Genomic DNA was extracted from peripheral blood using standard methods. Briefly, the yellow-top vacutainer tubes were centrifuged, aspirated off most of the serum, treated with red blood cell lysis buffer. Then the cells were lysed using nuclei lysis buffer and proteinase K, and the genomic DNA was precipitated using ammonium acetate and ethanol. Finally, the DNA pellet was washed, dried, and dissolved. Genomic DNA was fragmented, end-repaired, A-tailed, and ligated to methylated adaptors. The ligated samples will be pooled together to perform MHC capture using validated capture probes and custom panel from Twist Bioscience following the target enrichment standard hybridization protocol (Twist Bioscience). The pooled fragments were then bisulfite converted using the EZ DNA Methylation Gold kit (Zymo Research) at 64℃ for 2.5 hours and amplified using the KAPA HiFi HotStart Uracil+ ReadyMix PCR Kit.