The impact of next-generation sequencing technologies on HLA research

In the past decade, the development of next-generation sequencing (NGS) has paved the way for whole-genome analysis in individuals. Research on the human leukocyte antigen (HLA), an extensively studied molecule involved in immunity, has benefitted from NGS technologies. The HLA region, a 3.6-Mb segment of the human genome at 6p21, has been associated with more than 100 different diseases, primarily autoimmune diseases. Recently, the HLA region has received much attention because severe adverse effects of various drugs are associated with particular HLA alleles. Owing to the complex nature of the HLA genes, classical direct sequencing methods cannot comprehensively elucidate the genomic makeup of HLA genes. Thus far, several high-throughput HLA-typing methods using NGS have been developed. In HLA research, NGS facilitates complete HLA sequencing and is expected to improve our understanding of the mechanisms through which HLA genes are modulated, including transcription, regulation of gene expression and epigenetics. Most importantly, NGS may also permit the analysis of HLA-omics. In this review, we summarize the impact of NGS on HLA research, with a focus on the potential for clinical applications.