title: [Human leucocyte antigen gene (HLA-A, HLA-B, HLA-DRB1) frequencies in deceased organ donors].
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  The HLA-A,-B,-DRB1 allele, genotype and haplotype frequencies were determined in deceased organ donors in Medellín, Colombia.
  
  
  METHODS
  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.
  
  
  RESULTS
  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%).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Grupo de Inmunología Celular e Inmunogenética, Facultad de Medicina, Universidad de Antioquia, Medellín, Colombia.
authors.forename: Libia M
authors.initials: LM
authors.lastname: Rodríguez
authors.forename: Mabel C
authors.initials: MC
authors.lastname: Giraldo
authors.forename: Natalia
authors.initials: N
authors.lastname: García
authors.forename: Laura
authors.initials: L
authors.lastname: Velásquez
authors.forename: Sara C
authors.initials: SC
authors.lastname: París
authors.forename: Cristiam M
authors.initials: CM
authors.lastname: Alvarez
authors.forename: Luis F
authors.initials: LF
authors.lastname: García
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D003105:Colombia; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D015234:HLA-A Antigens / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D014019:Tissue Donors
chemical_list: D015234:HLA-A Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains