Atypical Multiple Sclerosis with Antibody to MOG
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.299157
Source of Support: None, Conflict of Interest: None
Keywords: Anti-MOG antibody, demyelinating CNS disease, multiple sclerosis, optic neuritis, transverse myelitis
A 23-year-old female presented with diminution of vision in the left eye for eight days and weakness of both lower limbs for four days.
Diminution of vision in the left eye was acute in onset described as a blurring of distant and near objects in all visual fields with impaired color vision. No associated headache or diplopia was present. The right eye vision was normal.
The weakness in both lower limbs was acute in onset and to the extent that she was bedbound and nonambulatory with support as well.
On examination, she had left eye optic neuritis with visual acuity of 6/60.
She had grade II Modified Ashworth Scale spasticity in both lower limbs with the power of 2/5 at all the joints in all range of movements, brisk knee, and ankle jerks bilaterally and extensor plantar. The motor examination of upper limbs were normal.
She had diminished touch, pain, and temperature sensation with the level at T3 and vertebral level T1.
Her routine laboratory investigations were normal. The cerebrospinal fluid (CSF) analysis showed mild pleocytosis (25 cells) with normal proteins and sugar values.
Her magnetic resonance imaging (MRI) brain showed punctate areas of altered signal intensities in bilateral centrum semiovale, subcortical white matter of cerebral hemispheres (periventricular), pons and left middle cerebellar peduncle which was hypointense on T1 and hyperintense on T2/fluid attenuated inversion recovery (FLAIR) images suggestive of demyelinating leisons [Figure 1] and [Figure 2].
Her MRI whole spine screen reported patchy areas of altered signal intensity at C3-C4-C5 and D1-D2 levels suggestive of demyelination (Images C) [Figure 3].
Oligoclonal bands (OCBs) were present in CSF. Visual evoked potential showed no potential in the left eye and minimally prolonged P100 values in right eye.
Her Expanded Disability Status Scale (EDSS) score was 8.
Diagnosis of multiple sclerosis (MS) as per revised McDonald Criteria was made with certain atypical features of mild pleocytosis, brainstem and cerebellar peduncle involvement apart from opticospinal (OS) involvement.
Therefore, the AQP4 and anti-MOG antibodies were sent, of which AQP4 was negative but anti-MOG was positive.
Therefore, the patient was diagnosed with atypical MS with autoantibodies to MOG.
She was given pulse methylprednisolone for five days.
She showed partial improvement with EDSS coming down to 4.5.
She was started on oral prednisolone 1 mg/kg, and to prevent relapse, she was given rituximab 375 mg/m2 once a week for four weeks.
After 1 month, her EDSS ambulation score was zero and the visual acuity in the left eye was 6/9.
Typical MS cases are largely anti-MOG-negative. In a study of 50 Japanese cases with AQP4-IgG-negative OSMS, just two were MOG-IgG-positive, but they had some features atypical for MS, such as bilateral optic neuritis, longitudinally extensive transverse myelitis, or moderate pleocytosis.
In our case, the patient had MRI brain lesions typical of MS and classified as definite MS based on revised McDonald criteria, but she had atypical features of mild pleocytosis, brainstem and cerebellar peduncle involvement apart from OS involvement.
In another study, the antibodies to MOG were found in about 5% (5/104) of preselected adult patients with MS. Patients with MS with antibodies to MOG showed typical MS lesions on brain MRI with concomitant severe brainstem and spinal cord involvement and had a severe disease course with high relapse rates.
Patients with MS who have antibodies to MOG may be at higher risk of progressive disease and need escalating therapies, as indicated by high relapse rates and lack of satisfactory response to several disease-modifying therapies (DMTs) in the past. Three of them had been treated with plasma exchange with a favorable response. Two patients showed a favorable response to rituximab, which is observed in MS as well as in patients with Neuromyelitis Optica Spectrum Disorder (NMOSD). Two other patients stabilized with natalizumab therapy supporting the diagnosis of MS rather than NMOSD.
Longitudinal analysis of up to nine years revealed fluctuations and reappearance of anti-MOG reactivity.
In our case, the patient showed a favorable response to pulse methylprednisolone and has been given rituximab to prevent relapse. We intend to keep a long follow-up to monitor for any relapse and will do an anti-MOG antibody test yearly to check for any fluctuation in its reactivity.
In conclusion, any patient showing typical MS lesions on the brain MRI with OCB present in CSF but having atypical features like mild pleocytosis with brainstem, cerebellar, or OS involvement should also be tested for autoantibodies to MOG, and if the test has a positive result, then he/she would require aggressive treatment approach in the form of plasma exchange, if resistant to pulse steroid therapy followed by either rituximab or natalizumab rather than trying other DMTs.
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Conflicts of interest
There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3]