Genotyping of 28 blood group alleles in blood donors from Mali: Prediction of rare phenotypes

Genotyping for Dombrock blood group alleles in Northern Pakistani blood donors

Genotyping can be used to identify rare blood group antigens and to solve suspected blood group discrepancies, particularly when serologic methods are limited. Unfortunately, only a few such studies have been performed in Pakistan. The present study was conducted to determine the frequency of Dombrock blood group alleles by genotyping samples from blood donors from the north of Pakistan. Blood samples were taken with consent from 300 blood donors; DNA was extracted and tested for DO*01 and DO*02 alleles by sequence-specific primer polymerase chain reaction (PCR-SSP), followed by gel electrophoresis. Allele frequencies were calculated. The observed and expected genotype frequencies were compared using the χ² test. The allele frequencies for DO*01 and DO*02 were 0.40 and 0.60, respectively. Genotype frequencies were in Hardy-Weinberg equilibrium. This study in Pakistani blood donors provides Dombrock blood group allele frequencies by PCR-SSP. This approach is efficient and economical and can be applied in developing countries. The findings can contribute to the development of in-house red blood cell panels, identification of rare blood types, and establishment of a national rare blood donor program.

Genotyping can be used to identify rare blood group antigens and to solve suspected blood group discrepancies, particularly when serologic methods are limited. Unfortunately, only a few such studies have been performed in Pakistan. The present study was conducted to determine the frequency of Dombrock blood group alleles by genotyping samples from blood donors from the north of Pakistan. Blood samples were taken with consent from 300 blood donors; DNA was extracted and tested for DO*01 and DO*02 alleles by sequence-specific primer polymerase chain reaction (PCR-SSP), followed by gel electrophoresis. Allele frequencies were calculated. The observed and expected genotype frequencies were compared using the χ² test. The allele frequencies for DO*01 and DO*02 were 0.40 and 0.60, respectively. Genotype frequencies were in Hardy-Weinberg equilibrium. This study in Pakistani blood donors provides Dombrock blood group allele frequencies by PCR-SSP. This approach is efficient and economical and can be applied in developing countries. The findings can contribute to the development of in-house red blood cell panels, identification of rare blood types, and establishment of a national rare blood donor program.

Blood group antigen and phenotype prevalence in the Korean population compared to other ethnic populations and its association with RBC alloantibody frequency

OBJECTIVES

This study aimed to analyse the allele frequency of blood group antigens in the Korean population and other ethnic populations and the association of blood group antigens with red blood cell (RBC) alloantibodies.

BACKGROUND

Blood group antigen genotyping can support patients undergoing frequent transfusions who have alloantibodies and antibodies against high-prevalence blood group antigens.

METHODS

Twenty-nine single nucleotide variations and 37 blood group antigens were tested. Samples requested for routine blood typing were collected from Jan to Apr 2016. Genotyping was performed on 145 Korean samples and was confirmed by bidirectional sequencing and serologic tests. The allele frequency data were compared with previous genotyping datasets (three datasets from Korea and one each from China, Europe, Asia, and the USA). Alloantibody frequencies and blood group antigens from the electronic medical record of 1772 cases were examined.

RESULTS

E antigen was higher in the Korean population compared to that of Asian and European populations. K, Kp^a , Fy^b and Do^a allele frequencies were lower compared to other ethnic populations. RBC alloantibodies with frequencies (%) greater than 1% from the 1772 cases were as follows: anti-E, 36·7%, anti-C, 17·7%; anti-c 7·39%; anti-M, 5·9%; anti-e, 5·2%; anti-Jk^a , 2·9%; and anti-Fy^a , 1·1%. Blood group antigens and alloantibody frequencies revealed inverse trends that did not reach statistical significance.

CONCLUSION

The allele frequency of blood group antigens assessed by high-throughput methods provided reliable and valuable information that could be used for maintaining donor pools and providing compatible blood for genotyped patients.

Predicted S and s phenotypes from genotyping results among Thai populations to prevent transfusion-induced alloimmunization risks

BACKGROUND

S and s antigens of the MNS system are of clinical importance because alloanti-S and -s have usually caused delayed hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Various red cell genotyping has been established to predict the phenotypes to solve serological test limitations.

OBJECTIVES AND METHODS

This study aimed to determine S and s genotype frequencies and to estimate the alloimmunization risks among central, northern and southern Thai populations. Altogether, 1237 blood samples from Thai blood donors were included. Only 150 samples were tested with anti-S and anti-s by indirect antiglobulin test. All samples were genotyped for GYPB*S and GYPB*s alleles using inhouse PCR with sequence-specific primer. Additionally, the allele frequencies were used to estimate alloimmunization risks and compare with other populations.

RESULTS

The phenotyping and genotyping results in 150 samples were in 100% concordance. The allele frequencies of GYPB*S in central, northern and southern Thais were 0.061, 0.040 and 0.097, and GYPB*s were 0.939, 0.960 and 0.903, respectively. The frequencies among central Thais were similar to those among northern Thai and Korean populations (P > 0.05) but significantly differed from those of Asian, Caucasian African American and Hispanic populations (P < 0.05). In addition, the risk of S alloimmunization among southern Thais (0.1566) was higher than those among central (0.1038) and northern Thais (0.0736).

CONCLUSION

This was the first study to report S and s predicted phenotypes and estimate alloimmunization risks among Thais, which is beneficial to prevent transfusion-induced alloimmunization among donors and patients.

Multiplex Lateral Flow Assay for Rapid Visual Blood Group Genotyping

Conventional blood group phenotyping by hemagglutination assays, carried out pretransfusion, is unsuitable in certain clinical situations. Molecular typing offers an alternative method, allowing the deduction of blood group phenotype from genotype. However, current methods require a long turnaround time and are not performed on-site, limiting their application in emergency situations. Here, we report the development of a novel, rapid multiplex molecular method to identify seven alleles in three clinically relevant blood group systems (Kidd, Duffy, and MNS). Our test, using a dry-reagent allele-specific lateral flow biosensor, does not require DNA extraction and allows easy visual determination of blood group genotype. Multiplex linear-after-the-exponential (LATE)-PCR and lateral flow parameters were optimized with a total processing time of 1 h from receiving the blood sample. Our assay had a 100% concordance rate between the deduced and the standard serological phenotype in a sample from 108 blood donors, showing the accuracy of the test. Owing to its simple handling, the assay can be operated by nonskilled health-care professionals. The proposed assay offers the potential for the development of other relevant single nucleotide polymorphism (SNP) panels for immunohematology and new applications, such as for infectious diseases, in the near future.