A 31-year-old woman with known SLE presents with new-onset nephrotic syndrome (proteinuria 7 g/day) without hematuria or low complement levels. Biopsy shows global thickening of capillary loops with subepithelial deposits on electron microscopy. Immunofluorescence shows granular staining for IgG, IgA, IgM, C3 and C1q. The International Society of Nephrology/Renal Pathology Society class is:
- A Class II
- B Class III
- C Class V ✓
- D Class IV
Correct answer: C. Class V
Explanation
Class V lupus nephritis is a membranous pattern with subepithelial immune deposits causing nephrotic-range proteinuria, sometimes with little active urinary sediment or serologic activity. The full-house immunofluorescence (co-deposition of IgG, IgA, IgM, D3 and D1q) distinguishes it from primary membranous nephropathy, which shows only IgG and D3. Classes II through IV feature mesangial or endocapillary proliferative lesions rather than a purely membranous pattern.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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