Kidney Diseases Caused by Complement Dysregulation: Acquired, Inherited, and Still More to Come

Table 1

C3 glomerulopathies.

Diseases	EM-findings	Alternative pathway abnormalities	Disease specific treatment options
Dense deposit disease	(i) Osmophilic wavy dense deposits within GBM, mesangial matrix, tubular BM	(i) Autoantibodies (C3Nef, FHAA, FBAA, C3-convertase AA); (ii) Mutations/genetic variations (CFH, CFI, CFB, MCP)	(i) Infusion of fresh frozen plasma; (ii) Plasmapheresis; (iii) Eculizumab; (iv) Immunosuppressive treatment (in case of autoantibodies)
C3 glomerulonephritis	(i) Mesangial, subendothelial, subepithelial and intramembranous deposits	(i) Mutations/genetic variations (CFH, CFI, MCP); (ii) Autoantibodies (C3Nef, FHAA)	(i) Eculizumab; (ii) Immunosuppressive treatment (in case of autoantibodies)
CFHR5 nephropathy	(i) Mesangial, subendothelial, subepithelial deposits	(i) CFHR5-mutation	(i) No treatment of proven efficacy; (ii) Plasma exchange associated with good outcome
Familial C3 glomerulopathy	(i) MPGN type III; (ii) Subendothelial, subepithelial deposits	(i) Familial hybrid CFHR3-1 gene autosomal dominant inheritance	(i) No treatment of proven efficacy

Abbreviations: C3: complement component 3, CFHR5: complement factor H related protein 5, CFH: complement factor H, CFI: complement factor I, MCP: membrane cofactor protein, FHAA: factor H autoantibody, FBAA: factor B autoantibody, (G) BM; (glomerular) basement membrane, MCP: membrane cofactor protein.