Antibodies to gliadin, gluten and reticulin glycoprotein in rheumatic diseases: elevated levels in Sjögren's syndrome.
An enzyme immunoassay was used to measure circulating antibodies to gluten, gliadin and to 'reticulin glycoprotein' in 25 patients with Sjögren's syndrome (SS), in 20 patients with rheumatoid arthritis without SS and in 19 patients with systemic lupus erythematosus without SS. Antibody levels to these three antigens were significantly higher in SS than in the other groups. In SS the level of antibodies to 'reticulin glycoprotein' correlated positively with the levels of antibodies to both gliadin and to gluten but not with the level of antibodies to SS-B antigen. Patients with primary SS had higher antibody levels to 'reticulin glycoprotein' than had patients with secondary SS, whereas no significant difference between primary and secondary SS was found in the levels of the antibodies to gliadin or to gluten. Circulating antibodies to gliadin, gluten and 'reticulin glycoprotein' have not been previously recognized in SS. Their occurrence suggests that small bowel injury may be a common finding in SS.