Recovery from Cidofovir-Resistent BK Virus-Associated Hemmorhagic Cystitis Post Cord Blood Transplant Following Rapid Taper of Immunosuppression

Hemorrhagic cystitis (HC) usually happens 2-4 weeks after Hematopoietic Stem Cell Transplantation (HSCT). BK virus associated HC is a severe complication after HSCT and usually sensitive to cidofovir treatment. Here we report a late onset BK virus-associated HC after a cord blood transplantation (HLA 5/6) followed by a failure treatment of cidofovir in an acute lymphoblastic leukemia patient. The patient was conditioned with an intensified conditioning regimen containing fludarabine, cytosine arabinoside, busulfan, cyclophosphamide and rabbit antithymocyte globulin (FABuCy+ATG). The late development of HC with the symptom of hematuria occurred 22 days after HSCT and was associated with BK virus. In two weeks, the hematuria progressed with the failure of hydration, alkalizing diuresis and reduction of immunosuppressant treatment. Surprisingly, treatment of cidofovir only transient lower BK virus copies and was proved to be a failure. Thereafter, early immunosuppressant withdrawal was applied followed by thymosin α1 injections to enhance immunity. Although the BKV was still high, HC recovered with mild and controllable GVHD. One year after HSCT, the patient remain well without HC as well as GVHD.