Progressive multifocal leukoencephalopathy after T‐cell replete HLA‐haploidentical transplantation with post‐transplantation cyclophosphamide graft‐versus‐host disease prophylaxis

: A 52-year-old man suffered from progressive multifocal leukoencephalopathy (PML) after human leukocyte antigen (HLA)-haploidentical transplantation with post-transplantation cyclophosphamide (PTCY). Mirtazapine, mefloquine, and cytarabine failed to improve his symptoms, and he finally died 4.5 months after PML onset. This is the first case report of a patient with PML after HLA-haploidentical transplantation with PTCY. Although T-cell replete HLA-haploidentical transplantation with PTCY has enabled early immune reconstitution, PML should be considered if a patient's mental condition deteriorates.