Anti-transglutaminase antibodies

Anti-transglutaminase antibodies (ATA) are autoantibodies against the transglutaminase protein. Antibodies serve an important role in the immune system by detecting cells and substances that the rest of the immune system then eliminates. These cells and substance can be foreign (for example, viruses) and also can be produced by the body (for example, cancer cells). Antibodies against the body's own products are called autoantibodies. Autoantibodies can sometimes errantly be directed against healthy portions of the organism, causing autoimmune diseases. Anti-transglutaminase antibodies (ATA) are autoantibodies against the transglutaminase protein. Antibodies serve an important role in the immune system by detecting cells and substances that the rest of the immune system then eliminates. These cells and substance can be foreign (for example, viruses) and also can be produced by the body (for example, cancer cells). Antibodies against the body's own products are called autoantibodies. Autoantibodies can sometimes errantly be directed against healthy portions of the organism, causing autoimmune diseases. ATA can be classified according to 2 different schemes: transglutaminase isoform and immunoglobulin reactivity subclass (IgA, IgG) toward transglutaminases. Antibodies to tissue transglutaminase (abbreviated as anti-tTG or anti-TG2) are found in patients with several conditions, including celiac disease, juvenile diabetes, inflammatory bowel disease, and various forms of arthritis. In celiac disease, ATA are involved in the destruction of the villous extracellular matrix and target the destruction of intestinal villous epithelial cellsby killer cells. Deposits of anti-tTG in the intestinal epithelium predict celiac disease. The endomysium is a layer of connective tissue that ensheaths a muscle fiber. The endomysium contains a form of transglutaminase called 'tissue transglutaminase' or 'tTG' for short, and antibodies that bind to this form of transglutaminase are called endomysial autoantibodies (EmA). The antiendomysial antibody test is a histological assay for patient serum binding to esophageal tissue from primate. EmA are present in celiac disease. They do not cause any direct symptoms to muscles, but detection of EmA is useful in the diagnosis of the disease. Antibodies to epidermal transglutaminase (eTG, also keratinocyte transglutaminase) are the autoantibodies believed to cause dermatitis herpetiformis. ATA IgA are more frequently found in Celiac Disease (CD); however, ATA IgG are found in CD and at higher levels when affected individual had the IgA-less phenotype. The IgA-less phenotype is more common in CD than the normal population; however, one haplotype, DQ2.5 is found in most CD, has genetic linkage to the IgA-less gene location. Most attention to anti-transglutaminase antibodies is given with respect to celiac disease. A recent study of children published in 2007 demonstrated that the level of ATA in correlates with the scalar Marsh score for the disease in the same patient. High levels (titers) of ATA are found in almost all instances of celiac disease. Given the association of ATA with celiac disease, and the prevalence of the latter, it is estimated that ~1% of the population have potentially pathogenic levels of ATA.