Were they aphthous ulcers? B vitamin deficiency (B12 and folate) is a common cause; cow's milk has been implicated, as has gluten- many celiacs also have aphthous ulcers. Other causes include trauma, sometimes...
WGA seems tied to a variety of autoimmune diseases; there's a good section (page 139-152) in "Protein Power" by the Drs. Eades providing a viable mechanism by which lectins may cause disease. See also Lectins...