The pathogenesis of gluten-sensitive enteropathies is unknown, although a peptidase deficiency and an immune defect have been postulated. The effect of plant-derived lectins on cells has led to an alternative concept in which a defect of the cell surface membrane allows gluten to act as a lectin and this reaction initiates cell toxicity. The proposed abnormality is viewed as a structural change produced by incomplete oligosaccharide chains in surface-membrane glycoproteins.