- Last Update On : 2013-02-26
Patients with celiac disease produce several antibodies including gliadin, endomysial, tissue transglutaminase (tTG), and reticulin. IgA antibodies usually predominate, but IgG antibodies are also synthesized. New tests for deamidated gliadin IgA and IgG have replaced the older gliadin antibody tests. Sensitivity and specificity of deaminated gliadin antibodies for untreated celiac disease is comparable to tTg antibodies.Inova Diagnostics has recently introduced a new screening test that simultaneously detects IgA and IgG antibodies to tissue transglutaminase (tTG) and deaminated gliadin peptide (QUANTA Lite® h-tTG/DGP Screen). The latter peptide is believed to be the immunodominant antigen in gluten. Deamination of gliadin by the enzyme tissue transglutaminase exposes specific B-cell epitopes. Studies have demonstrated that the sensitivity and specificity of deaminated gliadin antibodies for diagnosis of celiac disease are higher than unmodified gliadin and comparable to tTG antibodies. Antibody levels correlate with severity of enteropathy. Two percent of patients with celiac disease will be IgA deficient and unable to make IgA antibodies. Because the new test detects both IgA and IgG antibodies, it allows for the detection of celiac disease even with coexistent IgA deficiency.Approximately one year ago, our laboratory replaced a panel of individual tests with the Inova Celiac Screen. Gastroenterologists have been highly satisfied with its performance and report excellent correlation with small bowel biopsy results.