Studies of intestinal lymphoid tissue. X-observations on granular epithelial lymphocytes (gEL) in normal and diseased human jejunum.

A proportion of epithelial lymphocytes in various mammalian species is characterised by cells containing cytoplasmic granules. We have studied the total number of granular lymphocytes within surface and crypt epithelium of jejunal mucosae (per 10(4) micron2 muscularis mucosae) from six groups of subjects, comprising (i) young healthy volunteers (ii) family relatives of known coeliac patients, patients with gastrointestinal disorders associated with either (iii) normal or (iv) "flat" mucosae, and groups of (v) untreated and (vi) treated patients with coeliac disease. There was no difference in the absolute number of gEL between the three control groups with normal mucosal architecture, the proportion of granular to total EL per unit of tissue varying between 30-40%. In untreated coeliac mucosae, there was a significantly increased population of gEL, compared with the same control groups (p less than 0.001): the ratio of granular to total EL approximated 65%, and did not differ from flat-control mucosae in which the proportion of gEL was 55%. On withdrawal of gluten, the absolute number of gEL fell significantly in comparison with the untreated coeliac group (p less than 0.05). To further evaluate the effect of gluten challenge, granular lymphocytes were monitored during a five-day period in groups of treated coeliac patients orally challenged with increasing doses (500-3000 mg) of a peptic-tryptic digest of gluten. A significant rise in the absolute number of granular lymphocytes occurred at 12 h, but without any deterioration in mucosal architecture.