Wheat Gliadin peptide A5 has been found in pancreases of type 1 diabetics as have antibodies to A5. A5 mimics beta endorphin.
The pancreas monitors and holds endorphin, and secretes insulin in response. The insulin prevents muscles from consuming themselves in fight-or-flight situations.
Some immune systems recognize A5 as an invading antigen, and attack the pancreas. This does not mean that other carb proteins don’t mimic endorphin and cause the same autoimmune response. Gliadin A5 is just the best studied one.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119241/