I'd like to point out an interesting post from Peter at Hyperlipid. He discusses a paper that uses a novel technique to look for immune activation in the gut in response to wheat gluten. For the nerds: they challenged patient gut biopsies with gliadin fragments (gliadin is one of the proteins that make up gluten) and looked for expression of interleukin-15 (IL-15), a marker of activation of the innate immune system. The innate immune system is an old system (evolutionarily speaking) that predates the antibody-producing "adaptive immune system" and nonspecifically defends against pathogens.
Biopsies from 5 out of 6 patients showed an IL-15 response to at least one gliadin fragment. The implication is that the majority of people have an immune response to wheat, even if they don't have Celiac disease. The reason they aren't diagnosed as Celiac patients is they don't have circulating anti-gliadin antibodies (and they presumably don't yet have severe structural damage to their intestinal tract as judged by biopsy or endoscopy), but as the paper shows, people can react to gluten without producing antibodies via the innate immune system.
As someone who regularly does Western blots, I can say I'm not impressed by the quality of their data, but if this is confirmed more solidly and on a larger scale it would be HUGE. As you know if you've been following the blog, the small intestine has a lot of important functions: besides absorbing nutrients and secreting enzymes, it also plays an important role in regulating satiety and insulin secretion by the pancreas and overall insulin sensitivity. It's not an organ you want to damage.