Brain Atrophy in Relapsing Optic Neuritis Is Associated With Crion Phenotype

Area of Science:

• Neuroimmunology
• Neurology
• Ophthalmology

Background:

• Chronic relapsing inflammatory optic neuritis (CRION) is a common phenotype associated with myelin oligodendrocyte glycoprotein antibodies (MOG-Abs).
• Distinguishing CRION from relapsing inflammatory optic neuritis (RION) is challenging due to the lack of specific biomarkers.
• Previous research suggests widespread central nervous system (CNS) involvement in CRION patients.

Purpose of the Study:

• To investigate brain atrophy as a potential biomarker for CRION.
• To compare brain atrophy in patients with CRION, RION, and multiple sclerosis with optic neuritis (MS-ON).
• To assess the association between MOG-Abs status and brain atrophy.

Main Methods:

• A cross-sectional study of 31 patients (7 CRION, 11 RION, 13 MS-ON).
• Measurement of MOG-Abs and aquaporin-4 antibodies (AQ4-Abs).
• Calculation of brain atrophy using brain parenchyma fraction (BPF) via Neuroquant® software.

Main Results:

• MOG-Abs were detected in 4/7 CRION patients and 1/11 RION patients (p=0.046).
• No MS-ON patients tested positive for MOG-Abs.
• CRION patients exhibited significantly lower BPF compared to RION patients (70.6% vs. 75.3%, p=0.019), similar to MS-ON patients.

Conclusions:

• Brain atrophy is a characteristic feature of the CRION phenotype in idiopathic inflammatory relapsing optic neuritis.
• These findings indicate that the CNS, beyond the optic nerve, is a primary target in CRION.
• Further prospective studies are warranted to validate these results and explore their clinical implications.