Lupus Nephritis Classification

If < 50% of glomeruli are involved, it is focal. If >= 50% of glomeruli it is diffuse.

If < 50% of a glomerulus is involved, it is segmental. If >= 50% of a glomerulus is involved it is global.

Features of minimal mesangial (Class I):

(1) normal on light microscopy

(2) mesangial deposits seen on immunofluorescence (IF)

Features of mesangial proliferation (Class II):

(1) mesangial hypercellularity and/or matrix expansion

(2) mesangial deposits on immunofluorescence (IF)

(3) may show rare subepithelial or subendothelial deposits on IF or electron microscopy (EM)

Features of focal (Class III):

(1) < 50% of glomeruli affected

(2) subendothelial immune deposits

(3) subgroups

(3a) active (A)

(3b) chronic inactive with scarring (C)

(3c) both active and chronic (A/C)

Features of diffuse (Class IV):

(1) >= 50% of glomeruli affected

(2) subendothelial immune deposits

 (3) subgroups

(3a) segmental active: S(A)

(3b) global active: G(A)

(3c) segmental chronic inactive with scarring: S(C)

(3d) global chronic inactive with scarring: G(C)

(3e) segmental with both active and chronic: S(A/C)

(3f) global with both active and chronic: G(A/C)

Features of membranous (Class V):

(1) segmental or global subepithelial immune deposits

(2) may show Class III or IV changes

Features of advanced sclerosing (Class VI):

(1) >= 90% of glomeruli are globally sclerosed and inactive