BACKGROUND

Pre-transfusion testing is done to avoid transfusion morbidity from unexpected RBC antibodies. Available commercial kits from Western brands may not consider racial differences in antibody frequencies between East/Southeast Asians and Western populations. The limited number of blood banks in the Philippines precludes research on RBC antibody screening and identification in the country.

This study aimed to compare RBC antibody screening and identification methods in patients at a tertiary hospital in the Philippines, assess the frequency of major blood group antibodies using both techniques, and review clinical histories of discrepant and nonspecific cases.

Retrospective review showed 118 cases with both screening and identification tests using both conventional tube-based technique and column agglutination or gel-based technique. Antibody frequencies and discrepant or nonspecific results were recorded. Concordance rates were calculated, and differences between the two methods were analyzed using 95% confidence interval (95% CI). Clinical histories of discrepant and nonspecific cases were also reviewed.

The most frequent major blood group was Rh (41 cases or 34.7%), followed by MNS (34 cases or 28.8%) and Kidd (15 cases or 12.7%). The most common antibody was Anti-E (24 cases or 20.3%), followed by Anti-Mia (19 cases or 16.1%), and Anti-M and Anti-c (12 cases each, or 10.2% each). The concordance rate for screening was statistically significant at 72%. Concordance rate for identification was 59.3%, with significant difference in identifying Anti-Mia. Clinical histories for discrepant or nonspecific cases showed previous transfusions, pregnancy, lymphoproliferative conditions, and certain medications.

Statistically significant differences between the two methods were found, with the gel-based technique identifying more Anti-Mia cases. Negative results from the tube-based method do not fully exclude Anti-Mia. These discrepancies highlight the benefit of using both methods for comprehensive RBC antibody screening and identification, done as a complement to the other.

OBJECTIVE: To confirm the HLA genotypes of the samples including 4 cases of magnetic bead probe HLA genotyping result pattern abnormality and 3 cases of ambiguous result detected by PCR sequence-specific oligonudeotide probe (SSOP) method. METHODS: All samples derived from HLA high-resolution typing laboratory were detected by PCR-SSOP. A total of 4 samples of magnetic bead probe HLA genotyping result pattern abnormality and 3 samples of ambiguous result were further confirmed by PCR sequence-based typing (SBT) technology and next-generation sequencing (NGS) technology. RESULTS: A total of 4 samples of magnetic bead probe HLA genotyping result pattern abnormality were detected by PCR-SSOP method. The results of SBT and NGS showed that the HLA-A genotype of sample 1 did not match any known genotypes. NGS analysis revealed that the novel allele was different from the closest matching allele A*31:01:02:01at position 154 with G>A in exon 2, which resulting in one amino acid substitution at codon 28 from Valine to Methionine (p.Val28Met). The HLA-C genotype of sample 2 was C*03:119, 06:02, sample 3 was C*03:03, 07:137, and sample 4 was B*55:02, 55:12. A total of 3 samples with ambiguous result were initially detected by PCR-SSOP method. The re-examination results of SBT and NGS showed that the HLA-B genotype of sample 5 was B*15:58, 38:02, sample 6 was DRB1*04:05, 14:101, and sample 7 was DQB1*03:34, 05:02. Among them, alleles C*03:119, C*07:137 and DRB1*14:101 were not included in the Common and Well-documented Alleles (CWD) v2.4 of the Chinese Hematopoietic Stem Cell Donor Database. CONCLUSION The abnormal pattern of HLA genotyping results of magnetic probe by PCR-SSOP method suggests that it may be a rare allele or a novel allele, which needs to be verified by sequencing.
Humans ; Alleles ; Polymerase Chain Reaction ; Genotype ; High-Throughput Nucleotide Sequencing ; Histocompatibility Testing/methods* ; Technology

OBJECTIVE: To establish a based method flow cytometry to identify the antigen Jka in human red blood cells (RBCs) and verify its accuracy. METHODS: A total of 96 blood samples were enrolled in the study randomly from the voluntary blood donors in Shenzhen Blood Center. The RBCs were incubated with IgG anti-Jka primary antibody, and then labeled with the secondary antibody anti-IgG-Alexa Fluor 647. The fluorescence histograms of each sample were obtained by flow cytometry. Serological agglutination test was used to compare the accuracy of flow cytometry in the detecting of antigen Jka, while PCR-SSP and gene sequencing genotyping were used to verify the accuracy of flow cytometry in the detecting of the antigen in human RBCs. RESULTS: The results of flow cytometry for antigen Jka in human RBCs were consistent with those from serological tests. Samples that demonstrated higher serological agglutination intensity also showed higher fluorescence activity, which indicate more stronger of Jka antigen. The sensitivity of flow cytometry was higher than that of serological test; especially in distinguish Jka weak and negative samples. Flow cytometric results of all samples were consistent with the genotyping results, which confirmed the accuracy of flow cytometry. CONCLUSION The study established a new flow cytometry-based method successfully for the identification of Jka antigen of Kidd blood group in human RBCs. The Kidd blood group antigen Jka of different intensities can be accurately distinguished by the technique.
Blood Group Antigens ; Blood Grouping and Crossmatching ; Erythrocytes ; Flow Cytometry ; Humans ; Immunoglobulin G ; Kidd Blood-Group System

