Successful treatment of very severe aplastic anemia with double unrelated umbilical cord blood transplantation in a donor-specific antigen positive adult patient: A case report and review

To overcome the cell-dose barrier of cord blood, double unrelated umbilical cord blood transplantation (UCBT) has become increasingly common in adults with severe aplastic anemia (SAA). Pre-existing donor-specific anti-HLA antibodies (DSAs) represent a risk factor for graft failure (GF). Desensitization therapy should be conducted to reduce circulating DSA levels, thereby decreasing the risk of GF. This report details a case of a female patient with acquired SAA and pre-transplantation anti-HLA antibodies. Desensitization with rituximab, intravenous immunoglobulin (IVIG), and plasma exchange (PE) was performed before transplantation with a conditioning regimen of fludarabine (30 mg/m² for six days) and cyclophosphamide (50 mg/kg/d for four days). DSA titers were significantly reduced; the patient was successfully treated with double unrelated UCBT. Currently, complete remission (CR) status has been maintained for over a year after UCBT, with no signs of graft-vs-host disease. Our findings support the use of double-unit unrelated UCBT in adult patients with SAA when cell doses of single-unit UCB are inadequate. Monitoring and reducing DSA levels before and after UCBT is an efficient way to reduce the risk of GF.