Distribution OF ABO Predicated Phenotypes among Voluntary Blood Donors applying Next Generation Sequencing - Insights from Kenya

Abstract

Background: ABO system is a major determinant for blood transfusion and organ transplantation incompatibility. ABO histo-blood group antigens are sugars attached to glycolipids and glycoproteins on the surface of human cells and readily recognizable by antibodies which are naturally present in each person plasma/serum. Laboratory testing for ABO antigens and isoagglutinins is essential for safe and effective transfusion and transplantation. Testing for ABO antigens has traditionally depended on serologic testing which is limited in the determination of the weak subtypes risking the recipients to alloimmunisation especially those we are receiving ongoing transfusions with red cell such as sickle cell disease and oncology. . It has also impacted negatively in the management of rare red cell units. However, there is increasing need for evaluation of genetic analysis of ABO antigens, to enable evaluation of ABO blood group in cases where serologic testing may be ambiguous or impossible to accurately determine the presence of these antigens; plus having such data in a country. Thus, there is need to investigate the genotypes/Alleles responsible for ABO blood group phenotypes in the blood donor population to enhance safety in transfusion and transplantation practices.

 Methods: The study site was Kenya National Blood Transfusion Service and Red Cross lifeblood Brisbane, experimental design was employed, sample size determination was determined using Slovin's Formula Sampling Techniques, and purposeful sampling method was employed to achieve a representative sample. Next generation sequencing was employed to determine red cell alleles and predicted phenotypes. Sequencing was performed using the Illumina MiSeq platform with 12-plex pools and standard 300-cycle V2 chemistry.

Results: Out of the total 119 samples sequenced, ten phenotypes combinations were predicted: O (52.3%), A1 (16.2%), B (10.5%), A1 or B (6.8%), A1 or A2 (5.8%), A1 or Ax/Aweak (1.6%), B or B3 (1.6%), A1B (2%) A2B (2%).and Bweak (0.5%). This can be expressed as (O> A1> B > A1 or B > A1 or A2 > A1 or Ax/Aweak > B or B3 > A1B > A2B > Bweak.

Conclusion: The study findings elucidated the genotypes that are responsible for the ABO thirteen phenotypes in the identified Kenyan population. This data forms the basis or evidence to advocate for a blood group reference laboratory and a red cell panel that is African specific.