Anti-DGP IgA ELISA Kit (Anti Deamidated Gliadin Protein)

INTENDED USE

Human anti-DGP IgA ELISA kit can be used for measuring in vitro quantitative amounts of IgA-antibodies directed against anti deamidated gliadin protein epitopes (anti-DGP IgA) in human plasma and serum samples. This assay has a minimum analytical sensitivity limit of 1.0 U/ml.

BACKGROUND

Anti deamidated gliadin antibodies can be used for diagnosing celiac disease and many other related conditions that are sensitive to gluten for example dermatitis herpetiformis. In general, the specificity and sensitivity of AGA IgA tends to be slightly superior when compared to AGA IgG. However, many researchers will analyse both these tests simultaneously, this will result in increasing the specificity but reducing slightly the sensitivity. It has been shown that AGA IgG testing can be helpful in approx. 2% of celiac disease patients that are deficient in IgA. However, when looking at the general population then the positive prediction value of AGA is found to be relatively poor.

One of the main drawbacks for using deamidated gliadin antibodies is that they can also be found in people without celiac disease, therefore this test usually lacks specificity when compared to measuring transglutaminase and endomysium levels. The use of deamidated gliadin peptides (DGP IgA and DGP IgG) provides a means of measuring specific and accurate levels. Deamidated gliadin proteins or peptides have the ability bind to the HLA molecules of antigen-presenting cells. Once they are placed in context with specific HLA molecules, these fragments are recognised by corresponding T-helper cells. This process leads to an extensive immune response resulting in the formation of antibodies against deamidated gliadin protein (DGP) and tissue transglutaminase (tTG).

CONTENT

All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

• Divisible Microplate: Consisting of 12 modules of 8 wells each, anti-DGP bound to microwells.
• Calibrator A-F: Concentration 0, 6.3, 12.5, 25, 50, 100 U/ml.
• Control Positive and Control Negative.
• Sample Buffer P (5x).
• Enzyme Conjugate: Contains anti-human IgA antibodies, HRP labelled.
• Substrate: Tetramethylbenzidin (TMB).
• Stop Solution.
• Wash Buffer (50x).
• Instruction for Use.
• Certificate of Analysis.

SENSITIVITY

The minimum detection sensitivity level of IgA antibodies to deamidated gliadin protein epitopes (anti DGP IgA) using current anti-DGP IgA ELISA kit was 1.0 U/ml. The dynamic range for this assay is 6.3 – 100.0 U/ml.

ASSAY CHARACTERISTICS

– Measuring Range: 0 – 100 U/ml.
– Expected Values: Healthy blood donors display a cut-off 10 U/ml
– Results Interpretation: Negative: < 10 U/ml Positive: ≥ 10 U/ml
– Linearity: 81 – 100%
– Limit Of Detection (LOD): Functional sensitivity is 1 U/ml
– Intra Assay: 4.0 – 6.0%
– Inter Assay: 1.7 – 8.7%
– Interfering Substances: None
– Clinical Diagnosis: Sensitivity (70.0%), Specificity (100.0%), Overall agreement (86.7%).

REFERENCES

1. Deamidated gliadin peptides as targets for celiac disease-specific antibodies. Adv Clin Chem. (2007) 44: 35-63. Review. Mothes T.
2. Digesting all the options: laboratory testing for celiac disease. Crit Rev Clin Lab Sci. (2014) 51 (6): 358-78. Review. Barakauskas V.E., et al.
3. Overview of biomarkers for diagnosis and monitoring of celiac disease. Adv Clin Chem. (2015) 68: 1-55. Brusca I.
4. Deamidated gliadin peptides form epitopes that transglutaminase antibodies recognize. J Pediatr Gastroenterol Nutr. (2008) 46 (3): 253-61. Korponay-Szabó I.R., et al.
5. [Treating coeliac disease. How do we measure adherence to the gluten-free diet?] Rev Chil Pediatr. (2016) 87 (6): 442-448. Review. Aranda E.A. and Araya M.
6. Current trends and investigative developments in celiac disease. Immunol Invest. (2013) 42 (4): 273-84. Review. Samaşca G., et al.

ADDITIONAL INFORMATION

• Full Name: Anti-DGP IgA ELISA Kit (Anti Deamidated Gliadin Protein)
• Reactivity: Human
• Sample Type: Plasma, Serum
• Sensitivity: 1.0 U/ml

OTHER RELATED ELISA KITS

• Anti-DGP IgG ELISA Kit
• Anti-CCP ELISA Kit
• Cathepsin G Antibody ELISA Kit