title: Monocytes and peritubular capillary C4d deposition in acute renal allograft rejection.
abstract: BACKGROUND
  Peritubular capillary (PTC) deposition of complement split factor C4d in renal allografts has been shown to be closely associated with circulating antidonor antibodies and a marker for relatively poor graft survival. Monocyte/macrophage (MO) infiltration of renal allografts has been shown to adversely affect graft survival. The purpose of this study was to assess whether the two phenomena are related.
  
  
  METHODS
  Twenty-three biopsies (from 15 patients) demonstrated diffuse strong staining of PTC for C4d (C4d+ group) and acute tubular injury with or without significant cellular rejection, while 28 biopsies (with acute rejection) but negative for PTC C4d served as controls (C4d- group).
  
  
  RESULTS
  The C4d+ group demonstrated significantly greater glomerular and interstitial MO infiltration than did the C4d- group [3.4 +/- 2.0 vs. 0.2 +/- 0.3 MO/glomerulus, P < 0.0001; 12.9 +/- 9.2 vs. 6.5 +/- 5.0 MO/high power field (hpf), P = 0.0030]. Neutrophilic (PMN) infiltration of glomeruli and PTC was also significantly greater in the C4d+ group than in the C4d- one (0.8 +/- 0.6 vs. 0.3 +/- 0.3 PMN/glomerulus, P = 0.0003; 0.9 +/- 0.8 vs. 0.4 +/- 0.3 PTC PMN/hpf, P = 0.0035).
  
  
  CONCLUSIONS
  The results indicate a close association between PTC C4d deposition and MO infiltration, particularly glomerular, and confirm previous observations regarding the correlation of PTC C4d staining and PMN infiltration.
authors.affiliation: Department of Pathology, St. Paul's Hospital and the Unversity of British Columbia, Vancouver, BC, Canada. amagil@providencehealth.bc.ca
authors.forename: Alex B
authors.initials: AB
authors.lastname: Magil
authors.forename: Kathryn
authors.initials: K
authors.lastname: Tinckam
mesh_terms: D000208:Acute Disease; D000328:Adult; D001706:Biopsy; D002196:Capillaries / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003181:Complement C4 / Q000378:metabolism*; D015935:Complement C4b; D005260:Female; D005921:Glomerulonephritis / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D006084:Graft Rejection / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D016030:Kidney Transplantation; D007684:Kidney Tubules / Q000098:blood supply / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000473:pathology*; D010446:Peptide Fragments / Q000378:metabolism*
chemical_list: D003181:Complement C4; D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d