A 35-year-old woman with lupus develops nephrotic-range proteinuria. Renal biopsy shows diffuse global thickening of capillary walls with 'wire loop' appearance on light microscopy and granular subendothelial deposits on immunofluorescence. This corresponds to which ISN/RPS class of lupus nephritis?

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

Explanation

ISN/RPS Class IV (diffuse proliferative lupus nephritis) is the most severe and most common class in symptomatic lupus nephritis. The wire loop lesion represents massive subendothelial immune complex deposits distending capillary lumens. It affects >50% of glomeruli globally. Class V (membranous) shows subepithelial deposits and nephrotic syndrome without wire loops.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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