Anti-gliadin antibodies

Anti-gliadin antibodies are produced in response to

This antibody is found in ~80% of patients with coeliac disease.^[1][2] It is directed against the alpha/beta and gamma (α,β,γ) gliadins.

Anti-gliadin antibodies are frequently found with anti-transglutaminase antibodies.

Anti-gliadin IgE

The IgE antibodies are more typically found in

Individuals who have coeliac disease may have values in excess of 200^[citation needed]. There is the common expectation that removal of gluten results in the loss of AGA; however, since gluten is the target of the antibodies, that which would deplete them from the body, removal of gluten results in the benign circulation of antibodies. The half life of these antibodies is typically 120 days. Given an expected normal of 3 and assuming that the individual starts with a score of 203, we can predict the levels of AGA at various future time points. Based on these initial numbers, patients with very high AGA values may take 2 years to return to the normal range.

Refractory coeliac disease (RCD).

Diagnostic serology

Anti-gliadin antibodies were one of the first serological markers for coeliac disease. Problematic with AGA is the typical sensitivity and specificity was about 85%. Gliadin peptides which are synthesized as the deamidated form have much higher sensitivity and specificity, creating 2 serological tests for CD that approach biopsy diagnostic in performance.^[10][11]

Uses in testing

Anti-gliadin antibodies can be generated in mice or rabbits by immunizing whole purified gliadins, proteolytic fragments of gliadin, or synthetic peptides that represent epitopes of gliadin. After developing an immune response, B-cells from mice can be fused with immortalizing cells to form a

The R5 sandwich assay is another such assay. This assay can recognize wheat, barley and rye, which makes it ideal for evaluating the presence of contaminants in gluten-free foods that do not contain oat. This antibody is a recommended testing protocol in a proposed revision of the Codex Alimentarius.

The new standards came about in part because of new sensitive and specific testing procedures.^[14] These procedures are capable of detecting wheat or multiple cereals at concentrations as low as 1 part per million (PPM or 1 mg/kg). A new barley-sensitive ELISA called the R5 sandwich assay does not detect gluten in any of 25 pure oat varieties, but it does detect barley, wheat and rye.^[15]

References