Morphogenesis of Epithelial Lesions in the Lymphoid Patches of Fischer 344 Rats during Cyclosporine-A-Induced Prolonged Immunosuppression

Abstract

Alterations of intestinal lymphoid patches induced by cyclosporine A (CS-A) were studied in male Fischer 344 rats. Continuous treatment with CS-A (10 mg/kg b.w. by gavage daily) resulted in lymphocyte deficiency of the intestinal lymphoid patches followed by progressive replacement of the lymphoid tissue by cystic and glandular epithelial structures and single cells positive for epithelium-associated immunohistochemical markers. Cessation of CS-A administration led to regression of the alterations and a moderate recovery of the lymphoid patches. Morphologic changes induced at the epithelial-lymphoid border may be a useful parameter to estimate immunotoxicity.