Cotransplantation of haploidentical hematopoietic stem cells and allogeneic bone marrow‐derived mesenchymal stromal cells as a first‐line treatment in very severe aplastic anemia patients with refractory infections

Abstract

OBJECTIVES: In patients with very severe aplastic anemia (VSAA), neutropenia is prolonged and persistent, resulting in refractory overwhelming infections. Hematopoiesis recovery is urgently needed. METHODS: Six patients with de novo VSAA lacking HLA-identical sibling donors and those who experienced refractory infections underwent haploidentical related donor (HRD) hematopoietic stem cell transplantation (HSCT) as a first-line therapy. The conditioning regimen consisted of busulfan, cyclophosphamide, and rabbit antithymocyte globulin. Culture-expanded allogeneic bone marrow-derived mesenchymal stromal cells were infused on day 0 and day +14. RESULTS: From diagnosis to HSCT, 6 patients experienced a total of 28 episodes of persistent fever, and the median number was 4 (range, 3-7). All cases developed major bacterial infections and invasive pulmonary fungal infection pre-HSCT. The median time from diagnosis to HSCT was 2 months (range, 1-3.5 months). All patients achieved sustained, full donor chimerism, and the median time of myeloid recovery and platelet engraftment was 13 days (range, 9-19 days) and 15.5 days (range, 10-23 days), respectively. One patient died of aGVHD, and 5 patients are alive after a median follow-up of 21 months (range 17-40.5). CONCLUSIONS: Upfront HRD-HSCT may be a safe and promising choice for patients with VSAA in critical situations without suitably matched donors.