A patient with SLE develops nephrotic syndrome. Renal biopsy shows global thickening of all glomerular capillary walls on light microscopy, subepithelial and intramembranous deposits on EM, and granular IgG along the GBM on immunofluorescence. This corresponds to which WHO/ISN class of lupus nephritis?

• A Class V (membranous) ✓
• B Class III (focal proliferative)
• C Class IV (diffuse proliferative)
• D Class II (mesangial)

Explanation

Class V lupus nephritis (membranous) is characterized by diffuse thickening of capillary walls due to subepithelial immune deposits, presenting with nephrotic syndrome. This is analogous to idiopathic membranous nephropathy but with lupus serology. Class IV (diffuse proliferative) is the most severe and most common class. Class III affects <50% of glomeruli. Class II shows only mesangial deposits.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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