Clinical relevance of antibodies against myelin oligodendrocyte glycoprotein in different clinical types of multiple sclerosis

Aggressive Course of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD): An Illustration of Two Cases and Review of Literature

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a central nervous system demyelinating disease that has become a major source of morbidity among children and adults. In the first case, we present an 18-year-old Hispanic female with a recently resolved upper respiratory infection who presented with fever, headache, progressive quadriparesis, urinary retention, and encephalopathy. The hospital course involved autonomic dysfunction and prolonged intubation requiring tracheostomy and gastrostomy. Cerebrospinal fluid (CSF) showed pleocytosis and a positive MOG titer (1:40). Magnetic resonance imaging (MRI) showed longitudinally extensive cervicothoracic T2 hyperintensity and brain multifocal T2 hyperintensities. After high-dose intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG), she had full neurological recovery by the last follow-up. The second case is of a 22-year-old Hispanic male who presented with progressive lower extremity paresthesia and weakness over six weeks. CSF demonstrated pleocytosis, elevated protein, oligoclonal bands, and MOG antibody. MRI revealed multiple subcortical T2-hyperintense lesions and enhancing midcervical and lower thoracic lesions. Treatment with IVMP led to minor improvement with discharge on steroid taper and azathioprine. The patient's disease progressed with a fluctuating course requiring two readmissions with upper extremity weakness, right optic neuritis, and urinary sphincteric dysfunction with neuroradiologic worsening. Treatment throughout multiple admissions included intravenous steroids, IVIG, plasmapheresis, mycophenolate mofetil, and rituximab with minimal improvement, symptom recurrence, and progression of multifocal lesions. The patient died four months after the symptom onset. These cases had markedly different treatment responses despite similar baseline characteristics. The difference in morbidity and disability burden highlights the importance of further investigation of this condition through clinical trials.

The Clinical, Radiologic, and Prognostic Differences Between Pediatric and Adult Patients With Myelin Oligodendrocyte Glycoprotein Antibody-Associated Encephalomyelitis

Purpose: To evaluate the clinical differences between pediatric and adult patients with myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM).

Methods: We retrospectively reviewed the clinical features of pediatric and adult patients with MOG-EM in our center between November 2015 and October 2020.

Results: Twenty-eight pediatric patients and 25 adults were admitted to our study. Bilateral optic neuritis (BON) was the most common initial phenotype in the pediatric group but less common in the adult group (28.57 vs. 0%, p = 0.0119). Almost half of the adult patients presented with neuromyelitis optica spectrum disease (NMOSD), which was less prevalent among the pediatrics (48 vs. 21.43%, p = 0.0414). Visual impairment was the most common symptom in both groups during the initial attack (pediatric group, 39.29%; adult group, 64%) and throughout the full course (pediatric group, 57.14%; adult group, 72%). More pediatric patients suffered from fever than adult patients at onset (pediatric group, 28.57%; adult group, 4%; p = 0.0442) and throughout the full course (pediatric group, 39.29%; adult group, 12%; p = 0.0245). Multiple patchy lesions in subcortical white matter (pediatric group, 40.74%; adult group, 45%), periventricular (pediatric group, 25.93%; adult group, 35%), infratentorial (pediatric group, 18.52%; adult group, 30%) and deep gray matter (pediatric group, 25.93%; adult group, 20%) were frequent in all cases, no significant difference was found between the two groups, while bilateral optic nerve involvement was more frequent in pediatric group (61.54 vs. 14.29%, p = 0.0042) and unilateral optic nerve involvement was higher in adult group (64.29 vs. 15.38%, p = 0.0052). At the last follow-up, adult patients had a higher average EDSS score (median 1.0, range 0–3) than pediatrics (median 0.0, range 0–3), though not significant (p = 0.0752). Patients aged 0–9 years (61.54%) and 10–18 years (70%), and patients presenting with encephalitis/meningoencephalitis (100%) and ADEM (75%) were more likely to recover fully.

Conclusions: Visual impairment was the dominant symptom in both pediatric and adult patients, while fever was more frequent in pediatric patients. Data suggested that BON and bilateral optic nerve involvement were more common in pediatric cases whereas NMOSD and unilateral optic nerve involvement were more prevalent in adults. The younger patients and patients presenting with encephalitis/meningoencephalitis and ADEM tended to recover better.

MOG cell-based assay detects non-MS patients with inflammatory neurologic disease

Objective:

To optimize sensitivity and disease specificity of a myelin oligodendrocyte glycoprotein (MOG) antibody assay.

Methods:

Consecutive sera (n = 1,109) sent for aquaporin-4 (AQP4) antibody testing were screened for MOG antibodies (Abs) by cell-based assays using either full-length human MOG (FL-MOG) or the short-length form (SL-MOG). The Abs were initially detected by Alexa Fluor goat anti-human IgG (H + L) and subsequently by Alexa Fluor mouse antibodies to human IgG1.

Results:

When tested at 1:20 dilution, 40/1,109 sera were positive for AQP4-Abs, 21 for SL-MOG, and 180 for FL-MOG. Only one of the 40 AQP4-Ab–positive sera was positive for SL-MOG-Abs, but 10 (25%) were positive for FL-MOG-Abs (p = 0.0069). Of equal concern, 48% (42/88) of sera from controls (patients with epilepsy) were positive by FL-MOG assay. However, using an IgG1-specific secondary antibody, only 65/1,109 (5.8%) sera were positive on FL-MOG, and AQP4-Ab– positive and control sera were negative. IgM reactivity accounted for the remaining anti-human IgG (H + L) positivity toward FL-MOG. The clinical diagnoses were obtained in 33 FL-MOG–positive patients, blinded to the antibody data. IgG1-Abs to FL-MOG were associated with optic neuritis (n = 11), AQP4-seronegative neuromyelitis optica spectrum disorder (n = 4), and acute disseminated encephalomyelitis (n = 1). All 7 patients with probable multiple sclerosis (MS) were MOG-IgG1 negative.

Conclusions:

The limited disease specificity of FL-MOG-Abs identified using Alexa Fluor goat anti-human IgG (H + L) is due in part to detection of IgM-Abs. Use of the FL-MOG and restricting to IgG1-Abs substantially improves specificity for non-MS demyelinating diseases.

Classification of evidence:

This study provides Class II evidence that the presence of serum IgG1- MOG-Abs in AQP4-Ab–negative patients distinguishes non-MS CNS demyelinating disorders from MS (sensitivity 24%, 95% confidence interval [CI] 9%–45%; specificity 100%, 95% CI 88%–100%).

Intrathecal oligoclonal IgG synthesis in multiple sclerosis

The diagnosis of multiple sclerosis is based on dissemination in time and space. Before 2010 lack of evidence for dissemination in space could be substituted by a paraclinical test, cerebrospinal fluid (CSF) oligoclonal bands (OCBs). The present meta-analysis (13,467 patients) shows that the diagnostic specificity of OCB drops from 94% to 61% if inflammatory etiologies are considered. Importantly, this was not caused by poor laboratory practice. This review on CSF OCB further illustrates the conceptional problem of substituting dissemination in space with a biomarker. The potential prognostic value of intrathecal OCB will need to be tested prospectively.

Elevated intrathecal myelin oligodendrocyte glycoprotein antibodies in multiple sclerosis

OBJECTIVE

To evaluate antibodies to myelin oligodendrocyte glycoprotein (MOG) in the serum and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and control individuals.

DESIGN

Prospective case-control series.

SETTING

Academic referral center.

PATIENTS

Twenty-six controls with noninflammatory neurologic disease and 35 patients with MS donated serum and CSF for recombinant MOG (rMOG) antibody determination.

MAIN OUTCOME MEASURES

Serum and CSF rMOG antibody and albumin levels were used to calculate an rMOG index. Clinical disability, CSF markers, and magnetic resonance metrics were correlated with the rMOG index.

RESULTS

The rMOG index was elevated in MS patients compared with controls (P = .01). Patients with progressive MS exhibited elevated rMOG indexes compared with patients with relapsing-remitting MS (P = .04). The rMOG index was inferior to the IgG index in differentiating MS patients from controls. However, 7 of 16 patients with MS who had normal immunoglobulin G indexes had an elevated rMOG index. The rMOG index did not correlate with clinical disability, other CSF markers, or radiographic outcome measures.

CONCLUSIONS

The rMOG index, a marker of intrathecal MOG antibody production, may provide complementary information to routine CSF testing in the diagnosis of MS. Furthermore, intrathecal anti-MOG antibody production may be more pronounced in progressive than in relapsing forms of MS.

Immunopathogenesis of multiple sclerosis

Immunopathogenesis of multiple sclerosis is a complex process involving T cell mediated autoimmunity at initial stage of disease. A long standing view that Th1 cells are critical for early inflammatory development of lesions is challenging by recent findings that Th1 helper cells with Th17 phenotype are even more important. A complex autoimmunity of MS is further complicated with evidence that CD8 cells, regulatory T cells, clonal expansion of B cells, cells of myelin lineage, antibodies and complement, as well as process intrinsic to central nervous system contribute to the tissue destruction. Although there are a lot of evidences about inflammatory phase of MS, far less is known about mechanisms involved in degenerative phase of disease. It is not known weather quantitative, or qualitative differences in inflammatory response contributes to destruction of the tissue, or as it was shown experimentally demyelination may sometimes occur independent of T cells. Understanding of immunopathogenesis of MS especially regarding various stages of disease is necessary for clinicians in choosing optimal therapy of MS in individual patients. Influences of immunomodulatory treatment on various stages of MS immuno-pathogenesis are presented.

Primary-progressive multiple sclerosis

About 10-15% of patients with multiple sclerosis (MS) present with gradually increasing neurological disability, a disorder known as primary-progressive multiple sclerosis (PPMS). Compared with relapse-onset multiple sclerosis, people with PPMS are older at onset and a higher proportion are men. Inflammatory white-matter lesions are less evident but diffuse axonal loss and microglial activation are seen in healthy-looking white matter, in addition to cortical demyelination, and quantitative MRI shows atrophy and intrinsic abnormalities in the grey matter and the white matter. Spinal cord atrophy corresponds to the usual clinical presentation of progressive spastic paraplegia. Although neuroaxonal degeneration seems to underlie PPMS, the pathogenesis and the extent to which immune-mediated mechanisms operate is unclear. MRI of the brain and spinal cord, and examination of the CSF, are important investigations for diagnosis; conventional immunomodulatory therapies, such as interferon beta and glatiramer acetate, are ineffective. Future research should focus on the clarification of the mechanisms of axonal loss, improvements to the design of clinical trials, and the development of effective neuroprotective treatments.