Molecular analysis of the HLA-DRB genes in two tribes of Brazilian Indians.

The HLA-DRB1, -DRB3, -DRB4, and -DRB5 alleles of the Guarani and Kaingang Amerindians were characterized. Our previous serologic analyses detected three class II haplotypes among the Kaingang: DR2-DQ3, DR4-DQ3, and DR8-DQ4. In addition to these, the Guarani presented haplotype DR6-DQ3. Individuals typed serologically (67 Kaingang and 34 Guarani) were selected for molecular analyses. Using a set of 23 SSOs for hybridization of PCR products from generic DRB amplification six different haplotypes were identified, of which only three are shared by the two tribes. The oligonucleotide hybridization patterns are compatible, with haplotypes DRB1*1602-DRB5*02, DRB1*0404-DRB4*0101, DRB1*0802, and DRB1*0901-DRB4*0101 in the Kaingang tribe, and haplotypes DRB1*1602-DRB5*02, DRB1*0411-DRB4*0101, DRB1*1413-DRB3*0101, DRB1*0802, and DRB1*0901-DRB4*0101 among the Guarani. DRB1*1413 is a new allele, most closely related to DRB1*1402, which is common among South and North American Indians. At the segments analyzed, they differ solely at position 57, which is GAT (aspartic acid) in DRB1*1402 and AGC (serine) in DRB1*1413. This allele probably originated in South American Indians, resulting from a single segmental exchange event between alleles DRB1*1402 (the acceptor) and DRB1*0411.