RESUMEN
In this study we investigated the human leucocyte antigen-A (HLA-A), -B and DRB1 polymorphism of Native American population of Paraguay, the Guarani Indians. We found that the HLA variability consisted of 5 HLA-A, 7 HLA-B and 6 HLA-DRB1 groups of alleles and of several specific alleles (B*1504, B*3505, B*3912, B*4004, B*5104, DRB1*0411, DRB1*1413) common in other Native American populations. The comparison of the HLA polymorphism of the Guaranis from Paraguay with the «Mestizos¼ of Paraguay and the Spaniards showed that the «Mestizos¼ of Paraguay are genetically very distant from the Guarani Indians of Paraguay but much more close to the Spaniards. This can be explained, at least in part, by the history of the country. Our results are of importance in transplantation, in particular in the search for an unrelated donor for a Paraguayan patient requiring hematopoietic stem cell transplantation.
Asunto(s)
Antígenos HLA/genética , Indígenas Sudamericanos/genética , Polimorfismo Genético , Adolescente , Adulto , Anciano , Femenino , Frecuencia de los Genes/genética , Genética de Población , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Paraguay , Fenotipo , Adulto JovenRESUMEN
The genetic polymorphism of the Paraguayan population results from the admixture between South American Indians named Guaranis and Spaniards. In order to evaluate the genetic predominance in the Paraguayan population, we typed 50 healthy Paraguayans for HLA-DRB1 by molecular biology and compared their HLA-DRB1 polymorphism to that of the Guaranis and of two Spanish populations. Six significant differences of alleles frequencies were observed between Paraguayans and Guaranis--DRB1*01, 06 (13, 14), 15, 16, 07--whereas only one difference was observed with the Spaniards (DRB1*14). The DRB1*14 frequency was higher in Paraguayan than in the Spanish populations essentially due to the presence of DRB1*1402 related alleles (1402,06,13). These alleles are extremely rare in the Spanish populations whereas frequent in the Guaranis from Brazil and in South American Indian tribes living in the lymitrophe regions of Paraguay (Toba, Wichi and Terena). Thus, the presence of the DRB1*1402 related alleles (6%) in the Paraguayan population constitutes the major Indian contribution to the HLA-DR polymorphism of the Paraguayan population. The genetic distances between Paraguayans and the two Spanish populations were closer (.494 and .415) than that between Paraguayans and Guaranis (.958). Altogether these results suggest the predominance of the Spanish genetic in the Paraguayan population. Historical events are discussed to explain this predominance.