Celiac Disease/Other Gastrointestinal Diseases

 Tissue Transglutaminase Antibodies  | Anti-Gliadin Antibodies  |  Fecal Calprotectin

 

Tissue Transglutaminase Antibodies

Products

Article No.

No. of tests

EliA Celikey IgA 14-5517-01 4x12 tests
EliA Celikey IgG 14-5518-01 2x12 tests

Promotion Material

Performance Characteristics
EliA Celikey (anti-tTG), Gliadin (pdf)

Antigens

Tissue transglutaminase belongs to a diverse family of calcium-dependent enzymes that catalyze cross-link formation between proteins. tTG is widely distributed in human organs and is found associated with fibres surrounding smooth muscle and endothelias cells in connective tissue. tTG plays a role in extracellular matrix assembly and tissue repair mechanisms. Wheat gliadins can act as a substrate for the transglutaminase reactions.

Celikey uses human, recombinant tissue transglutaminase, produced in eukaryotic cells (Baculovirus/Sf9 system). 

Disease association, antibody prevalence and specificity

Celiac Disease

  • Clinical sensitivity: 96 %
  • Clinical specificity: 99 %

Disease activity

Anti-tissue transglutaminase antibodies may have a place in monitoring dietary compliance, with titres being negative in more than 70 % of treated patients with celiac disease.

Information about the disease

When is the measurement recommended?

Suspicion of Celiac Disease

Antibody isotype

IgA or IgG.

IgA-deficiency is a special challenge in celiac disease diagnostics. IgG anti-tTG antibodies are as characteristic for celiac patietns with IgA deficiency as IgA class anti-tTG antibodies for patients with normal serum IgA values.

References

Mäki M, Collin P (1997)  |  Brusco G, Muzi P, Ciccocioppo R, et al. (1999)  |  Troncone R, Maurano F, Rossi M, et al. (1999)  |  Hansson T, Dahlbom I, Hall J, et al. (2000) 

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Anti-Gliadin Antibodies

EliA Gliadin DP IgA and EliA Gliadin DP IgG
- first fully automated assays for deamidated gliadin peptide.
 

Products

Article No.

No. of tests

EliA Gliadin DP IgA 14-5538-01 4 x 12 tests
EliA Gliadin DP IgG 14-5539-01 4 x 12 tests
EliA Gliadin IgA 14-5519-01  
EliA Gliadin IgG 14-5520-01  

ImmunoCAP Gliadin IgA/ IgG -
not for sale in the U.S.

14-4425-35  

Promotion Material

Performance Characteristics
EliA Celikey (anti-tTG), Gliadin (pdf)

Antigens

The term "gluten" comprises a whole series of proteins in the endosperm of the cereal genera of wheat, rye, barley and oats. They serve as a source of nitrogen for the germinating embry and are subclassified as albumins, globulins, glutelins and the celiac disease inducing gliadins. Gliadin (molecular weight 16-40 kDa) is a mixture of about 50 components. On the basis of electrophoretic mobility, gliadins can be devided into four major fractions: alpha-, beta-, gamma- and omega-gliadins. A-gliadin, a component of alpha-gliadin of known primary amino acid sequence contains 32 glutamines and 15 prolines per 100 amino acid residues.

The Varelisa Gliadin Antibodies assays are coated with purified gliadin. 

Deamidated Gliadin Peptides

Recent research revealed that gliadin peptides crossing the mucosal border in CD patients are deamidated by tissue transglutaminase (tTG), which renders them much more immunogenic than unprocessed gliadin peptides. Thus, deamidated gliadin peptides represent more specific targets for the antibodies to gliadin which are produced in CD patients. 

The EliA Gliadin DP tests use the relevant synthetic deamidated gliadin peptides which gives them an excellent specificity. 

Disease association, antibody prevalence and specificity

  • Celiac disease = gluten-sensitive enteropathy (85-100 % of children with celiac disease during the active phase of the disease) 
  • Other gastroenterological disorders (about 21 % IgG, about 3 % IgA)

Information about the disease

Disease activity

When gluten is withdrawn from the diet of the patient with celiac disease, the IgA-AGA titer decreases rapidly to normal values while the IgG-AGA decreases slowly and may persist at low titer for moths or years. During a diagnostic gluten challenge, both IgG and IgA-AGA usually reach pathological values after some weeks or months of gluten ingestion. 

When is the measurement recommended?

  • Suspicion of Celiac Disease 
  • Differential diagnosis of childhood and adult forms of Celiac Disease 
  • Follow-up of gluten-free diets 
  • Suspicion of Dermatitis Herpetiformis

Antibody isotypes

IgA and IgG. IgA is more specific but less sensitive, IgG is sensitive but less specific, thus the determination of both isotypes is usually recommended. Patients with selective IgA deficiency can only be detected by screening with an IgG class antibody.

References

Mäki M, Collin P (1997)  |  Catassi C (1996)  |  Unsworth DJ (2000)  |  Troncone R, Ferguson A (1991)   

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Fecal Calprotectin

Products

Article No.

No. of tests

EliA Calprotectin
not for sale in the U.S.

14-5610-01 4 x 12 tests


Promotion Material

Performance Characteristics
EliA Calprotectin Folder (pdf)
EliA Calprotectin Detailer (pdf)

Stool Extraction
Stool Extraction (pdf)

Calprotectin

In contrast to other EliA tests, EliA Calprotectin is not an antibody test but measures the amount of the protein calprotectin in the patient’s stool.
Inflammation is characterized by an increased activity of immune cells (e.g. neutrophil granulocytes) which release pathogen attacking substances such as calprotectin.
In intestinal inflammation the barrier function of the intestinal wall is lost and neutrophil granulocytes migrate through the wall into the intestinal lumen. This leads to an elevated calprotectin level in the stool. The level of fecal calprotectin correlates directly to the number of neutrophil granulocytes in the intestinal lumen. As such it is specifically elevated in inflammatory bowel diseases (IBD) such as Crohn‘s disease and ulcerative colitis. The level of calprotectin in feces is approximately 6 times higher than in serum.

EliA Calprotectin wells are coated with a monoclonal calprotectin antibody which binds calprotectin present in the patient’s stool sample.

Sensitivity and Specificity

Fecal calprotectin is a very sensitive and specific marker for inflammation in the intestinal tract: as a first line test, a negative result can rule out an inflammatory process while a positive result may prioritize endoscopy in the diagnostic path. Almost 98 % of patients with inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis have an increased level of fecal calprotectin. The specificity of the test is almost 90 % (internal study).

Disease activity

Fecal calprotectin is an efficient marker for therapeutic effectiveness and mucosal healing since its level correlates well with endoscopic and histological findings in inflammatory bowel diseases. In recent studies it was shown that the fecal calprotectin level is able to predict relapse in Crohn‘s disease and ulcerative colitis.

When is the measurement recommended?

  • Suspicion of inflammatory bowel disease (IBD) such as Crohn’s disease or ulcerative colitis.
  • Differentiation from irritable bowel syndrome and other functional bowel disorders.
  • Monitoring of IBD.

References

Vermeire S et al. (2006)  |  Konikoff MR, Denson LA (2006)  |  Gisbert JP, McNicholl AG (2009)  |  Sutherland AD et al. (2008)  |  Gaya DR, Mackenzie JF (2002)  |  Aadland E, Fagerhol MK (2002)     

 

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As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.