In acute glomerulonephritis following a streptococcal infection, which antibody is commonly sought?

In acute glomerulonephritis following a streptococcal infection, which antibody is commonly sought?

• A. Anti-GBM antibodies
• B. Anti-dsDNA antibodies
• C. Anti-streptolysin O (ASO) antibodies
• D. ANCA

Answer: (C)

In poststreptococcal glomerulonephritis, clinicians look for evidence of a recent streptococcal infection by testing anti-streptolysin O antibodies. After a GAS infection, the body makes antibodies against streptolysin O, and the anti-streptolysin O (ASO) titer rises within a couple of weeks, often peaking a few weeks later. A high ASO titer supports the idea that a recent streptococcal infection preceded the kidney issue, which fits the immune-complex–mediated process of this GN. Other antibodies point to different diseases: anti-GBM antibodies suggest Goodpasture syndrome, anti-dsDNA antibodies are associated with SLE-related GN, and ANCA is linked to pauci-immune vasculitis–related GN. Elevated ASO is therefore the best indicator in this scenario because it specifically reflects a recent GAS infection that can trigger postinfectious glomerulonephritis.

In poststreptococcal glomerulonephritis, clinicians look for evidence of a recent streptococcal infection by testing anti-streptolysin O antibodies. After a GAS infection, the body makes antibodies against streptolysin O, and the anti-streptolysin O (ASO) titer rises within a couple of weeks, often peaking a few weeks later. A high ASO titer supports the idea that a recent streptococcal infection preceded the kidney issue, which fits the immune-complex–mediated process of this GN. Other antibodies point to different diseases: anti-GBM antibodies suggest Goodpasture syndrome, anti-dsDNA antibodies are associated with SLE-related GN, and ANCA is linked to pauci-immune vasculitis–related GN. Elevated ASO is therefore the best indicator in this scenario because it specifically reflects a recent GAS infection that can trigger postinfectious glomerulonephritis.