A 30-year-old woman develops hematuria, proteinuria, and hypertension two weeks after a streptococcal throat infection. Renal biopsy shows diffuse hypercellularity with neutrophil infiltration and 'humps' on the subepithelial surface on electron microscopy. The immunofluorescence pattern most likely shows:
- A Granular IgG and C3 in a starry-sky pattern ✓
- B Linear IgG along the glomerular basement membrane
- C Mesangial IgA deposits
- D No immune deposits
Correct answer: A. Granular IgG and C3 in a starry-sky pattern
Explanation
Post-streptococcal glomerulonephritis is an immune-complex–mediated nephritis where antigen-antibody complexes deposit in a granular 'starry-sky' pattern of IgG and C3, predominantly in the mesangium and subendothelial areas. Electron microscopy reveals characteristic subepithelial 'humps' representing these deposits. Linear IgG is the pattern of anti-GBM disease (Goodpasture syndrome), not PSGN.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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