Salvage HLA-haploidentical bone marrow transplantation with post-transplant cyclophosphamide in a patient with NEMO deficiency

Abstract

Graft failure is one of the most serious complications following hematopoietic cell transplantation (HCT). Rescue HCT is the only treatment option for graft failure. Recently, HLA-haploidentical HCT (Haplo-HCT) with post-transplant cyclophosphamide (PTCy) has shown promising results for hematologic malignancies, but its evidence for inborn errors of immunity (IEI) is limited. We report a successful salvage Haplo-HCT with PTCy following secondary graft failure in a patient with ectodermal dysplasia with immunodeficiency (EDA-ID) due to NEMO deficiency. The patient suffered from chronic diarrhea and Pneumocytis jirovecii pneumonia during his infancy. Following fludarabine and busulfan-based reduced intensity conditioning (RIC), he received HLA 7/8-matched unrelated bone marrow transplantation (BMT) at the age of one year. Engraftment was achieved on day 17. Ten months after BMT, he developed refractory pancytopenia. Haplo-BMT with PTCy from his father following RIC with fludarabine (150 mg/m²), melphalan (70 mg/m²), anti-thymocyte globulin (2.5 mg/kg), and 2 Gy of total body irradiation was conducted. Tacrolimus and mycophenolate mofetil were used for GVHD prophylaxis. Engraftment was achieved on day 12 without any comorbidities. Our result implicates the validity and safety of Haplo-HSCT with PTCy for patients with IEI.