A 26-year-old woman with SLE has proteinuria of 3.5 g/day without hematuria or low complement. Renal biopsy shows diffuse global thickening of the glomerular capillary walls, granular subepithelial IgG deposits on immunofluorescence, and only mild mesangial hypercellularity on light microscopy. According to the ISN/RPS classification, what is the class of her lupus nephritis?

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

Explanation

ISN/RPS class V lupus nephritis is defined by membranous involvement: global subepithelial immune deposits producing capillary wall thickening, typically presenting as pure nephrotic syndrome with bland urine sediment. Class IV would require diffuse endocapillary or extracapillary proliferation with large subendothelial wire-loop deposits and active urinary sediment, and class II is limited to mesangial deposits with hypercellularity. Recognizing class V matters because its treatment and prognosis differ from proliferative classes.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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