title: Borderline rejection in ABO-incompatible kidney transplantation.
abstract: The clinical results of ABO-incompatible (ABOi) and ABO-compatible (ABOc) kidney transplantation (KT) are similar. Protocol kidney biopsies (PKB) of ABOi transplant recipients show positivity for C4d without evidence of antibody-mediated rejection (ABMR), but little is known about the histologic progression.
  
  
  
  We evaluated histologic parameters in PKB at 12 months and also compared clinical outcome at 1 year. This is a prospective observational study conducted between 2009 and 2013. We performed 146/30 ABOc/ABOi consecutive living-donor KT with PKB as well as additional indication biopsies. In the ABOi group, the desensitization protocol consisted of rituximab, plasma exchange or immunoadsorption, and immunoglobulins.
  
  
  
  In indication biopsies during the first year, T-cell-mediated rejection Banff ≥immunoadsorption was 8.2% vs 6.7% (P=.561) and ABMR 4.8% vs 13.3% (P=.095). At 1 year, PKB (ABOc/ABOi) showed differences in borderline rejection lesions (6.8% vs 23.3% [P=.012]) and in C4d positivity in the ABOi group (P=.001). Interstitial fibrosis and tubular atrophy (IFTA) lesions (ABOc/ABOi) were 68.4% vs 63.2% (P=.348). Transplant glomerulopathy was 0.7% vs 3.3% (P=.373) at 1 year.
  
  
  
  Our PKB ABOi series shows at 1 year more borderline lesions independent of ABO titers, HLA incompatibility, and the presence of antidonor antibody, but do not show more IFTA nor transplant glomerulopathy. No clinical differences were observed between ABOi and ABO transplants.
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Sánchez-Escuredo
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Oppenheimer
authors.affiliation: Pathology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Manel
authors.initials: M
authors.lastname: Solé
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Revuelta
authors.affiliation: Apheresis Unit, Hemotherapy and Hemostasis Department, CDB, IDIBAPS Hospital Clinic, University of Barcelona, Barcelona, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Cid
authors.affiliation: Apheresis Unit, Hemotherapy and Hemostasis Department, CDB, IDIBAPS Hospital Clinic, University of Barcelona, Barcelona, Spain.
authors.forename: Miguell
authors.initials: M
authors.lastname: Lozano
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Miquel
authors.initials: M
authors.lastname: Blasco
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Esforzado
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Ricart
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Cofán
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Josep Vicens
authors.initials: JV
authors.lastname: Torregrosa
authors.affiliation: Transplant Service Foundation, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Paredes
authors.affiliation: Urology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Mireia
authors.initials: M
authors.lastname: Musquera
authors.affiliation: Immunology Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Ercilla
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Josep M
authors.initials: JM
authors.lastname: Campistol
authors.affiliation: Nephrology and Renal Transplant Department, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Fritz
authors.initials: F
authors.lastname: Diekmann
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000328:Adult; D000368:Aged; D001706:Biopsy; D001787:Blood Group Incompatibility / Q000150:complications* / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection / Q000175:diagnosis / Q000209:etiology* / Q000276:immunology; D006085:Graft Survival; D006801:Humans; D016030:Kidney Transplantation / Q000009:adverse effects*; D019520:Living Donors; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D066027:Transplant Recipients; D055815:Young Adult
chemical_list: D000017:ABO Blood-Group System
keywords: ABOi transplant; borderline rejection; protocol biopsies