Human platelet antigen allelic diversity in Peninsular Malaysia

Human platelet antigens (HPAs) are polymorphic and immunogenic glycoproteins encoded by biallelic genes on human chromosome 17 (HPA-1 to -4 and HPA-6 to -11), chromosome 5 (HPA-5), and chromosome 6 (HPA-15) and expressed on the surface of platelets. In the present study, we typed seven HPA loci (HPA-1 to -6 and HPA-15) by polymerase chain reaction using sequence-specific primer and sequence-based typing in 166 blood samples representing three Orang Asli groups (Semang, Senoi, and Proto-Malays) that inhabit Peninsular Malaysia. Combined with previous HPA data collected for Malay subethnic groups, Malays, Chinese, and Indians, our analyses showed high genetic diversity in Peninsular Malaysia, which is consistent with multiple settlements of the region by several founding ancestors (Semang, Senoi, and Proto-Malays) in the last 50,000 years. The gene pools of these ancient populations were then further shaped by various evolutionary pressures such as repeated founder effects, natural selection, and admixture with the relatively recent arrivals such as Chinese, Indians, and Malay subethnic groups. Medical consequences of this genetic complexity are also discussed, including the risks of platelet alloimmunization associated with random platelet transfusion and gestation. Immunohematology2016;32:143–160.