Primate liver tissue as an alternative substrate for endomysium antibody immunofluorescence testing in diagnostics of paediatric coeliac disease

• Measurement of antibodies is helpful in the diagnosis of coeliac disease.
• Primate oesophagus represents the standard substrate to detect endomysium antibodies (EmA).
• Primate liver sections also constitute a suitable tissue for testing of IgA-EmA.
• On liver tissue there is less interference by other autoantibodies.

BackgroundImmunofluorescence assays of antibodies against endomysium (EmA) on primate oesophagus sections represent the gold standard in serological testing for coeliac disease (CD). As alternative immunofluorescence technique, staining of primate liver tissue is in use. We compared performance and predictive power of IgA- and IgG-EmA on primate oesophagus and primate liver sections.MethodsSera of 298 paediatric biopsy-proven CD patients under gluten-containing diet and 574 disease controls were investigated. Samples were collected between 2004 and 2013 in six children's hospitals. The antibodies were assayed blinded to diagnoses and histological data. Sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were calculated for different assays.Results(Oesophagus vs liver): For IgA-EmA, sensitivity (0.953 vs 0.956) and specificity (0.981 vs 0.972) as well as PPV (0.963 vs 0.947) and NPV (0.976 vs 0.979) were comparable on both tissues. IgG-EmA on liver showed significantly higher sensitivity (0.520 vs 0.631; p = 0.006) but significantly lower specificity (0.995 vs 0.963; p = 0.002) and PPV (0.981 vs 0.899; p = 0.0002) than on oesophagus. NPV on liver was higher than NPV on oesophagus, however, the difference was not statistically significant (0.799 vs 0.834; p = 0.099).ConclusionPrimate liver can be used as alternative, equally well functioning substrate for IgA-EmA testing.