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Treating red blood cells (RBCs) with dithiothreitol (DTT) is a wildly-recommended to overcome the interference of the daratumumab (DARA) with blood compatibility testing. Nevertheless, DTT can be hard to obtain in the clinical laboratory, while its use in routine practice may be time-consuming. In the following study, we explored the feasibility of using a commercial 2-mercaptoethanol (2-ME) working solution or the time-saving Polybrene method to mitigate DARA interference.Antibody screening and cross-matching were performed using 2-ME or DTT-based indirect antiglobulin tests (IATs) and Polybrene method (with human IgG anti-E same IATs titer as DARA as positive control) on 37 samples. Most clinically important blood group antigens on RBCs were detected after treatment with 2-ME or DTT.Treating RBCs with 2-ME eliminates the DARA interference with the antibody screening or cross-matching; yet, K antigen is denatured during treatment. DARA does not interfere with antibody screening and cross-matching via Polybrene method, while 2+ agglutinations of anti-E antibody with the same titer (IATs method) as DARA could be observed in the positive controls via this method.2-ME-based IATs or Polybrene method could replace DTT-based IATs to mitigate DARA interference.

Background Treating red blood cells (RBCs) with dithiothreitol (DTT) is a wildly-recommended to overcome the interference of anti-CD38 immunotherapy with blood compatibility testing. Nevertheless, DTT can be hard to obtain in clinical laboratory, while its use in routine practice may be time-consuming. In the following study, we explored the feasibility of using a commercial 2-mercaptoethanol (2-ME) working solution or the time-saving polybrene method to mitigate the daratumumab (DARA) interference. Materials and Methods Antibody screening and cross-matching were performed using 2-ME or DTT-based indirect antiglobulin tests (IATs) and polybrene method (human IgG anti-E same IATs titer as DARA as positive control) on 37 samples, and these samples were from patients enrolled in the “Several methods resolve the interference of anti-CD38 monoclonal antibody on blood compatibility tests” clinical trial (www.chictr.org.cn identifier: ChiCTR2000040761). Most clinically important blood group antigens on RBCs were detected after treatment with 2-ME or DTT. Hemoglobin values were compared after 69 units RBCs were transfused with compatible cross-matching results by a 2-ME-based method or polybrene test. Results Treating RBCs with 2-ME eliminates the DARA interference with the antibody screening or cross-matching; yet, K antigen is denatured during treatment. DARA with 2+ agglutinations of anti-E control does not interfere with antibody screening and cross-matching via polybrene method. After RBCs transfusion with a negative cross-matching test by 2-ME-based IATs or polybrene method, hemoglobin significantly increased without adverse transfusion reactions. Conclusion 2-ME-based IATs or polybrene method could be used to mitigate DARA interference as DTT.

BACKGROUND: A weak ABO subgroup is one of the most important causes of an ABO blood grouping discrepancy. Here, we investigated the distribution of weak ABO subgroups in the Chinese population and identified ten novel weak ABO subgroup alleles. MATERIAL AND METHODS: We performed phenotype investigations by serological studies, analysed the DNA sequence of the ABO gene by direct sequencing or sequencing after cloning, and evaluated the role of glycosyltransferase mutations by in silico analysis and in vitro expression assay. RESULTS: Three hundred and fifty-one individuals with a weak ABO subgroup were detected among 1.45 million blood-typed subjects. Ten novel weak ABO subgroup alleles were identified. Molecular modelling and analysis of GTA mutation p.L339P suggested that the mutation may change the local conformation of GTA and reduce its stability. The in vitro expression assay showed that A antigen expression and agglutination of HeLa cells transfected with GTA mutant p.L339P decreased significantly compared to those of cells transfected with wild-type GTA. CONCLUSION: Ten novel weak ABO subgroup alleles were identified in the Chinese population. GTA mutant p.L339P may lead to a weak A phenotype by changing the local conformation of GTA and reducing its stability.

