What is demyelination (loss of the myelin sheath)?

From the Guidelines

Demyelinating disorders should be diagnosed and treated based on the most recent and highest quality evidence, with a focus on reducing morbidity, mortality, and improving quality of life, as outlined in the 2018 study on MOG encephalomyelitis diagnosis and antibody testing 1.

Key Considerations

• The diagnosis of demyelinating disorders, such as multiple sclerosis (MS), acute disseminated encephalomyelitis (ADEM), and MOG encephalomyelitis, requires careful consideration of clinical presentation, radiological findings, and antibody testing.
• The 2018 study provides recommendations for MOG-IgG testing in patients with acute CNS demyelination, including those with optic neuritis, myelitis, brainstem encephalitis, and other conditions.
• The presence of longitudinally extensive spinal cord lesions, optic nerve lesions, or other specific radiological findings, as well as certain clinical features such as simultaneous bilateral optic neuritis or severe visual deficit, should prompt consideration of MOG-IgG testing 1.

Treatment Approaches

• Treatment of demyelinating disorders typically involves the use of corticosteroids, such as methylprednisolone, to manage acute inflammation, as well as immunomodulatory medications and disease-modifying therapies to reduce disease activity and prevent long-term damage.
• The choice of treatment should be guided by the specific diagnosis, disease severity, and individual patient factors, with a focus on minimizing morbidity and mortality and improving quality of life 1.

Important Findings

• The 2018 study highlights the importance of considering MOG-IgG testing in patients with demyelinating disorders, particularly those with certain clinical and radiological features.
• The study also notes that MOG encephalomyelitis is more frequent in young children than in adults, and that the indications for MOG-IgG testing may be less rigorous in this population 1.

From the FDA Drug Label

Gd-enhancing lesions seen on brain MRI scans represent areas of breakdown of the blood brain barrier thought to be secondary to inflammation. In Study 2,383 patients who had recently experienced an isolated demyelinating event involving the optic nerve, spinal cord, or brainstem/cerebellum, and who had lesions typical of multiple sclerosis on brain MRI, received either 30 micrograms of AVONEX (n = 193) or placebo (n = 190) by intramuscular injection once weekly The answer to the question about demyelinating events is that AVONEX-treated patients demonstrated significantly lower Gd-enhanced lesion number after 1 and 2 years of treatment than placebo-treated patients.

• Key points:
  • Demyelinating events were studied in patients with multiple sclerosis.
  • AVONEX treatment resulted in lower Gd-enhanced lesion number.
  • The study suggests that AVONEX may be effective in reducing demyelinating events in patients with multiple sclerosis 2

From the Research

Demyelination and Multiple Sclerosis

• Demyelination is a key feature of multiple sclerosis (MS), a chronic inflammatory demyelinating central nervous system disease 3
• MS is characterized by loss of motor and sensory function, resulting from immune-mediated inflammation, demyelination, and subsequent axonal damage 3
• The disease can present in various forms, including relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), and primary progressive MS (PPMS) 4, 5

Treatment Options for Multiple Sclerosis

• Disease-modifying therapies (DMTs) are available for the treatment of MS, including interferon-beta-1a (IFNbeta-1a), interferon-beta-1b (IFNbeta-1b), and glatiramer acetate 4, 5
• These therapies have been shown to reduce relapse risk and preserve neurological function in patients with RRMS 4, 5
• The choice of treatment should be tailored to the individual patient's needs, taking into account factors such as efficacy, safety, and tolerability 4, 5

Effects of Treatment on Innate Immunity

• Interferon beta-1a (IFN) and glatiramer acetate (GA) have been shown to affect innate immunity cell populations in patients with MS 6
• A study found that IFN treatment was associated with a significant increase in monocytes (relative count) after 6 months of treatment 6
• The findings suggest that IFN treatment may modulate the immune response in MS by affecting monocyte function 6

Comparison of Treatment Options

• There is limited head-to-head trial data comparing the efficacy of different DMTs for MS 5, 7
• However, interferon beta and glatiramer acetate have been shown to be effective and safe treatments for MS, with a place in the treatment arsenal even with the availability of newer therapies 7