Glomerulonephritis classification schema with C4 glomerulopathy

Complement-mediated glomerulonephritis, that is, glomerulonephritis characterized by predominant deposition of complement factors with little or no immunoglobulin (Ig) can therefore be further subdivided into C3 glomerulopathy and C4 glomerulopathy. C3 glomerulopathy is characterized by bright staining for C3 with minimal or no immunoglobulin. However, C4 glomerulopathy is characterized by bright staining for C4d with minimal or no immunoglobulin. The difference in C4 glomerulopathy and C3 glomerulopathy lies in the essentially absent or minimal staining for C3 in C4 glomerulopathy. Why there is no staining for C3, because activation of C4 should presumably lead to the formation of C4 convertase and activation of C3, is not known at this time.