Immunocytochemistry of mucosal changes in patients infected with the intestinal nematode Strongyloides stercoralis

Aim-To investigate the immunopathological changes in duodenal tissues induced by strongyloidiasis and to relate these to degrees of clinical severity. Methods-Tissues taken from 21 patients showing mild, moderate or severe symptoms of strongyloidiasis, and from noninfected controls, were sectioned and stained immunocytochemically for IgA, secretory component (SC) and HLA-DR. Immunopathology was assessed by changes in numbers, intensity and distribution of stained cells. Results-Parasitised individuals showed villous atrophy and crypt hyperplasia. There was notable infiltration of the lamina propria by IgA positive plasma cells and of the epithelium by intraepithelial lymphocytes. Infection was also associated with increased expression of SC and decreased expression of HLA-DR in epithelial cells. Changes in all parameters correlated with degree of clinical severity. Conclusions-Profound mucosal changes are induced by strongyloidiasis. Some are analogous to those seen in coeliac disease, but others seem quite unusual. It is likely that these changes are functionally related to the immunopathophysiological consequences of infection seen in patients with severe disease.