In the overly sterile environment my characters live in, the AIs supplement probiotics with food servings for the humans.
Let's say one type of gut flora went extinct. The AIs are trying to fix the problem by experimenting with new probiotic ratios. If they overdosed one test group with L Salivarious, and the people's systems were already out of natural balance, could this spawn a new auto-immune disease?
I'd like the disease to have a broad collection of symptoms similar to MS, although I'm not sure how to do that. I don't want to posit the L Salivarious would attack the myelin sheath (I assume it would not).
What would too much L. Salivarious do to a body if it took on the vigor of an auto-immune disease?