A 42-year-old woman with SLE develops nephrotic syndrome and hypertension. Renal biopsy shows global mesangial and subendothelial immune complex deposits with 'full house' immunofluorescence (IgG, IgM, IgA, C3, C1q). This pattern corresponds to which WHO/ISN-RPS class of lupus nephritis that requires most aggressive immunosuppression?

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

Explanation

ISN/RPS Class IV (diffuse proliferative lupus nephritis) involves >50% of glomeruli with diffuse mesangial and subendothelial deposits and is the most severe form, carrying the highest risk of progression to end-stage renal disease. 'Full house' immunofluorescence (IgG, IgM, IgA, C3, C1q positivity) is a hallmark of lupus nephritis. Class IV requires induction therapy with high-dose corticosteroids plus cyclophosphamide or mycophenolate mofetil, followed by maintenance immunosuppression. Class V (membranous LN) shows subepithelial deposits.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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