HLA-DRB sequencing-based typing: an improved protocol which shows complete DRB exon 2 sequences and includes exon 3 of HLA-DRB4/5.

Several human leukocyte antigen (HLA)-DRB protocols for sequencing-based typing have been described. In general, the DRB1 amplification is performed using group-specific amplification primers (GSAPs) located in HVR I or intron 1. Only some protocols include amplification of DRB3, DRB4, and DRB5. However, prior knowledge obtained by alternative methods such as PCR-SSP is preferred for some protocols and a large amount of DNA is often required for adequate typing of HLA-DRB1. We describe a new protocol that uses GSAPs located in the introns, includes also sequencing of exon 3 to enable high resolution. This protocol allows DRB typing without prior knowledge of the HLA type.