Meningeal T cells associate with diffuse axonal loss in multiple sclerosis spinal cords.

Area of Science:

• Neuroscience
• Immunology
• Pathology

Background:

• Progressive multiple sclerosis (MS) involves diffuse axonal loss and inflammation in the brain.
• The relationship between axonal loss and inflammation in the spinal cord in MS is less understood.

Purpose of the Study:

• To investigate the link between diffuse axonal loss and inflammation in the spinal cord of patients with progressive MS.
• To determine if findings in the brain regarding axonal loss and inflammation are mirrored in the spinal cord.

Main Methods:

• Quantitative neuropathological assessment of inflammation and axonal loss.
• Analysis of cervical spinal cord tissue from 18 progressive MS patients and 5 controls.

Main Results:

• A 25% decrease in axonal density was observed in normal-appearing white matter (NAWM) of MS spinal cords compared to controls.
• Robust diffuse inflammation was present in both NAWM and meninges, with rare T-cell perivascular infiltrates.
• Axonal loss in NAWM correlated with MHC class II(+) microglia density and meningeal CD3(+) T-cell density.

Conclusions:

• Meningeal inflammation, particularly involving T cells and activated microglia, is linked to diffuse axonal loss in the MS spinal cord.
• This study underscores the connection between meningeal inflammation and parenchymal lesions in progressive MS.
• Findings suggest a specific role for meningeal immune cells in spinal cord pathology in MS.