Clinical observation of allogeneic hematopoietic stem cell transplantation for treating five cases of classic paroxysmal nocturnal hemoglobinuria

This study enrolled five patients with classic paroxysmal nocturnal hemoglobinuria (cPNH) who underwent allogeneic hematopoietic stem cell transplantation in our hospital from 2019 to 2023. All five patients were male, with a median age of 26 (range: 26-46) years. The median time from diagnosis to allo-HSCT was 5.5 (range: 3.6-18.0) years. The median PNH granulocyte clone size was 96.3% (ranged 90.0%-99.7%), and the median lactate dehydrogenase (LDH) level was 2 224 IU/L (8896-fold of the upper limit of normal). All patients were detected to have bone marrow hyperplasia by trephine biopsy. The stem cell source came from four haploidentical donors and one HLA-identical sibling donor. Among the five patients, three underwent myeloablative conditioning (MAC) and two underwent reduced-intensity conditioning (RIC) treatment. None of the patients experienced primary implantation failure. The neutrophil implantation time was 15 (range: 13-21) days, and the platelet implantation time was 24 (range: 13-60) days. The three patients developed grade II acute graft-versus-host disease (aGVHD). No patients developed grade Ⅲ/Ⅳ aGVHD. The two patients developed localized chronic GVHD (cGVHD), and no patients developed extensive cGVHD. PNH clones turned negative in all patients after 2 (range: 1-3) months of transplantation. At a median follow-up of 16 (range: 6-34) months, one patient died of relapse and infection, and the remaining four patients survived, of which two patients had discontinued all drugs.