Identification of three novel alleles of HLA‐DRB1 and HLA‐A in the Brazilian population†

Abstract

Two human leukocyte antigen (HLA)-DRB1 (HLA-DRB1*1376 and -DRB1*1465) and one HLA-A (HLA-A*2471) novel alleles have been identified in individuals from the Brazilian Bone Marrow Donor Registry. DNA sequencing of exon 2 for HLA-DRB1 alleles showed two and five nucleotide substitutions in -DRB1*1376 and -DRB1*1465, compared with closely related alleles, respectively. These substitutions result in a change of amino acid residues in HLA-DRB1*1376 at position 74 (Arg --> Glu) and in -DRB*1465 at positions 47 (Tyr --> Phe), 57 (Asp --> Ser) and 74 (Glu --> Ala). On the other hand, sequence analysis of exons 2 and 3 for HLA-A*2471 showed a single substitution, leading to a single amino acid change at position 151 (His --> Arg). These three novel alleles may have originated from other HLA alleles by gene conversion. However, it is also possible that HLA-A*2471 has evolved from one of the alleles of the HLA-A*2402 group through a point mutation.

Establishment of a Brazilian Line of Human Embryonic Stem Cells in Defined Medium: Implications for Cell Therapy in an Ethnically Diverse Population

“…There are hundreds of reported alleles for each locus, and the number is still rising as new ones are described. Currently, there is little information about HLA allele frequencies in admixtured populations (1). In particular, Brazil has a population of approximately 190 million individuals with a uniquely high degree of admixture, having different degrees of African, European, and Amerindian ancestry (30).…”

Tipificación molecular de los antígenos leucocitarios humanos, Estado del arte y perspectivas para los transplantes de células madre en Costa Rica

“…Desde hace unos 15 años, el número de alelos descubiertos se ha disparado exponencialmente y todos los días se publican nuevas secuencias de alelos de individuos de todas partes del mundo. [7][8][9][10] De hecho, se postula que, con la diversidad genética identificada hasta hoy, es posible la existencia de más de 11 millones de haplotipos del HLA, con miles de millones de combinaciones diploides posibles. 2 Este es quizás el aspecto más importante de la genética del HLA y, como se verá más adelante, representa un factor importantísimo y determinante en el papel de este sistema en la terapia por trasplantes.…”