Assessment of Gene Frequencies of Human Platelet Alloantigens in Rivers-State, Nigeria Based on ABO/Rhesus Blood Groups Distribution

Aim: The aim of this study was to assess the Gene Frequencies of Human Platelet Alloantigens in Rivers-State, Nigeria based on ABO/Rhesus blood groups distribution

Study Design: A randomized controlled trial.

Place and Duration of Study: Rivers State University Medical Centre, Port Harcourt, Safety Molecular Pathology Laboratory, Enugu State, Justcare clinical laboratory Port Harcourt Rivers State and University of Port Harcourt Teaching Hospital, between October 2019 and March 2020.

Methodology: The subjects consisted of apparently healthy individuals who were of Rivers State origin totaling 104 persons aged 17 to 42 years. They were under-graduate and post graduate students of Rivers State University of Port Harcourt. Five major ethnic groups were considered which included Ikwerre, Ogoni, Ijaw, Etche and Ogba. Their demographic information was collected using a sample register and a questionnaire. Samples were collected from the antecubital vein. 10ml of blood was collected, 5ml was transferred into EDTA sample bottle (Ethylene diamine tetracetic acid) while 2ml was dispensed into plain bottle and labeled accordingly. Serological testing including HIV (RVS) screening, HBsag, HCV and VDRL were all as part of the inclusion criteria immediately after samples were collected. The remaining sample was analyzed using genotyping of Human Platelet Antigens by High Resolution Melting Curve Analysis Polymerase Chain Reaction (HRM-PCR), while tile method also known as forward/cell grouping method which is based on haem-agglutination reaction was used for ABO/Rh blood grouping. The melt curve analysis was done using the MicPCR software while the frequency analysis was done using Number Cruncher Statistical Software (NCSS) Version 13. GraphPad Prism Version 8.0.2 was used to determine the statistical significance between the various HPA genotypes and the ethnic groups and p-values of < 0.05 were considered to be statistically significant. Results were presented in percentages, mean+/- standard deviation and in tables

Results: The results showed that the A+ blood group had highest frequencies of 19.2% and 17.7% for HPA-5 b/b and HPA-4 a/a, while the least was 0.8% each for HPA-3 a/a, HPA-4 b/b and HPA-5. For blood group B+, the highest were 20.0% (HPA-5 b/b) and 16.7% (HPA-3 b/b), and the least were 5.0% each for HPA-1 b/b and HPA-4 a/b, while blood group B- had highest frequencies for HPA-1 a/a, HPA-2 b/b, HPA-3 b/b, HPA-4 a/b and HPA-5 b/b (20.0% each). The blood group O+ HPA gene patterns had their highest values at 19.7% (HPA-5 b/b), 16.5% (HPA-4 a/a) and 13.7% (HPA-3 b/b) and the least was 7.9% (HPA-1 a/b), while for the blood group O-, the highest was observed for HPA-3 b/b and HPA-5 b/b (20.0% each) and the least for HPA-1 a/a and a/b, HPA-2 a/b and b/b, and HPA-4 a/b and b/b (10.0% each).

Conclusion: Based on the results, we conclude that A+ blood group had highest HPA frequencies. Whilst, the highest for blood group B+ were (HPA-5 b/b) and (HPA-3 b/b), and blood group B- had highest frequencies for HPA-1 a/a, HPA-2 b/b, HPA-3 b/b, HPA-4 a/b and HPA-5 b/b. The blood group O+ HPA gene patterns had their highest values (HPA-5 b/b), (HPA-4 a/a) and (HPA-3 b/b) and the least was (HPA-1 a/b), while for the blood group O-, the highest was observed for HPA-3 b/b and HPA-5 b/b and the least for HPA-1 a/a and a/b, HPA-2 a/b and b/b, and HPA-4 a/b and b/b.