A 27-year-old woman presents with hemoptysis, rapidly rising creatinine, and urinary sediment showing dysmorphic red cells and red cell casts. Renal biopsy shows crescentic glomerulonephritis with linear IgG deposition along the glomerular basement membrane. The antigen targeted in her disease is a component of:

• A Type IV collagen alpha-3 chain (NC1 domain) ✓
• B Proteinase 3 of neutrophil azurophilic granules
• C Myeloperoxidase
• D Phospholipase A2 receptor

Explanation

Goodpasture syndrome (anti-GBM disease) is caused by antibodies against the NC1 domain of the alpha-3 chain of type IV collagen, producing linear immunofluorescence on renal biopsy and pulmonary alveolar hemorrhage with crescentic GN. ANCA against proteinase 3 or MPO defines granulomatosis with polyangiitis and microscopic polyangiitis respectively, which show pauci-immune, not linear, staining.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.