Jejunal intraepithelial lymphocytes in coeliac disease: are they increased or decreased?

We have quantified intraepithelial lymphocytes in the same biopsy series (21 healthy controls, 14 untreated coeliacs, 15 treated coeliacs, five non-coeliac patients with an abnormal jejunal mucosa) both as counts/100 epithelial cells and using as reference value a fixed area of muscularis mucosae. As expected, the number of intraepithelial lymphocytes/100 epithelial cells was significantly higher in untreated and treated coeliacs than in healthy controls, as well as in untreated when compared with treated coeliac patients. Otherwise, the number of intraepithelial lymphocytes lying in the area of mucosal surface overlying a fixed area of muscularis mucosae was significantly lower in treated and untreated coeliacs, than in healthy controls, as well as in untreated when compared with treated coeliacs. A highly significant inverse correlation was found between the number of intraepithelial lymphocytes/100 epithelial cells and the mucosal surface area measured as surface to volume ratio. When the number of intraepithelial lymphocytes/100 epithelial cells was corrected for differences in surface to volume ratio, the results were very similar to those obtained by a muscularis mucosae related count. In five coeliacs both intraepithelial lymphocyte and enterocyte muscularis mucosae related counts rose after a period of gluten free diet but the mean per cent increase of enterocytes was significantly higher than that of lymphocytes. Our results are compatible with a decrease in the total number of intraepithelial lymphocytes in the entire small bowel in coeliac disease. In untreated coeliac mucosae, however, a derangement in the usual proportions of intraepithelial lymphocytes and enterocytes is evident and may be important in the pathogenesis of coeliac disease.