MOG Antibody Status Is Associated With Distinct Clinical Profiles and Treatment Responses in Chronic Relapsing...

Chronic relapsing inflammatory optic neuropathy (CRION) is a steroid-dependent form of optic neuritis with incompletely understood pathophysiology. The identification of myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) in a substantial patient subset has challenged the diagnostic and therapeutic management. The aim of this study was to investigate clinical profiles and treatment outcomes of patients with CRION, comparing MOG-IgG-positive (MOG+) and seronegative (MOG-) subgroups.

Patients from 6 European tertiary centers fulfilling diagnostic criteria for CRION were included. All underwent cell-based autoantibody testing. Clinical outcomes (visual acuity and annualized relapse rate), laboratory and imaging findings (MRI, OCT), and treatment responses were retrospectively analyzed.

Sixty patients were included (median age 33 years; 70% female); 27 (45%) were MOG+. MOG+ CRION was associated with later onset, higher annualized relapse rate (ARR) before treatment (median [IQR] 2 [1-3] vs 1 [1-2], p = 0.023), and a trend toward shorter interrelapse intervals. Additional distinguishing features included higher frequencies of antinuclear antibody positivity, elevated CSF interleukin-6, and extensive enhancement of the optic nerve on MRI. Relapse burden correlated with visual acuity decline and retinal thinning. In MOG+ patients, monoclonal antibody therapy reduced the ARR (n = 21; 2 [1-3] vs 0 [0-2], p = 0.024), primarily driven by tocilizumab (n = 11; 2 [1-3] vs 0 [0-1], p = 0.023). In MOG- patients, rituximab and azathioprine showed a trend toward ARR reduction.

CRION represents a heterogeneous syndrome encompassing distinct subgroups. Although MOG+ patients demonstrate higher disease activity, tocilizumab might represent a therapeutic option, though further validation is needed. Serologic testing is critical for treatment stratification and preventing relapses.