Patients with celiac disease can be identified based on detection of serum antibodies to deamidated gliadin peptides (DGP). Recombinant human monoclonal antibodies (hmAb) against gliadin are produced by cloning antibody genes from single immunoglobulin (Ig)A-producing plasma cells isolated from lesions of patients with celiac disease. We developed an assay to identify patients with celiac disease, based on the ability of antibodies from their serum to inhibit the binding of such a gliadin-specific hmAb (1002-1E03) to a specific peptide antigen (inhibition assay).