HLA typing in diverse populations. (2nd December 2016)

• Record Type: Journal Article
• Authors: Holdsworth, R.; Diviney, M.
• Is Part Of: ISBT science series. Volume 12:Number 1(2017)
• Page Start: 107
• Page End: 111
• Publication Date: 2016-12-02
• Subjects: human leucocyte antigens -- immunogenetics -- transplantation; Blood -- Periodicals; Blood -- Transfusion -- Periodicals; Immunohematology -- Periodicals; Immunopathology -- Periodicals; 615.39
• DOI: 10.1111/voxs.12322
• Languages: English
• ISSNs: 1751-2816

Abstract

Abstract : The human leucocyte antigens (HLA) genes are part of the major histocompatibility complex and are the most polymorphic gene complex in the human genome. The HLA genes are hyperpolymorphic, that is many forms of the genes (alleles) at each locus. The HLA molecules play a critical role in our immune defence, and the extreme diversity ensures a robust immune response. Over many generations, HLA types are retained through immune advantage which may be the basis of the high frequency of some HLA alleles in specific regions. Geographical, language or religious influences can further influence regional HLA allele frequency. The HLA gene hyperpolymorphism can make typing protocols very complex. HLA typing requires DNA‐based testing methods to identify the hundreds of nucleotide differences throughout the introns and exons of the HLA genes for each allele. The level of resolution of the HLA result depends on the type of assay used. Assay design and testing can be time‐consuming, and manufacturers may use 'smart' software with population reference data to estimate the most likely HLA alleles in the allele assignment. Other methods have utilized haplotype data for HLA typing assignment, but the identification of haplotypes by inference rather than direct sequencing of alleles may generate ambiguous results. Next‐generation sequencing assays are designed to detect the entire nucleotide sequence of the HLA gene and accurately assign HLA alleles without ambiguity. Diverse populations will have a wide range of HLA types, and this can lead to challenges in assigning HLA alleles.