Ultrastructural pathology of the rectal mucosa in Shigella dysentery.

Colonocyte damage in the rectal mucosa in shigellosis is the result of bacterial invasion and leads to ulceration. Additional factors in colonocyte damage may be the Shigella cytotoxin and, especially in colonic crypt cells, bacterial endotoxin. A vascular lesion was present in the lamina propria of the rectal mucosa, which resembled endothelial damage secondary to bacterial endotoxins. In patients with longer duration of symptoms, relative vascular insufficiency, activated lymphocytes, eosinophil and mast cell degranulation, and antibody-mediated colonocyte damage may all play a role.