The description of an amino acid sequence homology between the E1B-58-kDa protein of adenovirus 12 and gliadin has led to the suggestion that previous infection by this virus and subsequent exposure to gliadin could trigger the development of coeliac disease in susceptible individuals as a result of immunologic cross-reactivity. We have sought to measure specific antibodies to the E1B-58-kDa protein in 23 coeliac patients and 10 normal subjects. The sera were analysed by radioimmunoprecipitation with metabolically labelled adenovirus-12-transformed rat cells (which express the E1B-58-kDa protein), followed by separation on polyacrylamide gels. None of the coeliac sera had evidence of antibodies to the E1B-58-kDa protein. These data suggest that coeliac patients show little evidence of humoral immunity to the specific adenovirus 12 E1B-58-kDa protein implicated in the aetiology of coeliac disease.