes. Finally, the effect of the p.Arg352Gln mutation on Bw07 transferase was verified by virtual mutation, DUET structure prediction, molecular dynamics analysis, and in vitro cellular experiments.Results:The serological phenotypes of the proband and his mother were ABw and Bw, respectively, while his father was normal A. The ABO subgroup PCR-SSP assay identified the three genotypes as Bw07/A, Bw07/O, and A/A, respectively.Sanger sequencing further verified that the proband and his mother carried the Bw07 gene, and virtual mutation showed that the intermolecular forces were weakened by the R352Q mutation. DUET predicted that this p.Arg352Gln mutation could affect the thermodynamic stability of Bw07 transferase. Molecular dynamics analysis confirmed that the alteration of thermodynamic stability was mainly related to the appearance of large fluctuations in the amino acid backbone atoms in the 125-133, 193-198 and 336-354 regions, and in vitro cellular experiments further verified the weakened antigen synthesis of Bw07 transferase.Conclusion:The formation of the ABw07 phenotype is associated with the mutation of the highly conserved Arg352 to Gln in Bw07 transferase.
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【Objective】 To statistically analyze the perioperative results of patients with ABO-incompatible kidney transplantation (ABOi-KT), in order to explore the changes in blood group antibody of type-A/B recipients. 【Methods】 A total of 33 cases of blood group A/B ABOi-KT recipients in our hospital from January 2021 to October 2023 were recruited and divided into two groups of group A(n=18) and group B(n=15) according to the different blood types of recipient. The effects of preoperative plasmapheresis on antibody titer, antibody rebound and renal function after operation(serum urea nitrogen, creatinine and estimated glomerular filtration rate on the 1st, 3rd, 7th and 14th day) were analyzed between the two groups. According to the postoperative rebound of blood type antibodies, 33 recipients were divided into antibody rebound group(n=7) and non rebound group(n=26), and the differences in initial blood type antibody titers between the two groups were analyzed. 【Results】 There was no significant difference in the clearance rate of IgM with preoperative plasma exchange between the two groups (Z=-0.26, P>0.05); Levels of serum urea nitrogen and creatinine on the 1st, 3rd, 7th and 14th day after operation between group A and group B were not statistically significant(P>0.05), the same as eGFR. Group B was more prone to rebound antibody compared with group A (P0.05) between the two groups was found. 【Conclusion】 The patients type B receiving type AB kidney donors are more prone to rebound antibody after ABOi-KT operation compared to the the patients type A receiving type AB.
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【Objective】 To explore the impact of monoclonal anti-CD47(IBI188) on clinical pre-transfusion testing and its solutions, then compare it with monoclonal anti-CD38, so as to develop safe and rational transfusion strategies. 【Methods】 The blood typing, direct antiglobulin testing(DAT) and antibody screening were conducted by standard methods. Red blood cells(RBCs) were treated with fig protease, papain, trypsin and dithiothreitol(DTT) to observe whether the effect of monoclonal anti-CD47 could be eliminated. Cord RBCs and RBCs with different Rh phenotypes were cross-matched; Plasma samples were adsorbed with papain-treated O allogeneic RBCs. 【Results】 ABO reverse typing were affected by monoclonal anti-CD47 treatment, and all serum antibody screening were positive, and their DAT were negative or weakly positive. Neither enzyme nor DTT could weaken the effect of monoclonal anti-CD47 on antibody screening. In saline cross-matching, differences in agglutination intensity were corresponded to differences in CD47 expression on RBCs, but all RBCs agglutinated 2+ to 4+ by polybrene method and anti-human globulin method. Papain treated allogeneic RBCs can remove the monoclonal anti-CD47 in the serum through 3 to 4 rounds of absorption. 【Conclusion】 Monoclonal anti-CD47 interferes with pre-transfusion testing, which can be removed by allogeneic RBCs absorption(not suitable for antibody screening or cross-matching), but not by enzyme or DTT. Blood typing and antibody screening should be conducted before monoclonal anti-CD47 treatment and patients should be transfused with homozygous matched RBCs.
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【Objective】 To explore a simple method to remove the interference of monoclonal anti-CD38 from compatibility testing and evaluate its effectiveness and safety, in order to develop a reasonable clinical transfusion strategy. 【Methods】 Blood phenotype detection, direct antiglobulin testing(DAT) and antibody screening were carried out by standard methods. Antibody screening and cross-matching of serums after monoclonal anti-CD38 treatment were performed by anti-human globulin card with 0.2 mol/L or 0.04 mol/L dithiothreitol(DTT) treated red blood cells. 【Results】 The results showed that 0.04 mol/L DTT treated directly in the anti-human globulin card for 15 min can completely remove the interference of monoclonal anti-CD38 in antibody screening and cross-matching without compromising of the yielding of anti-K, anti-LW, anti-JMH and anti-Lub alloantibodies. However, the titer of IgM antibodies may decrease in different degrees, and antibody screening and cross-matching with saline methods are required to avoid the missed detection of IgM alloantibodies. All 12 patients had no acute or delayed haemolytic transfusion reactions and their routine blood tests showed that the red blood cells transfusion were effective. 【Conclusion】 Based on antibody screening and cross-matching plus saline method, the method of 0.04 mol/L DTT, treated directly in the anti-human globulin card, is safe, effective and simple, which can detect most alloantibodies.
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OBJECTIVE@#To explore the molecular basis for an A subtype of the ABO blood group.@*METHODS@#The forward and reverse typing of the ABO blood group were identified by gel card and test tube methods. The ABO gene of the patient was detected by PCR-sequence specific primer (PCR-SSP). Exons 1 to 7 of the ABO gene was amplified by PCR and sequenced. The ABO gene was also subjected to subclone sequencing for haplotype analysis.@*RESULTS@#The patient's red cells showed weak agglutination with anti-A but non-agglutination with anti-B. The patient's serum showed 1+ agglutination with A cells and 4+ agglutination with B cells. Based on above serological characteristics, the patient was defined as Aw subtype of the ABO blood group. Sequencing analysis showed that the patient was heterozygous for c.106G>T, c.188G>A, c.189C>T, c.220C>T, c.297A>G, c.467C>T, c.543G>C, c.646T>A, c.681G>A, c.771C>T, c.829G>A, in addition with a c.261G deletion. Combined with the result of subclone sequencing, the ABO genotype of the patient was determined as ABO*AW.33. new/O.01.02, which harbored c.467C>T and c.543G>C variants compared with ABO*A1.01 and c.543G>C variant compared with ABO*A1.02. The novel allele has been submitted to GenBank with an accession number of MK302122.@*CONCLUSION@#A novel allele of Aw33 subtype has been identified with its GTA transferase gene harboring c.467C>T and c.543G>C variants compared with A1.01.