[Successful T-cell-replete peripheral blood stem cell transplantation from an HLA 2 loci mismatched mother to her son with refractory anemia in myelodysplastic syndrome].

A 15-year-old male with refractory anemia in myelodysplastic syndrome underwent peripheral blood stem cell transplantation from his two-loci-mismatched haploidentical mother. The conditioning regimen was comprised of cyclophosphamide, busulfan, and fludarabine. Non-T-cell-depleted peripheral blood stem cells were infused with graft-versus-host disease (GVHD) prophylaxis consisting of tacrolimus and short-course methotrexate. Engraftment was confirmed on day 18, and complete chimera on day 29. Although the patient developed grade II acute GVHD following the transplantation, it responded rapidly to steroid administration. The subsequent course was uneventful, and he remains well in complete remission in 26 months after transplant. This successful experience suggests that maternal hematopoietic stem cell transplant for children, in specific immune tolerance based on the presence of microchimerism and compatibility of minor histocompatibility antigens between mother and child, may have given rise to the favorable preventing effect against severe GVHD.