[Investigation of Antigen and Gene Frequency of Kell(K) and Rh(D) Blood Groups in Xinjiang].

OBJECTIVE: To investigate the phenotypes and gene frequencies of Kell blood group system K antigen and Rh blood group system D antigen in Xinjiang, and summarize and understand the distribution of Kell(K) blood type and Rh(D) blood type in this area. METHODS: A total of 12 840 patients who met the inclusion criteria during physical examination and treatment in our hospital and 18 medical institutions in our district from January 1, 2019 to December 31, 2019 were collected for identification of Kell blood group system K antigen and Rh blood group System D antigen, and the distribution of K and D blood groups in different regions, genders and nationalities were investigated and statistically analyzed. RESULTS: The proportion of K positive in the samples was 1.39%, the highest was 1.91% in southern Xinjiang, and the lowest was 1.03% in northern Xinjiang(P<0.01). The proportion of Rh(D) negative samples was 2.75% and the gene frequency was 16.64%. The proportion of Rh(D) negative samples was 4.03% and the gene frequency was 20.10% in southern Xinjiang, followed by eastern Xinjiang and the lowest in northern Xinjiang (P<0.01). The frequency of K antigen in Uygur nationality was the highest, reaching 2.16%, Kirgiz 1.54%, and the distribution trend of D/d antigen was similar to that of K antigen. Among women, the K positive frequency of Kazak nationality was slightly higher than that of Mongolian nationality. The highest proportion of K positive in Uygur women was 2.38%, which was higher than that in Uygur men (1.86%). The frequency of d phenotype in Kazak women was 3.15%, which was higher than that in Kirgiz （2.89%） (P<0.01). CONCLUSION: The distributions of Kell(K) and Rh(D) blood groups in northern and southern Xinjiang and eastern Xinjiang had its own unique characteristics and differences. There are significant differences in blood group distribution among different ethnic groups and gender groups. In the future, k antigen detection can be included to further improve the investigation on the distribution of Kell blood group system in this region.

KEL1 negative red cell transfusions for females of current or future child-bearing potential: A clinical impact and feasibility study.

BACKGROUND: Anti-K is an alloantibody stimulated in response to the KEL1 antigen and may cause hemolytic disease of the fetus and newborn (HDFN). Provision of KEL1 negative blood to females of child-bearing potential was not our practice. We assessed the impact of our policy and assessed feasibility of a KEL1 negative transfusion policy. STUDY DESIGN AND METHODS: This is a cohort study spanning Jan 1, 2007-Jun 30, 2017 in Hamilton, Canada. Data were obtained via our institution's transfusion database. Chart reviews of females age ≤45 with anti-K were performed; data on RBC KEL1 phenotype were obtained from the blood supplier when needed to ascertain the cause of alloimmunization. Descriptive analysis of hospital KEL1 negative inventory demand and supply was performed. RESULTS: From Jan 2007-Jun 2017, 8.6% of all RBC units transfused were provided to females age ≤45. There were 111 females with detectable anti-K. Median age at time of antibody detection was 34 years (interquartile range 27-40) and 28 of 111 (25.2%) patients may have been alloimmunized by transfusion. Of 49 pregnancies, seven had complications due to anti-K. We estimated that our existing RBC inventory (with 16% units known to be KEL1 negative in 2017) is sufficient to meet demand and support a KEL1 negative transfusion policy for females age ≤45. CONCLUSION: Transfusion was responsible for alloimmunization in 25% of females with anti-K over 10 years. Analysis of supply and demand can be used to inform feasibility of a KEL1 negative transfusion policy.

Rare Blood Groups in ABO, Rh, Kell Systems - Biological and Clinical Significance.

