title: Risk factors for BK virus infection and BK virus-associated nephropathy under the impact of intensive monitoring and pre-emptive immunosuppression reduction.
abstract: BACKGROUND
  BK virus (BKV) nephropathy (BKVN) is an increasingly recognized cause of kidney allograft loss and is thought to be related to the newer, more potent immunosuppressive agents. However, the risk factors for different types of BKV infection under the impact of intensive monitoring and reduction of maintenance immunosuppression are not well understood.
  
  
  METHODS
  Quantitative BKV DNA surveillance in plasma/urine and cytological testing in urine were performed regularly within the first year post-transplantation in 229 kidney recipients. Patients with BK viremia and BKVAN treated with immunosuppression reduction were monitored for BKV every 3-6 months. All the patients were followed up for a minimum of 5 years to exclude later development of BKVAN. Potential variables were compared and analyzed using logistic regression model multivariate analysis to assess and rank the BKV infection-related factors.
  
  
  RESULTS
  Seventy-eight (34.1%) patients had decoy cells, 99 (43.2%) BK viruria, 38 (16.6%) BK viremia, and 7 (3.1%) BKVAN. Risk for decoy cells, BK viruria, and viremia, and BKVAN in univariate analyses were higher with tacrolimus (Tac) and deceased kidney donation. Multivariate analysis showed that Tac ([HR, 2.7; P = .008], [HR, 2.3; P = .016], [HR, 2.9; P = .032]) and deceased kidney donation ([HR, 2.5; P = .004], [HR, 2.6; P = .002], [HR, 2.1; P = .071]) were risk factors for BK decoy cells, BK viruria, and viremia, respectively. BKVAN was inclined to the patients with the combination of Tac and mycophenolate mofetil and longer BKV clearance time.
  
  
  CONCLUSIONS
  Tac and deceased kidney donation are independent risk factors for BKV infection under the impact of therapeutic drug monitoring.
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: G
authors.initials: G
authors.lastname: Huang
authors.affiliation: Department of Kidney Transplantation, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.affiliation: North Campus, Faculty of Medical Sciences, Sun Yat-sen University, Guangzhou, China.
authors.forename: X
authors.initials: X
authors.lastname: Liang
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: J
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: R
authors.initials: R
authors.lastname: Deng
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: G
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Pathology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China. Electronic address: dongyu19791979@163.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Department of Organ Transplantation, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: L
authors.initials: L
authors.lastname: Chen
mesh_terms: D000328:Adult; D001739:BK Virus / Q000235:genetics; D004279:DNA, Viral / Q000032:analysis; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy / Q000009:adverse effects*; D007166:Immunosuppressive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D007674:Kidney Diseases / Q000175:diagnosis / Q000209:etiology*; D016030:Kidney Transplantation; D008297:Male; D027601:Polyomavirus Infections / Q000150:complications* / Q000821:virology; D012307:Risk Factors; D014412:Tumor Virus Infections / Q000150:complications* / Q000821:virology
chemical_list: D004279:DNA, Viral; D007166:Immunosuppressive Agents