Variable activation of immune response by quinoa (Chenopodium quinoa Willd.) prolamins in celiac disease

Celiac disease is an enteropathy triggered by dietary gluten found in wheat, barley, and rye. The current treatment is a strict gluten-free diet. Quinoa is a highly nutritive plant from the Andes, with low concentrations of prolamins, that has been recommended as part of a gluten-free diet; however, few experimental data support this recommendation. We aimed to determine the amount of celiac-toxic prolamin epitopes in quinoa cultivars from different regions of the Andes and the ability of these epitopes to activate immune responses in patients with celiac disease. The concentration of celiac-toxic epitopes was measured by using murine monoclonal antibodies against gliadin and high-molecular-weight glutenin subunits. Immune response was assessed by proliferation assays of celiac small intestinal T cells/interferon-γ (IFN-γ) and production of IFN-γ/IL-15 after organ culture of celiac duodenal biopsy samples. Fifteen quinoa cultivars were tested: 4 cultivars had quantifiable concentrations of celiac-toxic epitopes, but they were below the maximum permitted for a gluten-free food. Cultivars Ayacuchana and Pasankalla stimulated T cell lines at levels similar to those for gliadin and caused secretion of cytokines from cultured biopsy samples at levels comparable with those for gliadin. Most quinoa cultivars do not possess quantifiable amounts of celiac-toxic epitopes. However, 2 cultivars had celiac-toxic epitopes that could activate the adaptive and innate immune responses in some patients with celiac disease. These findings require further investigation in the form of in vivo studies, because quinoa is an important source of nutrients for patients with celiac disease.