Cytokines are involved in the regulation of normal immune events and may be important in the development or perpetuation of immune events in inflammatory bowel disease. We have previously shown that normal human mononuclear cells from tonsil, spleen, and peripheral blood exhibit tissue and stimulus-specific patterns of cytokine mRNA expression. The aim of this study was to determine if disease-dependent differences of cytokine mRNA expression could be found in the intestine. Total RNA was isolated from intestinal mucosa and lamina propria mononuclear cells from inflammatory bowel disease patients and controls. cDNA probes specific for interleukins (IL)-1, -4, -5, and -6 and transforming growth factor-beta were used. IL-1 beta mRNA and TGF-beta mRNA steady state expressions were higher in inflammatory bowel disease specimens than in normal intestine. In addition, mononuclear cell specimens had stronger cytokine mRNA expression than mucosal specimens. The steady state mRNA expression of proinflammatory cytokines is higher in inflammatory bowel disease, consistent with the ongoing inflammation seen.