RESUMEN
The aim of this study was to estimate the HLA-A, HLA-B and HLA-DRB1 allele groups frequencies in a population of 1559 volunteer bone marrow donors from the northwestern region of São Paulo State grouped according to ethnicity. An additional objective was to compare the allele frequencies of the current study with data published for other Brazilian populations. The allele groups were characterized by the PCR-rSSO method using Luminex(®) technology. Twenty HLA-A, 32 HLA-B and 13 HLA-DRB1 allele groups were identified. The most common allele groups in European descent and mixed African and European descent samples were HLA-A*02, HLA-B*35 and HLA-DRB1*13, while HLA-A*02, HLA-B*35 and HLA-DRB1*11 were more common in African descent samples. The HLA-A*23, HLA-A*36, HLA-B*58 and HLA-B*81 allele groups were more common in sample from African descent than European descent, and the HLA-DRB1*08 was more common in mixed African and European descent than in European descent. Allele group frequencies were compared with samples from other Brazilian regions. The HLA-A*30 and HLA-A*23 were more common in this study than in the populations of Rio Grande do Sul and Paraná; and the HLA-A*01, HLA-B*18, HLA-B*57 and HLA-DRB1*11 were more common in this study than in the population of Piauí. The least frequent allele groups were HLA-A*31, HLA-B*15, HLA-B*40 and HLA-DRB1*08 for the population of Piauí, HLA-A*01 and HLA-A*11 for Parana, HLA-A*02 and -A*03 for Rio Grande do Sul and HLA-DRB1*04 for Paraná, Rio Grande do Sul and Piauí. These data provide an overview on the knowledge on HLA diversity in the population of the northwestern region of São Paulo State and show that the genes of this system are useful to distinguish different ethnic groups.