Polymorphism of HLA class I genes in the Brazilian population from the Northeastern State of Pernambuco corroborates anthropological evidence of its origin

Abstract

The allelic distribution of human leukocyte antigen (HLA) class I genes (HLA-A, HLA-B, and HLA-Cw) of the population from the State of Pernambuco in Northeastern Brazil was studied in a sample of 101 healthy unrelated individuals. Low to medium resolution HLA class I typing was performed using polymerase chain reaction-amplified DNA hybridized to sequence specific primers (PCR-SSPs). Twenty allele groups were detected for HLA-A, 28 for HLA-B, and 14 for HLA-Cw. The most frequent alleles were HLA-A*02(0.2871), HLA-B*15(0.1238), and HLA-Cw*04(0.2277), and the most frequent genotypes were A*02/A*02(0.0990), B*15/B*15(0.0594), and Cw*04/Cw*04 and Cw*07/Cw*07, both with a frequency of 0.0792. The observed heterozygosity for the studied loci was 79.21% for HLA-A, 87.13% for HLA-B, and 77.23% for HLA-Cw. The most frequent haplotype was A*02-Cw*04-B*35(0.0485), which is also present in Western European, Amerindian, and Brazilian Mulatto populations, but absent in African populations. Taken together, these data corroborate the historic anthropological evidences of the origin of the Northeastern Brazilian population from Pernambuco.

Typing class I HLA-A gene using a nested PCR-RFLP procedure

“…In previous reports of the HLA-A frequency in 3 geographically separate Brazilian subpopulations, Paraná (Southern Brazil), Pernambuco (Northeastern Brazil) and Minas Gerais (Southeastern Brazil), the frequencies were around 8-10% for HLA-A1, 26-29% for HLA-A2, 8-14% for HLA-A3, 10-14% for HLA-A24, and 5-9% for HLA-A68. In the present study, the frequencies of these alleles were 10% for A1, 27% for A2, 8.6% for A3, 7% for A24, and 8% for A68, showing orders of magnitude similar to those of the frequencies reported (13)(14)(15). Therefore, the more representative alleles reported for a highly heterogeneous population like the Brazilian one demonstrated a good resolution with the nested PCR-RFLP methodology and a high reliability using the typing procedures reported in the present study.…”

“…The most frequent HLA-A allele family in Brazil is the A2 group, but representative frequencies also occur for the A1, A3, A24, and A68 groups (13)(14)(15). In previous reports of the HLA-A frequency in 3 geographically separate Brazilian subpopulations, Paraná (Southern Brazil), Pernambuco (Northeastern Brazil) and Minas Gerais (Southeastern Brazil), the frequencies were around 8-10% for HLA-A1, 26-29% for HLA-A2, 8-14% for HLA-A3, 10-14% for HLA-A24, and 5-9% for HLA-A68.…”

“…In addition, blood samples from 70 randomly chosen individuals were evaluated by the PCR-RFLP methodology to compare their HLA-A distribution with the previously reported distribution within the Brazilian population (13)(14)(15). The most frequent HLA-A allele family in Brazil is the A2 group, but representative frequencies also occur for the A1, A3, A24, and A68 groups (13)(14)(15).…”

HLA-A, -B, and -DRB1 allelic and haplotypic diversity in a sample of bone marrow volunteer donors from Rio Grande do Sul State, Brazil

“…Brazil has an extremely diversified population, and the frequencies of alleles may vary according to the predominant ethnic group in the studied region. Previous studies were conducted on HLA frequency in Brazilian regions such as the states of Paran [6 -8], SÄo Paulo [9 -12], Rio de Janeiro [13], Minas Gerais [14], GoiÂs [15], PiauÎ [16], and Pernambuco [17]. Some of the data available in the literature were obtained by serologic typing methods.…”

Rio Grande do Norte, Brazil, voluntary bone marrow donors registry analysis

“…17 The more prominent resemblance of RN to MG and PR, rather than to PE or PI (which are geographically much closer), again highlights the fact that Caucasian populations most strongly influenced the ethnic configuration of RN, a phenomenon which was already well known for states in the Southern and Southeast of Brazil. [22][23][24][25][26] All thirteen allelic groups described for locus HLA--DRB1 were represented in the RN sample. None of the alleles were found at frequencies low enough to be con-RN sample.…”