Table 2.

Evidence of complement activation in systemic and renal-limited kidney diseases, typical changes seen in renal disease

DiseaseSerum C3Serum C4Staining on renal biopsy
Complement-mediated aHUSLowNormalEvidence of TMA, no specific staining
Dense deposit diseaseLowNormalDominant C3 in glomerulus (dense deposits in GBM on EM)a
C3 glomerulonephritisLowNormalDominant C3 in glomerulus (ill-defined deposits on EM)a
Lupus nephritisLowLow‘Full house’ of complement components (including C1q), as well as IgG, IgA and IgM
CryoglobulinaemiaNormalLowC1q and C4 staining, immune complexes in capillary loops and subendothelial space on LM
IgA nephropathyNormalNormalPredominant IgA deposition, C3 also commonly seena
Anti-GBM disease (Goodpasture's)NormalNormalLinear GBM IgG staining, frequent linear C3 and C1q staining observed
ANCA-associated vasculitisNormalNormalMajority have positive but weak staining for complement or immunoglobulin
Bacterial endocarditisLowLow/NormalC3 deposition, crescentic or endocapillary proliferative glomerulonephritis on LMa
Post-infectious glomerulonephritisLowNormalPredominant C3 staining, proliferative glomerular injurya
Antibody-mediated rejection of renal transplantNormalNormalPeritubular capillary and glomerular C4d deposition
Membranous nephropathyNormalNormalC3 and IgG deposition in sub-epithelial immune complexesa
  • a = staining for C3 will detect mainly activated C3 (C3b) and the fragments produced by factor I-mediated proteolytic breakdown (iC3b, C3dg and C3d); aHUS = atypical haemolytic uraemic syndrome; EM = electron microscopy; GBM = glomerular basement membrane; Ig = immunoglobulin; LM = light microscopy; TMA = thrombotic microangiopathy.