In the last 40 years different technical approaches have been used to detect and measure intestinal CD-associated autoantibody production: measurement of anti-reticulin antibodies in jejunal juice (80) or of anti-endomysium antibodies (EMA) and anti-TG2 IgA antibodies in feces (81), search of the same antibodies in cultured biopsy supernatants (56, 82–85) or detection of deposited anti-TG2 antibodies in duodenal fragments (86, 87), or of plasma cells secreting them (58) or, lastly, expression in intestinal phage libraries of RNA coding for the celiac autoantibodies (57), (Table 1). Here, TGM2 is linked to Cowden disease.