Anti-DGP IgA ELISA Kit

Deamidated Gliadin Peptides (DGP) are gliadin clumps from the deamidation reaction. These peptides help the immune system fight the gluten-related conditions such as Celiac Disease (CD). DGP is a widely used testing procedure for Celiac Disease where antibodies are inexact. The proteins in wheat, rye and barley are all made up of a protein called gliadin, which is sometimes touted as the main immune booster for Celiac disease. Celiac Disease is an autoimmune condition that happens when someone eats gluten and is prone to it. Healthy people take up and digest these proteins in a good way. Yet, in Celiac Disease, these proteins are overwhelmed by an immune system that crushes the gut. The most significant enzyme used to make DGP is tissue transglutaminase (tTG). tTG deamines the glutamine residues of gliadin to give it an immunomodulatory deamidated state. When the amide molecule is removed from glutamine residues, the peptide fragments become easier to detect by the immune system, prompting T-cell reactions that damage the cells of the small intestinal epithelium. DGP fragments act as biomarkers for Celiac disease and other gluten-induced illnesses by interacting with antibodies in the immune system. Deamidation boosts the immunogenicity of gliadin peptides, and some T-cells – especially CD4+ T-cells – recognise the tTG-derived gliadin peptides, attach them to MHC class II molecules, and provoke an immune reaction. This immune response can trigger a microbe-wide inflammatory response in the small intestine that results in villous atrophy and malnutrition.

The immune response to DGP occurs mostly via tTG in the small intestine (a critical component of Celiac disease). You can diagnose Celiac Disease and other gluten-related immune disorders if you detect certain antibodies to DGP in the serum. For DGP, the antibodies used are antibodies to immunoglobulin A (IgA) and Immunoglobulin G (IgG), though IgG antibodies are more sensitive for patients without IgA. Celiac Disease is a progressive, auto-immune disease. The first involves defective activation of the immune system, the second chronic and acute inflammatory conditions in the bowel, and finally intestinal inflammation. Villous atrophy, too, can result in patients whose progress is not always well-balanced. With Celiac Disease left undiagnosed and undertreated, intestinal damage worsens over time and malabsorption symptoms become more intense. Celiac Disease is typically diagnosed using signs, blood tests, and small bowel biopsy. The most common serological screening test is tTG-IgA. Nevertheless, in patients with the defect in IgA, the tTG-IgA test could fail. In such situations, DGP IgA and DGP IgG tests can be considered as an add-on diagnostic test to aid proper diagnosis of Celiac Disease. DGP testing helps diagnose Celiac disease early when standard antibody tests (tTG-IgA) are not positive. When a person has IgA deficiency, tTG-IgA may fail to offer sufficient diagnostic information, while DGP IgG is more sensitive and specific. When a person has been previously diagnosed with Celiac Disease, DGP can be used to track the course of the disease, especially if the patient has been exposed to gluten. DGP can also be used to detect the Celiac Disease cases even when classical antibodies (EMA, tTG) are negative. DGP testing is especially useful in the case of atypical or subclinical Celiac disease.

Figure 1. Pathogenesis of Celiac Disease (Source: Caio, G., et al., 2019)

The first-line treatment for Celiac patients is a life-long gluten-free diet to ward off further immune disruption and intestinal alteration. DGP tests not only assist in confirmation of Celiac Disease, but can also help you keep track of disease progression. After starting a gluten-free diet, DGP antibody levels typically decrease as the treatment proves effective. Conversely, if the patient is exposed to gluten in their diet, DGP antibody levels may rise again. Therefore, DGP testing provides a dynamic assessment of disease status, helping doctors understand the effectiveness of treatment and guiding patients on whether they are strictly following the gluten-free diet. Despite the significant value of DGP testing in diagnosing Celiac Disease, some limitations exist. First, changes in laboratory procedures and testing methodologies can influence the specificity and sensitivity of DGP testing, hence standardized testing protocols are essential for clinical use. Second, DGP testing is most useful for diagnosing and monitoring Celiac Disease, but it may not be as efficient for diagnosing other gluten-related disorders (such as non-celiac gluten sensitivity) or autoimmune diseases. Future breakthroughs in molecular biology and immunology may refine and improve DGP testing technologies. New testing methods, such as high-throughput screening, automated platforms, and more sensitive antibody detection technologies, could make DGP testing more efficient, accurate, and capable of identifying Celiac Disease patients earlier. In summary, DGP, generated through the action of tTG, is a key mediator in the immune response of Celiac Disease. Its identification can increase the precision of the diagnosis of celiac disease, particularly in patients with IgA deficiency and in situations when conventional antibody testing yields negative results. DGP is essential for early diagnosis and can be a useful tool for tracking disease activity and assessing the effectiveness of treatment. DGP testing could become a common way to diagnose and track celiac disease as technology develops, supporting early diagnosis and clinical management of the condition.

Figure 2. Progression of Small Intestinal Mucosal Changes in Celiac Disease (Source: Rivera, E, et al., 2013)

Deamidated Gliadin Peptide IgA ELISA Kit
Anti-DGP IgA Detection Kit
Anti-Deamidated Gliadin Peptide IgA Test Kit
DGP IgA ELISA