In post-streptococcal glomerulonephritis, the key mechanism of glomerular injury is:
- A Immune complex deposition activating complement (Type III hypersensitivity) ✓
- B Anti-GBM antibodies causing linear IgG deposition
- C ANCA-mediated pauci-immune necrotizing GN
- D T-cell mediated delayed hypersensitivity to streptococcal antigens
Correct answer: A. Immune complex deposition activating complement (Type III hypersensitivity)
Explanation
Post-streptococcal GN results from in situ or circulating immune complex deposition (subepithelial 'humps' on EM) activating complement via the classical pathway — a Type III hypersensitivity response. This leads to neutrophil recruitment and glomerular injury. Linear IgG is diagnostic of anti-GBM disease (Goodpasture syndrome), and pauci-immune GN is associated with ANCA vasculitis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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