Immune response patterns in coeliac disease. Serum antibodies to dietary antigens measured by an enzyme linked immunosorbent assay (ELISA).

Serum IgG, IgA and IgM activities to wheat, egg and cow's milk antigens were measured by an ELISA method in children and adults with coeliac disease (CD). In untreated patients, the IgA activity was characteristically raised to gluten antigens but often also to proteins from egg or cow's milk. Setting the upper reference range for gluten antibodies as the highest IgA reading obtained in healthy controls and patients with other intestinal disorders, IgA measurements afforded virtually 100% diagnostic sensitivity and specificity and detected 94% of children and 80% of adults with untreated CD. Such measurements, therefore, represent a valuable adjunct in the diagnosis of this disease. IgA activity to beta-lactoglobulin, casein or ovalbumin higher than the normal 95 percentile was found in 44-89% of untreated patients. Reduction of these antibody titres seemed to reflect relatively well the response to treatment with a gluten free diet, particularly the activity to beta-lactoglobulin. Monitoring of IgA antibodies to dietary antigens other than gluten may therefore be of particular importance in the follow-up of CD patients.