Flow-cytometric detection of lactase expression in normal and coeliac intestinal epithelium

Objective Enterocyte lactase expression is a useful marker of gluten toxici ty. In this study, the technique of flow cytometry was evaluated to quantif y lactase expression in coeliac disease (CD). Methods Duodenal enterocyte suspensions were obtained from 23 patients with CD, four patients with dermatitis herpetiformis (DH), and 33 control subje cts. The percentage of enterocytes; that reacted with anti-lactase monoclon al antibody was determined by flow cytometry. In some subjects, organ cultu re of duodenal biopsies in the presence of various stimuli (including glute n fractions) was performed before enterocyte analysis. Results This study demonstrated that lactase expression can be readily inve stigated semi-quantitatively using flow cytometry. Moreover, the level of e xpression correlated with the extent of mucosal damage in gluten-sensitive individuals. However, in organ culture experiments, lactase expression did not change in the presence of gluten or after marked T-cell activation for 48 h. Conclusions Measurement of enterocyte lactase expression by flow cytometry is a useful adjunctive test in the diagnosis and monitoring of gluten-sensi tive enteropathy. However, lactase expression is not a suitable marker of g luten-induced toxicity in organ culture. Eur J Gastroenterol Hepatol 13:897 -902 (C) 2001 Lippincott Williams & Wilkins.