Rostami K, et al. - The authors determined the optimal cut-off between normal and coeliac disease (CD) (Marsh III lesion) duodenal mucosa, based on intraepithelial lymphocytes (IEL) counts on >400 mucosal biopsy specimens using receiver operating characteristic (ROC) curve analysis. The ROC curve analyses revealed that a cut-off of 25 IEL/100 enterocytes optimised discrimination between normal control and CD biopsies for Marsh III lesions. They found no differences in IEL counts between Marsh III a, b and c lesions. There was an indication of a continuously graded dose-response by IEL to environmental (gluten) antigenic influence.