The ABO blood group system is the most important blood group system in clinical transfusion. Serological technology is a routine method for the identification of ABO blood groups, however, which have some limitations in the identification of complicated ABO samples with weakened antigens or antibodies, abnormal plasma proteins, polyagglutination, or cold agglutinin, etc. With the development of molecular biology technology, ABO blood group gene was cloned, and ABO blood group genotyping technology based on DNA was established. The genotyping technologies with different throughputs such as PCR-SSP, Droplet-AS-PCR, PCR-RFLP, PCR-SBT, SNaPshot, MALDI-TOF MS and NGS have emerged. Genotyping has overcome the limitations of serology, and has become an indispensable method to solve difficult blood type, providing strong support for the correct identification of ABO blood group, and providing guarantee for precision blood transfusion. This review summarizes the progress and application of ABO blood group genotyping methods.
ABO Blood-Group System/genetics* ; Blood Grouping and Crossmatching ; Genotype ; Humans ; Polymerase Chain Reaction/methods* ; Technology

OBJECTIVE: To identify and analysis three ABO variant Bw subtypes. METHODS: Serological assays were carried out to identify the ABO blood group of the proband. ABO gene was identified by Sanger sequencing. RESULTS: The genotype of three individuals are ABO*Bw.11/0.01.02, ABO*Bw.12/0.01.01, ABO*Bw.34/A1.02, receptively. Sequencing results showed that there were c.695T>C, c.278C>T, c.889G>A, resulting in variants in Leu232Pro, Pro93Leu and Glu297Lys, receptively. CONCLUSION Bw11, Bw12 and Bw34 subgroups were identified, and gene testing can be used as a supplement to determine the ABO blood group subtypes.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Exons ; Genotype ; Humans ; Phenotype ; Sequence Analysis

OBJECTIVE: Through analysis of ABO blood group gene typing technology, to assist in the identification of difficult clinical serological specimens. METHODS: A total of 10 forwardreverse typing ambiguous samples were collected from January 2021 to August 2021 in our hospital.ABO genotypes were analysed by gene sequencing. RESULTS: The genotypes of 10 ABO ambiguous blood group samples were A102/BW11, A102/BW12, O02/O02, A102/B303, A102/B101, BW11/O02, B101/O04, BW11/O01, BW11/O01, A101/O02, respectively. The genotype results of 6 cases was consistent with the serological phenotype, and the serological phenotype of 4 cases were different from the geno sequencing. CONCLUSION ABO blood groups genotyping technology combined with serological typing can be used for accurate typing of ambiguous blood group, and better ensure the safety of blood transfusion.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Exons ; Genotype ; Phenotype

OBJECTIVE: To investigate the effectiveness and safety of low concentration dithiothreitol (DTT) in removing the interference of monoclonal anti-CD38 on transfusion compatibility testing, and develop a reasonable clinical transfusion strategy. METHODS: The blood type, direct antiglobulin testing (DAT) and antibody screening were tested according to standard methods. Antibody screening cells and donor's red blood cells were treated by DTT 0.2, 0.1, 0.05, 0.02, 0.01 and 0.005 mol/L, and antibody screening and cross-matching of serums after monoclonal anti-CD38 treatment were performed by anti-human globulin card. RESULTS: The 0.01 mol/L DTT at 37℃ for 30 minutes could remove the effect of monoclonal anti-CD38 on antibody screening and cross-matching, meanwhile retain their effectiveness in detecting anti-K, anti-LW, anti-JMH, anti-Lu^b, anti-e, anti-Di^a and anti-Jk^a alloantibodies. All the 10 patients had no acute or delayed haemolytic transfusion reactions and their routine blood tests showed that the red blood cells transfusion was effective. CONCLUSION The 0.01 mol/L DTT is a safe and effective method for removing the interference of monoclonal anti-CD38 with transfusion compatibility testing, while retaining the ability to detect most alloantibodies.
Antibodies, Monoclonal/pharmacology* ; Blood Grouping and Crossmatching ; Blood Transfusion ; Dithiothreitol/pharmacology* ; Erythrocytes ; Humans ; Isoantibodies/pharmacology*

