title: Acute Rejection Phenotypes in the Current Era of Immunosuppression: A Single-Center Analysis.
abstract: BACKGROUND
  Besides 'definitive rejection', the Banff classification includes categories for 'suspicious for rejection' phenotypes. The aim of this study was to determine the frequency and phenotypes of rejection episodes in 316 consecutive renal transplants from 2009 to 2014 grouped into patients without/with pretransplant HLA-DSA (ptDSAneg, n = 251; ptDSApos, n = 65).
  
  
  METHODS
  All adequate indication (n = 125) and surveillance biopsies (n = 538) performed within the first year posttransplant were classified according to the current Banff criteria.
  
  
  RESULTS
  'Suspicious for rejection' phenotypes were 3 times more common than 'definitive rejection' phenotypes in biopsies from ptDSAnegpatients (35% vs 11%) and equally common in biopsies from ptDSApospatients (25% vs 27%). In both groups, 'suspicious for rejection' phenotypes were more frequent in surveillance than in indication biopsies (28% vs 16% in ptDSAnegpatients, and 37% vs 29% in ptDSApospatients). 'Borderline changes: 'Suspicious' for acute T-cell mediated rejection' (91%) were the dominant 'suspicious for rejection' phenotype in ptDSAnegpatients, whereas 'borderline changes' (58%) and 'suspicious for acute/active antibody-mediated rejection' (42%) were equally frequent in biopsies from ptDSApospatients. Inclusion of 'suspicious for rejection' phenotypes increased the 1-year incidence of clinical (ptDSAnegpatients: 18% vs 8%,P= 0.0005; ptDSApospatients: 24% vs 18%,P= 0.31) and (sub)clinical rejection (ptDSAnegpatients: 59% vs 22%,P< 0.0001; ptDSApospatients: 68% vs 40%,P= 0.004).
  
  
  CONCLUSIONS
  'Suspicious for rejection' phenotypes are very common in the current era and outnumber the frequency of 'definitive rejection' within the first year posttransplant.
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Wehmeier
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Amico
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Patricia
authors.initials: P
authors.lastname: Hirt-Minkowski
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Argyrios
authors.initials: A
authors.lastname: Georgalis
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Gideon
authors.initials: G
authors.lastname: Höenger
authors.affiliation: Institute for Pathology, University Hospital Basel, Basel, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Menter
authors.affiliation: Institute for Pathology, University Hospital Basel, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Mihatsch
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Felix
authors.initials: F
authors.lastname: Burkhalter
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Juerg
authors.initials: J
authors.lastname: Steiger
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Dickenmann
authors.affiliation: Institute for Pathology, University Hospital Basel, Basel, Switzerland.
authors.forename: Helmut
authors.initials: H
authors.lastname: Hopfer
authors.affiliation: Clinic for Transplantation Immunology and Nephrology, University Hospital Basel, Basel, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schaub