title: Incidence and outcomes of BK virus allograft nephropathy among ABO- and HLA-incompatible kidney transplant recipients.
abstract: OBJECTIVE
  ABO-incompatible kidney transplant recipients may have a higher incidence of BK virus allograft nephropathy (BKVAN) compared with ABO-compatible recipients. It is unclear whether HLA-incompatible recipients share this risk or whether this phenomenon is unique to ABO-incompatible recipients.   DESIGN, SETTING, PARTICIPATION,  MEASUREMENTS:  This study analyzed adult incompatible kidney transplant recipients from 1998 to 2010 (62 ABO-incompatible and 221 HLA-incompatible) and identified patients in whom BKVAN was diagnosed by biopsy (per protocol or for cause). This was a retrospective analysis of a prospectively maintained database that compared BKVAN incidence and outcomes between ABO- and HLA-incompatible recipients, respectively. BKVAN link to rejection and graft accommodation phenotype were also explored. The Johns Hopkins Institutional Review Board approved this study.
  
  
  RESULTS
  Risk for BKVAN was greater among ABO-incompatible than HLA-incompatible patients (17.7% versus 5.9%; P=0.008). Of BKVAN cases, 42% were subclinical, diagnosed by protocol biopsy. ABO-incompatibility and age were independent predictors for BKVAN on logistic regression. C4d deposition without histologic features of glomerulitis and capillaritis (graft accommodation-like phenotype) on 1-year biopsies of ABO-incompatible patients with and without BKVAN was 40% and 75.8%, respectively (P=0.04). Death-censored graft survival (91%) and serum creatinine level among surviving kidneys (1.8 mg/dl) were identical in ABO- and HLA-incompatible patients with BKVAN (median, 1399 and 1017 days after transplantation, respectively).
  
  
  CONCLUSIONS
  ABO-incompatible kidney recipients are at greater risk for BKVAN than HLA-incompatible kidney recipients. ABO-incompatible recipients not showing the typical graft accommodation-like phenotype may be at heightened risk for BKVAN, but this observation requires replication among other groups.
authors.affiliation: Renal Institute of Birmingham, Queen Elizabeth Hospital, Edgbaston, Birmingham, United Kingdom.
authors.forename: Adnan
authors.initials: A
authors.lastname: Sharif
authors.forename: Nada
authors.initials: N
authors.lastname: Alachkar
authors.forename: Serena
authors.initials: S
authors.lastname: Bagnasco
authors.forename: Duvuru
authors.initials: D
authors.lastname: Geetha
authors.forename: Gaurav
authors.initials: G
authors.lastname: Gupta
authors.forename: Karl
authors.initials: K
authors.lastname: Womer
authors.forename: Lois
authors.initials: L
authors.lastname: Arend
authors.forename: Lorraine
authors.initials: L
authors.lastname: Racusen
authors.forename: Robert
authors.initials: R
authors.lastname: Montgomery
authors.forename: Edward
authors.initials: E
authors.lastname: Kraus
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001739:BK Virus / Q000472:pathogenicity*; D015142:Baltimore / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D001787:Blood Group Incompatibility / Q000276:immunology*; D016009:Chi-Square Distribution; D015935:Complement C4b / Q000032:analysis; D003404:Creatinine / Q000097:blood; D005260:Female; D006084:Graft Rejection / Q000453:epidemiology / Q000276:immunology / Q000821:virology; D006085:Graft Survival; D006680:HLA Antigens / Q000276:immunology*; D006648:Histocompatibility; D006801:Humans; D015994:Incidence; D016030:Kidney Transplantation / Q000009:adverse effects / Q000276:immunology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010446:Peptide Fragments / Q000032:analysis; D027601:Polyomavirus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014412:Tumor Virus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000821:virology*; D055815:Young Adult
chemical_list: D000017:ABO Blood-Group System; D015415:Biomarkers; D006680:HLA Antigens; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d; D003404:Creatinine