Gut environmental factors and multiple sclerosis.

Commensal bacteria have maintained a symbolic relationship with the human body including the immune system and central nervous systems by co-evolving with humans for more than five million years. Recently, however, dysbiosis has emerged as a risk factor for various disorders including immune-mediated diseases. In this review, we discuss the interactions between commensal microbiota and the immune system and the association of immune-mediated diseases such as multiple sclerosis with microbial components and metabolic products as well as the presence of dysbiosis recently reported in multiple sclerosis patients.