Background: The frequency of ABO, Rh and Kell blood group antigens differs among populations of different ethnic ancestry. There are low-frequency antigens (<1%) and high-frequency antigens (>90%). A rare blood group is defined as the absence of a high-frequency antigen in the general population, as well as absence of multiple frequent antigens within a single or multiple blood group systems. Aim: To perform red blood cell typing and to calculate the antigen and phenotype frequencies, in order to identify rare blood group donors within the clinically most important АВО, Rh and Kell systems. Material and Methods: АВО, Rh (D, C, E, c, e) and Kell (K) antigen typing was performed using specific monoclonal sera and microplate technique, while Cellano (k) typing was performed with a monoclonal anti-k, antihuman globulin and column agglutination technique. Weak ABO subgroups were determined using the absorption elution method or molecular genotyping (PCR-SSP). Results: ABO antigen frequency is: A (40.89%), O (34.22%), B (16.97%), AB (7.92%) and weak ABO subgroups (0, 009 %). The established genotypes were AxO1 (0, 0026%) and AxB (0, 001%). Rh antigen frequency is: D (85.79%), C (71.7%), c (76.0%), E (26.0%) and е (97.95%). The most common Rh pheno-type is the DCcee (32.7%) while the rarest phenotype is the DCCEE phenotype (0. 003%). The prevalence of K and k antigen is 7.5% and 99.94%, respectively. The frequency of the rare phenotype K+k- is 0.06%. Conclusion: Large scale phenotyping of blood group antigens enables the identification of blood donors with rare blood groups for patients with rare phenotypes or with antibodies to high-frequency antigens and to frequent antigens within one or more blood group systems.

Novel KEL allele associated with loss of Kpb identified in a white blood donor.

The importance of identifying variant alleles among blood donors is significant to the safety of transfusion for recipients. Molecular methods have become more prominent in the routine process of antigen typing donor units. Some variant antigens cannot be detected using only serologic methods. Molecular testing allows the determination of nucleotide sequences that are used to predict a phenotype. Antigens of the Kell blood group system are known for being highly immunogenic and causing adverse reactions upon antibody formation. A female white blood donor who typed Kp(b-) using serologic methods on multiple donations since 2005 was the subject of a typing discrepancy investigation. Routine genotyping using a commercial genotyping kit (HemoID DQS Panel; Agena Bioscience, San Diego, CA) predicted the donor to type Kp(a+b+). Investigation of the discrepancy between these two results identified a rare single nucleotide variant in the KEL gene at nucleotide position c.948G>T that alters amino acid residue 316 from tryptophan (Trp) to cysteine (Cys). After discovery of the novel allele, adsorption and elution studies were performed to see if there was weakened Kpb expression. The elution studies yielded negative results, which indicated that Kpb is not expressed. The KEL transcripts expressed by the donor were determined using cDNA analysis, and the predicted amino acid sequence of the novel allele was modeled to investigate the impact of the amino acid sequence on the structure of the KEL polypeptide. Both SWISS-MODEL and Robetta software were used to evaluate the impact of the p.Trp316Cys on the three-dimensional protein structure. There was no conformational change noted with SWISS-MODEL, whereas the Robetta software showed a significant conformational change compared with the normal Kp(b+) reference sequence. Because the donor is homozygous for variants associated with k and Jsb expression, it was not possible to determine whether the novel allele is associated with loss of Kpb only or loss of all Kell antigens.

McLeod syndrome with a novel XK frameshift mutation: A case report.

RATIONALE: McLeod syndrome (MLS) is a rare X-linked neurohematologic disorder caused by loss-of-function mutations in the XK gene. However, variations in the XK gene remain to be elucidated. Here, we report the clinical phenotype and genetic features of a patient with MLS caused by a novel frameshift mutation in the XK gene. PATIENT CONCERNS: A 44-year-old man presented with chorea, cognitive impairment, mental disorders, and seizures accompanied by peripheral neuropathy, hyperCKemia, and acanthocytosis. The proband's mother had a mild chorea. One older brother who died 10 years ago without a confirmed diagnosis showed symptoms of both chorea and mental disorders, while the other brother also developed mild chorea. DIAGNOSIS: The patient was diagnosed with MLS based on the family history, clinical manifestations, and accessory examinations. Whole-exome sequencing studies revealed a novel frameshift mutation resulting from a nucleotide variation in exon 2 (452delA) that leads to an amino acid residue conversion from Gln to Arg and early termination of the XK protein (Gln151ArgfsTer2). The patient and one of his older brothers were hemizygotes, and his mother was heterozygous. INTERVENTIONS: The patient was treated with haloperidol to control chorea and levetiracetam to control seizures. OUTCOMES: Six months after treatment, the proband was seizure-free, but showed little improvement in chorea and cognitive dysfunction. LESSON: We describe a family with MLS caused by a novel frameshift mutation in the XK gene. The causes of the mild clinical presentation in the proband's mother require further investigation.

Noninvasive diagnostics of fetal KEL*01.01 allele from maternal plasma of immunized women using digital PCR protocols.

