A 38-year-old man with nephrotic-range proteinuria has a biopsy showing thickened GBMs with subepithelial deposits. Serum testing for phospholipase A2 receptor (PLA2R) antibodies is positive. This finding indicates:

• A Secondary membranous nephropathy due to hepatitis B
• B Primary (idiopathic) membranous nephropathy ✓
• C Lupus nephritis class V
• D Drug-induced membranous nephropathy

Explanation

Anti-PLA2R antibodies are present in about 70 to 80 percent of patients with primary membranous nephropathy and are considered diagnostic of the idiopathic form. Their presence argues against secondary causes such as hepatitis C infection, drugs like penicillamine, and malignancy, in which PLA2R serology is typically negative. Lupus nephritis class V shows full-house immunofluorescence with multiple immunoglobulins and complements rather than isolated PLA2R reactivity. Titers also correlate with disease activity.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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