Proliferative lupus nephritis vs Membranous / sclerosing lupus nephritis

Class III is focal proliferative lupus nephritis involving less than half of glomeruli; Class IV is diffuse proliferative disease involving at least half and is often the most aggressive active class.

Class V is membranous lupus nephritis with nephrotic proteinuria; Class VI is advanced sclerosing disease with mostly scarred glomeruli and chronic irreversible damage.

Immune-complex driven active glomerular inflammation produces proliferative lesions, nephritic sediment, and risk of rapid progression.

Class V immune deposits thicken capillary walls and produce nephrotic syndrome; Class VI reflects end-stage scarring rather than active immune-complex inflammation.

Class III (focal proliferative, less than 50 percent of glomeruli) and Class IV (DIFFUSE proliferative, 50 percent or more of glomeruli, the most common and most severe class) lupus nephritis are nephritic disease: hematuria with RBC casts, sub-nephrotic proteinuria, hypertension, declining GFR, elevated creatinine, low complement (C3 and C4 low), anti-dsDNA antibodies; full-house immunofluorescence on biopsy (IgG, IgM, IgA, C3, C1q). Induction with high-dose corticosteroids plus mycophenolate or cyclophosphamide; maintenance with mycophenolate or azathioprine.

Class V (membranous) lupus nephritis is nephrotic: heavy proteinuria above 3.5 g/day, hypoalbuminemia, edema, with subepithelial immune deposits on biopsy resembling primary membranous nephropathy (granular IgG and C3 plus mesangial deposits in lupus); complement is normal more often than in proliferative classes. Class VI (advanced sclerosing, more than 90 percent globally sclerotic glomeruli) is irreversible scarred kidney with no inflammation to suppress; management focuses on slowing CKD progression and preparing for renal replacement therapy.