Transglutaminase-Antikörper

Transglutaminases are a very large family of enzymes, including the tissue transglutaminases of the intestine, which according to new findings are subdivided into several isoenzymes.

Tissue transglutaminase is a cytoplasmic enzyme that is released in the intestine when cells are damaged. It catalyzes the linking of glutamine side chains with lysine. If no lysine is present, gliadin is deamidated, resulting in glutamic acid. It is assumed that the cross-linking of deamidated gliadin and transglutaminase induces an autoimmune response in coeliac disease. Antibodies against tissue transglutaminase of the IgG and IgA type are determined as part of celiac disease diagnostics, whereby IgG antibodies have a significantly lower sensitivity (caution: IgA deficiency).

In coeliac disease, specific IgA antibodies against transglutaminase 2 are now considered almost pathognomonic (sensitivity and specificity > 95%). In addition to coeliac disease, the so-called NCGS syndromes (Non-Celiac Gluten Sensitivity) are known as further gluten-dependent enteropathies. Here, antibodies against gliadin of the IgA/IgG type and, more specifically, antibodies against deaminated gliadin are found.

It has long been known that dietary gluten can also trigger psychomotor reactions such as gluten ataxia: "The Celiac Brain". In 2016, it was shown for the first time that a high percentage of IgG/IgA antibodies against transglutaminase 6 occur in gluten-associated CNS reactions, which have not only diagnostic but also pathological significance.

Carriers coated with human tissue transglutaminase bind antibodies present in the patient sample. After adding enzyme-labeled antibodies against human IgA-AK (EliA IgA Conjugate), an antibody-conjugate complex is formed and a developer solution is added. After an incubation period, the reaction is stopped and the fluorescence of the reaction mixture is measured. The level of the measurement signal is directly proportional to the amount of specific IgA antibodies against tissue glutaminase in the sample.

It has long been known that dietary gluten can also trigger psychomotor reactions such as gluten ataxia: "The Celiac Brain". In 2016, it was shown for the first time that a high percentage of IgG/IgA antibodies against transglutaminase 6 occur in gluten-associated CNS reactions, which have not only diagnostic but also pathological significance.

NCGS with CNS symptoms is a serious complication of eating gluten-containing foods. Possible complications include gluten ataxia, polyneuropathies and the occurrence of depression. They are also discussed in schizophrenia and epilepsy.