Lupus Nephritis (LN) - Classification

• Class I: Minimal Mesangial LN: no clinical renal disease
• Class II:Mesangial-proliferative LN: mild clinical renal disease; minimally active urinary sediment; mild to moderate proteinuria (never nephrotic) but may have active serology
• Class III:  Focal proliferative LN: <50% of glomeruli involved,  more active sediment, increased proteinuria, HTN, can be active or chronic
• Class IV: Diffuse proliferative LN: >50% of glomeruli involved; may be segmental or global involvement. Most severe with active sediment, HTN, heavy proteinuria (frequent nephrotic syndrome), reduced GFR; serology very active.
• Class V: Membranous LN GN: significant proteinuria, often less active serologies
• Class VI: Advance sclerosing LN (>90% glomerulosclerosis)

**some patients, especially those with mesangial or membranous GN will present with clinical renal disease before they have fulfilled 4 of the 11 ARA criteria for SLE.

(Victoria Kelly MD, 10/12/10)