A renal biopsy from a 45-year-old man with nephrotic syndrome shows thickened GBM with 'spike and dome' pattern on silver stain and granular IgG + PLA2R deposits on immunofluorescence. The primary autoantigen in this condition is located on:
- A Mesangial cells
- B Glomerular endothelial cells
- C Podocyte foot processes ✓
- D Parietal epithelial cells of Bowman's capsule
Correct answer: C. Podocyte foot processes
Explanation
In primary (idiopathic) membranous nephropathy, anti-PLA2R (phospholipase A2 receptor) antibodies target PLA2R expressed on the podocyte surface. In situ immune complex formation with subepithelial deposition activates the complement pathway (C5b-9 MAC) leading to podocyte injury and proteinuria. This confirms podocytes as the primary antigen-bearing target. PLA2R is present in ~70-80% of primary MN cases; THSD7A antibodies account for another ~3-5%.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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