An update to Kidd blood group system

Since publication of the original Immunohematology review of the Kidd blood group system in 2015 (Hamilton JR. Kidd blood group system: a review. Immunohematology 2015;31:29-34), knowledge has mushroomed pertaining to gene structure, alleles causing variant and null phenotypes, clinical significance in renal transplant and hemolytic disease of the fetus and newborn, and physiologic functions of urea transporters in non-renal tissues. This review will detail much of this new information.

Two new JK silencing alleles identified by single molecule sequencing with 20-Kb long-reads

BACKGROUND

The Kidd blood group gene SLC14A1 (JK) accounts for approximately 20 Kb from initiation codon to stop codon in the genome. In genomic DNA analysis using Sanger sequencing or short-read-based next generation sequencing, it is difficult to determine the cis or trans positions of single nucleotide variations (SNVs), which are occasionally more than 1 Kb away from each other. We aimed to determine the complete nucleotide sequence of a 20-Kb genomic DNA amplicon to characterize the JK allelic variants associated with Kidd antigen silencing in a blood donor.

STUDY DESIGN AND METHODS

The Jk(a-b-) phenotype was identified in this donor by standard serological typing. A DNA sample obtained from whole blood was amplified by long-range PCR to obtain a 20-Kb fragment of the SLC14A1 gene, including the initiation and stop codons. The fragment was then analyzed by Sanger sequencing and single-molecule sequencing. Transfection and expression studies were performed in CHO cells using the expression vector construct of JK alleles.

RESULTS

Sanger sequencing and single-molecule sequencing revealed that the donor was heterozygous with JK*01 having c.276G>A (rs763262711, p.Trp92Ter) and JK*02 having c.499A>G (rs2298719, p.Met167Val), c.588A>G (rs2298718, p.Pro196Pro), and c.743C>A (p.Ala248Asp). The two JK alleles identified have not been previously described. Transfection and expression studies indicated that the CHO cells transfected with JK*02 having c.743C>A did not express the Jkb and Jk3 antigens.

CONCLUSIONS

We identified new JK silencing alleles and their critical SNVs by single-molecule sequencing and the findings were confirmed by transfection and expression studies.

High-Throughput Next-Generation Sequencing of the Kidd Blood Group: Unexpected Antigen Expression Properties of Four Alleles and Detection of Novel Variants

Background

The blood supply for patients with foreign ethnic backgrounds can be challenging, as they often have blood group and HPA patterns that differ from the variants prevalent in the German population. In addition, hemoglobinopathies requiring regular blood transfusion may be more common in such populations. High-throughput genotyping tests can facilitate the identification of the most compatible blood products, thereby reducing the risk of transfusion reactions. The present study reports the results of a molecular study for the Kidd (JK) blood group. Allele frequencies and antigen prevalence data are presented for >8,000 individuals of various origins.

Material and Methods

More than 8,000 blood donors were genotyped for 22 blood group systems and 5 HPA genes using an amplicon-based next-generation sequencing (NGS) approach. As part of the test system, we focused on the JK system in more detail. Double-ARMS PCR analysis was performed for the haplotype phasing of the JK1/JK2 and two more common synonymous polymorphisms. We performed transcript analysis to detect potential alternative splice products. For a subset of samples, a comparison between serotype and red cell genotype was conducted. Allele frequencies were determined for geographically different panels of individuals.

Results

We successfully genotyped the JK blood group for 99.6% of the samples. Haplotype phasing revealed 96 different alleles. For several alleles that carry one of the synonymous SNVs c.588A>G and c.810G>A, we could not confirm the reported JK phenotypes. We found a higher frequency of JK:1 alleles for all populations except Iraqis. JK*01W.01 alleles were more common in the Asian groups and sub-Saharan Africans. A variant of the allele JK*02N.01 was present exclusively in Southeast Asians.

Conclusion

Genotyping for JK antigens with a targeted NGS assay can easily be performed in routine. The interpretation that c.588A>G leads to a weak phenotype and c.810G>A to a null phenotype is questionable. IDs as well as the descriptions of alleles carrying these SNVs should be revised in the ISBT JK table.

The frequencies of Kidd blood group antigens and phenotypes among Saudi blood donors in Southwestern Saudi Arabia

BACKGROUND

The patients who require transfusion are prevalent in the Jazan Province, Saudi Arabia. Therefore, it is essential to know the frequency of blood group antigens in such a population. The Kidd blood group system (JK) has two antithetical antigens, Jka and Jkb. Antibodies to these antigens may result in delayed hemolytic transfusion reactions. The present study investigated the frequencies of Jka and Jkb and the phenotypes among Saudi blood donors living in the Jazan Province.

