DNA was extracted from whole blood using the
EZ1 DNA Blood 350 µl Kit or
QIAsymphony DSP DNA Mini Kit (192) (Qiagen, Hilden, Germany). Whole gene characterization (5′UTR to 3′UTR) for HLA-A, B, C, DQA1, DPA1, and DQB1 and key region characterization (exon 2 to 3′UTR) of HLA-DRB1, DRB3, DRB4, DRB5, and DPB1 was performed using the Holotype HLA kit version 2 (Omixon, Budapest, Hungary). Libraries were sequenced using
MiSeq Sequencer (Illumina, California, USA) and sequence data were analyzed using the HLA Twin version 2.5 (Omixon, Budapest, Hungary).
HLA eplets were obtained from allelic data using the computer algorithm HLAMatchmaker v02 for HLA class I and v02.2 for HLA class II genes (
www.epitopes.net) which uses a database of alleles to define a string of eplets for each allele. Only eplets registered to be experimentally confirmed by antibody testing (antibody-verified eplets) were used in this analysis.
Allele or eplet carrier rates (relative frequencies) were calculated respectively as the proportion of subjects expressing a specific allele or eplet within the total study sample. Composite genotypes (HLA types) and their corresponding epitypes were calculated respectively as the numbers of subjects within the sample expressing each unique combination of alleles or eplets at all the 11 allelic HLA gene loci.
Tran J.N., Günther O.P., Sherwood K.R., Fenninger F., Allan L.L., Lan J., Sapir-Pichhadze R., Duquesnoy R., Claas F., Marsh S.G., McMaster W.R, & Keown P.A. (2021). High-throughput sequencing defines donor and recipient HLA B-cell epitope frequencies for prospective matching in transplantation. Communications Biology, 4, 583.