GP2 and Crohn disease: TSPAN8 is expressed in the gastrointestinal tract and several carcinomas (Agaësse et al, 2017; Zhu et al, 2017; Zhao et al, 2018), and GP2 is expressed in the pancreas and gastrointestinal tract (Ohno & Hase, 2010; Cogger et al, 2017); loss of tolerance to GP2 is associated with Crohn's disease and primary sclerosing cholangitis (Werner et al, 2013; Tornai et al, 2018).