Given the loss of tolerance to GP2 in CD and assuming a role of GP2 in antigen presentation and immunomodulation in the small intestine, we i) assessed the prevalence of autoantibodies against GP2 in active and inactive CD, ii) looked for an association between anti-GP2 antibody positivity and clinical phenotype, and iii) investigated anti-GP2 IgA and IgG in sera from patients with histologically proven CD at the time of diagnosis and under gluten-free diet (GFD). Here, GP2 is linked to Cowden disease.