title: Resolution of ambiguous HLA genotyping in korean by multi-group-specific sequence-based typing.
abstract: OBJECTIVE
  To evaluate a multi-group-specific sequence-based typing (SBT) method for resolving ambiguous results from human leukocyte antigen (HLA) genotyping.
  
  
  METHODS
  A total of 50 samples that showed ambiguous genotypes for at least two HLA loci from HLA-A, -B, -C and -DRB1 by the conventional SBT assay were evaluated using a new SBT test, the AVITA plus assay. The most likely HLA genotypes for the respective samples considering allele frequencies in Korean were concordant between the AVITA and conventional SBT assays.
  
  
  RESULTS
  An average of 3.3 loci among the HLA-A, -B, -C and -DRB1 loci per sample gave results with two or more possible allele combinations with the conventional SBT, and 48 (96.0%) out of 50 showed reduced numbers of possible genotypes for at least one HLA locus with the AVITA. A total of 41, 43, 42, and 38 cases among the 50 samples showed ambiguous results for HLA-A, -B, -C, and -DRB1 typing by the conventional SBT, respectively. The average numbers of possible allele combinations for the respective four HLA loci were 8.2, 6.7, 5.9, and 3.2, and they were reduced to 1.5, 2.2, 4.4, and 1.8, respectively, by the AVITA. Ambiguity was resolved by the AVITA in 33 (80.5%), 31 (72.1%), 17 (40.5%) and 28 (73.7%) samples among the ambiguous cases from the conventional SBT for HLA-A, -B, -C, and -DRB1 typing, respectively.
  
  
  CONCLUSIONS
  The multi-group-specific SBT method considerably reduced the number of ambiguous results, and thus may be useful for accurate HLA typing in clinical laboratories.
authors: Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Yongjung
authors: Y
authors: Park
authors: Biowithus Life Science Institute, Seoul, Korea.
authors: Cha Eun
authors: CE
authors: Yoon
authors: College of Animal Bioscience & Technology, Konkuk University, Seoul, Korea.
authors: Oh-Joong
authors: OJ
authors: Kwon
authors: Division of Transplantation Surgery, Department of Surgery,The Research Institute for Transplantation, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Yu-Seun
authors: YS
authors: Kim
authors: Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea. kimhs54@yuhs.ac.
authors: Hyon-Suk
authors: HS
authors: Kim
mesh_terms: D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006680:HLA Antigens / Q000235:genetics*; D006650:Histocompatibility Testing; D006801:Humans; D016133:Polymerase Chain Reaction
chemical_list: D006680:HLA Antigens
keywords: Human leukocyte antigen; ambiguity; high resolution; multi-group-specific PCR; sequence-based typing