BK virus nephropathy without hemorrhagic cystitis after cord blood stem cell transplantation: a case report

Abstract

BK virus is associated with hemorrhagic cystitis, ureteritis, ureteral stenosis and renal dysfunction with interstitial nephritis in immunocompromised patients. Hemorrhagic cystitis is a characteristic symptom in patients with BKV infection receiving bone marrow transplant. Here, we report the patient of BKV nephropathy after cord blood stem cell transplantation whose initial manifestation was renal dysfunction with interstitial nephritis without hemorrhagic cystitis. A 12-year-old girl with acute lymphoblastic leukemia was treated with cord blood stem cell transplantation because of treatment failure of chemotherapy. On the 13^th day after transplantation, decoy cells were detected in urine sediment and increase of urine and blood BKV copy numbers was observed. The diagnosis of BKV nephropathy was made and confirmed by renal biopsy. Tacrolimus was withdrawn and stopped but renal dysfunction was not improved. High dose intravenous immunoglobulin was administered and her renal dysfunction was improved. The patient of BKV nephropathy without hemorrhagic cystitis is rare, but physicians should differentiate BKV nephropathy from other causes of renal dysfunction after stem cell transplantation such as transplantation related treatment including chemotherapy, antibiotics and immunosuppressive drugs.