Human leucocyte antigen gene (HLA-A, HLA-B, HLA-DRB1) frequencies in deceased organ donors

• Published in: Biomédica Vol. 27; no. 4; pp. 537 - 547
• Main Authors: Rodríguez, Libia M, Giraldo, Mabel C, García, Natalia, Velásquez, Laura, París, Sara C, Alvarez, Cristiam M, García, Luis F
• Format: Journal Article
• Language: Spanish
• Published: Colombia 01-12-2007
• Subjects: Adolescent; Adult; Aged; Alleles; Child; Child, Preschool; Colombia; Female; Gene Frequency; Genetic Predisposition to Disease; Haplotypes; HLA-A Antigens - genetics; HLA-B Antigens - genetics; HLA-DR Antigens - genetics; HLA-DRB1 Chains; Humans; Male; Middle Aged; Pregnancy; Tissue Donors; Colombia
• ISSN: 0120-4157
• DOI: 10.7705/biomedica.v27i4.172

Genetic characterization of the human leucocyte antigen (HLA) system has provided insights into mechanisms of susceptibility to diverse diseases and immunological phenomena during pregnancy, as well as providing evidence for compatibility in the selection of organ transplant donors and recipients.
The HLA-A,-B,-DRB1 allele, genotype and haplotype frequencies were determined in deceased organ donors in Medellín, Colombia.
The genotypes of 926 deceased donors were evaluated over a 17-year period (1989- 2006). HLA-A, HLA-B and HLA-DRB1 typing was performed by sequence specific primer-polymerase chain reaction (SSP-PCR). Maximum likelihood frequencies were estimated by the zipper version of expectation maximation algorithm. Hardy-Weinberg equilibrium were determined by an exact test analogous to Fishers test by using Markovs chain, and linkage disequilibrium between pairs of loci.
Twenty-two, 43 and 14 alleles were identified for HLA-A, -B and -DRB loci, respectively. The most frequent were A*02, A*24, B*35, and DRB1*04. A deficiency in the proportion of heterozygotes in HLA-A and B loci (p<0.01 and p<0.00001, respectively). The most frequent haplotypes were as follows: HLA-A*24, B*35 (7.7%) for HLA-A,-B; HLA-B*35, DRB1*04 (6.4%) for HLA-B,-DRB1 and HLA-A*24, DRB1*04 (8.9%) for HLA-A,-DRB1. For the 3 loci HLA-A,-B,-DRB1, the most frequent haplotypes were A*24, B*35, DRB1*04 (4.6%) and A*24, B*61, DRB1*04 (2.0%).
These results confirm the three-ethnic ancestry of the Medellin population. The predominance of Caucasian admixture differs from many other Latin-American populations and can serve as a reference for comparative studies of these populations as well as applications within the Medellin population.