Studies of intestinal lymphoid tissue. VI--Proliferative response of small intestinal epithelial lymphocytes distinguishes gluten- from non-gluten-induced enteropathy.

Several diseases of the small intestine, including gluten-sensitivity, present with malabsorption and a "flat" mucosa. Determination of the mitotic index of epithelial lymphocytes provides a simple, objective method of assessing, and thus of predicting, whether a flat mucosa is due to gluten-sensitivity (index greater than 0.2%), or not (index less than 0.2%). The use of this index in circumstances especially likely to cause diagnostic confusion--for example, intestinal lymphoma; Crohn's jejunitis of immunodeficiency--is illustrated in this paper. Of seven cases, five (two primary lymphoma, three immunodeficiency) had been treated with a gluten-free diet without benefit; a mitotic index performed on the initial biopsy in each of these patients could have predicted from the outset that none was gluten-sensitive. Of the remaining two cases, determination of the mitotic index on the biopsy initially obtained from a man with severe hypogammaglobulinaemia would have indicated that he was also gluten-sensitive. Empirical use of a gluten-free diet was avoided in the other patient (with flat small intestinal mucosa and low mitotic index) in whom the diagnosis was ultimately shown to be due to Crohn's disease of jejunum.