Frequency of human platelet antigens (HPA) in the Greek population as deduced from the first registry of HPA‐typed blood donors

Background and Objectives Human platelet antigens (HPA) play a central role in foetal and neonatal alloimmune thrombocytopenia (FNAIT), post‐transfusion purpura and some cases of platelet therapy refractoriness. The frequency distribution of HPA had not been studied in the Greek population before we started to create a registry of HPA‐typed apheresis platelet donors. The aim of this study was the determination of the frequency of various HPA in the Greek population, through the establishment of a registry of typed donors. Materials and Methods Here, we report on the first 1000 platelet donors of Greek origin who gave informed consent and were genotyped for 12 pairs of antithetical HPA by Single Specific Primer‐Polymerase Chain Reaction (SSP‐PCR), including HPA‐1, HPA‐3, HPA‐5 and HPA‐15. Antigen frequencies are reported, and allele frequencies were calculated and compared with other European and non‐European populations. Tested donors cover all ABO and Rhesus D antigen spectrum. Results Antigen and allele frequencies are very similar to other White populations. The frequency of HPA‐1bb is 2.9% in our study, and the frequency of HPA‐2b, HPA‐4b, HPA‐9b and HPA‐15b is also slightly higher than in other literature reports, while the frequency of HPA‐15b was found higher than that of HPA‐15a. Conclusion We report antigen and allele frequencies for a large array of clinically significant HPA for the first time in the Greek population. Frequencies are consistent with other European populations. This registry of HPA‐typed platelet donors, available to donate on demand, is an important asset for the treatment of FNAIT cases in Greece.