What is the antigen that is responsible for Crohn's disease? Is it always the same one? Also the original article doesn't mention Crohn's at all, just celiac.

It seems interesting that one galactose molecule (alphagal [1, 2]) is immunogenic in xenotransplantation and tick allergy, but two galactose molecules (pGal) are tolerogenic in this case

1- Identification of carbohydrate structures that bind human antiporcine antibodies: implications for discordant xenografting in humans https://pubmed.ncbi.nlm.nih.gov/1566430/

2- Identification of alpha-galactosyl and other carbohydrate epitopes that are bound by human anti-pig antibodies: relevance to discordant xenografting in man https://pubmed.ncbi.nlm.nih.gov/7521740/