Due to the differences in human and mouse MHC antigens, the transplantation of human PBMCs often causes graft‐versus‐host disease (GVHD) in hu‐PBL mice in the short term, leading to weight loss, a hunching posture, hair loss, and decreased activity; GVHD can even result in death, thus shortening the experimental window.64, 65, 66. The gene discussed is HLA-C; the disease is graft versus host disease.