METHODS

One hundred and forty-three samples from anonymous Saudi volunteer blood donors in the Jazan Province were serotype to detect Jka and Jkb using gel card technology and determine the phenotypes of the JK blood group system.

RESULTS

The prevalence of Jka and Jkb antigens were 90.64% (n = 126) and 69.40% (n = 93), respectively. The JK phenotypes were 34.96% Jk(a + b - ) (n = 51), 12.59% Jk(a - b + ) (n = 18), 52.45% Jk(a + b + ) (n = 75), and 0% Jk(a - b - ). The frequencies of the JK phenotypes in the Jazan population were significantly different from those in the Asian population (P < 0.05).

CONCLUSIONS

We reported the frequencies of the Jka and Jkb antigens and the distribution of the JK phenotypes in a group of Saudi blood donors in the Jazan Province, Saudi Arabia. The phenotype Jk(a + b + ) was the most common among the study population. Furthermore, this study emphasizes the significance of identifying the frequency of JK antigens and phenotypes in the provinces of Saudi Arabia.

Different Types of Minor Blood Group Incompatibility Causing Haemolytic Disease of Neonates in one of the National Children's Medical Centre in China

Purpose

To review the neonatal cases with different types of minor blood group incompatible haemolytic diseases in China, and to improve the clinical understanding and management.

Materials and Methods

Seven cases from January, 1st, 2013 to December 31st, 2019 were searched out and reviewed retrospectively. All clinical data and laboratory findings were collected.

Results

There were totally seven cases enrolled including three cases of MNS, three of Diego, and one of Kidd combined with Rh, anti-RhE incompatibility. Among the seven cases, two had intrauterine transfusion, two underwent exchange transfusion, five received intravenous immune globulin, five cases developed anaemia, and three of them had transfusion. But among them, only four were found to have positive antibody screening and three were confirmed HDN with antibody types antenatally.

Conclusion

The clinical presentation is diverse. Antibody screening followed by the technique of peak systolic velocity in the fetal middle cerebral artery (MCA-PSV) helps to filter out the severe cases.

Kidd Blood Group Genotyping for Thalassemia Patient in Iran

We aimed to determine the JK genotype in thalassemia patients from Iran using different molecular methods to compare with phenotyping results. We also aimed to standardize for the first time, the Tetra-Primer ARMS PCR method for JK genotyping. The serology method cannot correctly determine the phenotype of blood group antigens in patients with multiple blood transfusions. Peripheral blood samples were taken from two hundred alloimmunized thalassemic patients in Tehran Adult Thalassemic Clinic. The samples were tested phenotypically by routine serological methods. After DNA Extraction, SSP-PCR was performed. DNA sequencing and PCR-RFLP were used to confirm the SSP-PCR results. Discrepancies were found between the phenotype and genotype in 32 out of 200 cases. In 16 cases phenotype was determined as Jk (a + b +) but genotype was JK*A/JK*A, in 14 cases phenotype was Jk (a + b +) while the genotype showed JK*B/JK*B, 1 case had been phenotyped as Jk (a + b -) but it was genotyped as JK*A/JK*B and 1 case had been phenotyped as Jk (a - b +) but it was genotyped as JK*A/JK*B. Serological results for a few samples could not be confirmed because of mix-field agglutination. The genotyping however verified the presence of Kidd alleles. Molecular methods are a valuable tool to predict blood group phenotypes in multi-transfused patients in order to select RBC units for a perfect matching improving blood transfusion and preventing alloimmunization. Also Tetra-Primer ARMS PCR is simple and cost effective methods that could be alternative by conventional Molecular methods.

Physiological functions of urea transporter B

Urea transporters (UTs) are membrane proteins in the urea transporter protein A (UT-A) and urea transporter protein B (UT-B) families. UT-B is mainly expressed in endothelial cell membrane of the renal medulla and in other tissues, including the brain, heart, pancreas, colon, bladder, bone marrow, and cochlea. UT-B is responsible for the maintenance of urea concentration, male reproductive function, blood pressure, bone metabolism, and brain astrocyte and cardiac functions. Its deficiency and dysfunction contribute to the pathogenesis of many diseases. Actually, UT-B deficiency increases the sensitivity of bladder epithelial cells to apoptosis triggers in mice and UT-B-null mice develop II-III atrioventricular block and depression. The expression of UT-B in the rumen of cow and sheep may participate in digestive function. However, there is no systemic review to discuss the UT-B functions. Here, we update research approaches to understanding the functions of UT-B.

