Immunological changes in tropical sprue.

Immunological measurements in 85 southern Indian patients with tropical sprue were compared with two groups of controls, namely, 150 patients with gastrointestinal diseases not associated with malabsorption, and 57 normal asymptomatic subjects. A significant increase in intraepithelial lymphocytes in jejunal surface and crypt epithelium, related to the severity of the mucosal morphological abnormality, was the most significant finding in tropical sprue. Measurements such as increased serum concentrations of IgG, IgE, complement component C4 and orosomucoid, gastric parietal cell antibodies and lymphopaenia with a low peripheral blood T cell count, which were found in patients with sprue, differed significantly from the healthy control group but not from the group of gastrointestinal controls without malabsorption. The ability to produce functional antibodies was preserved in tropical sprue. The results suggest that the small intestinal enterocyte abnormality in tropical sprue is not the result of a primary immunological process but that the observed alterations are a sequelae of mucosal damage and compromised integrity of the mucosal barrier.