title: A 25% error rate in serologic typing of HLA-B homozygotes.
abstract: The microlymphocytotoxicity technique has been the accepted method for HLA class I typing since the early 1960s. However, it is often difficult to distinguish two related alleles expressed in an individual due to the cross-reactive nature of the alloantibodies used in this technique. This is especially evident at the HLA-B locus, whose more than 180 alleles fall into only 4 major interrelated cross-reactive antigen groups. To estimate the error rate in serologic typing due to the cross-reactive nature of sera, we used polymerase chain reaction with sequence-specific primers (PCR-SSP) amplification to retype 40 individuals who were previously typed as serologic HLA-B locus homozygotes. PCR-SSP revealed that 10 of these 40 individuals (25%) were actually heterozygous at their HLA-B loci. The HLA-B locus alleles of 9 of these 10 discrepant individuals were further analyzed by denaturing gradient gel electrophoresis followed by direct sequencing. The sequence analysis confirmed that all nine individuals were indeed HLA-B locus heterozygotes. This surprisingly high error rate in serologic definition of HLA-B molecules argues for the use of rapid DNA-based techniques in HLA class I typing, even in the setting of solid organ transplantation.
authors.affiliation: Histocompatibility and Molecular Diagnostics Laboratory, University of Wisconsin Hospital and Clinics, Madison, USA.
authors.forename: D F
authors.initials: DF
authors.lastname: Lorentzen
authors.forename: K K
authors.initials: KK
authors.lastname: Iwanaga
authors.forename: K J
authors.initials: KJ
authors.lastname: Meuer
authors.forename: T L
authors.initials: TL
authors.lastname: Moritz
authors.forename: D I
authors.initials: DI
authors.lastname: Watkins
mesh_terms: D000595:Amino Acid Sequence; D000918:Antibody Specificity; D018070:Biological Specimen Banks; D003429:Cross Reactions; D004247:DNA / Q000235:genetics; D015343:DNA Probes, HLA; D003951:Diagnostic Errors; D004591:Electrophoresis, Polyacrylamide Gel; D005069:Evaluation Studies as Topic; D005805:Genes, MHC Class I; D015235:HLA-B Antigens / Q000032:analysis* / Q000235:genetics; D006650:Histocompatibility Testing / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D006720:Homozygote; D006801:Humans; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012698:Serologic Tests / Q000592:standards / Q000706:statistics & numerical data; D009927:Tissue and Organ Procurement
chemical_list: D015343:DNA Probes, HLA; D015235:HLA-B Antigens; D015345:Oligonucleotide Probes; D004247:DNA