HLA-DRB1*04 high resolution typing.

High resolution typing for HLA-DR4 is required to identify the individual subtypes. In this study a panel of DR4-positive samples was typed by both sequencing-based typing (SBT) and oligohybridization (PCR sequence-specific oligonucleotide; PCR-SSO). SBT reveals the highest resolution; moreover, ambiguous DRB1*04 allelic combinations can be resolved by a selective amplification of the individual alleles and subsequent sequencing. An extended DR4-specific PCR-SSO makes high resolution typing possible; however, an additional protocol is required to resolve ambiguities.