Anti-gliadin antibodies (AGA)

Antibodies against gliadin peptides from wheat. They occur in coeliac disease, in some people with wheat or gluten sensitivity and also in people without symptoms. Is looked at when assessing the intestinal mucosa.

What anti-gliadin antibodies show

Gliadin is part of the gluten protein in wheat; related proteins are found in rye and barley. Gliadin is rich in the amino acids proline and glutamine, which is why the digestive enzymes cannot break it down completely – longer fragments remain and reach the gut lining. There the immune system comes into contact with them, and B cells can form antibodies of the IgA and IgG classes against gliadin. A distinction is made between antibodies against native gliadin (AGA) and against deamidated gliadin peptides (DGP), in which the enzyme transglutaminase 2 has altered individual glutamine building blocks.

Anti-gliadin antibodies not detected – what does it mean?

The immune system had not formed a measurable antibody response against gliadin at the time of sampling. The antibodies are only formed as long as gluten is eaten; if gluten was previously left out or greatly reduced, they decline. With an inborn lack of IgA, which occurs more often in people with coeliac disease, IgA antibodies can be absent even though an immune reaction is present – which is why total IgA is looked at as well.

Anti-gliadin antibodies detected – what does it mean?

A positive result shows that the immune system has reacted to gliadin fragments. This occurs in coeliac disease, where antibodies against transglutaminase 2 are also formed and T cells inflame the gut lining. Antibodies against native gliadin are, however, also found in some people with wheat or gluten sensitivity without coeliac disease, in other conditions with a more permeable gut lining and in some people without symptoms. Antibodies against deamidated gliadin peptides are more closely linked to coeliac disease. They are therefore interpreted together with the antibodies against transglutaminase 2 and total IgA.

The interpretation is given in your report.