Background The impact of hyperfibrinogenemia on short-term outcomes after acute ischemic stroke (AIS) is still not well understood. Objective We investigated the association between hyperfibrinogenemia upon hospital admission and the short-term prognosis of AIS patients. Methods A total of 3,212 AIS patients enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city were included in the present study. Hyperfibrinogenemia was defined as having a serum fibrinogen＞4.0g/L. Cox proportional hazard and logistic regression models were used to estimate the effect of hyperfibrinogenemia on all-cause in-hospital mortality and poor discharge outcome (modified Rankin Scale score≥3) in AIS patients. Results During hospitalization, 106 patients (3.3%) died from all-cause and 1226 (38.2%) patients experienced poor functional outcome at discharge. Multivariable model adjusted for age, sex, baseline National Institutes of Health Stroke Scale score, white blood cell count and other covariates, showed that hyperfibrinogenemia was associated with a 1.76-fold increase in the risk of in-hospital mortality (hazard ratio [HR] 1.76; 95% confidence interval [CI], 1.10-2.81; P-value=0.019). However, there was no significant association between hyperfibrinogenemia and poor outcome at discharge (adjusted odds ratios[OR]1.15; 95% CI 0.86-1.53; P-value=0.338). Sensitivity and subgroup analyses also confirmed a significant association between hyperfibrinogenemia and in-hospital mortality. Conclusion In patients with AIS, hyperfibrinogenemia at the time of admission was independently associated with increased in-hospital mortality.

Background Identifying genetic variants of the ABO gene may reveal new biologic mechanisms underlying variant phenotypes of the ABO blood group. We report the molecular genetic analysis of 322 apparently unrelated ABO subgroup individuals in an estimated 2.1 million donors. Study Design and Methods We performed phenotype investigations by serology studies, analyzed the DNA sequence of the ABO gene by direct sequencing or sequencing after cloning, and evaluated promoter activity by reporter assays. Results In 62 rare ABO alleles, we identified 29 novel ABO subgroup alleles in 43 apparently unrelated subgroup individuals and their four available pedigrees. Of these alleles, one was a deletion-mutation allele, four were hybrid alleles, and 24 were point-mutation alleles. Most of the point mutations were detected in Exons 6 to 7, while several others were also detected in Exons 1 to 5 or splicing regions. One ABO promoter mutation, −35 to −18 del, was found and verified to reduce promoter activity, as determined by dual luciferase assays. Two mutations, 7G>T and 52C>T, carrying the premature terminal codons E3X and R18X in the 5′-region, were found to be associated with the very weak ABO subgroups “Ael” and “Bel.” Conclusion Twenty-nine ABO subgroup alleles were newly linked to different kinds of ABO variations. We provide the first evidence that promoter abnormality is involved in the formation of weak ABO phenotypes. We also described the first naturally occurring ABO alleles with premature terminal codons in the 5′-region that led to Ael and Bel phenotypes.

Identifying genetic variants of the ABO gene may reveal new biologic mechanisms underlying variant phenotypes of the ABO blood group. We report the molecular genetic analysis of 322 apparently unrelated ABO subgroup individuals in an estimated 2.1 million donors.We performed phenotype investigations by serology studies, analyzed the DNA sequence of the ABO gene by direct sequencing or sequencing after cloning, and evaluated promoter activity by reporter assays.In 62 rare ABO alleles, we identified 29 novel ABO subgroup alleles in 43 apparently unrelated subgroup individuals and their four available pedigrees. Of these alleles, one was a deletion-mutation allele, four were hybrid alleles, and 24 were point-mutation alleles. Most of the point mutations were detected in Exons 6 to 7, while several others were also detected in Exons 1 to 5 or splicing regions. One ABO promoter mutation, -35 to -18 del, was found and verified to reduce promoter activity, as determined by dual luciferase assays. Two mutations, 7GT and 52CT, carrying the premature terminal codons E3X and R18X in the 5'-region, were found to be associated with the very weak ABO subgroups "Ael" and "Bel."Twenty-nine ABO subgroup alleles were newly linked to different kinds of ABO variations. We provide the first evidence that promoter abnormality is involved in the formation of weak ABO phenotypes. We also described the first naturally occurring ABO alleles with premature terminal codons in the 5'-region that led to Ael and Bel phenotypes.

BACKGROUND: Bx is a very rare ABO blood group phenotype and the molecular mechanism underlying it still remains largely unknown. This study reports two novel Bx alleles in two Chinese individuals. STUDY DESIGN AND METHODS: Serologic investigations including serum transferase activity assay were performed with standard methods. DNA sequences of all seven exons and exon-intron boundaries of ABO gene were analyzed using genomic DNA by polymerase chain reaction and direct DNA sequencing or sequencing after gene cloning. RESULTS: Bx phenotypes were diagnosed in these two individuals. DNA analysis revealed that the ABO gene of the two Bx individuals was heterozygous of O01/B alleles. Two novel heterozygous mutations 905A>G and 541T>C were identified, respectively, which resulted in the amino acid changes D302G and W181R in the B glycosyltransferases. The mutations were not found in 120 randomly selected samples. CONCLUSION: Amino acid substitutions resulted from novel mutations 905A>G and 541T>C on ABO gene change highly conserved regions of the enzyme and may reduce the activity of the glycosyltransferases, leading to the Bx phenotype.