Anti-Tissue Transglutaminase (tTG)
Now a Rapid Approach for Diagnosis of Celiac Disease
Celiac disease is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward. Symptoms include chronic diarrhea, failure to thrive (in children) and fatigue, but these may be absent, and symptoms in other organ systems have been described. A growing portion of diagnoses are being made in asymptomatic persons as a result of increased screening.
Celiac disease is caused by a reaction to gliadin, a prolamin (gluten protein) found in wheat, and similar proteins found in the crops of the tribe Triticeae (which includes other cultivars such as barley and rye). Upon exposure to gliadin, and certain other prolamins, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the small-bowel tissue, causing an inflammatory reaction. That leads to a truncating of the villi lining the small intestine (villous atrophy). This interferes with the absorption of nutrients. The only known effective treatment is a lifelong gluten-free diet.
Anti-transglutaminase antibodies (tTG) are found in an overwhelming majority of cases. Tissue transglutaminase modifies gluten peptides into a form that may stimulate the immune system more effectively.
Serological blood tests are the first-line investigation required to make a diagnosis of celiac disease. Serology for anti-tTG antibodies has superseded older serological tests and has a high sensitivity (99%) and specificity (>90%) for identifying celiac disease. Modern anti-tTG assays rely on a human recombinant protein as an antigen.
Historically three other antibodies were measured: anti-reticulin (ARA), anti-gliadin (AGA) and anti-endomysium (EMA) antibodies. Guidelines recommend that a total serum IgA level is checked in parallel, as celiac patients with IgA deficiency may be unable to produce the antibodies on which these tests depend ("false negative"). In those patients, IgG antibodies against transglutaminase (IgG-tTG) may be diagnostic.
Now in Saridar Lab, Anti-Tissue Transglutaminase Antibodies (IgG & IgA) are available and the run out time is only 72 hours, so a rapid approach for diagnosis of Celiac Disease is now available.