An early strategy by Sblattero et al. [109] was to study the immune response against tissue transglutaminase by building an immune library from the peripheral blood lymphocytes (PBLs) of a patient with celiac disease and performing a selection against four related antigens (α-gliadin, β-lactoglobulin, human tissue transglutaminase, and guinea pig transglutaminase). Here, TGM2 is linked to celiac disease.