I can't say I understand what this is saying so hopefully one of you more scientific folks can explain it. From what I can understand there seems to be a link from having had Epstein Barr (mono nucleosis, chronic fatique syndrom) and pre-dispose people to developing autoimmune diseases like IBD and several others. The article is from 2018. I googled and didn't see anything newer at first glance.
https://www.nature.com/articles/s41588-018-0102-3