The review article published by the journal Frontiers in Pediatrics in December of 2018 is titled, Microbial Transglutaminase Is Immunogenic and Potentially Pathogenic in Pediatric Celiac Disease.
The commonly considered trigger for these intestinal disorders is gluten, a protein substance found in grain-based foods that due to satisfying industrial bakery purposes has been artificially and naturally boosted by selective wheat breeding to increase wheat’s gluten content.
Gluten makes commercially baked goods more cohesive and easier to deal with by the food industry. And today’s hybrid wheat is much higher in gluten content than wheat 50 to 100 years ago.
Beyond that inherent gluten content, the rise of microbial transglutaminase (mTg) used for processing foods to make them more palatable, improve texture, and increase shelf life has increased considerably, and it is something you won’t see on ingredient labels. As a processing enzyme, it’s technically not considered an ingredient, thus labeling it is not required.
Celiac disease is one of many autoimmune diseases where the immune system attacks one’s own organs and tissues and causes chronic inflammation.
Summarizing the authors’ understanding of how mTg appears to be a major source of Celiac disease and other gut inflammatory conditions, it could be stated accurately that mTg compounds attach to gluten fragments causing the immune system to respond with antibodies.
In his own article covering this review paper, Dr. Ronald Hoffman explains microbial transglutaminase (mTg) and its use with a final irony:
It’s synthesized from bacteria, in huge “brew” vats. The resultant product is used in food processing to improve the texture of doughs. It’s also made from animal blood into so-called “meat glue”—hence its application to the manufacture of processed meat, fish balls, and imitation crab meat (surimi).
OK, you’ve gone gluten-free, and now eat gluten-free baked goods made from alternative flours like rice, corn, amaranth, or cassava. Guess what? They may be processed with mTg!
Going gluten-free won't protect you from potential leaky-gut triggering bacteria. In addition to enriching the texture, plasticity, and cohesiveness of dough from grain gluten sources, mTg manufacturers claim it is highly useful for gluten-free products as well. (Source)
While asserting that correlation is not causation, the authors do point to mTg as an obvious suspect for intestinal disorders from dietary sources worthy of further investigation.