Table 1.

International society of nephrology/renal pathology society 2003 classification of lupus nephritis[11,12]

Class	Name			Light microscopy	Immunofluorescence
I	Minimal mesangial LN			Normal	Mesangial immune deposits
II	Mesangial proliferative LN			Mesangial hypercellularity or mesangial matrix expansion	Mesangial immune deposits
III	Focal LN	A	Active lesions	Segmental, or global glomerulonephritis (< 50% of glomeruli)	Diffuse subendothelial immune deposits
		A/C	Active and chronic lesions
		C	Chronic lesions
IV	Diffuse LN	A	Active lesions	Segmental, or global glomerulonephritis LN (> 50% glomeruli)	Diffuse subendothelial immune deposits
		A/C	Active and chronic lesions
		C	Chronic lesions
V	Membranous LN				Global or segmental subepithelial immune deposits
VI	Advanced sclerosing LN			LN (> 90% globally Sclerosed glomeruli without residual activity)

Class V may occur in combination with class III or IV, in which case both will be diagnosed. LN: Lupus nephritis.