Molecular genetic analysis of the Jk(a-b-) phenotype in Chinese: A novel silent recessive JK allele

The Jk(a-b-) phenotype, referred to as Jknull, is rare in most populations. This blood type is characterized by the absence of Kidd glycoprotein on the surface of red blood cells (RBCs) and moderately reduced ability to concentrate urine. The molecular basis for Jknull phenotype includes splice-site mutations, missense mutations, and a partial gene deletion in the JK(SLC14A1) gene that encodes the human urea transporter protein. In this study, we have analyzed 10 Chinese Jknull samples to determine their molecular bases. In addition to the well known Polynesian Jknull allele, three Jknull alleles were detected including one novel Jknull allele: JKA (130A, 220G).

Production of human monoclonal anti-Jk3, recognising an epitope including the Jk(a) /Jk(b) polymorphic site of the Kidd glycoprotein

BACKGROUND AND OBJECTIVES

The Kidd blood group system consists of polymorphic antigens, Jk(a) (JK1) and Jk(b) (JK2), and a high-incidence antigen, Jk3. Anti-Jk3 is often observed in immunised Jk(a-b-) individuals. In this study, we aimed to establish a human hybridoma cell line secreting monoclonal anti-Jk3 (HIRO-294).

MATERIALS AND METHODS

Peripheral blood lymphocytes of a Filipino woman with the Jk(a-b-) phenotype having anti-Jk3 were transformed with Epstein-Barr virus and then hybridised with the myeloma cell line JMS-3 using the polyethylene glycol (PEG) method. The reactivity and specificity of the anti-Jk3 were examined by serology and flow cytometry.

RESULTS

Four hybridoma clones secreting anti-Jk3 were established and the antibody from one of these clones, HIRO-294, was examined. The reactivity of HIRO-294 was positive with 227 Jk(a+b-) red blood cells (RBCs), 298 Jk(a-b+) RBCs, and 1043 Jk(a+b+) RBCs, but was negative with 21 Jk(a-b-) RBCs. Eluates from Jk(a+b-) RBCs and Jk(a-b+) RBCs sensitised with the anti-Jk3 were cross-reacted with Jk(a-b+) RBCs and Jk(a+b-) RBCs, respectively. The reactivity of HIRO-294 was enhanced by the treatment of RBCs with ficin, trypsin, pronase and α-chymotrypsin, but was not changed by their treatment with neuraminidase, dithiothreitol and ethylenediaminetetraacetic acid (EDTA) glycine acid (GA). The RBCs sensitised by the anti-Jk3 were not agglutinated with the commercial reagents of anti-Jk(a) and anti-Jk(b) by saline test, whereas the nonsensitised RBCs or those sensitised by monoclonal anti-D [HIRO-3, immunoglobulin G (IgG) class] were agglutinated with those reagents.

CONCLUSIONS

We established a human hybridoma cell line secreting monoclonal anti-Jk3 (HIRO-294). This antibody had unique specificity, recognising the Kidd glycoprotein including the Jk(a) /Jk(b) polymorphic site.

A rare case of anti-jk3 antibody detected on pre-transfusion investigation

We report a 47-year-old Malay lady, para 4 + 1, with known medical history of hypertension whom presented at Emergency Department with severe anaemia, most likely secondary to menorrhagia caused by uterine fibroids. Her haemoglobin was 5.5 g/dl and she was transfused with three units of packed cell without any adverse reaction, her haemoglobin level increased to 9.8 g/dl. She was then planned for total abdominal hysterectomy and bilateral salpingo-oophorectomy later. Four months later when she came for the elective surgery, her pre transfusion investigations showed blood group as B Rh D positive, with a probable R1R1 phenotype. Her antibody screening was positive in all the three panel cells. Further testings showed a negative Direct Coomb's test and negative autocontrol, antibody identification showed pan-agglutination reaction on all 11 panel cells with enzyme enhancement. Patient's red cell phenotype was Jk(a-b-). Anti-Jk3 was suspected and further confirmed in the reference laboratory by phenotyping as well as negative urea lysis test. This case report highlights an extremely rare but clinically significant anti-JK3 antibody detected during pretransfusion testing. This phenotype is rare in the white population, more commonly seen in various polynesians. Increased awareness among the blood bank personnel regarding the variability of the blood group phenotype and the capricious nature of the Kidd antibodies may contribute to the better management of these patients.