Celiac disease tests do not reflect ongoing mucosal damage

Last Updated: 2017-06-02

By Will Boggs MD

NEW YORK (Reuters Health) - Tests for serum transglutaminase (tTG) and endomysial antibodies (EMA) fail to detect persistent villous atrophy in many patients with celiac disease on gluten-free diets, according to a meta-analysis.

Serum tTG and EMA IgA antibody tests, commonly used to screen for celiac disease, were not intended for routine monitoring of patients with celiac disease, but are nevertheless commonly used and advocated by several gastroenterology societies for that purpose.

Dr. Donald R. Duerksen from the University of Manitoba, in Winnipeg, Canada, and colleagues assessed whether serum tTG or EMA IgA antibody tests are useful biomarkers of villous atrophy in patients with celiac disease treated with a gluten-free diet in their meta-analysis of 26 studies.

In 11 studies including 1,088 patients, the estimated sensitivity of tTG IgA was 50% and its specificity was 83% for detecting persistent villous atrophy on a gluten-free diet, the team reports in Gastroenterology, online May 22.

Similarly, in 20 studies including 1,189 patients, EMA IgA had an estimated sensitivity of 45% and a specificity of 91% for detecting persistent villous atrophy.

Overall accuracy (as measured by the area under the summary receiver operating characteristic curve) was 78.1% for tTG IgA (87.9% for children) and 87.1% for EMA IgA (80.6% for children).

Sensitivities and specificities of tTG and EMA IgA antibodies were similar for detecting Marsh 2 or 3 lesions.

"This contrasts with the high-sensitivity (tTG IgA, 85-95%; EMA IgA, 80-90%) and high specificity (tTG IgA, 95-99%; EMA IgA, 95-100%) of these tests in untreated celiac disease,” the researchers note.

“Although widely available, and relatively non-invasive, serum tTG IgA and EMA IgA antibodies are poorly correlated with mucosal outcomes,” they conclude. “Most patients with celiac disease have negative antibody tests on a gluten-free diet, even those with persistent mucosal damage.”

“A positive test result is helpful as this has good specificity for persistent villous atrophy and signals probable ongoing gluten ingestion,” the authors explain. “Such a finding should prompt dietary assessment and review with a dietitian with expertise in celiac disease. A negative antibody test is much less informative and should not be interpreted as an indicator of mucosal recovery nor as a proxy for gluten-free diet adherence.”

Dr. Consolato Sergi from the University of Alberta, in Edmonton, Canada, who recently reviewed the challenges in diagnosing celiac disease, and Dr. Vincenzo Villanacci from the University of Brescia, Italy, told Reuters Health in a joint email, "The most important point is the necessity of a multidisciplinary team for the diagnosis of gluten-sensitive enteropathy or celiac disease, particularly in a time where gluten-free diet may be considered a fashionable trend. Both the regular follow-up of these patients and the proper use of resources, as well as the collegial approach for a second opinion, may be part of the future directions in the pediatric and adult gastroenterological settings and may need to be targeted soon.”

“Both of us support the correct evaluation of a tissue biopsy, which is invaluable for the huge amount of information that is provided to both the pathologist and clinician,” they conclude. “In fact, some proposals to avoid biopsy are the source of a continuing debate among experts of gastroenterology. In our opinion, the biopsy remains the gold standard in the 21st century.”

Dr. Duerksen did not respond to a request for comments.

SOURCE: http://bit.ly/2rrnh1d

Gastroenterology 2017.