title: Glomerular and tubular C4d depositions in IgA nephropathy: relations with histopathology and with albuminuria.
abstract: BACKGROUND
  C4d has been used as an evaluation marker for antibody-mediated rejection for solid organ transplantation. Although some studies have proposed that complement activation is involved in renal diseases, very little information is available on pathogenesis. This study was conducted to investigate C4d deposition in IgA nephropathy and to find its relations with histopathology and albuminuria.
  
  
  METHODS
  This retrospective study included 23 patients who underwent renal biopsy at our medical center. The WHO grade of IgA nephropathy, interstitial inflammation and fibrosis, C4d staining and medical records including sex, age, and urine albumin were reviewed.
  
  
  RESULTS
  Thirteen patients (56.5%) were positive for C4d staining in the glomerulus and eleven patients (47.8%) were positive in the tubular epithelium. Glomerular C4d deposition was associated with albuminuria (p=0.044), and tubular C4d deposition was associated with a higher grade of IgA nephropathy (p=0.014).
  
  
  CONCLUSIONS
  Activation of the complement system was involved in renal damage and was identified through deposition of C4d in the glomerulus and tubules. Positive C4d staining in the glomerulus and the tubules may be associated with functional damage related to glomerular filtration and poor renal outcome.
authors: Department of Pathology, School of Medicine, Catholic University of Daegu, Daegu, Korea.
authors: Young-In
authors: YI
authors: Maeng
authors: Min-Kyung
authors: MK
authors: Kim
authors: Jae-Bok
authors: JB
authors: Park
authors: Chang-Ho
authors: CH
authors: Cho
authors: Hoon-Kyu
authors: HK
authors: Oh
authors: Woo Jung
authors: WJ
authors: Sung
authors: Kwan-Kyu
authors: KK
authors: Park
mesh_terms: D000419:Albuminuria / Q000209:etiology; D003167:Complement Activation / Q000502:physiology*; D015935:Complement C4b / Q000032:analysis*; D005260:Female; D005455:Fluorescent Antibody Technique; D005922:Glomerulonephritis, IGA / Q000150:complications / Q000473:pathology*; D006801:Humans; D007678:Kidney Glomerulus / Q000473:pathology*; D007684:Kidney Tubules / Q000473:pathology*; D008297:Male; D010446:Peptide Fragments / Q000032:analysis*; D012189:Retrospective Studies
chemical_list: D010446:Peptide Fragments; D015935:Complement C4b; C032261:complement C4d
keywords: Albuminuria; C4d; IgA; grade; nephropathy
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