ALS and BFS are a multi-system disease because of our body's response to commands by our CNS. Because the nervous system instructs our body and systems to act, overreact or respond, one's auto-immune system could be impacted. If there is a nervous system disorder, such as in BFS, you may notice more symptoms without explanation. When my "BFS" began, I developed sinus and allergic symptoms that I did not experience before while exposed to the same environment. All, I think, is caused by a nervous system that is communicating instructions at the wrong time or without a true need to do so. I could be wrong. I'm just being analytical.PS I watched a testimony by an ALS patient who stated that anxiety and stress aggravate his symptoms, a possible example and how it is similar to BFS.