Allo-antibodies produced by K-negative pregnant women against a fetal K antigen from the Kell blood group system may cause hemolytic disease of the fetus and newborn (HDFN). Predicting the fetal K antigen using noninvasive prenatal testing (NIPT) is important for decisions concerning management of pregnancies. Digital and droplet digital PCR techniques permit the detection of fetal single nucleotide variant with a higher specificity and sensitivity than real-time polymerase chain reaction (PCR). AIM: The aim was to evaluate and compare protocols for fetal KEL*01.01 genotyping using different assays and digital PCR platforms. METHODS: DNA isolated from 59 pregnant women (9-39 weeks of gestation, 49 with anti-K) was tested using home-made and custom-ordered KEL*01.01/KEL*02 assays with Droplet Digital™ and QuantStudio™3D. The results were compared with fetal/neonatal genotypes/phenotypes. RESULTS: Fetal KEL*01.01 results using all tested protocols were concordant with fetal/neonatal KEL*01.01 genotypes/phenotypes. None of the tested combinations of assays or digital PCR platforms gave false KEL*01.01-negative results, but inconclusive KEL*01.01 reads were observed in all tested protocols. For 36 cases compared using two digital PCR platforms and assays, there were not statistically significant differences in a level of fetal KEL*01.01 fraction (p < .72). CONCLUSION: Independent of the applied dPCR and ddPCR platforms and KEL*01.01 assays, prediction of the fetal KEL*01.01 is highly reliable. Before implementation in routine practice further validation of the KEL*01.01 protocol with a larger group of pregnant women should be performed.

The effect of extended c, E and K matching in females under 45 years of age on the incidence of transfusion-induced red blood cell alloimmunisation.

Maternal alloantibodies directed against fetal red blood cell (RBC) antigens may cause potentially life-threatening haemolytic disease of the fetus and newborn (HDFN). Dutch transfusion guidelines therefore prescribe preventive cEK matching for all (pre-)fertile females. To quantify the impact of cEK matching, we compared overall and antigen-specific cumulative RBC alloimmunisation incidences in females and males aged <45 years. Among a multicentre cohort comprised of patients who received their first and subsequent RBC unit between 2005 and 2019, first-formed RBC alloantibodies were detected in 47 of 2998 (1·6%) females and 49 of 2507 (2·0%) males. Comparing females and males, overall alloimmunisation incidences were comparable (3·1% [95% confidence interval (CI) 2·1-4·4] versus 3·5% (95% CI 2·4-4·9, P = 0·853) after 10 units transfused). However, cEK alloimmunisation incidences were significantly lower among females (0·6% (95% CI 0·3-1.5) versus 2·2% (95% CI 1·5-3·4, P = 0·001) after 10 units transfused). Yet, despite cEK-matching guidelines being in effect, 6·5%, 3·6% and 0·2% of all RBC units remained mismatched for c, E or K antigens respectively. Most of these mismatches were almost always due to emergency settings. Even though cEK alloimmunisation was not prevented completely, implementation of cEK matching resulted in an alloantigen-exposure risk reduction of up to 98%.

Prevalence of Kell Blood Group System in Blood Donors of Makkah City, Saudi Arabia.

BACKGROUND: The Kell blood group system has different types of antigens, which have immunogenic properties; therefore, it is considered as the third clinically significant blood group in blood transfusion. Patients that lack Kell antigen may produce antibodies that may cause transfusion reaction. This study is the first report on Kell antigen system distribution in blood donors in Makkah city which is important to improve transfusion services. Therefore, the aim of the current study is to determine the distribution of Kell antigens and phenotypes among blood donors in Makkah city, Saudi Arabia. METHODS: This is a retrospective study to determine the prevalence of Kell antigens among blood donors, who come to donate blood in Al Noor specialist hospital, Makkah city. The sample size was 150 donors with a minimum age of 18 years. RESULTS: The most common Kell antigens were k antigen (96%) and Kpb (98%), while the less common were K antigen (18.7%) and Kpa (3.3%). The two most common Kell phenotypes are Kp(a-b+) (95%) and K-k+ (79.3%), while the two least common Kell phenotypes are Kp(a-b-) (1.3%) and Kp(a+b-) (0.6%). CONCLUSIONS: This is the first study that set out to determine the prevalence of Kell antigens and phenotypes among blood donors in Makkah city. This study showed that there is a variation in Kell antigen and phenotype distribution. The Kell blood group system has an important impact on transfusion medicine.

