The patients weren't crazy—Knut Lundin was sure of that. But their ailment was a mystery. They were convinced gluten was making them sick. Yet they didn't have celiac disease, an autoimmune reaction to that often-villainized tangle of proteins in wheat, barley, and rye. And they tested negative for a wheat allergy. They occupied a medical no man's land.
http://www.sciencemag.org/news/2018/05/what-s-really-behind-gluten-sensitivity?utm_campaign=news_weekly_2018-05-25&et_rid=389974365&et_cid=2075185