title: [Analysis of BK viruria on the long term graft survival in renal transplant recipients].
abstract: OBJECTIVE
  To observe the clearance of BK viruria and long-term graft survival in renal transplant recipients with BK virus (BKV) infection under the protocol of our center.
  
  
  METHODS
  Urine was taken from 229 renal transplant recipients,who were transplanted between March 2006 to October 2008, for BKV cytological testing and real-time PCR for BKV DNA at 1, 3, 6, 9, and 12 months after transplantation. Graft biopsies were analyzed for SV40-T by immunohistochemical method. Recipients were treated according to the BKV infection protocol of our center and were monitored for BKV and graft function. All the patients were followed for at least 5 years.
  
  
  RESULTS
  By 1 year post-transplant, urinary decoy cells, BK viruria, and BKV associated nephropathy (BKVAN) occurred in 78, 99, and 7 patients, respectively. The median followed-up time was 63.6 (3.0-88.0) months. After reduction of immunosuppression, 81 (81.8%) patients cleared BK viruria with a mean time of (12.1 ± 1.9) months. When compared with non-BKVAN patients, BKVAN patients had a higher median peak level of BK viruria (2.07 × 10⁹ vs 9.28 × 10⁵ copies/ml, P=0.002), lower frequency of clearance (3/7 vs 78/92, P=0.006), longer BK viruria clearance time ((45.4 ± 6.4) vs (8.7 ± 1.5) months, P=0.001). The 1, 3, 5-year graft survival in BK viruria patients were 99.0%, 95.9% and 89.6% respectively, which were not significantly different from those in non-BK viruria patients (97.7%, 95.5% and 93.7%, P=0.289). Graft function of BK viruria patients were not statistical significance compared with non-BK viruria patients (serum creatinine level 5 years post-transplant: (105.7 ± 30.9) vs (111.3 ± 4.6) µmol/L, P=0.322). Graft function of BKVAN patients at 5 years post-transplant was stable without significantly difference from non-BKVAN patients (serum creatinine level: (127.6 ± 41.0) vs (108.3 ± 39.3) µmol/L, P=0.204).
  
  
  CONCLUSIONS
  On the premise of intensively and regularly BKV monitoring and preemptive reduction of immunosuppression, BK viruria and BKVAN can not impact on the long-term graft survival in renal transplant recipients.
authors.affiliation: Department of Organ Transplantation, First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Huang
authors.forename: Changxi
authors.initials: C
authors.lastname: Wang
authors.forename: Yanchun
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Luo
authors.forename: Jiguang
authors.initials: J
authors.lastname: Fei
authors.forename: Suxiong
authors.initials: S
authors.lastname: Deng
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Guodong
authors.initials: G
authors.lastname: Chen
authors.forename: Qian
authors.initials: Q
authors.lastname: Fu
authors.forename: Ronghai
authors.initials: R
authors.lastname: Deng
authors.affiliation: Email: guhuil@mail.sysu.edu.cn.
authors.forename: Jiang
authors.initials: J
authors.lastname: Qiu
authors.forename: Lizhong
authors.initials: L
authors.lastname: Chen
mesh_terms: D001739:BK Virus; D001706:Biopsy; D006085:Graft Survival; D006801:Humans; D016030:Kidney Transplantation; D027601:Polyomavirus Infections; D060888:Real-Time Polymerase Chain Reaction; D066027:Transplant Recipients; D014412:Tumor Virus Infections