Diversity of variant alleles encoding Kidd, Duffy, and Kell antigens in individuals with sickle cell disease using whole genome sequencing data from the NHLBI TOPMed Program.

BACKGROUND: Genetic variants in the SLC14A1, ACKR1, and KEL genes, which encode Kidd, Duffy, and Kell red blood cell antigens, respectively, may result in weakened expression of antigens or a null phenotype. These variants are of particular interest to individuals with sickle cell disease (SCD), who frequently undergo chronic transfusion therapy with antigen-matched units. The goal was to describe the diversity and the frequency of variants in SLC14A1, ACKR1, and KEL genes among individuals with SCD using whole genome sequencing (WGS) data. STUDY DESIGN AND METHODS: Two large SCD cohorts were studied: the Recipient Epidemiology and Donor Evaluation Study III (REDS-III) (n = 2634) and the Outcome Modifying Gene in SCD (OMG) (n = 640). Most of the studied individuals were of mixed origin. WGS was performed as part of the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program. RESULTS: In SLC14A1, variants included four encoding a weak Jka phenotype and five null alleles (JKnull ). JKA*01N.09 was the most common JKnull . One possible JKnull mutation was novel: c.812G>T. In ACKR1, identified variants included two that predicted Fyx (FY*X) and one corresponding to the c.-67T>C GATA mutation. The c.-67T>C mutation was associated with FY*A (FY*01N.01) in four participants. FY*X was identified in 49 individuals. In KEL, identified variants included three null alleles (KEL*02N.17, KEL*02N.26, and KEL*02N.04) and one allele predicting Kmod phenotype, all in heterozygosity. CONCLUSIONS: We described the diversity and distribution of SLC14A1, ACKR1, and KEL variants in two large SCD cohorts, comprising mostly individuals of mixed ancestry. This information may be useful for planning the transfusion support of patients with SCD.

Genomic analyses of KEL alleles in alloimmunized thalassemia patients from Iran.

OBJECTIVES: Serological methods are unreliable for red blood cells (RBCs) antigen typing in multi-transfused thalassemia patients due to the presence of donor RBCs in the recipient's circulation and interfering antibodies. Kell blood group system is important in transfusion medicine and Kell antibodies have shown as the most prevalent antibodies in thalassemia patients. We intended to determine the genotype of Kell antigens among Iranian alloimmunized thalassemia patients using molecular methods and compare the results with serological phenotyping. METHODS: Two hundred thalassemia patients participated in this study. Blood group phenotype was performed by the serological method, while the genotype was determined for KEL*01, KEL*02, KEL*03, and KEL*04 alleles using PCR-Sequence Specific Primer (PCR-SSP) method. The genotypes of patients with incompatibility between phenotype and genotype were re-evaluated by Restriction Fragment Length Polymorphism-PCR (RFLP-PCR) and confirmed by DNA sequencing in all cases. RESULTS: Ten patients were found with discrepancies between genotype and phenotype; however, there was a complete agreement between the results of SSP-PCR, RFLP-PCR, and DNA sequencing. Six discrepancies were found in the KEL*01/KEL*02 allele when serologically phenotyped as K-k+. One patient with K-k- and three patients with Kpa-Kpb + phenotype were identified as KEL*01/KEL*02 and KEL*03/KEL*04, respectively. CONCLUSION: It can be concluded that molecular genotyping is more reliable compared with the serological method, especially in the patients who have received multiple transfusions. Therefore, using a combination of these techniques can lead to a better matched transfusion in these patients.

Poly(I:C) causes failure of immunoprophylaxis to red blood cells expressing the KEL glycoprotein in mice.

