Treatment of Anti-MOG Antibody Disease
For acute attacks, initiate high-dose intravenous methylprednisolone at 1000 mg/day (or 30 mg/kg up to 1000 mg/day) for 3-5 days immediately, followed by a prolonged oral corticosteroid taper over several weeks to months to prevent early relapse. 1, 2
Acute Phase Management
First-Line Treatment
- Administer IV methylprednisolone 1000 mg/day for 3-5 days as the cornerstone of acute therapy for all presentations including optic neuritis, transverse myelitis, brainstem encephalitis, or encephalitis 1, 2, 3
- Start treatment immediately upon clinical suspicion without waiting for antibody confirmation if the presentation is highly suggestive 2
Escalation for Inadequate Response
- Proceed to plasma exchange (5-7 exchanges) or immunoadsorption if no improvement occurs after 3-5 days of IV steroids, as this is effective in severe, steroid-refractory cases 2, 3
- Consider IVIG as an alternative adjunct therapy, though plasma exchange is preferred for severe cases 3
Critical Post-Acute Management
- Implement a prolonged oral corticosteroid taper over weeks to months rather than rapid discontinuation, as 50-60% of patients relapse during steroid dose reduction 2, 3
- Do not taper steroids too rapidly, as symptom flare-ups frequently occur with premature reduction 2
Long-Term Maintenance Therapy
Indications for Chronic Immunosuppression
- Initiate maintenance therapy after the acute phase in patients with relapsing disease (approximately 50-60% of cases) 2, 4
- Consider starting maintenance therapy even after a first attack in patients with severe presentations, given the higher-than-expected relapse rates (up to 56% in some cohorts) occurring predominantly within the first year 4
Preferred Maintenance Options
- B-cell depleting therapies (rituximab, ocrelizumab, ofatumumab) show particularly good responses and are emerging as first-line maintenance agents, with relapses occurring immediately after B-cell reconstitution 2
- IVIG is emerging as probably the most effective therapy for relapsing MOGAD based on accumulating evidence 3
- Alternative options include chronic low-dose corticosteroids, mycophenolate mofetil, or azathioprine for patients who cannot receive biologics 4
Monitoring Strategy
- Retest MOG-IgG antibodies 6-12 months after the initial attack to assess prognosis, as antibody disappearance may indicate monophasic disease and potentially allow discontinuation of maintenance therapy 2, 5
- If long-term immunosuppression is discontinued due to seronegativity, close monitoring of MOG-IgG serostatus is highly recommended, as transient seroconversion can occur and antibodies may rise again at relapse 5
- Be aware that the interval between first and second attack varies considerably, with some patients experiencing their second attack only after several years 5
Critical Pitfalls to Avoid
Disease-Modifying Therapies to Avoid
- Do not use interferon-beta or natalizumab, as these MS disease-modifying therapies can worsen MOG-positive disease and increase relapse rates 1, 2
- Traditional MS therapies differ fundamentally from MOGAD treatment and may lead to worse outcomes 1
Diagnostic Confirmation Requirements
- Ensure MOG-IgG was detected by cell-based assay using full-length human MOG as the target antigen, as this is the gold standard methodology 2, 5
- Serum is the specimen of choice for MOG-IgG testing, not CSF, since MOG-IgG is produced mostly extrathecally 2
- Obtain MRI of brain and spine to document demyelinating lesions compatible with the clinical syndrome 2
Clinical Recognition Challenges
- Recognize that CSF may show neutrophilic pleocytosis and lack oligoclonal bands, which can mimic CNS infection rather than typical demyelinating disease 2
- Be aware that MOG-IgG concentrations are higher during acute attacks than during remission and lower while on immunosuppression, so timing of testing matters 2