Incidence and risk factors of late-onset hemorrhagic cystitis after single umbilical cord blood transplantation with myeloablative conditioning regimen.

To explore the incidence and risk factors of late-onset hemorrhagic cystitis (LOHC) in patients undergoing single umbilical cord blood transplantation for hematological malignancies. Clinical data from 234 patients who consecutively underwent single UCBT using a myeloablative conditioning regimen without antithymocyte globulin in our center were retrospectively analyzed. In total, 64 (27.4%) patients developed LOHC with a median onset time of 40.5 (range 8–154) days, and 15 (6.4%) patients gradually developed grade III–IV LOHC. The incidence of LOHC was marginally higher in adults (31.0%) than in children (23.7%) (p = 0.248). HLA matching ≤ 6/8 (HR = 2.624, 95% CI 1.112–6.191, p = 0.028) was an independent risk factor for LOHC. The overall survival of LOHC patients (59.8%, 95% CI 61.7–85.5%) was significantly lower than that of patients without LOHC (86.8%, 95% CI 79.6–91.6%) at 130 days post transplantation (p = 0.036). Patients with less well-matched grafts have a higher incidence of LOHC. Inherent deficiencies in immunity in the context of HLA disparity and more intense pharmacologic immunosuppression after severe acute graft-versus-host disease may contribute to viral activation. Prevention and treatment of LOHC have the potential to prolong long-term survival.