title: Risk factors in the progression of BK virus-associated nephropathy in renal transplant recipients.
abstract: OBJECTIVE
  BK virus-associated nephropathy (BKVAN) is an important cause of allograft dysfunction in kidney transplant recipients. It has an unfavorable clinical course, and no definite treatment guidelines have yet been established. Here, we report our center's experience with biopsy-proven BKVAN and investigate factors associated with its progression.
  
  
  METHODS
  From January 2004 to April 2013, 25 patients with BKVAN were diagnosed by biopsy at Seoul St. Mary's Hospital. Of the 25 patients, 10 were deceased-donor transplant recipients and 15 were living-donor transplant recipients. Three of the patients underwent retransplantation. The primary immunosuppressant used was tacrolimus in 17 patients and cyclosporine in eight patients.
  
  
  RESULTS
  BKVAN was observed at a mean duration of 22.8 ± 29.1 months after transplantation. The mean serum creatinine level at biopsy was 2.2 ± 0.7 mg/dL. BKVAN occurred with acute rejection in eight patients (28%). Immunosuppression modification was performed in 21 patients (84%). Additionally, leflunomide and intravenous immunoglobulin were administered to 13 patients (52%) and two (8%), respectively. Allograft loss occurred in five patients (27.8%) during the follow- up period at 0.7, 17.1, 21.8, 39.8, and 41.5 months after the BKVAN diagnosis. Advanced stages of BKVAN, increased creatinine levels, and accompanying acute rejection at the time of BKVAN diagnosis increased the risk of allograft failure.
  
  
  CONCLUSIONS
  The clinical outcomes in patients with biopsy-proven BKVAN were unfavorable in the present study, especially in patients with advanced-stage BKVAN, poor renal function, and acute allograft rejection.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hae Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: In-Ae
authors.initials: IA
authors.lastname: Jang
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Dongjae
authors.initials: D
authors.lastname: Lee
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Kang
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Bum Soon
authors.initials: BS
authors.lastname: Choi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Cheol Whee
authors.initials: CW
authors.lastname: Park
authors.affiliation: Department of Hospital Pathology, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yeong Jin
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Chul Woo
authors.initials: CW
authors.lastname: Yang
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yong-Soo
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Byung Ha
authors.initials: BH
authors.lastname: Chung
mesh_terms: D000328:Adult; D064591:Allografts; D000998:Antiviral Agents / Q000627:therapeutic use; D001739:BK Virus / Q000472:pathogenicity*; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D003404:Creatinine / Q000097:blood; D018450:Disease Progression; D005260:Female; D006084:Graft Rejection / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D006085:Graft Survival; D006801:Humans; D016867:Immunocompromised Host; D007166:Immunosuppressive Agents / Q000009:adverse effects; D053208:Kaplan-Meier Estimate; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009894:Opportunistic Infections / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D027601:Polyomavirus Infections / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000821:virology*; D056910:Republic of Korea; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014412:Tumor Virus Infections / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology / Q000821:virology*
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D007166:Immunosuppressive Agents; D003404:Creatinine
keywords: BK virus; Kidney transplantation; Nephropathy