Plasma cell alterations in ulcerative colitis. An electron microscopic study.

Colon biopsies from 37 young patients with active ulcerative colitis (UC) were investigated by electron microscopy with special regard to the inflammatory infiltrate of the lamina propria mucosae, which is characterized by lymphocytes, macrophages and plasma cells. There are close topographical relations between plasma cells and other inflammatory cells. In particular, different forms of plasma cells occur, which mainly differ in shape and contents of their rough endoplasmic reticulum (RER). The different degrees of development and dilatation of the RER express different functional states. The frequent occurrence of Russell bodies, Mott cells and necrobiotic plasma cells is explained as a--at least partial--pathologic alteration of plasma cells in UC. In context with recently published immunohistochemical findings these observations permit the assumption of an imbalance of the local Ig-system in UC.