Human platelet-specific antigens frequencies in the Argentinean population

The frequencies of several human platelet antigens (HPAs) vary between different populations and are a major determinant for the prevalence of HPA alloimmunization and its clinical associated entities. The aim of this study was to characterize the allele frequencies of seven HPA systems in two different ethnic groups from the Argentinean city of Rosario, the major population and a minority Amerindian group recently arrived from the north of the country, the Tobas. A total of 192 healthy unrelated individuals from blood donors and hospital staff from the Hospital Italiano Garibaldi and 27 unrelated Toba Amerindians were genotyped for HPA-1, -2, -3, -4, -5, -6 and -15 systems by polymerase chain reaction with sequence specific primers (PCR-SSP). The present data showed that the distribution of the HPA alleles among Argentineans from Rosario is quite similar to that reported among Europeans. The frequencies seen in Tobas, although limited by the small number of aboriginal samples studied, are similar to those reported for other Amerindians populations. Statistically significant differences were found for the genotype distribution of HPA-1, -3, -5 and -15 between both groups, indicating important differences in the potential risk of HPA alloimmunization associated to transfusion and pregnancy. The study of these polymorphisms represents the first step in the elucidation of pathological conditions that are underdiagnosed in our population. It allowed us to establish a panel of characterized blood donors necessary for the serological work out and as a source for compatible platelets transfusion.