title: Transient versus persistent BK viremia and long-term outcomes after kidney and kidney-pancreas transplantation.
abstract: OBJECTIVE
  The objective was to study the long-term impact of transient versus persistent BK viremia on kidney transplant outcomes.
  
  
  METHODS
  In total, 609 recipients who underwent kidney transplant from 2007 to 2011 were screened at months 1-12 for the occurrence of polyomavirus BK viremia; 130 patients (21.7%) developed BK viremia during the first year post-transplant. BK viremia patients were classified according to duration of infection (more or less than 3 months), and BK viral loads (more or less than 10,000 copies/ml) were classified as transient low viremia (n=42), transient high viremia (n=18), persistent low viremia (n=23), and persistent high viremia (n=47). All patients were followed a median of 36 (3-66) months. The rates of BK polyomavirus-associated nephropathy, acute rejection, and 1-year graft function were compared with the polyomavirus BK-negative control group.
  
  
  RESULTS
  Patient and graft survival were not significantly different among the groups. Graft function (creatinine; milligrams per deciliter) at 1 year was significantly worse in the persistent high viremia (1.75±0.6) and transient high viremia (1.85±0.7) groups compared with aviremic controls (1.47±0.4; P=0.01 and P=0.01, respectively). The incidence of BK polyomavirus-associated nephropathy was limited to the persistent high viremia group (1.3%, P<0.001). The transient high viremia (50%) and persistent high viremia (34%) groups showed significantly (P=0.01) increased incidence of acute rejection versus aviremic controls (21.5%), transient low viremia (19%), or persistent low viremia (17.3%) groups.
  
  
  CONCLUSIONS
  Low viral load BK viremia, either transient or persistent, was not associated with long-term transplant outcomes. Persistent high viremia was associated with a greater risk for BK polyomavirus-associated nephropathy and subsequent graft dysfunction. Although transient high viremia was not associated with BK polyomavirus-associated nephropathy, it was associated with worse graft function. These data support the role of surveillance for BK viremia after transplant.
authors.affiliation: Glickman Urological and Kidney Institute,, †Department of Quantitative Health Sciences, and, ‖Department of Infectious Disease in the Medicine Institute, Cleveland Clinic, Cleveland, Ohio;, ‡Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina, §Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Nissreen
authors.initials: N
authors.lastname: Elfadawy
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Flechner
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Schold
authors.forename: Titte R
authors.initials: TR
authors.lastname: Srinivas
authors.forename: Emilio
authors.initials: E
authors.lastname: Poggio
authors.forename: Richard
authors.initials: R
authors.lastname: Fatica
authors.forename: Robin
authors.initials: R
authors.lastname: Avery
authors.forename: Sherif B
authors.initials: SB
authors.lastname: Mossad
mesh_terms: D001739:BK Virus / Q000472:pathogenicity*; D005260:Female; D006084:Graft Rejection / Q000821:virology; D006085:Graft Survival; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D015994:Incidence; D053208:Kaplan-Meier Estimate; D016030:Kidney Transplantation / Q000009:adverse effects* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D016035:Pancreas Transplantation / Q000009:adverse effects* / Q000401:mortality; D027601:Polyomavirus Infections / Q000175:diagnosis / Q000401:mortality / Q000821:virology*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014412:Tumor Virus Infections / Q000175:diagnosis / Q000401:mortality / Q000821:virology*; D019562:Viral Load; D014766:Viremia / Q000175:diagnosis / Q000401:mortality / Q000821:virology*
chemical_list: D007166:Immunosuppressive Agents