Human platelet antigen genotyping of platelet donors at a transfusion center in northern Pakistan

Objective: The study aimed to specify the allele frequency of Human platelet antigen (HPA-1 to HPA-5 and HPA-15) platelets in blood donors at a transfusion center in Northern Pakistan.Material and Methods: This cross-sectional analytical study was conducted at Armed Forces Institute of Transfusion (National University of Medical Sciences) Rawalpindi from 1 January to 31 December 2021. We executed HPA genotyping of 384 healthy, inapplicable platelet and whole blood donors by polymerase chain reaction with sequence-specific primers for 06 biallelic systems (HPA-1 to -5 and -15) that have been associated with platelet antigen alloimmunization. Results: The allele frequency of HPA-1a/1b, -2a/2b, -3a/3b, -4a/4b, -5a/5b, and -15a/15b in this population is 0.91/0.09, 0.92/0.08, 0.72/0.28, 1/0, 0.89/0.11, 0.58/0.42 respectively. The mismatch probability percentage of platelet antigens HPA-1 to -5 and -15 ranges from 13.8 to 36%, and the incompatibility risk is highest for HPA-15. HPA-1b, -2b, -4b, and -5b homozygosity is 0.5%, 0.5%, 0 and 7.8%, while homozygosity of HPA-3b and -15b is 13.8% and 28.6%, respectively.Conclusion: Polymerase chain reaction with sequence-specific primer (PCR-SSP) is a valid method for HPA screening in blood donors. Evaluating HPA in our region may be an initial step towards devising a registry of platelet donors and foreshadowing platelet alloimmunization and treatment in our territory. Keywords: Allele frequency, Alloimmunization, Genotypes, Human platelet antigens (HPA), Mismatch probability, PCR-SSP, Real-time polymerase chain reaction