A significant percentage of patients who have the diarrhea problems of celiac sprue have IgA (most specific &  sensitive Ab test for celiac sprue, at least 90% for each) anti-endomysial (anti-EMA) antibodies circulating in their blood. Endomysial antibodies (EMA) are directed toward the morphological sheath around the smooth and striated muscle bundles of the middle third of the esophagus and were discovered in 1978. This is an IFA-type test. When the clinical suspicion for celiac disease is not very high, the presence of this antibody (or the anti-gliadin IFA-type antibody) may serve as an indication for capsule or endoscopic duodenal/small bowel biopsy to help make or refute the diagnosis of celiac disease [about the disease, GSE]. Monkey esophagus (good for EMA, ASMA, and anti-skin) is the classical substrate (honeycomb pattern is positive), but the EMA antigens are found in human, rat, and others and in such as stomach, jejunum, and umbilical cord.

Anti-reticulin antibody was an original GSE-associated antibody, followed by anti-gliadin and anti-EMA. There is also a newer test in an EIA/ELISA format called the tTG test which detects anti-endomysial  IgA Ab because that Ab (same as the IFA Ab )  has affinity for the tTG (tissue transglutaminase) cross-linking enzyme (the specific antigen in the EMA-positive perimuscular sheath), especially when it is complexed to gliadin as a test substrate (antibodies to gliadin-tTG complex). In the USA, the prevalence of these antibodies among Caucasian blood donors is 0.3-0.4% (whereas the prevalence of GSE cases among USA Caucasians is 0.3-1.0%...that is, every person with GSE may not yet be anti-tTG positive).

Situations having undetectable antibodies:

• earliest stage of disease (may not even be diagnosable disease by biopsy)
• small intestinal lymphoma
• refractory sprue (previous biopsy-proven celiac sprue but with failure to become well on a gluten-free diet)
• IgA-deficient individuals (one in 500 persons in USA) won't have the appropriate IgA Ab positivity and yet have celiac disease

Situations having detectible antibodies:

• celiac sprue cases, active and untreated
• 5% false positive rate in cases clinically suspect for celiac disease (GSE) but subsequently proven not GSE³
• this antibody decreases/disappears with treatment and is very good for checking on dietary compliance and treatment success

Synonyms: tTG test, anti-EMA

References:

1. Sleisinger and Fordtran's: Gastrointestinal and Liver Diseases, 6th Ed., vol. 2, 1998.
2. James Goeken, MD, CAP Today, August 2000, page 66
3. Goldstein, NS and Underhill, J, Morphologic Features Suggestive of Gluten Sensitivity in Architecturally Normal Duodenal Biopsy Specimens,  AJCP 116(1):63-71, July 2001.
4. Carter JB, NewsPath, March 2008 (celiac serology review).