Editing Multiple sclerosis (section)

=== Infectious agents ===

Early evidence suggested the association between several viruses with human demyelinating [[encephalomyelitis]], and the occurrence of demyelination in animals caused by some viral infections.<ref name="pmid15721830">{{cite journal | vauthors = Gilden DH | title = Infectious causes of multiple sclerosis | journal = The Lancet. Neurology | volume = 4 | issue = 3 | pages = 195–202 | date = March 2005 | pmid = 15721830 | doi = 10.1016/S1474-4422(05)01017-3 | pmc = 7129502 }}</ref> One such virus, [[Epstein–Barr virus|Epstein-Barr]] [[Herpesviridae#Human herpesvirus types|virus]] (EBV), can cause [[infectious mononucleosis]] and infects about 95% of adults, though only a small proportion of those infected later develop MS.<ref>{{cite journal | vauthors = Soldan SS, Lieberman PM | title = Epstein-Barr virus and multiple sclerosis | journal = Nature Reviews. Microbiology | volume = 21 | issue = 1 | pages = 51–64 | date = January 2023 | pmid = 35931816 | pmc = 9362539 | doi = 10.1038/s41579-022-00770-5 }}</ref><ref name="Aloisi20222" /><ref name="Bjornevik2022">{{cite journal | vauthors = Bjornevik K, Cortese M, Healy BC, Kuhle J, Mina MJ, Leng Y, Elledge SJ, Niebuhr DW, Scher AI, Munger KL, Ascherio A | title = Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis | journal = Science | volume = 375 | issue = 6578 | pages = 296–301 | date = January 2022 | pmid = 35025605 | doi = 10.1126/science.abj8222 | s2cid = 245983763 | bibcode = 2022Sci...375..296B }} See lay summary: {{cite news |vauthors=Gallagher J |title=Is a virus we all have causing multiple sclerosis? |url=https://www.bbc.com/news/health-61042598 |work=BBC |date=13 April 2022 |archive-date=25 April 2022 |access-date=14 April 2022 |archive-url=https://web.archive.org/web/20220425142547/https://www.bbc.com/news/health-61042598 |url-status=live }}</ref><ref name="Hassani-2018" /> A study of more than 10 million US military members compared 801 people who developed MS to 1,566 matched controls who did not. The study found a 32-fold increased risk of MS development following EBV infection. It did not find an increased risk after infection with other viruses, including the similar [[cytomegalovirus]]. These findings strongly suggest that EBV plays a role in MS onset, although EBV alone may be insufficient to cause it.<ref name="Aloisi20222" /><ref name="Bjornevik2022" />

The [[Epstein–Barr virus nuclear antigen 1|nuclear antigen of EBV]], which is the most consistent marker of EBV infection across all strains,<ref>{{cite journal | vauthors = Münz C | title = Epstein-barr virus nuclear antigen 1: from immunologically invisible to a promising T cell target | journal = The Journal of Experimental Medicine | volume = 199 | issue = 10 | pages = 1301–1304 | date = May 2004 | pmid = 15148332 | pmc = 2211815 | doi = 10.1084/jem.20040730 }}</ref> has been identified as a direct source of autoreactivity in the human body. These antigens appear more likely to promote autoimmunity in vitamin D-deficient persons. The exact nature of this relationship is poorly understood.<ref>{{cite journal | vauthors = Miclea A, Bagnoud M, Chan A, Hoepner R | title = A Brief Review of the Effects of Vitamin D on Multiple Sclerosis | journal = Frontiers in Immunology | volume = 11 | pages = 781 | date = 2020-05-06 | pmid = 32435244 | pmc = 7218089 | doi = 10.3389/fimmu.2020.00781 | doi-access = free }}</ref><ref name="Ward 988–1005" />