Notably, CD patients with pouchitis exhibit elevated levels of anti-GP2 IgA [107], and elevated levels of anti-GP2 IgA autoantibodies have also been detected in a minority of UC patients, particularly those with primary sclerosing cholangitis (PSC) as an extraintestinal manifestation [108, 109]. This evidence concerns the gene CD79A and pancreatic serous cystadenoma.