Interleukin-10 expression in intestine of Crohn disease

Inflammatory bowel diseases are considered to be related to dysregulation of pro- and anti-inflammatory cytokines in the intestinal wall. We investigated the levels of TNF alpha, IFN gamma, and IL-10 mRNA expression in intestinal tissues resected from the patients with Crohn disease (CD) (n=29), ulcerative colitis (UC) (n=8), and controls (n=8) using reverse transcription-polymerase chain reaction (RT-PCR). In addition, we examined the relationship between the expression of these cytokine mRNA and their clinical conditions using CD activity index (CDAI) and Nutritional Surgical Risk Index (NSRI). Compared with controls, tissues in CD showed high levels of TNF alpha and IFN gamma mRNA expression both in inflamed and non-inflamed tissues, and showed high levels of IL-10 mRNA expression in inflamed tissues. In UC, high levels of IL-10 mRNA expression were detected both in inflamed and non-inflamed UC tissues, while those of TNF alpha and IFN gamma were not. In 80% of CD tissues (n=23), levels of IL-10 and TNF alpha expression were interrelated. While the remaining tissues (n=6) showed low levels of IL-10 expression despite high levels of TNF alpha expression in inflamed CD tissues, and 4 of these 6 patients had high CDAI and low NSRI. Furthermore, in low nutritional CD patients (NSRI <40, n=13), the levels of IL-10 mRNA to inhibit pro-inflammatory cytokines were poorer than in good nutritional patients (NSRI greater than or equal to 40, n=16). These findings suggest the over-expressions of TNF alpha and IFN gamma in CD, and less producibility of IL-10 against these cytokine might lead to development of severe CD.