Sorry about the death of one of the authors.
I think it's interesting that some people claim that the increased presence of MAP in CD could be attributed to increased permeability, an innocent bystander, or cross reactivity.
None of the 47 children with UC have MAP specific antibodies, nor do the adults with celiac disease. It can be used as a specific diagnostic method to differentiate CD from UC. MAP is very specific to the ileum in ruminants and primates.
The reluctance of some people to acknowledge the presence of some very specific bacteria in CD: AIEC, MAP, Campylobacter concisus, is plain ridiculous. Since it's not just of academic importance, it's a diagnostic tool that can differentiate CD from UC, especially in classic ileal disease.
They do want to use highly unreliable tests like ASCA, which likely IS cross reactivity, something that isn't even specific to CD.