Outcomes of allogeneic hematopoietic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria compared to paroxysmal nocturnal hemoglobinuria-aplastic anemia syndrome

Objective To compare the outcomes of allogeneic hematopoietic stem cell transplantation(allo-HSCT)for paroxysmal nocturnal hemoglobinuria(PNH)with paroxysmal nocturnal hemoglobinuria-aplastic anemia(PNHAA)syndrome.Methods The outcomes of 46 patients who received allo-HSCT(16 PNH patients,30 PNH-AA patients)from July 10,2007 to June 2,2018 were analyzed retrospectively.The conditioning regimen was busulfan,cyclophosphoramide,and ATG in haploidentical donors and unrelated donors.Patients with matched sibling donors were treated with the fludarabine,cyclophosphamide and ATG regimen.Results There were no differences of baseline data between the 2 groups except gender distribution and the numbers of haploidentical donor transplantation.The median values of absolute nucleated cell counts were 10.58(3.83-13.83)×10^8/kg in the PNH group and 10.81(3.96-33.40)×10^8/kg in the PNH-AA group(P=0.668).The median doses of CD34+cells infused were 5.00(3.14-8.42)×10^6/kg and 3.57(1.97-6.17)×10^6/kg(P=0.002),respectively.All patients obtained complete engraftment.The median time for myeloid engraftment were 11(7-14)days in the PNH group and 12(10-26)days in the PNH-AA group(P=0.003).The median time for platelet engraftment were 13(11-16)days and 18(12-75)days(P=0.002),respectively,after a median follow-up of 36(4-132)months in the PNH group and 26(4-75)months in the PNH-AA group(P=0.428).There were no differences of incidence rates of acute graft-versus-host disease(aGVHD),chronic GVHD and infection between PNH and PNH-AA groups(P>0.05).No patient occurred early death and relapse.The estimated 3-year overall survival(OS)of PNH and PNH-AA groups were(100.0±0.0)%and(85.7±6.6)%(P=0.141),GVHD-free and failurefree survival(GFFS)were(100.0±0.0)%,(78.7±7.7)%(P=0.067).Conclusion allo-HSCT is effective for patients with PNH and PNH-AA syndrome.The preliminary results indicate that myeloid and platelet engraftment in PNH group were faster than PNH-AA group.There were no differences in OS and GFFS between PNH group and PNH-AA group.