Complement-mediated renal diseases after kidney transplantation - current diagnostic and therapeutic options in de novo and recurrent diseases

Table 1 Morphological features of C3 glomerulopathy

	Morphological features of C3G
Light microscopy	Active lesions
	Mesangial expansion with or without hypercellularity
	Endocapillary hypercellularity including monocytes and/or neutrophils
	Capillary wall thickening with double contours (combination of capillary wall thickening + mesangial increase is referred to as a membranoproliferative pattern)
	Fibrinoid necrosis
	Cellular/fibrocellular crescents
	Chronic lesions
	Segmental or global glomerulosclerosis
	Fibrous crescents
IF microscopy	Typically dominant C3 staining
Electron microscopy	DDD: Dense osmiophilic mesangial and intramembranous electron dense deposits.
	C3GN: Amorphous mesangial with or without capillary wall deposits including subendothelial, intramembranous and subepithelial EDD
	Subepithelial “humps” may be seen in both DDD and C3GN

Adapted from Goodship et al[12]. C3G: C3 glomerulopathy; DDD: Dense deposit disease; C3GN: C3 glomerulonephritis; EDD: Electron dense deposits, fibrinoid necrosis.