What is the cause of Multiple Sclerosis (MS)?
Multiple sclerosis (MS) is a neurodegenerative disease of uncertain etiology. In MS, neurodegeneration is thought to be secondary to autoimmune-mediated damage. However, no cohesive explanation yet exists as to how environmental factors interact to induce a neurodegenerative autoimmune response. Insufficient sunlight exposure and chronic viral infections have been proposed as unrelated environmental risk factors for MS. Colleen Hayes and Donald Achaeson suggest that these risk factors may act synergistically to enable the pathogenic autoimmune response. Low ultraviolet light (UVL) exposure depletes vitamin D3 stores, and low vitamin D3 levels correlate strongly with high MS risk. The central nervous system converts vitamin D3 into 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), a biologically active hormone with antiinflammatory and neuro-protective functions that depend on IL-10-producing regulatory lymphocytes. Herpesvirus infection also correlates with MS risk. Some herpesviruses like Epst
