title: Complement fragment C4d deposition in peritubular capillaries in acute humoral rejection after ABO blood group-incompatible human kidney transplantation.
abstract: BACKGROUND
  Acute humoral rejection (AHR) is the most important risk factor for early graft loss in ABO-incompatible (ABO-i) kidney transplantation (RTx). The pathogenesis and diagnostic criteria for AHR after ABO-i RTx remain unclear. Complement fragment C4d deposition in peritubular capillaries (PTC), which is a sensitive indicator for activation of the classical complement pathway, was studied to establish the pathologic diagnostic indicator of AHR.
  
  
  METHODS
  Forty-four graft biopsy specimens from 19 patients with ABO-i living donors were analyzed within 90 days after RTx. Nineteen biopsy specimens with acute rejection after ABO-compatible (ABO-c) living-related RTx were used as controls. Diffuse and bright C4d deposition in PTC was considered significantly positive.
  
  
  RESULTS
  All of 8 recipients with AHR showed significantly positive C4d in PTC in the ABO-i group, but 9 of 11 recipients without AHR were negative. In the ABO-c RTx group, 16 of 19 recipients were negative for C4d in PTC. The prevalence of C4d in PTC was significantly higher in ABO-i RTx (P<0.05).
  
  
  CONCLUSIONS
  C4d deposition is valuable as a specific and sensitive indicator for AHR, even of mild severity, in ABO-i RTx.
authors.affiliation: The Third Department of Internal Medicine, Nagoya City University Medical School, Nagoya, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Kato
authors.forename: Kunio
authors.initials: K
authors.lastname: Morozumi
authors.forename: Oki
authors.initials: O
authors.lastname: Takeuchi
authors.forename: Tadashi
authors.initials: T
authors.lastname: Oikawa
authors.forename: Katsushi
authors.initials: K
authors.lastname: Koyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Usami
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Shimano
authors.forename: Akinori
authors.initials: A
authors.lastname: Ito
authors.forename: Keiji
authors.initials: K
authors.lastname: Horike
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Susumu
authors.initials: S
authors.lastname: Toda
authors.forename: Asami
authors.initials: A
authors.lastname: Takeda
authors.forename: Kazuharu
authors.initials: K
authors.lastname: Uchida
authors.forename: Toshihito
authors.initials: T
authors.lastname: Haba
authors.forename: Genjiro
authors.initials: G
authors.lastname: Kimura
mesh_terms: D000017:ABO Blood-Group System; D000208:Acute Disease; D001787:Blood Group Incompatibility; D002196:Capillaries / Q000378:metabolism; D003181:Complement C4 / Q000378:metabolism*; D015935:Complement C4b; D035061:Control Groups; D006084:Graft Rejection / Q000378:metabolism*; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology*; D007684:Kidney Tubules / Q000098:blood supply*; D010446:Peptide Fragments / Q000378:metabolism*
chemical_list: D000017:ABO Blood-Group System; D003181:Complement C4; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d