Diagnostic criteria for IRGN include at least three of the following: (i) clinical or laboratory evidence of infection preceding or concurrent with glomerulonephritis, (ii) low serum complement levels, (iii) endocapillary proliferative and exudative glomerulonephritis, (iv) C3-dominant or co-dominant glomerular immunofluorescence staining, and (v) hump-shaped subepithelial deposits on electron microscopy [7]. Here, C3 is linked to glomerulonephritis.