Screening of the adult population in Iran for coeliac disease: comparison of the tissue-transglutaminase antibody and anti-endomysial antibody tests.
BACKGROUND AND AIMS
Population-based studies for the prevalence of coeliac disease (CD) in west-Asian countries are scarce. We aimed to determine the prevalence of gluten-sensitive enteropathy (GSE) in the general population of northern and southern Iran, and evaluate the sensitivity and specificity of the anti-endomysial antibody (EMA) immunofluorescent test and the enzyme-linked immunosorbent assay-based test for determination of the IgA anti-tissue transglutaminase antibody (tTG-Ab) using the human recombinant transglutaminase antigen for the detection of CD in screening the asymptomatic adult population.
MATERIAL AND METHODS
Using a stratified random sampling method we enrolled a total of 2799 individuals (1438 from Sari and 1361 from Kerman). The mean age was 33.7 years (range 18-66), with 1398 men. IgA anti-tissue transglutaminase (tTG) and IgA anti-EMA were determined in the serum of all subjects. Those participants with a positive serology for any of the two tests underwent small intestinal biopsy, and were classified according to revised Marsh criteria histologically. A diagnosis of GSE was based on positive serology and a compatible histopathological finding. The maximum likelihood latent class model was used to estimate the sensitivity and specificity of the two tests.
Twenty-nine cases showed positive IgA tTG-Ab (15 men and 14 women, mean age 35.4 years, range 18-59), whereas only five were simultaneously positive for EMA. Except for two subjects with normal small bowel histology (Marsh 0), all other subjects were found to have biopsy findings compatible with GSE: 18 Marsh I, five Marsh II, three Marsh IIIa and one Marsh IIIc lesions. he prevalence of GSE was 0.96% or 1:104. The sensitivity and specificity of the human-recombinant IgA tTG-Ab assay were 100 and 99%, respectively, whereas the results for IgA EMA were 19 and 100%, respectively. The IgA EMA was positive in cases with advanced mucosal lesions of the small bowel. The mean serum value of IgA tTG-Ab was higher in patients with severe enteropathy compared with those showing slight mucosal changes (P<0.05).
The minimum prevalence of gluten sensitivity among the general population of northern and southern Iran is 1:104. The best screening test for the detection of GSE in the general population is IgA tTG-Ab.
Digestive Disease Research Centre, Tehran University of Medical Sciences, Tehran, Iran.
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Enzyme-Linked Immunosorbent Assay
Fluorescent Antibody Technique, Indirect
Sensitivity and Specificity
Research Support, Non-U.S. Gov't