Incidence and risk factors for hemorrhagic cystitis in unmanipulated haploidentical transplant recipients

Background. Hemorrhagic cystitis (HC) is a common complication after hematopoietic allogeneic stem cell transplantation (HSCT) associated with intensity of the conditioning regimen, cyclophosphamide (Cy) therapy, and BK polyomavirus (BKPyV) infection. Methods. We analyzed 33 consecutive haploidentical (haplo) HSCT recipients transplanted for hematologic diseases. Eleven patients had a previous transplant. Median follow-up was 11 months. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine + mycophenolate mofetil and post-HSCT Cy. Results. Thirty-two of 33 patients achieved neutrophil recovery. Cumulative incidence (CI) of platelet recovery was 65%. CI grade II-IV acute GVHD was 44%. Twenty patients developed HC in a median time of 38 days. CI of HC at day 180 was 62%. BKPyV was positive in blood and urine of 91% of patients at HC onset. HC resolved in 18/20 patients. Factors associated with HC were previous transplant (P = 0.01) and occurrence of cytomegalovirus reactivation before HC (P = 0.05). Grade II-IV acute GVHD was not associated with HC (P = 0.62). CI of day 180 viral infections was 73%. Two-year overall survival (OS) was 50%; HC did not impact OS (P = 0.29). Conclusion. The incidence of HC after haplo with post-HSCT Cy is high and is associated with morbidity, especially in high-risk patients such as those with a previous transplant history and with impaired immune reconstitution.