The human microbiome in multiple sclerosis: pathogenic or protective constituents?
The human microbiome is comprised of commensal and pathogenic microorganisms, which exert diverse effects in close proximity to the site of intection as well as in remote tissues through immune-mediated mechanisms. Multiple infectious agents have been implicated in the pathogenesis of multiple sclerosis (MS) with variable findings depending on the agent, techniques, and disease phenotype. Herein, the contributions of individual infectious agents to MS and their effects on the immune and nervous systems are reviewed, focusing on herpes viruses, coronaviruses, retroviruses, and synchronic infections. While infectious agents are often assumed to be pathogenic, their effects might also be beneficial to the host in the long-term, depending on age and the type of immunogen/pathogen exposure, as proposed by the hygiene hypothesis. The human microbiome has potential impact on future diagnostic and therapeutic issues in MS.
Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
Christopher
C
Power
Joseph M
JM
Antony
Kristofor K
KK
Ellestad
André
A
Deslauriers
Rakesh
R
Bhat
Farshid
F
Noorbakhsh
D000818:Animals; D002490:Central Nervous System / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D020805:Central Nervous System Viral Diseases / Q000150:complications*; D006801:Humans; D054892:Metagenome / Q000235:genetics; D008954:Models, Biological; D009103:Multiple Sclerosis / Q000235:genetics / Q000382:microbiology* / Q000473:pathology