I concede the last statement. Very difficult to get a level analytical playing field over long periods of time.
I'm not really able to understand the 'memory system' of immune cells. I just phoned my son for a briefing, (stress and the immune system is one of his focus subjects.) but he was driving, so I'll have to wait for that.
What does seem strange to the layman, is the level of 'learning' within the cells themselves. So, it takes me away from a direct control of some misguided processing in the brain - as so much is going on at cell level. However, I still think there is a high likelihood there is some sort of master control that becomes confused. It so often seems to be linked to factors like stress.
I claimed at the time I felt wholewheat bread made me ache. It seemed to be 100% hit rate. I went on to enjoy years of eating such bread.
It was the period all those years ago that prompted me to try not eating wheat this time around - with almost total success. (the soap thing blurs the certainty.)
Another issue is the products they use on the wheat. A Uni professor neighbor can't touch the stuff, but she can eat bread again when she's in a different state (of the US). Clearly that slews any results from hit and miss self help.
I'll try to get a clearer picture, then steer back to the OP's point of sudden and disabling reactions.