A 28-year-old woman with SLE develops nephrotic-range proteinuria. Renal biopsy shows diffuse global endocapillary hypercellularity and 'wire loop' deposits on light microscopy. Immunofluorescence shows a 'full house' pattern (IgG, IgM, IgA, C3, C1q). This corresponds to which ISN/RPS 2018 class?

• A Class V (Membranous Lupus Nephritis)
• B Class III (Focal Lupus Nephritis)
• C Class IV (Diffuse Lupus Nephritis) ✓
• D Class II (Mesangial Proliferative Lupus Nephritis)

Explanation

ISN/RPS Class IV diffuse lupus nephritis is the most severe and common form, characterized by global endocapillary hypercellularity (>50% of glomeruli involved), 'wire loop' deposits (massive subendothelial immune complexes), and the classic 'full house' immunofluorescence. Class V shows diffuse subepithelial deposits (membranous pattern). Class III involves <50% of glomeruli (focal). Class II shows only mesangial involvement.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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