IFL- and ELISA-antigliadin antibodies recognize different antigenic reactivities from those of R1-antireticulin and antiendomysial antibodies.

In order to establish whether antigliadin antibodies, detected by indirect immunofluorescence (IFL-AGA), display the same antibody reactivity as ELISA-AGA or whether they cross-react with reticulin antibodies (R1-ARA and antiendomysial--EmA), sera from 16 untreated coeliac patients were repeatedly absorbed with crude gliadin dissolved in ethanol/water solution. The comparison between antibody activities before and after absorption demonstrated that IFL-AGA and ELISA-AGA are nothing but a single antibody, as both of them completely disappeared or markedly reduced their titre after incubation with crude gliadin. Moreover, AGA reactivity differs from the reactivity of antibodies directed against reticulin, as R1-ARA and EmA titres were not affected by crude gliadin absorption. The absolute absence of cross-reactivity between IFL-AGA and R1-ARA is further confirmed by the removal of the former and persistence of the latter after gliadin absorption in the 9 sera positive for both antibodies. Sera of coeliac patients, therefore, show only two discrete antibody reactivities, one directed to gliadin and the other to reticulin components.