Abstract

The numbers of mast cells and of IgE-containing immunocytes in the bowel wall of patients suffering from Crohn's disease of ulcerative colitis have been estimated and the results compared with those found in normal control specimens. In ulcerative colitis there is a slight rise in the number of mast cells and it appears that these participate in the inflammatory process in a non-specific manner; the number of IgE-containing immunocytes is not significantly altered. In Crohn's disease there is an almost total absence of stainable mast cells in affected areas of the bowel, together with a marked decrease in IgE-containing immunocytes. It is suggested that these findings are due to degranulation of mast cells and consumption of IgE as a result of an immediate hypersensitivity reaction in the bowel wall, this being one component of the protein inflammatory and immunological response to the entry of a variety of antigenic material.