Do dietary antibodies still play a role in the diagnosis and follow-up of coeliac disease? A comparison among different serological tests.

OBJECTIVE

Comparison between the usefulness of immunological markers and intestinal biopsy in the diagnosis and follow-up of coeliac disease.

MATERIALS AND METHODS

Serum antibodies to gliadin, several dietary proteins and endomysium were appraised in 27 patients with biopsy proven coeliac disease, both while untreated and 6-8 months after gluten withdrawal, when an intestinal biopsy was repeated. Forty-six healthy volunteers entered the study as controls. Antibodies to gliadin and dietary proteins were assessed by ELISA, antibodies to endomysium by indirect immunofluorescence using monkey oesophagus as antigen.

RESULTS

Mean antibody levels to dietary proteins were significantly higher in untreated patients as compared to controls. Their titers decreased after gluten withdrawal, but a significant difference was found, except for casein, for the IgA class only. However, because of their unlinear and unpredictable behaviour, they showed a poor reliability. Antigliadin antibodies showed higher diagnostic accuracy, although they also produced false-positive and false-negative results. Anti-endomysium antibodies, albeit the more expensive, proved the more reliable, due to their 100% specificity.

CONCLUSION

To date, anti-endomysium antibodies are the most reliable marker for coeliac disease: a positivity warrants an intestinal biopsy. The actual role of antibodies to gliadin, cheaper than endomysium, is during follow-up when many determinations are needed. Antibodies to dietary proteins, useful in the pre-endomysium era, only have a historical role.