Intraepithelial lymphocytes in the jejunal mucosa of malnourished rats.

Intraepithelial lymphocytes (IEL) have been counted in the jejunal mucosa of adult Wistar rats submitted to a protein-free diet for 84 days and of a control group receiving a 20% casein diet, in order to evaluate the effect of protein deprivation. Relative counts (IEL/100 epithelial cells), absolute counts (number of IEL per millimetre of muscularis mucosae), and the proportion of lymphocytes crossing the basement membrane have been evaluated. Both relative and absolute IEL counts were diminished but the proportion of crossing lymphocytes was greatly increased in the malnourished group. The low number of IEL seemed to be related to lymphatic vessel dilatation in the lamina propria. The possibly primary effect of malnutrition on IEL counts in our experimental model and the eventual role of the observed lymphatic dilatation have been discussed.