Which CSF protein would be measured when investigating active demyelination in multiple sclerosis?

Which CSF protein would be measured when investigating active demyelination in multiple sclerosis?

• A. CSF albumin to serum albumin ratio
• B. α1-Antitrypsin
• C. Myelin basic protein
• D. Ceruloplasmin

Answer: (C)

Active demyelination in multiple sclerosis releases myelin components into the CSF. Myelin basic protein is a major constituent of the myelin sheath, so when myelin is damaged, MBP leaks into the CSF. Elevated MBP in CSF is therefore a signal of recent or ongoing demyelination, making it the most specific marker among the options for active demyelination. The other options aren’t as directly linked to myelin breakdown. The CSF albumin to serum albumin ratio reflects blood–CSF barrier permeability rather than demyelination itself. α1-antitrypsin is a protease inhibitor found in plasma and CSF that isn’t a specific marker of myelin damage. Ceruloplasmin is a copper-binding protein and not a standard CSF marker for demyelination.

Active demyelination in multiple sclerosis releases myelin components into the CSF. Myelin basic protein is a major constituent of the myelin sheath, so when myelin is damaged, MBP leaks into the CSF. Elevated MBP in CSF is therefore a signal of recent or ongoing demyelination, making it the most specific marker among the options for active demyelination.

The other options aren’t as directly linked to myelin breakdown. The CSF albumin to serum albumin ratio reflects blood–CSF barrier permeability rather than demyelination itself. α1-antitrypsin is a protease inhibitor found in plasma and CSF that isn’t a specific marker of myelin damage. Ceruloplasmin is a copper-binding protein and not a standard CSF marker for demyelination.