There are a lot of interesting insights in this article, and a lot of immunology that I don't understand. Several links from it are also of interest.
Here is one tidbit that might have broader appeal: the reason gliadin (another article worth reading at Wikipedia) formed in conjunction with the 'new wheat' that was easy to pick and store was to dissuade mammalian predators of it. In other words, it was an active defense mechanism that increased survivability.
To appreciate what this might mean, I recommend this article:
It turns out that early-onset and late-onset gluten sensitivies are different...
Even though the gluten article is highly technical, it's got a lot of interesting facts, too - I recommend it. Maybe someday I'll distill it....