Quantification of the lymphocytic infiltrate in jejunal epithelium in giardiasis

The intraepithelial lymphocytes of the jejunal mucosa from patients with giardiasis and from control patients were counted in coded serial sections. Patients with giardiasis and normal intestinal absorption and control patients who had lived and travelled in tropical areas had similar counts, which were higher than those reported for controls from temperate areas. Where giardiasis was accompanied by malabsorption of one substance the mean count was significantly higher than that of controls (P less than 0.02). In those patients with giardiasis and malabsorption of two or three substances the mean count was significantly higher than that of controls (P less than 0.02) and that of patients with giardiasis and normal absorption (P less than 0.05). After treatment, intraepithelial lymphocyte counts declined consistently in patients with malabsorption. An association between raised intraepithelial lymphocyte counts and malabsorption is indicated. The possible significance of this finding is discussed.