Rapid high-resolution HLA genotyping by MinION Oxford nanopore sequencing for deceased donor organ allocation

Recently, HLA epitopes on donor HLA molecules have been shown to be important in the success of solid organ transplantation. However, these epitopes can only be defined using high-resolution typing results of which are often not available prior to deceased donor allocation. The ability to perform high-resolution typing at all HLA loci for deceased organ donor allocation prior to transplantation would have major clinical benefits, in particular for highly sensitised recipients. We, therefore, developed a rapid high-resolution next generation sequencing (NGS) HLA typing (ONT-Rapid HR HLA) method for on-call deceased donor allocation using the AllType 11 loci single-tube assay (OneLambda Inc), modified in-house to reduce polymerase chain reaction amplification time, and the Oxford Nanopore single-molecule sequencing platform on the Flongle flow cell. The ONT-Rapid HR HLA method was validated on 42 samples previously typed by current on-call sequence-specific oligonucleotide (HistoSpot) and NGS methods (AllType/Ion Torrent). High-resolution typing obtained using the ONT-Rapid HR HLA typing method was 100% concordant with both the current SSO and NGS methods, and in some cases, obtained higher resolution than either of the current methods. The rapid ONT-Rapid HR HLA typing method was able to obtain these typing results at all loci in 4 to 4.5 hours. The novel ONT-Rapid HR HLA typing method is the first reported NGS HLA typing method utilised for deceased donor allocation. The ability to provide high-resolution HLA typing on deceased donors before implantation will in the future allow improvements in matching, which will ultimately provide clinical benefits to patients.