M-type phospholipase A2 receptor (PLA2R) antibodies are found in approximately 70-80% of primary membranous nephropathy. These antibodies deposit as immune complexes in which glomerular compartment?
- A Subendothelial space between endothelium and GBM
- B Subepithelial space between podocytes and GBM ✓
- C Mesangium adjacent to the hilar region
- D Intramembranous within the lamina densa of GBM
Correct answer: B. Subepithelial space between podocytes and GBM
Explanation
In primary (idiopathic) membranous nephropathy, anti-PLA2R antibodies target PLA2R antigen expressed on podocyte foot processes. Immune complexes form in situ in the subepithelial space between podocytes and the GBM. These deposits appear as 'spikes' on silver stain and electron-dense deposits on EM, and are responsible for the complement-mediated disruption of the filtration barrier causing proteinuria. Subendothelial deposits are characteristic of proliferative GN (class III/IV lupus).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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