In post-streptococcal glomerulonephritis, the pathological mechanism involves 'humps' on electron microscopy. These subepithelial humps consist primarily of:

• A Anti-GBM antibody deposits
• B Immune complexes (IgG + complement) deposited after streptococcal antigen planting ✓
• C Fibrin thrombi in capillary lumens
• D Amyloid fibrils in the mesangium

Explanation

In post-streptococcal GN, streptococcal antigens (likely nephritis-associated plasmin receptor and streptococcal pyrogenic exotoxin B) plant in the glomeruli and then form immune complexes in situ or are deposited as circulating immune complexes, leading to large subepithelial 'humps' on EM, which are IgG and C3 deposits. This triggers complement activation and neutrophil recruitment, causing the nephritic syndrome.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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