Table 1.

The classification of lupus nephritis, including lupus podocytopathy, with associated clinical presentation

ClassBiopsy FindingsClinical FeaturesPatients Presenting with Nephrotic Syndrome, %
Class I: minimal mesangial LNNo LM abnormalities; isolated mesangial IC deposits on IF and/or EMNormal urine or microscopic hematuria0
Class II: mesangial proliferative LNMesangial hypercellularity or matrix expansion with mesangial IC deposits on IF and/or EMMicroscopic hematuria and/or low-grade proteinuria0
Lupus podocytopathyNormal glomeruli, FSGS, or mesangial proliferation on LM; IC deposits absent or limited to mesangium on IF and/or EM; diffuse and severe foot process effacement on EMNephrotic syndrome>90
Class III: focal LN<50% of Glomeruli on LM display segmental (<50% of glomerular tuft) or global (>50% of glomerular tuft) endocapillary and/or extracapillary proliferation or sclerosis; mesangial and focal subendothelial IC deposits on IF and EMNephritic urine sediment and subnephrotic proteinuria30
Class IV: diffuse LN≥50% of glomeruli on LM display endocapillary and/or extracapillary proliferation or sclerosis; mesangial and diffuse subendothelial IC deposits on IF and EMNephritic and nephrotic syndromes, hypertension, reduced kidney function50
Class V: membranous LNaDiffuse thickening of the glomerular capillary walls on LM with subepithelial IC deposits on IF and EM with or without mesangial IC depositsNephrotic syndrome80
Class VI: advanced sclerosing LN>90% of Glomeruli on LM are globally sclerosed with no residual activityAdvanced CKD<10
  • Lupus podocytopathy, listed separately here, is not a distinct classification according to the International Society of Nephrology/Renal Pathology Society classification but rather, a concomitant diagnosis made alongside class I or class II LN. LN, lupus nephritis; LM, light microscopy; IC, immune complex; IF, immunofluorescence; EM, electron microscopy.

  • a Class V may coexist with class III or IV, in which case both classes are diagnosed.