A 52-year-old man has nephrotic-range proteinuria. Kidney biopsy shows subepithelial immune deposits with spike formation on silver stain. Serum anti-PLA2R antibody is strongly positive. What is the significance of this finding?

• A It indicates secondary membranous nephropathy due to malignancy
• B It excludes membranous nephropathy and suggests focal segmental glomerulosclerosis
• C It mandates immediate rituximab therapy regardless of proteinuria level
• D It confirms primary (idiopathic) membranous nephropathy and predicts a poorer spontaneous remission rate ✓

Explanation

Anti-PLA2R antibodies are found in about 70 to 80 percent of patients with primary membranous nephropathy and are rare in secondary forms (lupus, hepatitis D, malignancy, drugs). A positive titre therefore supports idiopathic disease, and higher titres correlate with greater disease activity and lower likelihood of spontaneous remission. Treatment decisions still depend on proteinuria magnitude and risk assessment, not the antibody alone, so rituximab is not automatically indicated.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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