What causes Multiple Sclerosis (MS) flares?

From the Guidelines

Multiple Sclerosis (MS) flares are caused by a combination of genetic, immunological, and environmental factors, including inflammation and autoimmune responses.

Key Factors Contributing to MS Flares

• Inflammation: MS is characterized by an inflammatory component, with MRI-based quantification of inflammatory activity in pathology being focal or diffuse and associated with neurodegenerative processes 1.
• Autoimmune responses: The disease is considered an autoimmune condition, where the immune system attacks the myelin sheath, leading to demyelination and axonal damage.
• Genetic and environmental factors: Research suggests that genetic, immunological, and environmental factors, such as a common virus, may all be involved in the complex etiology of MS 1.

Triggers for MS Flares

• Infections: Certain infections, such as those caused by the JC virus, can increase the risk of MS flares, particularly in patients treated with immunomodulatory therapies like natalizumab 1.
• Immunosuppressant use: The use of immunosuppressants, including natalizumab, can increase the risk of MS flares, particularly in patients with a history of immunosuppressant use 1.

Monitoring and Management of MS Flares

• MRI scanning: Regular MRI scanning can help monitor disease activity and detect potential flares early on 1.
• Anti-JCV antibody testing: Regular testing for anti-JCV antibodies can help identify patients at increased risk of developing progressive multifocal leukoencephalopathy (PML), a rare but serious complication of MS treatment 1.

From the Research

Causes of Multiple Sclerosis (MS) Flares

• MS flares can be triggered by various factors, including:
  • Infections, such as viral upper respiratory infections (URIs) 2
  • Microbial infections, including bacteria and viruses, such as Chlamydia pneumoniae, Staphylococcus aureus, and Epstein-Barr virus 3, 4
  • Environmental factors, such as vitamin D deficiency, obesity, and smoking 4, 5
• The exact causes of MS flares are not fully understood, but it is believed that genetic and environmental factors contribute to the onset and progression of the disease 4, 5, 6
• The immune system plays a key role in MS pathogenesis, with immune dysregulation leading to the infiltration of the central nervous system (CNS) by immune cells, triggering demyelination, axonal damage, and neurodegeneration 6
• Common upper respiratory, gastrointestinal, and urogenital tract infections have also been associated with MS exacerbations 3
• Interactions between genetic and environmental factors have been studied, and dietary factors and changes in the gut microbiota are emerging as possible modulators of the disease risk 4