title: Association of BK viremia with human leukocyte antigen mismatches and acute rejection, but not with type of calcineurin inhibitor.
abstract: BACKGROUND
  BK viremia and polyomavirus-associated nephropathy (PVN) represent a significant problem after kidney transplantation. Both are associated with intensified immunosuppression, but other risk factors and the impact of a screening program on outcome are incompletely understood.
  
  
  METHODS
  Here, we report on the short- and long-term outcome of a cohort of patients, who were transplanted in 2006/2007 and included in a newly introduced systematic 3-monthly screening for BK viremia at the University Hospital Zurich. In patients testing positive for BK viremia, screening frequency was intensified and immunosuppression reduced. Patients with suspected PVN underwent transplant biopsy.
  
  
  RESULTS
  Among 152 included patients, 49 (32%) tested positive for BK viremia, but only 8 developed biopsy-proven PVN. BK viremia had a significant impact on estimated glomerular filtration rate and proteinuria in the first 2 years. Acute rejection episodes and the number of human leukocyte antigen (HLA) mismatches were the strongest independent predictors of BK viremia in a multiple logistic model. In contrast, no particular immunosuppressive agent or regimen was associated with enhanced risk.
  
  
  CONCLUSIONS
  Taken together, systematic BK viremia screening led to detection of a high percentage of viremic patients. With adjustment of immunosuppression, an excellent outcome was achieved. The independent association of HLA mismatches with BK viremia suggests impaired polyomavirus immunosurveillance in highly mismatched allografts.
authors.affiliation: Division of Nephrology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Hässig
authors.forename: M
authors.initials: M
authors.lastname: Roos
authors.forename: A
authors.initials: A
authors.lastname: Etter
authors.forename: W
authors.initials: W
authors.lastname: Bossart
authors.forename: N
authors.initials: N
authors.lastname: Müller
authors.forename: M
authors.initials: M
authors.lastname: Schiesser
authors.forename: R P
authors.initials: RP
authors.lastname: Wüthrich
authors.forename: T
authors.initials: T
authors.lastname: Fehr
mesh_terms: D000328:Adult; D000368:Aged; D064591:Allografts / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D001379:Azathioprine / Q000627:therapeutic use; D001739:BK Virus; D000077552:Basiliximab; D015331:Cohort Studies; D016572:Cyclosporine / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate; D006084:Graft Rejection / Q000276:immunology* / Q000517:prevention & control; D006680:HLA Antigens / Q000276:immunology; D006648:Histocompatibility / Q000276:immunology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007674:Kidney Diseases / Q000276:immunology* / Q000821:virology; D016030:Kidney Transplantation; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D027601:Polyomavirus Infections / Q000276:immunology*; D011507:Proteinuria / Q000276:immunology; D011758:Pyrroles / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use; D016559:Tacrolimus / Q000627:therapeutic use; D014412:Tumor Virus Infections / Q000276:immunology*; D014766:Viremia / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D007166:Immunosuppressive Agents; D011758:Pyrroles; D011799:Quinazolines; D011993:Recombinant Fusion Proteins; C543528:sotrastaurin; D016572:Cyclosporine; D000077552:Basiliximab; D009173:Mycophenolic Acid; D001379:Azathioprine; D016559:Tacrolimus
keywords: BK nephropathy; BK virus; HLA matching; acute rejection; immunosuppression; kidney transplantation; polyomavirus-associated nephropathy