I am sure you know people who have decided to go gluten-free because they want to be healthy. However, for most of these people buying gluten free products is just a way of throwing money away since only about 1-2% of Europeans suffer gluten intolerance (celiac disease). Could it be that a bacterium is behind celiac disease? People affected with celiac disease have to avoid gluten, a protein present in cereals like wheat, because when exposed to it, their immune system will recognise them as antigens and drive an inflammatory response in the intestine. This can eventually lead to various symptoms like stomach pains, bloating, or diarrhea among others. What drives celiac disease? Like in many other diseases, it is known that there is a genetic component to the disease, but also that environmental factors play a key role in the onset of the disease symptoms. Now, an international research collaboration has shown that a certain type of bacteria could be behind the onset of celiac disease, at least for certain patients. The results of their study, published in Nature Structure and Molecular Biology 1, show that isolated T cell receptors from celiac patients could recognise protein fragments of certain bacteria. What does this mean? T cell receptor are key to gluten intolerance T cells are elements of the immune system that recognise pathogens thanks to their receptors, which are specific for certain antigens, or protein fragments. Once a T cell receptor finds its specific antigen, an immune response sets off and, because the immune system has “memory”, these T cells will learn to recognise the antigen much faster and produce a bigger immune reaction the next time they come in contact. Coming back to celiac disease, if a bacterium has protein elements with a similar structure to gluten, and a person with a certain T cell receptor type is exposed to this bacteria, the next time this receptor finds a similar antigen, gluten, will produce an enhanced immune response because it mistakes your cereal with an infection. While this is interesting research, and it offers an explanation to some gluten intolerance cases, it doesn’t explain fully this complex immune disease. However, it might help in developing better early detection tools for the disease or even treatments that will allow this poor people to enjoy a fresh-from-the-oven wheat croissant.