Figure 1.

Proposal of an initial diagnostic algorithm for coeliac disease (CD). After screening with anti-transglutaminase (tTG), and taking into account the high negative predictive value of HLA typing, study of mandatory intestinal biopsy would include phenotyping of intraepithelial lymphocytes (IEL). The proportion of “total IEL” is calculated with respect to the cellularity of the epithelium while the proportions of “γδ IEL” and “natural killer (NK)-like IEL” are relative to the total IEL. The combined analysis of the pathology and the “IEL lymphogram” allows for a correct classification of >95% of patients after the first biopsy, reducing the need for subsequent invasive procedures. N, normal values.