TGM2 and celiac disease: Finally, in our study we observed in the CD patients a positive correlation between IgA AZA antibodies and IgA AGA and IgA DPG; the last one is an important serological biomarker with a high sensitivity and specificity in untreated, biopsy-proven celiac disease and is comparable also with the tissue transglutaminase (tTG) IgA antibody test [38].