Objective: Removal of the dietary wheat protein gluten protects against autoimmune diabetes in animal models. Furthermore, elimination of dietary gluten reduces the frequency of type 1 diabetes in patients with celiac disease. Herein we test the hypothesis that gluten is the driving antigen for type 1 diabetes-associated islet autoimmunity.
Research design and methods: Seven autoantibody-positive, first-degree relatives of patients with type 1 diabetes were placed on a gluten-free diet for 12 months followed by gluten reexposure for 12 months. Gliadin antibodies as well as the diabetes-related antibodies insulin autoantibody (IAA), GAD antibody (GADA), and tyrosin phosphatase IA2 antibody (IA-2A) were measured every 3 months; oral glucose tolerance tests were performed every 6 months. Changes in autoantibody titers were compared with those observed in a matched historical cohort.
Results: A reduction in IgG gliadin antibody titers was observed during the gluten-free period, but titers of diabetes-associated autoantibodies changed independently of gluten exposure. Type 1 diabetes-associated islet autoantibody levels at the end of the gluten-free diet period were not significantly different from those before commencement of the diet (P = 0.2) or at the end of the gluten reexposure period (P = 0.4). Changes in individual subjects were identified, but no differences were noted between the gluten-free and the gluten re-exposure periods, and the changes were similar to those observed in the historical control cohort (P = 1.0). Major titer reductions (>50%) in the gluten-free period were observed in only one subject for all antibodies. Type 1 diabetes developed in this subject and in a second subject during the gluten reexposure period.
Conclusions: The findings do not support the hypothesis that gluten is a driving antigen in type 1 diabetes.