A patient presents with glomerulonephritis and pulmonary hemorrhage. What is the likely diagnosis, and what is the targeted molecule?

A patient presents with glomerulonephritis and pulmonary hemorrhage. What is the likely diagnosis, and what is the targeted molecule?

• A. Wegener's granulomatosis; antibodies against neutrophil components
• B. SLE; anti-dsDNA
• C. Goodpasture's syndrome; antibodies against basement membranes
• D. Post-streptococcal glomerulonephritis; immune complexes in glomeruli

Answer: (C)

Autoimmune attack on basement membranes causing both kidney and lung damage fits Goodpasture’s syndrome. Circulating autoantibodies target components of the basement membranes in glomeruli and in the alveolar walls, leading to glomerulonephritis and pulmonary hemorrhage. The key target is the basement membrane itself—specifically type IV collagen in the glomerular and alveolar basement membranes. This binding activates inflammation and can produce a characteristic linear pattern of antibody deposition along the basement membranes on immunofluorescence. This contrasts with other conditions: Wegener’s (granulomatosis with polyangiitis) involves ANCA-associated vasculitis with granulomatous inflammation; SLE involves anti-dsDNA; post-streptococcal GN is driven by immune complexes.

Autoimmune attack on basement membranes causing both kidney and lung damage fits Goodpasture’s syndrome. Circulating autoantibodies target components of the basement membranes in glomeruli and in the alveolar walls, leading to glomerulonephritis and pulmonary hemorrhage. The key target is the basement membrane itself—specifically type IV collagen in the glomerular and alveolar basement membranes. This binding activates inflammation and can produce a characteristic linear pattern of antibody deposition along the basement membranes on immunofluorescence. This contrasts with other conditions: Wegener’s (granulomatosis with polyangiitis) involves ANCA-associated vasculitis with granulomatous inflammation; SLE involves anti-dsDNA; post-streptococcal GN is driven by immune complexes.