Table 1. Original World Health Organization (WHO) classification of lupus nephritis (1974)
Class I | Normal glomeruli (by light microscopy, immunofluorescence, and electron microscopy) |
Class II | Purely mesangial disease |
a. Normocellular mesangium by light microscopy but mesangial deposits by immunofluorescence or electron microscopy | |
b. Mesangial hypercellularity with mesangial deposits by immunofluorescence or electron microscopy | |
Class III | Focal proliferative glomerulonephritis (<50%) |
Class IV | Diffuse proliferative glomerulonephritis (≥50%) |
Class V | Membranous glomerulonephritis |