[Unrelated hematopoietic stem cell transplantation with post-transplant cyclophosphamide for myelodysplastic syndrome with anti-HLA antibodies].

A 65-year-old woman was diagnosed with myelodysplastic syndrome following the detection of pancytopenia, and allogeneic hematopoietic stem cell transplantation was planned. No HLA-matched related or unrelated donor was available. Anti-HLA antibody screening showed broad, high mean fluorescence intensity (MFI) antibodies against HLA-A, -B, -C, and -DR. The maximum MFI was 21,919, and high-MFI donor-specific antibodies (DSA) against HLA-haploidentical related donors were detected. Because reduced-intensity conditioning and graft-versus-host disease (GVHD) prophylaxis with post-transplant cyclophosphamide were planned, donor selection prioritized avoidance of DSA over HLA compatibility. Consequently, peripheral blood stem cell transplantation was performed from an unrelated donor with two HLA mismatches. Engraftment was achieved promptly, and neither acute nor chronic GVHD developed. The patient remains in complete remission at nine months after transplantation.