Radioimmunoassay for antigliadin-antibodies using 14C-labelled gliadin.

A sensitive radioimmunoassay for antibodies to gliadin has been developed. Gliadin from wheat gluten was labelled with [1-14C]acetic anhydride to a specific activity of 2.6 X 10(6) dpm/mg. Immunological evidence is presented that the antigen was not essentially altered by the labelling procedure. Experimentally-induced antigliadin antibodies or sera of patients with coeliac disease (CD) were reacted with labelled gliadin and the immune complexes formed precipitated by antiglobulin. Precipitating antibodies were determined by incubating CD sera with labelled gliadin and measuring the radioactivity in precipitates formed without the addition of second antibody. Comparison with other methods for the detection of antigliadin antibodies, including immunoelectrophoresis, immunodiffusion and passive hemagglutination indicated that total and precipitating antibodies were determined only by RIA. The assay also provides information on the immunoglobulin class of antigliadin-antibodies present in sera of patients with coeliac disease.