Serum antibodies against gliadin and reticulin in a family study of coeliac disease

The familial occurence of coeliac disease is well known. In every day practice, however, diagnosis of coeliac disease is not frequently established in the relatives of patients. As it did not seem practicable to biopsy all relatives, several tests were investigated in selecting individuals for intestinal biopsy in a family study. 55 index patients out of 54 families with biopsy-proven coeliac disease and 165 of their first grade relatives underwent the study. Immunofluorescent gliadin and reticulin antibodies were determined, and additionally laboratory tests were done. These included haemoglobin, serum iron, serum protein and albumin, serum immunoglobulins and blood xylose. The immunofluorescent gliadin antibody assay using red cells coated with gliadin proved to be superior to the other methods. False negatives came to 8.7%, and false positives 10.9%, in healthy relatives. Gliadin antibodies could be found five times more frequently in healthy relatives than in normal controls. This finding indicates a genetic predisposition to the formation of gliadin antibodies in coeliac families.Ninety-one percent of index coeliac children had IgG-antigliadin in their sera while on a normal diet. During gluten-free diet, and in adult patients, results were less convincing. All relatives with antigliadin titres greater than 8 have been biopsied, and all with titres above 64 were shown to have coeliac disease. The prevalence of coeliac disease found in this study was 5.5%. In the active state of coeliac disease in children, gliadin antibody determination thus is a valuable diagnostic tool but in selecting relatives for biopsy there are limitations to the wide application of the test. Although reticulin antibodies are more specific for coeliac disease than gliadin antibodies, determination of antireticulin proved to be much less sensitive.Supported by Deutsche Forschungsgemeinschaft Gr 278/6 and Ste 305/1