Polyclonal anti-D (Rh immune globulin [RhIg]) therapy has mitigated hemolytic disease of the newborn over the past half century, although breakthrough anti-D alloimmunization still occurs in some treated females. We hypothesized that antiviral responses may impact the efficacy of immunoprophylaxis therapy in a type 1 interferon (IFN)-dependent manner and tested this hypothesis in a murine model of KEL alloimmunization. Polyclonal anti-KEL immunoprophylaxis (KELIg) was administered to wild-type or knockout mice in the presence or absence of polyinosinic-polycytidilic acid (poly[I:C]), followed by the transfusion of murine red blood cells (RBCs) expressing the human KEL glycoprotein. Anti-KEL alloimmunization, serum cytokines, and consumption of the transfused RBCs were evaluated longitudinally. In some experiments, recipients were treated with type 1 IFN (IFN-α/ß). Recipient treatment with poly(I:C) led to breakthrough anti-KEL alloimmunization despite KELIg administration. Recipient CD4+ T cells were not required for immunoprophylaxis efficacy at baseline, and modulation of the KEL glycoprotein antigen occurred to the same extent in the presence or absence of recipient inflammation. Under conditions where breakthrough anti-KEL alloimmunization occurred, KEL RBC consumption by inflammatory monocytes and serum monocyte chemoattractant protein-1 and interleukin-6 were significantly increased. Poly(I:C) or type I IFN administration was sufficient to cause breakthrough alloimmunization, with poly(I:C) inducing alloimmunization even in the absence of recipient type I IFN receptors. A better understanding of how recipient antiviral responses lead to breakthrough alloimmunization despite immunoprophylaxis may have translational relevance to instances of RhIg failure that occur in humans.

Genetic polymorphisms of blood donors in Algeria through blood groups ABO, RH, and Kell.

Our study included 2465 blood donors unrelated from both sexes, originating from Msila (Algeria), at Msila Blood Transfusion Center (CTS), with the aim of performing an anthropogenetic characterization of the population of M'sila, by studying the three-erythrocyte polymorphic systems ABO, Rhesus, and Kell with their allele frequencies. This allowed us to demonstrate after a multi-varied comparative analysis through principal components analysis (PCA) and hierarchical cluster analysis (HCA) On the one hand, comparing the population of Msila to the different regions of Algeria where we found a genetic proximity with the great south of Algeria going towards the south-east of Algeria. On the other hand, the comparative analysis of Msila's population with other populations in the world based on historical, geographical and cultural profile, by building a tri-hybrid potential parenting model (North Africa, Mediterranean and Middle orient) through the three blood systems, allowed us to identify four potential parents including Egypt and Libya (North Africa) and Saudi Arabia and South Yemen (Middle East), Regarding the third strand of our tri-hybrid model, we did not find any potential parental link with the northern shore of the Mediterranean (southern Europe) despite the historical and geographical link that exists. This study allowed us to share the map of Algeria genetically into two blocks: a North block and a South block. It also allowed us to trace a retrograde genetic route through the time of the M'sila population, thus determining these potential parental origins.

Establishment of KEL*01 and KEL*02 Genotyping to Recruit Uncommon, Kell-positive, Reagent Red Cells Among Thai Blood Donors.

BACKGROUND: The reagent red blood cells used to screen and identify antibodies have to include K+ cells in all batch productions. The data of K/k phenotypes among differing Thai blood donor populations remains unknown; hence, mass screening for uncommon K+ donors by serological test has some limitations. Implementing K/k genotyping may be useful to predict uncommon K+ donors to overcome this challenge. This study aimed to establish an in-house K/k genotyping technique and to report KEL*01 and KEL*02 allele frequencies among three Thai blood donor populations to increase the selection of K+ donors in rare blood group databases. METHODS: A total of 2,239 DNA samples obtained from 1,512 central, 427 southern, and 300 northern Thai blood donors were included. The KEL*01 and KEL*02 genotyping using PCR with sequence-specific primers (PCR-SSP) was developed and validated. All samples were genotyped using developed PCR-SSP. Moreover, the possibility of finding group O and predicted K+ phenotypes among Thai blood donor populations was calculated. RESULTS: The DNA controls were validated using two sets of primer combinations and the results of KEL*01 and KEL*02 genotyping were in agreement. The KEL*01 allele frequencies were 0.0007, 0.0047, and 0.0000, and KEL*02 allele frequencies were 0.9993, 0.9953, and 1.0000 among central, southern, and northern Thai donors, respectively. In addition, mass screening among 3,795 and 566 donors in central and southern Thai populations was required to find at least one group O and predicted K+ phenotypes. CONCLUSIONS: The in-house PCR-SSP for KEL*01 and KEL*02 genotyping provided reproducible and accurate results with cost effectiveness. Our results confirmed the low KEL*01 allele frequencies among Thais. PCR-SSP could be used as an alternative technique to simply increase the number of uncommon predicted K+ phenotypes for reagent red blood cell recruitments.