Longitudinal change in TSPO PET imaging in progressive multiple sclerosis

Area of Science:

• Neuroimmunology
• Radiology
• Neurology

Background:

• Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system.
• Innate immune system activation is implicated in MS pathogenesis.
• Assessing innate immune burden non-invasively is crucial for understanding disease progression.

Purpose of the Study:

• To evaluate changes in innate immune burden over two years in progressive MS patients.
• To compare innate immune activity between MS patients and healthy controls (HC).
• To utilize Positron Emission Tomography (PET) with PK11195 to quantify neuroinflammation.

Main Methods:

• Pilot study involving 15 progressive MS patients and 16 age-matched HC.
• PK11195-PET imaging was used to measure translocator protein (TSPO) expression, a marker of neuroinflammation.
• Imaging was performed at baseline and at 12 and 24 months.

Main Results:

• MS patients exhibited higher baseline PK11195 uptake in normal-appearing white matter (NAWM) and gray matter regions compared to HC.
• A significant increase in PK11195 uptake was observed in MS patients' NAWM, cortex, thalamus, and putamen at 12 months.
• No further significant increase in PK11195 uptake was noted between 12 and 24 months in the subgroup of patients assessed at 24 months.

Conclusions:

• Progressive MS is associated with increasing innate immune activity in the brain.
• PK11195-PET imaging can detect longitudinal changes in neuroinflammation in MS.
• These findings suggest a dynamic role for innate immunity in the progression of multiple sclerosis.