Anti-transglutaminase antibodies (ATA) are antibodies found more frequently in certain autoimmune diseases. High levels (titers) of ATA are found in almost all instances of coeliac disease. Given the association of ATA with coeliac disease, and the prevalence of the latter it is estimated that ~1% of the population have potentially pathogenic levels of ATA. ATA can be classified according to 2 different schemes. Transglutaminase isoform and the reactivity of immunoglobulin subclass (IgA, IgG) toward transglutaminases.

Anti-tissue transglutaminase Antibodies to tissue transglutaminase (ATA or anti-tTG) are found in patients with coeliac disease. ATA are sometimes found in other autoimmune diseases, such as juvenile diabetes. ATA are involved in the destruction of the villous extracellular matrix and target the destruction of intestinal villous epithelial cells by killer cells. Deposits of anti-tTG in the intestinal epithelium predict coeliac disease.