A 10-year-old boy with a 3-day history of oliguria and hematuria after an upper respiratory infection is found to have crescents in >50% of glomeruli on biopsy with linear IgG deposits along the GBM on immunofluorescence. Which additional autoantibody test is most likely to be positive?

• A Anti-MPO (p-ANCA)
• B Anti-PLA2R antibody
• C Anti-C1q antibody
• D Anti-GBM antibody against the NC1 domain of type IV collagen alpha-3 chain ✓

Explanation

Linear IgG deposits along the GBM on immunofluorescence is the hallmark of anti-GBM disease (Goodpasture syndrome), caused by autoantibodies against the NC1 domain of the alpha-3 chain of type IV collagen. When lungs are also involved (pulmonary hemorrhage), it is called Goodpasture syndrome. Anti-MPO (p-ANCA) causes pauci-immune crescentic GN with no/scanty immune deposits. Anti-PLA2R causes membranous nephropathy. Anti-C1q is associated with lupus nephritis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.