Background : Paroxysmal nocturnal hemogolbinuria (PNH) is an acquired clonal hematological disorder characterized by intermittent episodes of hemolysis, a predisposition to venous thrombosis, defective hemopoiesis, and occasionally, transition to leukemia. Because PNH is a stem cell disorder, treatment with androgen or corticosteroids may only be a palliative measure, and allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment. We report here our experience of eight PNH patients who underwent HSCT.
Methods : Between January 1997 and July 2001, 8 patients, aged 16 to 47 (median 27.5), underwent HSCT for PNH at the Catholic Hemopoietic Stem Cell Transplantation Center. Median time from diagnosis to HSCT was 60.5 months (range 5-165 months). Two different conditioning regimens included busulfan (16㎎/㎏) and cyclophosphamide (120㎎/㎏) or TBI 1,200c㏉ and cyclophosphamide (120㎎/㎏). Graft-versus-host disease (GVHD) prevention was cyclosporine with methotrexate (MTX)(N= 6), FK506 with MTX(N=1) or cyclosporine with T-cell depletion of donor marrow (N=1).
Results : Four deaths occurred in the first post-transplant year. Deaths were from graft failure (N=1), pneumonia (N=1) and veno-cclusive disease/thrombotic thrombocytopenic purpura (N=2). Four patients (50%) remain alive at a median of 26 months (range 1-60 months) and 5-year probability of survival was 66.7% after HLA-matched sibling HSCT. Grade Ⅰ or Ⅱ acute GVHDs occurred in 3 patients and chronic GVHD did not develop in 5 patients other than 3 patients who died within 100 days post-transplant.
Conclusion : This study suggests that HSCT is an effective therapeutic option for PNH. Further studies are needed to decide the appropriate conditioning regimens to overcome treatment-related mortality after transplantation.

Keywords: Paroxysmal nocturnal hemoglobinuria, Graft versus host disease, Hematopoietic stem cell transplantation,