Note the prevalence of ASCA seropositivity in both ileal Crohn's disease and Celiac disease. But lack of ASCA in Crohn's disease involving the colon and UC.
You could blame this on increased ileal permeability, but when you look at the data on celiac diseae, the high prevalence of celiac among CD, the adaptive immune response in crohn's disease directed at yeasts, and lack of other sereological markers that one would expect, this isn't a good explanation.
Note also that healthy first degree relatives have high ASCA serpositivity, much higher than controls, which can not be easily explained by increased permeability.
Interesting. I have ileal Crohn's, am celiac too, and am ASCA negative. But then again, I am a bit of a curious case, with limited symptoms, so far mild disease, and I react negatively to EEN. Perhaps there is a link between EEN and ASCA?