OBJECTIVE: To identify the ABO positive and negative stereotypic inconsistencies in a dizygotic twin with positive stereotypic patterns and mixed agglutination, and explore the application of serological characteristics and gene sequence in congenital blood group chimeras. METHODS: ABO blood group identification, Rh and MN typing were performed using the microcolumn gel method and ABO genotyping was performed using the PCR-SSP method. RESULTS: In this patient, both anti-A and anti-B tubes had mixed hemagglutination of red blood cells, and the anti-ABO tube was AB type. The Rh typing of the patient was CcDEe. Mixed agglutination of red blood cells was observed in both anti-M and anti-N tubes in MN typing. The patient's father and mother was normal Type O and AB, respectively. There were three alleles in the ABO gene of the patient, O0101 came from his father, while A102 and B01 came from his mother. CONCLUSION The patient has two groups of red blood cells (type A and B). Because the patients is a dizygotic twin, these two groups of red blood cells can be chimeras formed by blood exchange between the twins. Through gene sequencing, it can be determined that the patient is a congenital A/B blood type chimera.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Genotype ; Humans ; Polymerase Chain Reaction

OBJECTIVE: Three cases of rare alleles of HLA-C with zero mismatched PCR-SBT results were analyzed by full-length sequencing to determine the true genotypes. METHODS: Three rare HLA-C alleles with zero mismatched PCR-SBT results were screened from clinical transplant matching samples, and the full-length sequence was detected by next-generation sequencing technology. RESULTS: The results of PCR-SBT typing of 3 samples were: HLA-C*03:04, 12:167; HLA-C*07:291, 15:02; HLA-C*01:43, 08:16. Other alleles were not in the CWD table of common and confirmed HLA alleles in China (version 2.3) except common allele HLA-C*03:04, HLA-C*15:02. NGS full-length sequencing revealed that the HLA-C genotypes of the three samples were a combination of common alleles and novel alleles, and the three novel alleles had a base mutation in exons 6, 2, and 4, respectively. The novel allele sequences have been submitted to the Genbank database (MK629722, MK335474, MK641803), which were officially named HLA-C*03:04:74, HLA-C*15:192, HLA-C*08:01:25 by the WHO HLA Nomenclature Committee. The HLA high-resolution typing results of 3 samples were: HLA-C*03:04:74, HLA-C*12:03; HLA-C*07:02, HLA-C*15:192; HLA-C*01:02, HLA-C*08:01:25. CONCLUSION HLA typing results containing rare alleles should be treated cautiously, and the full-length sequence should be verified by NGS or cloning. The laboratory finally confirmed that the 3 cases of PCR-SBT zero mismatch HLA-C genotypes are the combination of common alleles and novel alleles by NGS sequencing, which provides an accurate basis for clinical transplantation matching and enriches the human HLA genetic database.
Alleles ; Genotype ; HLA-C Antigens/genetics* ; High-Throughput Nucleotide Sequencing ; Histocompatibility Testing/methods* ; Humans ; Polymerase Chain Reaction/methods* ; Sequence Analysis, DNA

OBJECTIVE: To analyze the molecular characteristics of a recombinant allele of the ABO blood group. METHODS: The ABO phenotype was determined with the tube method. The coding regions of the ABO and FUT1 genes were analyzed by PCR-sequence based typing. The ABO alleles of the proband were determined by allele-specific primer sequencing. The full sequences of the ABO gene of the proband and her mother were determined through next generation sequencing. RESULTS: The red blood cells of the proband did not agglutinate with anti-H, and the sequence of the FUT1 gene was homozygous for c.551_552delAG.The proband was thereby assigned as para-Bombay. Bi-directional sequencing also found that she was heterozygous for c.261G/del,467C>T,c.526C>G,c.657C>T,c.703G>A,c.796C>A,c.803G>C and c.930G>A of the coding regions of the ABO gene. Allele-specific primer sequencing also found her to carry a ABO*A1.02 allele and a recombinant allele from ABO*O.01.01 and ABO*B.01. The recombination site was located between nucleotide c.375-269 and c.526, and the allele was maternally derived. CONCLUSION An recombinant allele of the ABO gene has been identified, which has originated from recombination of ABO*O.01.01 with the ABO*B.01 allele.
ABO Blood-Group System/genetics* ; Alleles ; Blood Grouping and Crossmatching ; Female ; Fucosyltransferases/genetics* ; Genotype ; Humans ; Phenotype ; Recombination, Genetic