title: Conversion to mTOR-inhibitors with calcineurin inhibitor elimination or minimization reduces urinary polyomavirus BK load in kidney transplant recipients.
abstract: OBJECTIVE
  Polyomavirus BK (BKV) reactivation causes allograft dysfunction in some kidney transplant recipients. The use of mammalian target of rapamycin (mTOR) inhibitor-based immunotherapy is associated with a lower incidence of polyomavirus-associated nephropathy compared with other immunosuppressants. This retrospective study assessed whether conversion to mTOR inhibitor-based immunotherapy directly reduced urinary BKV load.
  
  
  METHODS
  A total of 63 kidney recipients were divided into mTOR inhibitor-conversion (21 patients) and nonconversion (42 patients) groups. Urinary BKV loads were determined before and at least 6 months after the conversion.
  
  
  RESULTS
  The results demonstrated that urinary BKV titer was significantly reduced in the conversion group (3.94 ± 0.43 copies (log)/mL to 2.49 ± 0.19 copies (log)/mL) and remained unaltered in the nonconversion group (3.19 ± 0.20 copies (log)/mL to 2.90 ± 0.20 copies (log)/mL). In addition, the percentage of patients with reduced urinary BKV load was significantly higher in the conversion group (76.2% vs. 42.9%). The estimated glomerular filtration rate after 24 months mTOR inhibitor conversion was significantly increased compared with that in the nonconversion group. Conversion to mTOR-inhibitor-based immunotherapy was the only factor associated with an increase in estimated glomerular filtration rate.
  
  
  CONCLUSIONS
  This study reveals an association of conversion to mTOR-inhibitor-based immunotherapy with the reduction of urinary BKV load.
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chieh-Li
authors.initials: CL
authors.lastname: Yen
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ya-Chung
authors.initials: YC
authors.lastname: Tian
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Hsin-Hsu
authors.initials: HH
authors.lastname: Wu
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Cheng-Hao
authors.initials: CH
authors.lastname: Weng
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Yung-Chang
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Kun-Hua
authors.initials: KH
authors.lastname: Tu
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Shou-Hsuan
authors.initials: SH
authors.lastname: Liu
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Cheng-Chia
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ping-Chin
authors.initials: PC
authors.lastname: Lai
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ji-Tseng
authors.initials: JT
authors.lastname: Fang
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Cheng-Chieh
authors.initials: CC
authors.lastname: Hung
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Yang
authors.affiliation: Kidney Research Center, Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taipei, Taiwan; Department of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan. Electronic address: r5259@cgmh.org.tw.
authors.forename: Yi-Jung
authors.initials: YJ
authors.lastname: Li
mesh_terms: D000328:Adult; D001739:BK Virus / Q000187:drug effects*; D003404:Creatinine / Q000097:blood; D000068338:Everolimus / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007167:Immunotherapy; D007674:Kidney Diseases / Q000453:epidemiology* / Q000821:virology; D016030:Kidney Transplantation; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000188:drug therapy*; D011183:Postoperative Complications / Q000188:drug therapy / Q000821:virology; D012189:Retrospective Studies; D020123:Sirolimus / Q000627:therapeutic use; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D013624:Taiwan; D019562:Viral Load / Q000187:drug effects
chemical_list: D007166:Immunosuppressive Agents; D000068338:Everolimus; D003404:Creatinine; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus
keywords: kidney transplantation; mammalian target of rapamycin; polyomavirus BK; viruria