title: Apoptosis in kidney and pancreas allograft biopsies.
abstract: BACKGROUND
  Apoptosis is a particular form of cell death involved in the elimination of somatic cells. In this study, the occurrence of apoptotic cells in kidney and pancreas allograft biopsies was analyzed and correlated with the number of infiltrating macrophages and lymphocytes and granzyme B expression.
  
  
  METHODS
  Kidney and pancreas biopsies from patients submitted to simultaneous pancreas-kidney transplantation were classified into three groups: acute rejection, chronic rejection, and transplant cases without evidence of rejection. Formalin-fixed paraffin biopsies were used to identify apoptosis by the terminal deoxynucleotidyl transferase [TdT]-mediated dUTP nick end labeling (TUNEL) method.
  
  
  RESULTS
  In normal kidney, only few apoptotic cells were observed. In contrast, in kidney-allograft biopsies, the TUNEL signal was detected in the nuclei of tubular epithelial cells and also in mononuclear cells scattered in the interstitium. In pancreas biopsies, numerous apoptotic cells were detected in acinar cells, in ducts, and occasionally in islets. The number of apoptotic cells in acute pancreas rejection was significantly higher compared with acute rejection of kidney grafts (50+/-14 vs. 21+/-4 cells/mm2; P<0.05). In kidney biopsies, there was a positive correlation between apoptosis and macrophages (r=0.51; P<0.005), and apoptosis versus T lymphocytes (r=0.45; P<0.05). In pancreas biopsies, the number of apoptotic cells correlated only with the number of macrophages (r=0.41; P<0.05).
  
  
  CONCLUSIONS
  Apoptosis occurs in kidney and pancreas allograft biopsies, markedly in acute rejection in pancreas biopsies. Although apoptosis may reflect a mechanism of down-regulation of the allograft immune response by eliminating infiltrating cells, the elimination of graft cells may result in graft damage, particularly in pancreas transplantation.
authors.affiliation: Renal Pathophysiology Laboratory, Nephrology Division, University of São Paulo, Brazil. irenenor@usp.br
authors.forename: Irene L
authors.initials: IL
authors.lastname: Noronha
authors.forename: Sabrina G
authors.initials: SG
authors.lastname: Oliveira
authors.forename: Tatiana S
authors.initials: TS
authors.lastname: Tavares
authors.forename: Arianni
authors.initials: A
authors.lastname: Di Petta
authors.forename: Wagner V
authors.initials: WV
authors.lastname: Dominguez
authors.forename: M
authors.initials: M
authors.lastname: Perosa
authors.forename: Tercio
authors.initials: T
authors.lastname: Genzini
authors.forename: João E
authors.initials: JE
authors.lastname: Romão
authors.forename: Hugo
authors.initials: H
authors.lastname: Abensur
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Moura
authors.forename: Dino Martini
authors.initials: DM
authors.lastname: Filho
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D001938:Brazil; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery; D003928:Diabetic Nephropathies / Q000601:surgery; D006801:Humans; D007249:Inflammation / Q000473:pathology; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation / Q000473:pathology*; D010179:Pancreas / Q000473:pathology; D016035:Pancreas Transplantation / Q000473:pathology*; D012189:Retrospective Studies